de Havilland DHC-8 Dash 8

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for all De Havilland Aircraft of Canada Limited Model DHC-8 airplanes. This AD was prompted by reports of cracked barrel nuts at the wing front spar and horizontal stabilizer to vertical stabilizer joint. This AD requires repetitive inspections for cracking and corrosion of the affected barrel nuts and applicable corrective actions. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and - 402 airplanes. This AD was prompted by multiple in-service reports of cracks in elevator power control unit (PCU) brackets (fittings) and the elevator front spar. This AD requires replacing bushings and installing new washers on the elevator PCU arm fitting assembly, installing doublers at the front spar of the elevator structure assembly, replacing horizontal stabilizer rear spar elevator PCU fittings, and applicable on-conditions actions. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is superseding Airworthiness Directive (AD) 2019-16- 09, which applied to certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. AD 2019-16-09 required one-time inspections for cracks and damage of the elevator power control unit (PCU) brackets and surrounding area, horizontal stabilizer rear spar, elevator front spar, and related investigative and corrective actions if necessary. Since the FAA issued AD 2019-16-09, new findings have been reported as a result of maintenance activities and/or inspections. This AD continues to require certain actions in AD 2019-16-09 and requires repeating the inspections one time and performing applicable on- condition actions. This AD also removes an airplane model from the applicability and provides optional terminating action for repetitive inspections. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is superseding Airworthiness Directive (AD) 2022-01- 02, which applied to certain De Havilland Aircraft of Canada Limited Model DHC-8-400, -401, and -402 airplanes. AD 2022-01-02 required inspecting for corrosion of the nacelle to wing rear spar attachment pins, and the nacelle to landing gear attachment pins, and doing all applicable corrective actions. This AD was prompted by a determination that some operators were unable to identify the airplanes subject to each requirement. This AD continues to require the actions specified in AD 2022-01-02, clarifies the affected airplanes for each required action, and revises the applicability by removing Model DHC-8-400 airplanes; as specified in Transport Canada AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and - 402 airplanes. This AD was prompted by a report of an in-flight event where isolation valve caution messages were received. This AD requires inspecting the fuse/shuttle valve serial numbers, and replacing certain fuse/shuttle valves, as specified in a Transport Canada AD, which is incorporated by reference (IBR). The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is superseding Airworthiness Directive (AD) 2021-25-12 and AD 2022-11-11, which applied to certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and -402 airplanes. AD 2021-25-12 required repetitive lubrications of the trailing arm of the nose landing gear (NLG). AD 2021-25-12 also required revising the existing maintenance or inspection program to include new and revised airworthiness limitations. AD 2022-11-11 required a modification to the NLG shock strut assembly. This AD continues to require the actions specified in AD 2021-25-12 and AD 2022-11-11 and requires replacement of the pivot pin and tow fitting assembly with a new, improved pivot pin and tow fitting assembly and prohibits the installation of affected parts. This AD was prompted by a determination that the pivot pin and tow fitting assembly of the NLG must be replaced. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and - 402 airplanes. This AD was prompted by reports of moisture in the wing- to-fuselage joint, between the mating front spar and rear spar frame segments. This AD requires a visual inspection of the fuselage front and rear spar frames, an ultrasonic test if applicable, other specified actions, and repair if necessary. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for all De Havilland Aircraft of Canada Limited Model DHC-8-401 and -402 airplanes. This AD was prompted by a determination that new or more restrictive airworthiness limitations are necessary. This AD requires revising the existing maintenance or inspection program, as applicable, to incorporate new or more restrictive airworthiness limitations. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and - 402 airplanes. This AD was prompted by reports that the saddle washer (radius filler) for the front and rear spar joints may have been incorrectly manufactured for several years. This AD requires inspecting the horizontal stabilizer to vertical joint for gaps and bending of the saddle washer and adjacent washers, and replacing parts if necessary. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and - 402 airplanes. This AD was prompted by reports of the main landing gear (MLG) aft door not opening when using the alternate extension system. This AD requires a one-time inspection of the spring box assembly, repetitive inspections of the cam assembly and alternate release cable assembly, corrective actions if necessary, and a replacement of certain alternate release cable assemblies. In addition, this AD requires certain aircraft maintenance manuals tasks when installing the cam assembly or alternate release cable assembly. This AD also prohibits the installation of affected parts. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and - 402 airplanes. This AD was prompted by reports of corrosion on the horizontal stabilizer lower center skin panel, including a finding of corrosion where the skin thickness had been substantially reduced, which affected design margins. This AD requires inspecting the horizontal stabilizer lower center skin panel for corrosion, and reworking, repairing, or replacing the lower center skin panel if necessary. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and - 402 airplanes. This AD was prompted by an investigation of incorrectly manufactured sleeves that were potentially installed in the main landing gear (MLG) forward door linkage assembly. This AD requires review of technical records and inspections to determine if a discrepant sleeve is installed, replacement of any discrepant sleeve and re-identification of the MLG forward door linkage assembly. This AD also prohibits the installation of affected parts. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. This AD was prompted by reports of flap power unit (FPU) pressure switch failures resulting in flap inoperative events. This AD requires replacing the FPU or replacing the FPU pressure switch and reidentifying the FPU. This AD also prohibits the installation of affected parts. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. This AD was prompted by a report that electrical bonding jumpers had been installed on fuel scavenge lines even after the removal was required by previous AD rulemaking and that electrical bonding jumpers may have been installed in production or in service at other locations. This AD requires an inspection for electrical bonding jumpers and brackets on the fuel scavenge and vent lines at specific wing locations, and if installed, removal or modification of those jumpers and brackets. This AD also requires a records check to determine if certain maintenance tasks were performed and removal, modification, or rework if those tasks were performed. This AD also prohibits the use of earlier versions of certain maintenance tasks. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-402 airplanes. This AD was prompted by an investigation that found that the actual operating temperatures within the integrated flight cabinet (IFC) were significantly higher than anticipated during certification. This AD requires a modification to improve the IFC cooling capacity. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is superseding Airworthiness Directive (AD) 2020-04- 20, which applied to certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. AD 2020-04-20 required repetitive inspections of certain parts for discrepancies that meet specified criteria, and replacement as necessary; repetitive inspections of certain parts for damage and wear, and rework of parts; and electrical bonding checks of certain couplings. AD 2020-04-20 also required revising the existing maintenance or inspection program, as applicable, to incorporate new or more restrictive airworthiness limitations. For certain airplanes, AD 2020-04-20 allowed a modification that terminates the repetitive inspections. This AD continues to require the actions in AD 2020-04-20, revises the applicability by adding airplanes, and requires, for certain airplanes, the previously optional rework and retrofit of certain parts of the fuel system. Doing the rework and retrofit terminates the retained initial and repetitive inspections in this AD. This AD was prompted by reports of wear on fuel couplings, bonding springs, and sleeves as well as fuel tube end ferrules and fuel component end ferrules, and by a determination that a more robust lightning ignition protection design is necessary. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. This AD was prompted by reports of broken P-clamps on the pressure relief line and the motive flow line in the fuel tanks, and a subsequent determination that certain service information lacked instructions for maintaining appropriate clearance between certain fuel tubes and their support brackets, and may also have led to incorrect installation of certain Teflon<SUP>TM</SUP> sleeves. This AD was also prompted by a determination that new or more restrictive airworthiness limitations are necessary. This AD requires inspecting the motive flow line, vent line, and related parts, and adding support or additional clearance if necessary. This AD also requires inspection, and replacement or relocation if necessary, of affected Teflon<SUP>TM</SUP> sleeves on the vent line, and installation of Teflon<SUP>TM</SUP> sleeves on the vent line at additional wing stations. This AD also requires revising the existing maintenance or inspection program, as applicable, to incorporate new or more restrictive airworthiness limitations. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and - 402 airplanes. This AD was prompted by reports of nose wheel steering (NWS) hydraulic motors jamming during pushback or towing. This AD requires doing an inspection to determine the part number and serial number of the NWS hydraulic motor, and re-identifying or replacing the NWS hydraulic motor if necessary. This AD also prohibits the installation of certain NWS hydraulic motors. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and - 402 airplanes. This AD was prompted by reports that following a main landing gear (MLG) extension, one of the MLGs could not be locked in the gear down position due to deterioration of greasing effectiveness over time. This AD requires repetitive lubrication of the MLG assembly. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for all De Havilland Aircraft of Canada Limited Model DHC-8-401 and -402 airplanes. This AD was prompted by reports of bleed air leaks in the wing box area and failure of the leak detection shroud. This AD requires removing and inspecting the affected V-band coupling and check valve seals, doing corrective actions if necessary, and replacing the coupling and seals with a redesigned assembly. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and - 402 airplanes. This AD was prompted by reports of a possible hard contact between the #2 top high level sensor (HLS) terminal screw head and the #6 outer wing fuel access panel stiffener flange. This AD requires removing and replacing or reworking the #6 outer wing fuel access panel assembly. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-400, -401, and -402 airplanes. This AD was prompted by a report that the epoxy primer on the internal bore of the nacelle and landing gear attachment pins was not applied, and corrosion on the internal bore of the wing rear spar attachment pins was found. This AD requires doing a detailed visual inspection of the nacelle to wing rear spar attachment pins, and the nacelle and landing gear attachment pins, for any corrosion, and doing all applicable corrective actions. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and - 402 airplanes. This AD was prompted by reports of loss of hydraulic fluid and annunciation of the check fire detect light. This AD requires doing a detailed visual inspection for chafing and proper clearance of the left-hand (LH) and right-hand (RH) main landing gear (MLG) primary zone advanced pneumatic detector (APD) sensing lines, the hydraulic tube assemblies, and the surrounding structure, and doing all applicable corrective action. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-400, -401, and -402 airplanes. This AD was prompted by a report of cracking found on a main landing gear (MLG) drag strut assembly. This AD requires a records review to determine if an affected MLG drag strut assembly is installed, repetitive detailed inspections for cracking of affected strut assemblies, a one-time magnetic particle inspection for cracking, and on-condition actions if necessary. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-102, -103, and -106 airplanes; Model DHC-8-201 and -202 airplanes; Model DHC-8- 301, -311, and -315 airplanes; and Model DHC-8-400, -401, and -402 airplanes. This AD was prompted by reports that mounting nuts attaching the rudder actuator bracket to the vertical stabilizer have been found cracked or missing due to hydrogen embrittlement. This AD requires a one-time inspection of the rudder actuator bracket mounting nuts, and corrective actions if necessary. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. This AD was prompted by a report that a number of nacelle A- frames were not manufactured in accordance with engineering drawings. This AD requires, depending on airplane configuration, removing the fasteners on the nacelle A-frame side brace sub-assemblies, doing an eddy current inspection for cracking, cold-working the holes, installing oversize fasteners, re-identifying the reworked side brace fitting and A-frame, and repair if necessary. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-400, -401, and -402 airplanes. This AD was prompted by a report of main landing gear (MLG) retractions after striking an obstacle or severe wheel imbalance after a tire failure. This AD requires inspections for correct height of the lock link over-center stop pin and for correct gaps of the left-hand and right-hand MLG downlock proximity sensors, replacement of the shim if necessary, corrective actions, and installation of a new, improved proximity sensor electronic unit (PSEU) with software changes. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is superseding Airworthiness Directive (AD) 2015-17- 08, which applied to certain Bombardier, Inc. Model DHC-8-400 series airplanes. AD 2015-17-08 required installing new cable assemblies with a pull-down resistor. This AD requires modifications to the nose wheel steering (NWS) system. This AD was prompted by a report indicating that several failure modes of the NWS system may cause the loss of feedback from both rotary variable differential transformers to the steering control unit. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is superseding Airworthiness Directive (AD) 2015-14- 01, which applied to certain Bombardier, Inc., Model DHC-8-400 series airplanes. AD 2015-14-01 required a detailed inspection for loose bolts on the aft translating door crank assembly, and removal and reinstallation of the bolts. This AD retains the inspections of AD 2015-14-01 and adds airplanes to the applicability. For all airplanes, this AD also requires a modification of the door crank handle, which will terminate the inspection requirements. This AD was prompted by reports of loose bolts that are intended to secure the translating door crank assembly to the outside handle shaft, and of sealant missing from these bolts on another translating door. The FAA is issuing this AD to address the unsafe condition on these products.

July 14, 2020 Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is superseding Airworthiness Directive (AD) 2010-23- 04, which applied to all De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. AD 2010-23-04 required repetitive detailed inspections of the nacelle attachment fittings for cracks, a conductivity inspection of the nacelle attachment fittings, and replacement if necessary. This AD continues to require these inspections and replacement if necessary, removes a certain inspection requirement for certain airplanes, and adds a new requirement to replace the rear spar fitting and nacelle attaching structure with a new nacelle attachment fitting. This AD was prompted by a determination that it is necessary to do a replacement with new nacelle attachment fittings. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. This AD was prompted by a report that certain elevator power control unit (PCU) arm fittings have nonconforming fillet radii. This AD requires an inspection for affected elevator PCU assemblies, inspections of affected elevator PCU arm fittings for nonconforming fillet radii and cracks, replacement if necessary, and re- identification of the affected elevator PCU assemblies. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. This AD was prompted by reports of wear on fuel couplings, bonding springs, and sleeves as well as fuel tube end ferrules and fuel component end ferrules. This AD requires repetitive inspections of certain parts for discrepancies that meet specified criteria, and replacement as necessary; repetitive inspections of certain parts for damage and wear, and rework of parts; and electrical bonding checks of certain couplings. This AD also requires revising the existing maintenance or inspection program, as applicable, to incorporate new or more restrictive airworthiness limitations. For certain airplanes, this AD allows a modification that would terminate the repetitive inspections. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. This AD was prompted by a report of a quality escape in the manufacturing of advanced pneumatic detector (APD) switches, which consisted of the presence of contamination on the switch contact pin. This AD requires identification and testing, and reidentification or replacement if necessary, of affected APDs. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and - 402 airplanes. This AD was prompted by a report that certain fuselages were delivered with nonconforming keel tension fittings and stringer end fittings. This AD requires a detailed visual inspection of stringer end fittings and keel fittings for loose or working fasteners, signs of wear, and corrosion, and repair if necessary; and a general visual inspection of the keel tension fitting and stringer end fittings, as applicable, and repairs and replacement of the keel and stringer end fittings if necessary. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is superseding Airworthiness Directive (AD) 2009-09- 02, which applied to certain Bombardier, Inc., Model DHC-8-400 series airplanes. AD 2009-09-02 required repetitive inspections for damage of certain main landing gear (MLG) forward stabilizer brace assemblies, repetitive inspections for cracking of both MLG forward stabilizer braces, liquid penetrant inspections for cracking, and corrective actions if necessary. This AD retains the existing actions and also requires installation of an elbow restrictor. This AD was prompted by reports of failures of the aft hinge of the MLG forward stabilizer brace due to fatigue cracks. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is superseding Airworthiness Directive (AD) 2011-18- 15, which applied to certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. AD 2011-18-15 required initial and repetitive torque checks of the bolt preload; detailed inspection of the barrel nuts and cradle for cracking, pitting, and corrosion if the bolt preload is correct; and replacement of certain hardware if necessary. This AD continues to require those actions. This AD also requires new inspections and replacement of certain hardware, which would terminate the repetitive torque checks and inspections; and removes airplanes from the applicability. This AD was prompted by in- service reports of cracked barrel nuts found at the front spar locations of the wing-to-fuselage attachment joints, and a loose washer in the barrel nut assembly. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Model DHC-8-400 series airplanes. This AD was prompted by reports of the nose landing gear (NLG) locking in a partially extended position due to loose bushings on the lock link of the NLG locking mechanism. This AD requires repetitive inspections of the bushings and the lower lock link of the NLG for discrepancies, and corrective actions if necessary. This AD also requires replacement of the lower lock link of the NLG, which terminates the repetitive inspections. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-400 series airplanes. This AD was prompted by reports of cracked elevator power control unit (PCU) brackets on the horizontal stabilizer rear spar and cracking on the elevator front spar. This AD requires one-time inspections for cracks and damage of the elevator PCU brackets and surrounding area, horizontal stabilizer rear spar, and elevator front spar, and related investigative and corrective actions if necessary. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-400 series airplanes. This AD was prompted by a report of a cracked outboard spoiler actuator mounting bracket. This AD requires repetitive inspections of the outboard spoiler actuator mounting brackets, replacement of any cracked bracket, and eventual replacement of all brackets with a re-designed part that would terminate the repetitive inspections. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-102, -103, and -106 airplanes; Model DHC-8-200 series airplanes; and Model DHC-8-300 series airplanes. This AD was prompted by the reported loss of an elevator spring tab balance weight prior to takeoff. This AD requires inspecting the two balance weights and the two hinge arms on each elevator spring tab, and corrective actions if necessary. The FAA is issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-102, -103, and -106 airplanes; Model DHC- 8-200 series airplanes; and Model DHC-8-300 series airplanes. This AD was prompted by a report that a certain modification to the auto relight system is incompatible with a certain beta lockout system modification and could result in de-activation of the auto ignition feature of the No. 2 engine. This AD requires an inspection of the auto ignition system and applicable rectification. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

We are superseding Airworthiness Directive (AD) 2016-24-03, which applied to certain Bombardier, Inc., Model DHC-8-400 series airplanes. AD 2016-24-03 required repetitive detailed inspections of barrel nuts and cradles, a check of the bolt torque of the preload indicating (PLI) washers, and corrective actions if necessary. This AD retains the requirements of AD 2016-24-03 and requires modifying the airplane by installing a sealing disk to a certain location and replacing certain barrel nuts. This AD was prompted by reports of cracked and corroded barrel nuts found at the mid-spar location of the horizontal-stabilizer-to-vertical-stabilizer attachment joint, and the issuance of new service information that includes a terminal modification. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-400 series airplanes. This AD was prompted by a report of uncommanded deployment of the ground spoilers when the power levers were advanced for takeoff, which was caused by faulty switches in the power lever module. This AD requires revising the maintenance or inspection program, as applicable. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-400 series airplanes. This AD was prompted by reports of arcing and smoke emanating from the windshields. This AD requires a revision to the maintenance or inspection program, as applicable, to include an inspection of the windshield moisture seal for signs of cracks, erosion, wear, and other deterioration; doing that inspection and repair if necessary; and re-torqueing the screws that fasten the windshield heater terminal lugs and applying sealant to the screw heads of the windshield heaters. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

We are superseding Airworthiness Directive (AD) 2014-05-28, which applied to certain Bombardier, Inc., Model DHC-8-400 series airplanes. AD 2014-05-28 required revising the maintenance or inspection program, as applicable. This AD requires revising the maintenance or inspection program, as applicable, to include a revised task. This AD was prompted by a determination that the interval from Maintenance Review Board (MRB) task number 323100-202 should not be escalated, and that Certification Maintenance Requirements (CMR) task number 323100-102 should be applicable to all Model DHC-8-400 series airplanes, regardless of which main landing gear (MLG) up-lock assembly is installed. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-400 series airplanes. This AD was prompted by reports that operation of fuselage doors was interrupted due to corrosion in certain door roller bearings. This AD requires a one-time detailed inspection of the bearings for corrosion, and replacement if necessary. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

We are superseding Airworthiness Directive (AD) 2016-13-14, which applied to certain Bombardier, Inc., Model DHC-8-400 series airplanes. AD 2016-13-14 required an inspection to determine if certain left and right main landing gear (MLG) retract actuator rod ends were installed, repetitive liquid penetrant inspections (LPIs) of affected left and right MLG retract actuator rod ends, and corrective actions if necessary. This new AD retains the actions specified in AD 2016-13-14 and also requires replacement of the left and right MLG retract actuator rod ends. This AD was prompted by a report of a cracked MLG retract actuator rod end. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-400 series airplanes. This AD was prompted by the failure of the fire control amplifier (FCA), which was likely caused by an electrical short in a discharged squib for a fire extinguishing bottle. This AD requires replacing certain circuit breakers. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-401 and -402 airplanes. This AD was prompted by the discovery of cracking on two test spoiler power control unit (PCU) manifolds during testing by the manufacturer. This AD requires replacement of affected spoiler PCUs. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

We are superseding Airworthiness Directive (AD) 2014-25-01, which applied to certain Bombardier, Inc., Model DHC-8-400 series airplanes. AD 2014-25-01 required modifying the nose landing gear (NLG) trailing arm and installing a new pivot pin retention mechanism. This AD instead requires modifying the NLG shock strut assembly. This AD was prompted by reports of discrepancies of a certain bolt at the pivot pin link, resulting in corrosion of the bolt. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

We are superseding Airworthiness Directive (AD) 2014-20-09, which applied to certain Bombardier, Inc., Model DHC-8-400 series airplanes. AD 2014-20-09 required an inspection for missing clamps that are required to provide positive separation between the alternating current (AC) feeder cables and the hydraulic line of the landing gear alternate extension, and related investigative and corrective actions if necessary. This new AD requires removing airplanes from the AD applicability. This AD was prompted by reports of missing clamps that are required to provide positive separation between the AC feeder cables and the hydraulic line of the landing gear alternate extension. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-102, -103, -106, -201, -202, -301, -311, and -315 airplanes. This AD was prompted by reports of undamped main landing gear (MLG) extension in-service. This AD requires replacement of the MLG retraction actuator rod-ends on both MLG assemblies. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-401 and DHC-8-402 airplanes. This AD was prompted by a report that a pilot was unable to move the rudder pedal due to an obstruction. This AD requires an inspection to determine if wiring shrouds are present, and modifying the wiring shrouds if necessary. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of interruptions in the airstair door operation. This AD requires repetitive inspections and modification of the handrail hardware. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc., Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-102, -103, and -106 airplanes; and Model DHC-8-200 and DHC-8-300 series airplanes. This AD was prompted by reports of incorrect installation of the auto-ignition system due to crossed wires at one of the splices in the auto-relight system. This AD requires inspecting the auto-ignition system for correct wiring, and doing corrective actions if necessary. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of interior emergency lights remaining "ON" following routine operational checks of the emergency light system. This AD requires changing the wiring gauge for the affected emergency lights power supplies wiring to prevent overheating in the wires. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are superseding Airworthiness Directive (AD) 2012-08-11 for certain Bombardier, Inc. Model DHC-8-400 series airplanes. AD 2012-08- 11 required repetitive inspections for defects and damage of the retract port flexible hoses on the main landing gear (MLG) retraction actuators, and replacement if necessary. This AD continues to require the actions in AD 2012-08-11, requires reorientation of the retraction actuator of the MLG, and removes airplanes from the applicability. This AD was prompted by test results that showed that failure of a retract port flexible hose of a MLG retraction actuator could cause excessive hydraulic fluid leakage. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by a determination by the manufacturer that shims might not have been installed between certain longerons and longeron joint fittings. This AD requires various repetitive and detailed visual inspections of the affected areas and corrective actions if necessary. This AD also provides terminating action for certain repetitive inspections. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of cracked and corroded barrel nuts found at the mid-spar location of the horizontal-stabilizer-to-vertical-stabilizer attachment joint. This AD requires repetitive detailed inspections of each barrel nut and cradle, a check of the bolt torque of the preload indicating (PLI) washers, and corrective action if necessary. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-102, -103, and -106 airplanes, Model DHC- 8-200 series airplanes, and Model DHC-8-300 series airplanes. This AD was prompted by several occurrences of loss of airspeed data on both pilot and co-pilot air speed indicators due to the accumulation of ice on the pitot probes caused by inoperative pitot probe heaters. This AD requires replacing the existing circuit breakers in the pitot heater system. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-102, -103, and -106 airplanes; and Model DHC-8-200 and -300 series airplanes. This AD was prompted by a report of heat damage found on a nacelle firewall after an unsuccessful engine ground start and several events of heat damage found on direct current starter/generator terminal block assemblies. This AD requires an inspection to detect damage on the nacelle firewalls and the terminal block assemblies and to make sure the insulating sleeves are installed and have no damage, and corrective action if necessary. We are issuing this AD to address the unsafe condition on these products.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for all Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by a revision by the manufacturer to the Certification Maintenance Requirements (CMR) of the Airworthiness Limitation Items (ALI), in the Maintenance Requirement Manual (MRM), that introduces a new CMR task that requires repetitive operational checks of the propeller overspeed governor. This AD requires revising the airplane maintenance or inspection program, as applicable, to incorporate a new CMR task. We are issuing this AD to prevent dormant failure of the propeller overspeed governor, which may lead to a loss of propeller overspeed protection and result in high propeller drag in flight.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by a malfunctioning No. 2 engine intake heater with corrosion on the thermostats and the fuselage skin where the thermostats made contact with the aircraft fuselage skin. This AD requires a general visual inspection for corrosion of the thermostats' mounting surfaces and fuselage skin surface, corrective actions if necessary, and relocating the existing thermostats. We are issuing this AD to prevent corrosion within the thermostats that might cause the switch mechanism to seize in the open position and prevent the activation of the associated engine air intake heater. An inactive engine air intake heater could lead to an engine failure.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes. This AD was prompted by reports of chafing damage due to insufficient clearance on the main landing gear (MLG) stabilizer brace, the nacelle A-frame structure, and the adjacent electrical wiring harnesses. An insufficient fillet radius may also exist on certain airplanes. This AD requires, depending on airplane configuration, an inspection of the nacelle A-frame structure for insufficient fillet radius; an inspection for cracking of affected structure, and rework or repair if necessary, and rework of the nacelle A-frame structure; repetitive inspections of the nacelle A-frame structure and the MLG stabilizer brace for insufficient clearance and damage, and repair if necessary, and rework of the nacelle A-frame structure, which would terminate the repetitive inspections; installation of new stop brackets and a shim on each MLG stabilizer brace assembly; and rework of the electrical wiring harnesses in the nacelle area. We are issuing this AD to detect and correct chafing damage and subsequent premature cracking and fracture of the nacelle A-frame structure, which could result in failure of the MLG stabilizer brace and loss of the MLG down-lock indication, which could adversely affect the safe landing of the airplane.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-102, -103, -106, -201, -202, -301, -311, and -315 airplanes. This AD was prompted by a report of a pilot commanding an in-flight engine shut down in response to a low oil pressure warning indication. Further investigation revealed the mounting studs in the engine mounted alternating current (AC) generator mounting plate were pulled out of position and the threaded interface in the plate was corroded. This AD requires repetitive inspections for discrepancies on certain AC generator mounting adapters, and replacing discrepant adapters with serviceable ones. This AD also requires revising the maintenance program to incorporate a repetitive task specified in certain temporary revisions. We are issuing this AD to detect and correct corrosion in the AC generator mounting plate, which could result in a gap between the AC generator and the generator mounting plate, and cause loss of engine oil and consequent engine failure.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier Model DHC-8-400 series airplanes. This AD was prompted by a report of several cracks found on the forward passenger airstair door step assembly. This AD requires an inspection to determine the serial number of the airstair door step assembly, and if necessary, an electronic tap test, reidentification of the airstair door step assembly, and replacement of the airstair door step assembly. We are issuing this AD to detect and correct cracks in the forward passenger airstair door step assembly; such cracking could propagate and result in the structural failure of the steps and impede the evacuation of passengers in the event of an emergency egress situation.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-102, -103, -106, -201, -202, -301, -311, and -315 airplanes. This AD was prompted by reports of un-annunciated failures of the direct current (DC) starter generator, which caused caution indicators of the affected systems to illuminate and prompted emergency descents and landings. This AD requires replacing the DC generator control units (GCUs) with new GCUs and replacing the GCU label. We are issuing this AD to prevent a low voltage condition on the left main DC bus, which, during critical phases of flight, could result in the loss of flight management, navigation, and transponder systems, and could affect continued safe flight.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of inadvertent deployment of a single outboard spoiler during flight. This AD requires replacement of the power control units (PCUs) for the outboard spoilers with upgraded PCUs. We are issuing this AD to prevent leakage of the piston head seal and piston rod seals of the outboard spoiler PCUs, which could result in inadvertent spoiler deployment and reduced controllability of the airplane.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes. This AD was prompted by a report of a main landing gear (MLG) parking brake becoming dislodged from its mounting bracket due to an improperly installed quick release pin of the hand pump lever. This AD requires removing the hand pump lever of the parking brake from the right-hand side nacelle. We are issuing this AD to prevent an unsecured lever from migrating from its stowed position, fouling against the MLG, and subsequently puncturing the nacelle structure, which could adversely affect the safe landing of the airplane.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of chafing of the fuel lines due to contact with the surrounding structures in the fuel tank. This AD requires replacing and modifying fuel lines, revising the maintenance or inspection program, as applicable, to include critical design configuration control limitations (CDCCL) and airworthiness limitation (AWL) items, and, for certain airplanes, removing certain clamps and mounting hardware. We are issuing this AD to prevent chafing of the fuel lines in the fuel tank, which could result in potential ignition sources in the fuel tank in the event of a lightning strike and consequent fire or explosion.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by an in-service report of an uncommanded and unannunciated nose wheel steering during airplane pushback from the gate. This AD requires installing new cable assemblies with a pull-down resistor. We are issuing this AD to prevent an uncommanded nose wheel steering during takeoff or landing in the event of an open circuit in the steering system, and possible consequent runway excursion.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are superseding Airworthiness Directive (AD) 2015-10-01 for certain Bombardier, Inc. Model DHC-8-400 series airplanes. AD 2015-10- 01 required inspection for correct assembly of the main landing gear (MLG) alternate extension system reservoir lid, and corrective action if necessary. This new AD revises the applicability. This AD was prompted by the discovery of two errors in the applicability of AD 2015-10-01. We are issuing this AD to, in the event of a failure of the primary MLG extension system, prevent failure of the alternate MLG extension system to fully extend the MLG into a down-and-locked position, which could result in collapse of both left-hand and right- hand MLG sides during touchdown.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-102, -103, -106, -201, -202, -301, -311, and -315 airplanes. This AD was prompted by fuel system reviews conducted by the manufacturer. This AD requires revising the maintenance or inspection program, as applicable, to incorporate new limitations for fuel tank systems. We are issuing this AD to prevent potential ignition sources within the fuel system, which could result in a fuel tank explosion.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by a report of loose bolts that are intended to secure the translating door crank assembly to the outside handle shaft. This AD requires a detailed inspection for loose bolts on the aft translating door crank assembly, and removal and reinstallation of the bolts. We are issuing this AD to prevent loose bolts from falling out. If both bolts become loose or fall out after the door is closed and locked, the door cannot be opened from inside or outside, which could impede evacuation in the event of an emergency.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of corrosion in the low-rate discharge tubes of the fire protection system leading to the forward baggage compartment, and perforation of one or more tubes. This AD requires repetitive checks for leakage of the discharge tubes of the fire protection system. This AD also mandates eventual replacement of all existing aluminum tube assemblies with new, improved corrosion-resistant stainless steel tube assemblies. We are issuing this AD to prevent perforation of the low- rate discharge tubes, which could result in insufficient fire extinguishing agent reaching the forward baggage compartment in the event of a fire, which could result in damage to the airplane and injury to the occupants.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by a report that during production, an incorrect clevis was used, resulting in improper installation onto the alternate release cable of the main landing gear (MLG). This AD requires a detailed visual inspection of the emergency release clevis of the MLG to determine if an incorrect clevis has been installed, and if necessary, replacing the clevis with a correct clevis and clevis pin. We are issuing this AD to detect and correct improper installation of the clevis, which could cause loss of the alternate release system and prevent the MLG from extending and retracting, and could consequently affect the airplane's continued safe flight and landing.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are superseding Airworthiness Directive (AD) 2014-06-08 for certain Bombardier, Inc. Model DHC-8-100, -200, and -300 series airplanes. AD 2014-06-08 required repetitive functional checks of the nose and main landing gear, and corrective actions if necessary; and also provided optional terminating action modification for the repetitive functional checks. This new AD requires a terminating action modification. This AD was prompted by a report that the emergency downlock indication system (EDIS) had given a false landing gear down- and-locked indication and a determination that a terminating action modification is necessary to address the identified unsafe condition. We are issuing this AD to detect and correct a false down-and-locked landing gear indication, which, on landing, could result in possible collapse of the landing gear.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by fuel system reviews conducted by the manufacturer. This AD requires replacing a fitting that is part of the refuel control solenoid valve assembly. We are issuing this AD to prevent the potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of two in-service incidents where one side of the main landing gear (MLG) did not achieve down-lock. This AD requires doing a detailed inspection of the apex joints of the stabilizer brace lock link in the MLG for clearance; rectifying and repairing the clearance gap, if necessary; and lubricating the apex joints of the stabilizer brace lock link in the MLG. We are issuing this AD to detect and correct insufficiently greased stabilizer brace lock linkage of the MLG and over-torqued lock linkage attachment bolts, which could lead to the failure to extend and down-lock the MLG, and could affect the safe landing of the airplane.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of swing arm assemblies of engine fuel feed ejector pumps detaching from the outlet port of the engine fuel feed ejector pump and partially blocking the engine fuel feed line. This AD requires installing a restrictor into the engine fuel feed line. We are issuing this AD to prevent blocked engine fuel flow and possible engine flameout.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes. This AD was prompted by reports of rudder bearings falling out of the fore rudder hinge bracket during assembly. This AD requires a proof load test and detailed inspections; and installation of a new bearing, reaming, or repair of the bearing if necessary. We are issuing this AD to detect and correct improper bearing installation, which could result in abnormal wear and potential increased freeplay in the rudder system, and resultant airframe vibration, leading to compromise of the flutter margins of the airplane.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-102, -103, -106, -201, -202, -301, -311, and --315 airplanes. This AD was prompted by reports of dual alternating current (AC) generator failure during flight. The failure was attributed to wire chafing along the wing lower flap shroud. This AD requires revising the maintenance program to incorporate certain tasks for the electrical wiring interconnection system inspection program. We are issuing this AD to prevent failure of both AC generators due to wire chafing, which could result in loss of power to the anti-icing heaters for the elevator horn, engine inlet, and propeller, and consequent ice accumulation in these areas, which could adversely affect the controllability of the airplane.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are superseding Airworthiness Directive (AD) 2011-15-09 for certain Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes. AD 2011-15-09 required repetitive inspections for proper operation of the main landing gear (MLG) alternate extension system (AES), and corrective actions if necessary. This new AD requires, for certain airplanes, new repetitive inspections for proper operation of the MLG AES, and corrective actions if necessary. This new AD also requires eventually replacing the MLG AES cam mechanism assembly with a new assembly, which terminates the repetitive inspections for those airplanes. This AD was prompted by a determination that, for certain airplanes not affected by AD 2011-15-09, a different MLG AES cam mechanism assembly was installed, resulting in input lever fractures and inability to open the MLG door; those assemblies could be subject to the same unsafe condition in AD 2011-15-09. We are issuing this AD to prevent improper operation of the cam mechanism or rupture of the door release cable, which could result in loss of control of the airplane during landing.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of failure of the high pressure shutoff valves (HPSOVs) causing the timer and monitor unit (TMU) to become inoperative since the HPSOV and the TMU are on the same circuit breaker. This AD requires a wiring modification to segregate the HPSOV power supply from the TMU. We are issuing this AD to prevent an inoperative TMU, which could result in the loss of the automatic de-icing mode, and lead to an increased workload for the flight crew and loss of control of the airplane.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-102, -103, -106, -201, -202, -301, -311, and -315 airplanes. This AD was prompted by reports of a fractured wing-to-fuselage strut attachment joint bolt. This AD requires a torque check of all wing-to-fuselage strut attachment joint bolts, and repair or replacement if necessary. For certain airplanes, this AD also requires a detailed inspection for corrosion, damage, and wear of each wing-to-fuselage strut attachment joint bolt and associated hardware, and replacement if necessary; and a borescope inspection for corrosion and damage of the bore hole and barrel nut threads, and repair or replacement if necessary. We are issuing this AD to detect and correct fractured strut attachment joint bolts, which could result in reduced structural integrity of the wing-to-fuselage strut attachment joint and subsequent loss of the wing.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-102, -103, and -106 airplanes; and DHC-8- 200 and DHC-8-300 series airplanes. This AD was prompted by a report of a beta warning horn (BWH) system failing to activate when the beta mode was triggered. This AD requires modifying the BWH microswitch installation. We are issuing this AD to prevent the inadvertent activation of ground beta mode during flight, which could lead to engine overspeed, engine damage or failure, and consequent reduced controllability of the airplane.

Airworthiness Directives; Bombardier Inc., Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-102, -103, -106, -201, -202, -301, -311, and -315 airplanes. This AD was prompted by results from fuel system reviews conducted by the manufacturer. This AD requires accomplishing modifications to the fuel system. We are issuing this AD to prevent the potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane.

Airworthiness Directives; Bombardier, Inc.

We are adopting a new airworthiness directive (AD) for all Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by a report that a batch of main landing gear (MLG) door actuators with a certain part number having certain serial numbers could be assembled with the scraper installed backward. This AD requires repetitive functional checks of the MLG alternate extension system (AES) and eventual replacement of certain MLG door actuators with actuators that have either been reworked or do not have certain serial numbers. We are issuing this AD to prevent incorrectly installed scrapers, which could hinder the operation of the MLG AES, and result in failure of the MLG AES on one side, and consequent unsafe asymmetrical landing configuration.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by a report of a translating door handle jamming during opening of an aft door. This AD requires replacing the handle shaft with a new single-piece machined handle shaft on the aft entry and service doors, and requires revising the maintenance program by incorporating a new airworthiness limitation task. We are issuing this AD to prevent a migrated pin from jamming a translating door handle, which could prevent opening of the door and impede an emergency evacuation.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-102, -103, and -106 airplanes; and Model DHC-8-200, -300, and -400 series airplanes. This AD was prompted by reports of excessive wear found in the clevis (bolt) hole where the rod assembly attaches to the rudder/brake pedal bellcrank, due to prolonged fretting. This AD requires measuring the bellcrank clevis holes, inspecting for cracking of the bellcrank, and re-working the clevis holes with steel bushings, or replacing the bellcrank. We are issuing this AD to detect and correct a worn or cracked clevis hole, which could cause failure of the bellcrank on one side, with subsequent asymmetric braking and consequent runway excursion.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes. This AD was prompted by reports of movement of the rudder pedals being impeded due to corrosion of the trunnion shaft of the rudder feel trim unit (RFTU). This AD requires an inspection to determine if certain RFTUs are installed, an operational check for signs of seizure of affected parts, repetitive lubrication of certain RFTUs, and replacement of the RFTU if necessary. Installing replacement RFTUs having conformal bushings terminates the repetitive lubrication requirements. We are issuing this AD to detect and correct any sign of rough movement or seizure of the trunnion shaft and its bushing, which could cause a rudder control jam or a large and rapid alternating rudder input leading to a structural failure of the vertical fin.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of advance pneumatic detectors (APDs) for engine fire/ overheat detector assemblies failing to reset after activation due to permanent deformation of the detector switch diaphragm after being exposed to high temperatures. This AD requires replacing all three APDs with new detector assemblies. We are issuing this AD to prevent a continued engine fire indication in the cockpit after the actual fire has been extinguished, which is misleading and might influence the pilot to conduct a potentially hazardous "off-airport" landing.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-102, -103, and -106 airplanes. This AD was prompted by a report of cracking in a lower longeron in a nacelle. This AD requires repetitive inspections for cracking of the lower longerons in the nacelles, and replacement with new longerons or repair if necessary. Additionally, this AD specifies an optional terminating action. We are issuing this AD to detect and correct such cracking, which could result in degradation of the structural integrity of the nacelle and possible collapse of the main landing gear (MLG).

Airworthiness Directives; Bombardier, Inc. Airplanes

We are superseding airworthiness directive (AD) 2012-14-04 for certain Bombardier, Inc. Model DHC-8-100, -200, and -300 series airplanes. AD 2012-14-04 required replacing certain parking brake accumulators. This new AD retains this requirement. This new AD also requires installing restraint devices around the parking brake accumulator end caps. We are issuing this AD to prevent failure of a parking brake accumulator screw cap or end cap resulting in loss of the number 2 hydraulic system and damage to airplane structures, which could adversely affect the controllability of the airplane.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are superseding airworthiness directive (AD) 2011-13-08 for certain Bombardier, Inc. Model DHC-8-400 series airplanes. AD 2011-13- 08 required a free-play check for excessive free-play of the shaft swaged bearing installed in the tailstock end of each elevator power control unit (PCU), and replacing any PCU on which the bearing exceeds allowable limits with a serviceable PCU. This new AD adds airplanes to the applicability from that of AD 2011-13-08. This AD was prompted by a determination that additional airplanes are affected by the identified unsafe condition. We are issuing this AD to detect and correct excessive free-play of the swaged bearings, which could lead to excessive airframe vibrations and difficulties in pitch control, and consequent loss of controllability of the airplane.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of chafing found on the main landing gear (MLG) yoke. The chafing was attributed to contact between the nacelle fire detection wires and the MLG yoke. This AD requires inspections of the nacelle fire detection wires and the MLG yoke for damage; replacing nacelle fire detection wires, if necessary; repairing the MLG yoke, if necessary; and installing brackets and associated hardware to secure the fire detection wires. We are issuing this AD to prevent chafing between the nacelle fire detection wires and the MLG yoke. Chafing could lead to cracking and subsequent failure of the MLG yoke, which could adversely affect the safe landing of the airplane. In addition, chafing of the nacelle fire detection wires could cause them to fail and prevent the detection of a fire in the nacelle assembly.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-102, -103, -106, -201, -202, -301, -311, and -315 airplanes. This AD was prompted by reports of the loss of the fixed frequency system, leading to the loss of power to the left and right buses and all systems serviced by these buses. This AD requires modification of the wiring and changes to existing airworthiness limitations. We are issuing this AD to prevent loss of the fixed frequency system, which could lead to loss of a number of the pilot's and co-pilot's flight instruments, in addition to other avionics systems.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes. This AD was prompted by reports of an in-service incident where the propeller de- icing system became unavailable due to burnt/chafed wires within the alternating current contactor box (ACCB). This AD requires inspection for chafing, damage, and loose wiring within an ACCB and repair if necessary; and requires rework and re-identification of the wiring installation within each ACCB. We are issuing this AD to detect and correct damaged, chafed, or loose wiring within an ACCB, which could affect the operation of the windshield heater, ice detector, angle of attack (AOA) vane heater, pilot probe heater, engine intake heater, or propeller de-icing system, and subsequently adversely affect the airplane's flight characteristics in icing conditions.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by cases of on-ground failure of the screw cap or end cap of hydraulic accumulators on other airplane models, resulting in high-energy impact damage to adjacent systems and structure. This AD requires inspecting for a part number and replacing the affected parking brake hydraulic accumulator, and relocating the parking brake accumulator, on the subject airplanes. We are issuing this AD to prevent failure of the screw caps and/or end caps of the parking brake hydraulic accumulator, which could result in damage to the airplane's primary structures, with potential adverse effect on the airplane's controllability.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of alternating current (AC) generator failures in-service due to incomplete fusion in the weld joint of the rotor band assembly. This AD requires inspecting the AC generator to determine the part number, and replacing the AC generator if necessary. We are issuing this AD to prevent rotor windings from coming in contact with the generator housing, which could result in debris contaminating and potentially blocking the engine oil scavenge system, leading to loss of oil pressure and an in-flight shutdown of the engine.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are superseding an existing airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. That AD currently requires a modification to trim the edge of the bumper plate, including performing an inspection for damage or cracks of the bumper plate and base fitting, and replacing any damaged or cracked part. That AD also currently requires, for certain airplanes, reidentifying the bumper plate. This new AD requires, for airplanes on which the reidentification is done, an operational check of the alternate extension system of the main landing gear (MLG), and repair if necessary. This AD was prompted by the determination that an operational check must be done after reidentifying the bumper plate to ensure the identified unsafe condition is addressed. We are issuing this AD to detect and correct failure of the MLG to extend and lock, which could adversely affect the safe landing of the airplane.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of chafing between the wire harness along the wing leading edge and the inboard end rib of the wing leading edge due to insufficient clearance. This AD requires inspecting the wire harness along the leading edge for chafing damage, and repair if necessary; and relocating and installing new anchor nuts. We are issuing this AD to detect and correct chafing damage to the wire harness along the wing leading edge, which if not corrected, could lead to the loss of the airframe de-icing system, and could become a possible ignition source causing fire.

Airworthiness Directives; Bombardier Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports that the automatic de-icing mode became unavailable due to a failure of the timer and monitor unit (TMU). This AD requires replacing the TMU. We are issuing this AD to prevent loss of the automatic de- icing mode and consequent increased workload for the flightcrew, which, depending on additional failures, could lead to loss of control of the airplane.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by chafing on high pressure fuel lines due to improper installation of an expandable pin on the lower cowl assembly. This AD requires installing spring clips and repositioning the lanyard attachment points at the forward end and the forward firefloor of the lower cowl. We are issuing this AD to prevent chafing of the high pressure fuel lines, which if not corrected, could cause fuel leakage in a fire zone.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8 series airplanes. This AD was prompted by reports that various pushrods had been manufactured with tubes having the incorrect heat treatment. This AD requires replacing the affected pushrod assembly. We are issuing this AD to prevent loss of rudder control, reduced directional control of the airplane on the ground, or a jammed nose landing gear (NLG) door that could prevent the NLG from retracting or extending.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of cracking of certain fuel access panels of the outer wing. This AD requires an external inspection, and if necessary an internal inspection, to determine if certain fuel access panels are installed, and replacement if necessary; optional repetitive inspections for cracking of the fuel access panels, and replacement if necessary, would defer the internal inspection; and eventual replacement of affected fuel access panels with new panels. We are issuing this AD to prevent cracking of fuel access panels, which could result in arcing and ignition of fuel vapor in the outer wing fuel tank during a lightning strike.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by a report of the inability to open the airstair door while on the ground, because the airstair door seal did not deflate, which prevented the airstair door from opening. This AD requires changing the wiring that controls the pneumatic shut-off valve. We are issuing this AD to prevent the airstair door seal from not deflating, which could result in the airstair door not opening and could impede evacuation in the event of an emergency.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD was prompted by reports of difficulties in opening the airstair door. This AD requires inspecting the structure and gearbox drain paths for blockages by sealant, and removing any blockages. We are issuing this AD to detect and correct drain paths blocked by sealant, resulting in an airstair door that is unable to be opened, which could hinder evacuation in the event of an emergency.

Airworthiness Directives; Bombardier, Inc.

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-102, -103, and -106 airplanes. This AD requires a general visual inspection for chamfer of the upper edge of each leaf spring, and rework if necessary. This AD also requires installing a new friction brake nut. This AD was prompted by reports that it was possible to inadvertently move the power levers through the flight idle gate into the beta range due to an un-chamfered leaf spring in the friction brake that may contact the power lever latch when the friction adjusting knob is fully loosened. We are issuing this AD to detect and correct an unsafe condition where both engines can inadvertently be operated in beta mode during flight and consequently reduce controllability of the airplane.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Model DHC-8-102, -103, and -106 airplanes and Model DHC-8-200, -300, and -400 series airplanes. This AD was prompted by reports of cracking of the DHC-8 Series 100 rudder actuator mounting bracket. This AD requires modifying the mounting adapters of the power control unit (PCU). We are issuing this AD to prevent loss of both rudder PCU actuators which could result in free play of the rudder control surface and loss of controllability of the airplane.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes. This AD requires an inspection of a certain alternating current (AC) power wire bundle for damage, and repair if necessary. Additionally, this AD requires segregating the wire bundle into two wire bundles and installing Teflon tubing. This AD was prompted by multiple reports of the loss of certain AC systems caused by a burnt AC power wire bundle. We are issuing this AD to prevent the loss of ice protection systems for the angle of attack vanes, pitot probes, engine inlets, and windshields, and consequent loss of or misleading airspeed indication and increased workload for the flight crew, which could lead to loss of control of the airplane.

Airworthiness Directives; Bombardier, Inc. Airplanes

We are superseding an existing airworthiness directive (AD) that applies to certain Bombardier, Inc. Model DHC-8-300 series airplanes. This AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for Bombardier, Inc. Model DHC-8-201 and -202 airplanes with FAA Supplemental Type Certificate (STC) ST00753NY (Transport Canada Civil Aviation (TCCA) STC SA97-106) installed. This AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

Airworthiness Directives; Bombardier Inc. Model DHC-8-102, -103, -106, -201, -202, -301, -311, and -315 Airplanes; Equipped With Certain Cockpit Door Installations

We are superseding an existing airworthiness directive (AD) that applies to the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

Airworthiness Directives; Bombardier, Inc. Model DHC-8-400 Series Airplanes

We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as: