Twin Commander (Aero Commander)

Airworthiness Directives; Twin Commander Aircraft LLC Airplanes

We are adopting a new airworthiness directive (AD) for certain Twin Commander Aircraft LLC Models 690, 690A, and 690B airplanes. This AD requires inspection for cracking of the outer fuselage attachments, the lower wing main spar, the vertical channels, the upper picture window channels, aft cabin pressure web, external wing to fuselage fillets, and fasteners; repair or replacement of damaged parts as necessary; and modification of the structure with reinforced parts. This AD was prompted by cracks found in the upper picture window frame channels, left- and right-hand wing main spar frame support channels, and aft pressure bulkhead web. This condition, if not corrected, could result in structural failure of the airplane. We are issuing this AD to correct the unsafe condition on these products.

Airworthiness Directives; Twin Commander Aircraft LLC Models 690, 690A, and 690B Airplanes

We are adopting a new airworthiness directive (AD) for certain Twin Commander Aircraft LLC Models 690, 690A, and 690B airplanes. This AD requires you to inspect between the surface of the left-hand (LH) and right- hand (RH) upper wing skins and the engine mount beam support straps for any signs of corrosion, replace the upper steel straps with parts of improved design, and modify both wings. This AD results from reports that corrosion was found between the mating surfaces of the wing upper skin surface and the engine mount beam support straps. We are issuing this AD to detect and correct corrosion on the engine mount beam support straps and the upper wing skins, which could result in failure of the engine mount beam support straps. This failure could lead to loss of the engine and possible loss of control of the airplane.

Airworthiness Directives; Twin Commander Aircraft Corporation Models 690, 690A, and 690B Airplanes

We are adopting a new airworthiness directive (AD) for all Twin Commander Aircraft Corporation (Twin Commander) Models 690, 690A, and 690B airplanes. This AD requires you to inspect, visually and using fluorescent dye penetrant, the support structures for the inboard and center aileron hinge fittings on both wings for cracks and replace any cracked support structure. This AD requires you to reinforce the support structures for the inboard and center aileron hinge fittings on both wings. This AD results from reports that cracks were found in the support structures for the inboard and center aileron hinge fittings on both wings. We are issuing this AD to detect and correct cracks in the support structures for the inboard and center aileron hinge fittings on both wings, which could result in aileron failure. This failure could lead to reduced controllability or loss of control of the airplane.

Airworthiness Directives; Twin Commander Aircraft Corporation Models 690D, 695A, and 695B Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to certain Twin Commander Aircraft Corporation (TCAC) Models 690D, 695A, and 695B airplanes. This AD requires you to initially inspect and modify and repetitively inspect areas of the wing and fuselage structure for fatigue damage and modify or replace any damaged parts. This AD is the result of tests that show that the service life of certain airplane parts cannot be reached unless an inspection and modification program (with any necessary replacements or modifications if fatigue damage is found) is incorporated. The actions specified by this AD are intended to detect and correct fatigue damage in the wing and fuselage areas without reducing the service life of the airplane. Such undetected and uncorrected damage could result in structural failure with consequent loss of control of the airplane.

Airworthiness Directives; Twin Commander Aircraft Corporation 600 Series Airplanes

This document adopts a new airworthiness directive (AD) that applies to all Twin Commander Aircraft Corporation (Twin Commander) 600 series airplanes. This AD requires you to revise the Airplane Flight Manual (AFM) to include requirements for activating the airframe pneumatic deicing boots. This AD is the result of reports of in-flight incidents and an accident that occurred in icing conditions where the airframe pneumatic deicing boots were not activated. The actions specified by this AD are intended to assure that flightcrews have the information necessary to activate the pneumatic wing and tail deicing boots at the first signs of ice accumulation. Without this information, flightcrews could experience reduced controllability of the aircraft due to adverse aerodynamic effects of ice adhering to the airplane prior to the first deicing cycle.

Airworthiness Directives; Twin Commander Aircraft Corporation 500, 680, 690, and 695 Series Airplanes

This action confirms the effective date of Airworthiness Directive (AD) 98-08-25 R1, which applies to certain Twin Commander Aircraft Corporation (Twin Commander) 500, 680, 690, and 695 series airplanes. AD 98-08-25 R1 requires replacing the nose landing gear (NLG) drag link bolt with an approved heat-treated bolt that has the manufacturer's serial number, manufacture date, and the last three digits of the drawing number (055) on the bolt head; and changing the bolt part number (P/N) to be installed on Models 690D and 695A from P/N ED10055 to P/N 750076-1. This AD was the result of the FAA inadvertently transposing the serial numbers of the 4 affected Model 695A airplanes. The actions specified in this AD are intended to prevent the NLG from collapsing due to failure of a drag link bolt, which could result in loss of control of the airplane during landing operations.

Airworthiness Directives; Twin Commander Aircraft Corporation 500, 680, 690, and 695 Series Airplanes

This amendment revises Airworthiness Directive (AD) 98-08-25, which currently requires replacing the nose landing gear (NLG) drag link bolt with an approved heat-treated bolt that has the manufacturer's serial number, manufacture date, and the last three digits of the drawing number (055) on the bolt head on certain Twin Commander Aircraft Corporation (Twin Commander) 500, 680, 690, and 695 series airplanes; and changing the bolt part number (P/N) to be installed on Models 690D and 695A from P/N ED10055 to P/N 750076-1. The FAA inadvertently transposed the serial numbers of the 4 affected Model 695A airplanes. This AD retains the same actions of AD 98-08-25, and corrects the serial numbers of these 4 airplanes. Three of the four airplanes are not on the U.S. Register and the other one is already in compliance with the actions of AD 98-08-25. The actions specified in this AD are intended to continue to prevent the NLG from collapsing due to failure of a drag link bolt, which could result in loss of control of the airplane during landing operations.

Airworthiness Directives; Twin Commander Aircraft Corporation Models 500, 500-A, 500-B, 500-S, 500-U, 520, 560, 560-A, 560-E, 560-F, 680, 680-E, 680FL(P), 680T, 680V, 680W, 681, 685, 690, 690A, 690B, 690C, 690D, 695, 695A, 695B, and 720 Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to Twin Commander Aircraft Corporation Models 500, 500-A, 500- B, 500-S, 500-U, 520, 560, 560-A, 560-E, 560-F, 680, 680-E, 680FL(P), 680T, 680V, 680W, 681, 685, 690, 690A, 690B, 690C, 690D, 695, 695A, 695B, and 720 airplanes. This action requires revising the FAA-approved Airplane Flight Manual (AFM) to specify procedures that would prohibit flight in severe icing conditions (as determined by certain visual cues), limit or prohibit the use of various flight control devices while in severe icing conditions, and provide the flight crew with recognition cues for, and procedures for exiting from, severe icing conditions. This AD is prompted by the results of a review of the requirements for certification of these airplanes in icing conditions, new information on the icing environment, and icing data provided currently to the flight crew. The actions specified by this AD are intended to minimize the potential hazards associated with operating these airplanes in severe icing conditions by providing more clearly defined procedures and limitations associated with such conditions.

Airworthiness Directives; Twin Commander Aircraft Corporation 500, 680, 690, and 695 Series Airplanes

This amendment supersedes Airworthiness Directive (AD) 96-12- 08 on certain Twin Commander Aircraft Corporation (Twin Commander) 500, 680, 690, and 695 series airplanes, which currently requires replacing the nose landing gear (NLG) drag link bolt with one that has been manufactured with the proper heat-treatment. This action will retain the requirements of AD 96-12-08, add an additional model and additional serial numbers to the applicability section of the AD, and require replacing bolt part number (P/N) ED10055 with bolt P/N 750076-1 on certain Models 690D and 695A airplanes. This action is prompted by a defective manufacture of a certain lot of drag link bolts used in the NLG. The actions specified by this AD are intended to prevent the NLG from collapsing caused by a failed drag link bolt, which could result in loss of control of the airplane during landing operations.

Airworthiness Directives; Twin Commander Aircraft Corporation 500, 600, and 700 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to all Twin Commander Aircraft Corporation (Twin Commander) 500, 600, and 700 series airplanes. This AD requires installing access holes in both wing leading edges and repetitively inspecting the forward attach brackets and straps for cracks. Reports of cracks in the wing to fuselage attachment brackets and straps, wing station (WS) 24, and fuselage frames prompted this action. The actions specified by this AD are intended to detect cracks at the wing to fuselage attach points, which, if not detected and corrected, could cause structural failure and loss of control of the airplane.

Airworthiness Directives; Twin Commander Aircraft Corporation 500, 520, 560, 680, 681, 685, 690, 695, and 720 Series Airplanes

This amendment supersedes Airworthiness Directive (AD) 94-04- 17, which currently requires the following on Twin Commander Aircraft Corporation (Twin Commander) 500, 520, 560, 680, 681, 685, 690, 695, and 720 series airplanes: inspecting (one-time) the flap system for cables with broken wires or pulleys with worn cable clips, replacing any damaged parts, and replacing the master pulley and cable with new parts of improved design. This AD requires inspecting all flap system cable grooves for the correct width, inspecting all flap system pulleys for rubbing on the support brackets, inspecting all flap pulley cable assemblies for frayed wires, and reworking or replacing any parts with discrepancies. This AD results from several reports of worn and frayed flap system cables attributed to flap pulley grooves that are too narrow. The actions specified by this AD are intended to prevent failure of a flap system cable caused by fatigue, which could result in loss of control of the airplane.

Airworthiness Directives; Twin Commander Aircraft Corporation 680, 681, 690, and 695 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to certain Twin Commander Aircraft Corporation (Twin Commander) 680, 681, 690, and 695 series airplanes. This action requires installing a placard warning the pilot to observe turbulent air penetration speeds. Two accidents involving Model 690 airplanes where the affected airplanes encountered turbulence while descending at high speeds prompted this action. The actions specified by this AD are intended to prevent structural damage to the airplane caused by excessive turbulence, which could result in loss of control of the airplane.

Airworthiness Directives; Twin Commander Aircraft Corporation 685, 690, and 695 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that [[Page 32584]] applies to certain Twin Commander Aircraft Corporation (Twin Commander) 685, 690, and 695 series airplanes. This action requires initially inspecting the vertical stabilizer for cracks, modifying any cracked vertical stabilizer, and, if not cracked, either repetitively inspecting or modifying the vertical stabilizer. Several reports of the vertical stabilizer cracking in different areas prompted this action. The actions specified by this AD are intended to prevent failure of the vertical stabilizer as a result of cracking, which, if not detected and corrected, could result in loss of control of the airplane.

Airworthiness Directives; Twin Commander Aircraft Corporation Models 690C and 695 Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to certain Twin Commander Aircraft Corporation (Twin Commander) Models 690C and 695 airplanes. This action requires initially inspecting the wing structure for cracks, modifying any cracked wing structure, and, if not cracked, either repetitively inspecting or modifying the wing structure. Results of full-scale fatigue testing that indicated areas in the wing that are subject to fatigue cracks prompted this action. The actions specified by this AD are intended to prevent wing damage caused by fatigue cracking, which, if not detected and corrected, could progress to the point of structural failure.