Piper PA-31 Navajo/Cheyenne

Airworthiness Directives; Piper Aircraft, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Piper Aircraft, Inc. Models PA-31, PA-31-300, PA-31-325, and PA-31-350 airplanes. This AD was prompted by fatigue cracking in the fuselage station (FS) 332.00 bulkhead common to the horizontal stabilizer front spar attachment. This AD requires repetitive inspections to detect cracks in the bulkhead and any necessary repairs. This AD also provides an optional modification if no cracks are found that will greatly reduce the likelihood of the specified cracks. We are issuing this AD to correct the unsafe condition on these products.

Airworthiness Directives; Piper Aircraft, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Piper Aircraft, Inc. Models PA-31T, PA-31T1, PA-31T2, PA-31T3, and PA- 31P-350 airplanes. This AD requires repetitive detailed visual inspections of the wiring below the main circuit breaker panel for proper clearance and evidence of damage and rerouting or replacing wires and/or parts as necessary. This AD was prompted by a fatal accident where evidence of thermal damage in this area was found. We are issuing this AD to correct the unsafe condition on these products.

Airworthiness Directives; Piper Aircraft, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Piper Aircraft, Inc. Model PA-31-350 airplanes. This AD was prompted by a report of an engine fire caused by a leak in the fuel pump inlet hose. This AD requires inspecting the fuel hose assembly and the turbocharger support assembly for proper clearance between them, inspecting each assembly for any sign of damage, and making any necessary repairs or replacements. We are issuing this AD to correct the unsafe condition on these products.

Airworthiness Directives; Piper Aircraft, Inc. Airplanes

We are superseding Airworthiness Directive (AD) 96-12-12, which applies to certain Piper Aircraft, Inc. Models PA-31, PA-31-300, PA-31-325, and PA-31-350 airplanes. AD 96-12-12 requires a one-time inspection of the bulkhead assembly at fuselage station (FS) 317.75 for cracks and the installation of one of two reinforcement kits determined by whether cracks were found during the inspection. This new AD requires repetitive inspections of the bulkhead assembly at FS 317.75 for cracks, repair of cracks as necessary, and the installation of a reinforcement modification. This AD was prompted by cracks found in the FS 317.75 upper bulkhead. We are issuing this AD to correct the unsafe condition on these products.

Airworthiness Directives; Piper Aircraft, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Piper Aircraft, Inc. Models PA-23-250, PA-24-250, PA-24-260, PA-24-400, PA-30, PA-31, PA-31-300, PA-31P, PA-39, and PA-E23-250 airplanes. This AD was prompted by an accident caused by fuel starvation where the shape of the wing fuel tanks and fuel below a certain level in that tank may have allowed the fuel to move away from the tank outlet during certain maneuvers. This AD requires installing a fuel system management placard on the airplane instrument panel and adding text to the Limitations Section of the pilot's operating handbook (POH)/airplane flight manual (AFM). We are issuing this AD to correct the unsafe condition on these products.

Airworthiness Directives; Piper Aircraft, Inc.

We are superseding Airworthiness Directive (AD) 76-06-09 for certain Piper Aircraft, Inc. Model PA-31P airplanes. AD 76-06-09 required repetitive inspection of certain exhaust system parts with replacement of parts mating with the turbocharger, as necessary, and allowed installation of a certain tailpipe v-band coupling as terminating action. This new AD requires the use of new service information and expands the scope of the inspections of the turbocharger exhaust system. This AD was prompted by reports of exhaust system failures, new service information, and the tailpipe v-band coupling used for terminating action is obsolete. We are issuing this AD to correct the unsafe condition on these products.

Airworthiness Directives; Piper Aircraft, Inc. Airplanes

We are superseding an existing airworthiness directive (AD) for all Piper Aircraft, Inc. Models PA-31, PA-31-325, and PA-31-350 airplanes. That AD currently requires a detailed repetitive inspection of the exhaust system downstream of the turbochargers and repair or replacement of parts as necessary. This new AD requires visual repetitive inspections, expanding the inspection scope to include the entirety of each airplane exhaust system. This AD was prompted by reports of exhaust system failures upstream of aircraft turbochargers and between recurring detailed inspections. We are issuing this AD to correct the unsafe condition on these products.

Airworthiness Directives; Piper Aircraft, Inc. Airplanes

We are superseding an existing airworthiness directive (AD) for certain Piper Aircraft, Inc. (type certificate previously held by The New Piper Aircraft Inc.) Models PA-31T and PA-31T1 airplanes. That AD currently requires correcting a model identification error on the aircraft data plate. Since we issued that AD, we have become aware that some owner/operators of the affected airplanes modified the aircraft data plate in error because of confusion in the serial number applicability. Because of the confusion, the manufacturer has issued new service information to clarify affected airplane serial numbers. This new AD requires determining the airplane model based on the serial number and modifying the aircraft data plate to properly identify the airplane model. This new AD also requires doing a detailed search for all applicable airworthiness related documents that apply to any airplane that has an incorrectly marked data plate and take necessary corrective actions based on the search findings. We are issuing this AD to correct the unsafe condition on these products.

Airworthiness Directives; Piper Aircraft, Inc. Airplanes

We are revising an existing airworthiness directive (AD) for certain Piper Aircraft, Inc. Models PA-23, PA-23-160, PA-23-235, PA-23- 250, PA-23-250 (Navy UO-1), PA-E23-250, PA-31, PA-31-300, PA-31-325, PA-31-350, PA-31P, PA-31P-350, PA-31T, PA-31T1, PA-31T2, PA-31T3, PA- 42, PA-42-720, and PA-42-1000 airplanes that are equipped with a baggage door in the fuselage nose section (a nose baggage door). That AD currently establishes life limits and replacement requirements for safety-critical nose baggage door components and repetitive inspections and lubrication of the nose baggage door latching mechanism and lock assembly. This new AD removes the requirement for the nose baggage door compartment interior light inspection and retains the other requirements from AD 2009-13-06, Amendment 39-15944. This AD was prompted by further investigation and a request for an alternative method of compliance (AMOC). We are issuing this AD to correct the unsafe condition on these products.

Airworthiness Directives; Piper Aircraft, Inc. PA-23, PA-31, and PA-42 Series Airplanes

We are adopting a new airworthiness directive (AD) for certain Piper Aircraft, Inc. (Piper) PA-23 series airplanes and all PA-31 and PA-42 series airplanes. This AD establishes life limits for safety- critical nose baggage door components. This AD also requires you to replace those safety-critical nose baggage door components and repetitively inspect and lubricate the nose baggage door latching mechanism and lock assembly. This AD results from several incidents and accidents, including fatal accidents, where the nose baggage door opening in flight was listed as a causal factor. We are issuing this AD to detect and correct damaged, worn, corroded, or non-conforming nose baggage door components, which could result in the nose baggage door opening in flight. The door opening in flight could significantly affect the handling and performance of the aircraft. It could also allow baggage to be ejected from the nose baggage compartment and strike the propeller. This failure could lead to loss of control.

Airworthiness Directives; The New Piper Aircraft, Inc. Models PA-31, PA-31-300, PA-31-325, PA-31-350, PA-31P, PA-31T, PA-31T1, PA-31T2, PA-31T3, and PA-31P-350 Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to all The New Piper Aircraft, Inc. (Piper) Models PA-31, PA- 31-300, PA-31-325, PA-31-350, PA-31P, PA-31T, PA-31T1, PA-31T2, PA- 31T3, and PA-31P-350 airplanes. This AD requires you to install an inspection hole (or use for inspection the tooling hole in the rudder bottom rib), conduct a detailed visual inspection of the rudder torque tube and associated ribs for corrosion, and, if corrosion is found, replace or repair the rib/rudder torque tube assembly. This AD is the result of reports of rudder tube corrosion. The actions specified by this AD are intended to detect and correct corrosion in the rudder torque tube assembly and rudder rib, which could result in failure of the rudder torque tube. This failure could lead to loss of rudder control.

Airworthiness Directives; The New Piper Aircraft, Inc. Models PA-31, PA-31-300, PA-31-325, PA-31-350, PA-31P, PA-31T, PA-31T1, PA-31T2, PA-31T3, and PA-31P-350 Airplanes

This amendment supersedes three existing airworthiness directives (AD's) that apply to certain The New Piper Aircraft, Inc. (Piper) Models PA-31, PA-31-300, PA-31P, PA-31T, and PA-31T1 airplanes. These AD's currently require you to repetitively inspect and/or modify the elevator structure. This AD initially retains the inspection and modification requirements that are currently required; adds certain other airplane models to the AD applicability; and requires a modification at a certain time period, as terminating action for the currently required repetitive inspections. This action coincides with the Federal Aviation Administration's (FAA) policy of incorporating modifications, when available, that will terminate the need for repetitive inspections. The actions specified by this AD are intended to continue to detect and correct damage to the elevator structure. A damaged elevator structure could lead to reduced or loss of control of the airplane.

Airworthiness Directives; The New Piper Aircraft, Inc. (formerly Piper Aircraft Corporation) PA-31 Series Airplanes

This amendment supersedes Airworthiness Directive (AD) 80-26- 05, which currently requires you to repetitively inspect the main landing gear (MLG) inboard door hinges and attachment angles for cracks on certain The New Piper Aircraft, Inc. (Piper) PA-31 series airplanes. AD 80-26-05 also requires you to replace any cracked MLG inboard door hinge or attachment angle with parts of improved design. This AD results from the Federal Aviation Administration's policy on aging commuter-class aircraft and the determination that an improved design MLG inboard door hinge and attachment assembly, when incorporated, will eliminate the need for the currently required repetitive short-interval inspections; however, we have received reports of cracks in the improved design MLG inboard door hinge assemblies on the affected airplanes. This AD retains the current repetitive inspections contained in AD 80-26-05, and requires inspections on the improved design parts. The actions specified by this AD are intended to detect and correct cracked MLG inboard door hinge assemblies. These cracked door hinge assemblies could result in the MLG becoming jammed, with consequent loss of control of the airplane during landing operations.

Airworthiness Directives; The New Piper Aircraft, Inc. PA-31 Series Airplanes

This document adopts a new airworthiness directive (AD) that applies to all The New Piper Aircraft, Inc. PA-31 series airplanes that are equipped with pneumatic deicing boots. This AD requires revising the Airplane Flight Manual (AFM) to include requirements for activation of 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 activate the pneumatic wing and tail deicing boots at the first signs of ice accumulation. This action will prevent reduced controllability of the aircraft due to adverse aerodynamic effects of ice adhering to the airplane prior to the first deicing cycle.

Airworthiness Directives; The New Piper Aircraft, Inc. Models PA- 31, PA-31-300, PA-31-325, PA-31-350, and PA-31P-350 Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to certain The New Piper Aircraft, Inc. (Piper) Models PA-31, PA-31-300, PA-31-325, PA-31-350, and PA-31P-350 airplanes. This AD requires installing access holes for the inspection of the elevator spar; inspecting the elevator ice protection boots for looseness and reinstalling or replacing the elevator ice protection boots if looseness is found. This AD also requires repetitively inspecting the elevator spars for cracks, and replacing the elevators or elevator spar assemblies with parts of improved design either at a certain time period or when cracks are found, whichever occurs first. This AD is the result of reports of cracks developing in the elevator spar inboard of the outboard hinge location on the affected airplanes. The actions specified by this AD are intended to prevent failure of the elevator spar caused by fatigue cracking, which could result in reduced airplane controllability.

Airworthiness Directives; The New Piper Aircraft, Inc. Models PA- 31, PA-31-300, PA-31-325, PA-31-350, and PA-31P-350 Airplanes

This amendment supersedes Airworthiness Directive (AD) 81-15- 04 R1, which currently requires repetitively inspecting for cracks at the elevator outboard hinge attachment on the horizontal stabilizer rear spar on certain The New Piper Aircraft, Inc. (Piper) Models PA-31, PA-31-300, PA-31-325, PA-31-350, and PA-31P-350 airplanes, and if cracks are found, incorporating a spar and hinge bracket assembly kit. This AD requires repetitively inspecting the horizontal rear spar in the area of the outboard hinge attachment and the outboard hinge attach bracket for cracks. When cracks are found or at a certain accumulation of time-in-service (TIS), this AD also requires modifying the horizontal stabilizer spar by incorporating an improved stabilizer spar and hinge bracket assembly kit that will terminate the repetitive inspections. This AD is prompted by several field reports of cracks found during routine inspections on airplanes already in compliance with AD 81-15-04 R1. The actions specified by this AD are intended to prevent failure of the horizontal stabilizer rear spar caused by cracks at the elevator outboard hinge attachment, which could result in loss of control of the airplane.

Airworthiness Directives; The New Piper Aircraft, Inc. Models PA- 31, PA-31-300, PA-31-325, and PA-31-350 Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to certain The New Piper Aircraft, Inc. (Piper) Models PA-31, PA-31-300, PA-31-325, and PA-31-350 airplanes. This AD requires replacing the lower spar splice plate and reworking the lower spar caps. This AD results from numerous reports of fretting and cracking of the lower spar splice plates on Piper PA-31 series airplanes in Australia, and a report of one incident in the United States. The actions specified by this AD are intended to prevent failure of the lower spar splice plate caused by fretting and cracking, which could result in loss of control of the airplane.

Airworthiness Directives; The New Piper Aircraft, Inc. Models PA- 31, PA-31-300, PA-31-325, PA-31-350, and PA-31P Airplanes

This amendment supersedes Airworthiness Directive (AD) 79-01- 04, which currently requires repetitively inspecting the elevator bungee spring for cracks or surface deformities on certain Piper Aircraft Corporation (known currently as The New Piper Aircraft, Inc.) Model PA-31-350 airplanes, and replacing any elevator bungee spring with cracks or surface deformities. This AD retains the repetitive inspection and replacement requirements from AD 79-01-04 on The New Piper Aircraft, Inc. (Piper) Model PA-31-350 airplanes until an elevator bungee spring of improved design is installed, and requires these repetitive inspection and replacement requirements on certain other Piper PA-31 and PA-31P series airplanes not affected by AD 79-01- 04. This AD also requires replacing the elevator bungee link with a link of improved design on all affected airplanes except for the Piper Model PA-31P airplanes, and repetitively replacing the elevator bungee spring on all affected airplanes. This AD results from reports of cracked elevator bungee springs on airplanes incorporating the older design elevator bungee spring that are not affected by AD 79-01-04, and by reports of cracked elevator bungee springs on airplanes that have improved design elevator bungee springs installed. The actions specified by this AD are intended to prevent failure of the elevator bungee spring, which could result in a reduction in elevator control and consequent loss of control of the airplane.

Airworthiness Directives; The New Piper Aircraft Corporation Models PA-23, PA-23-160, PA-23-235, PA-23-250, PA-E23-250, PA-30, PA- 39, PA-40, PA-31, PA-31-300, PA-31-325, PA-31-350, PA-34-200, PA-34- 200T, PA-34-220T, PA-42, PA-42-720, PA-42-1000 Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to The New Piper Aircraft Corporation (Piper) Models PA-23, PA- 23-160, PA-23-235, PA-23-250, PA-E23-250, PA-30, PA-39, PA-40, PA-31, PA-31-300, PA-31-325, PA-31-350, PA-34-200, PA-34-200T, PA-34-220T, PA- 42, PA-42-720, PA-42-1000 airplanes. This action requires revising the FAA-approved airplane flight manual (AFM) to specify procedures that will 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 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; The New Piper Aircraft, Inc. Models PA- 31T, PA-31T1, PA-31T2, PA-31T3, PA-42, PA-42-720, and PA-42-1000 Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to all The New Piper Aircraft, Inc. (Piper) Models PA-31T, PA- 31T1, PA-31T2, PA-31T3, PA-42, PA-42-720, and PA-42-1000 airplanes. This AD requires amending the Limitations Section of the airplane flight manual (AFM) to prohibit the positioning of the power levers below the flight idle stop while the airplane is in flight. This AFM amendment will include a statement of consequences if the limitation is not followed. This AD results from numerous incidents and five documented accidents involving airplanes equipped with turboprop engines where the propeller beta was improperly utilized during flight. The actions specified by this AD are intended to prevent loss of airplane control or engine overspeed with consequent loss of engine power caused by the power levers being positioned below the flight idle stop while the airplane is in flight.

Airworthiness Directives; The New Piper Aircraft, Inc. Models PA31, PA31-300, PA31-325, PA31-350, and PA31P Airplanes

This amendment supersedes Airworthiness Directive (AD) 81-11- 04 that applies to The New Piper Aircraft, Inc. (Piper) Models PA31, PA31-300, PA31-325, and PA31-350 airplanes that have Cleveland nose wheel assembly part number (P/N) 40-76B installed. AD 81-11-04 currently requires inspecting the nose wheel flange for cracks. The repetitive inspections terminate by replacing the nose wheel assembly with Cleveland P/N 40-140, which is an improved design. This action is prompted by the lack of designation of Piper Model PA31P in the Applicability section of AD 81-11-04, and the subsequent failure of a nose wheel assembly on a Piper Model PA31P airplane during taxiing operations. The actions specified by this AD are intended to prevent the failure of the nose wheel, which if not corrected, could result in loss of control of the airplane during taxiing, take-off, or landing operations.

Airworthiness Directives; The New Piper Aircraft, Inc. (Formerly Piper Aircraft Corporation) Model PA-31T2 Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to The New Piper Aircraft, Inc. (Piper) Model PA-31T2 airplanes that have a Parker Hannifin Wheel and Brake Conversion Kit 199-111 installed in accordance with Supplemental Type Certificate (STC) SA599GL. This action requires rerouting the landing gear emergency extension line. This AD results from three incidents of the brake cylinder contacting the landing gear emergency extension air line on both wheel wells. The actions specified by this AD are intended to prevent the brake cylinder from chafing against the landing gearemergency extension air line when the gear is in the up and locked position, which could result in damage to the air line and subsequent loss of emergency gear extension capability.

Airworthiness Directives; The New Piper Aircraft, Inc. (Formerly Piper Aircraft Corporation) PA-31, PA-31P, and PA-31T Series Airplanes

This document supersedes AD 75-26-18, which currently requires modifying the landing gear selector cable forward attachment pin assembly by installing a safety lock wire on certain The New Piper Aircraft Inc., (Piper) PA-31, PA-31P, and PA-31T series airplanes. The action will require the same action as AD 75-26-18. An incorrect designation of Piper Model PA-31 airplanes as Piper Model PA-31-310 airplanes in AD 75-26-18 prompted the proposed AD action. The actions specified by this AD are intended to prevent the landing gear selector cable forward attachment pin assembly from becoming separated from the powerpack control arm, which, if not corrected, could cause loss of landing gear retraction or extension.

Airworthiness Directives; The New Piper Aircraft, Inc. (Formerly Piper Aircraft Corporation) PA31, PA31P, and PA31T Series Airplanes

This amendment supersedes Airworthiness Directive (AD) 93-25- 08, which currently requires replacing the main landing gear (MLG) actuator reinforcement bracket with a part of improved design on certain The New Piper Aircraft, Inc. (Piper) PA31, PA31P, and PA31T series airplanes. This AD action will require the same action as AD 93- 25-08. An incorrect designation of Piper Model PA31-310 airplanes made in AD 93-25-08 prompted the proposed AD action. The actions specified by this AD are intended to prevent the MLG from extending, when not selected and while the airplane is in flight, caused by actuator reinforcement bracket failure, which could result in substantial airplane damage or loss of control of the airplane.

Airworthiness Directives; The New Piper Aircraft, Inc. (Formerly Piper Aircraft Corporation) PA23, PA31, PA31P, PA31T, and PA42 Series Airplanes

This amendment supersedes Airworthiness Directive (AD) 86-17- 07, which currently requires replacing all hydraulic hoses with hydraulic hoses of an improved design on certain The New Piper Aircraft, Inc. (Piper) PA23, PA31, PA31P, PA31T, and PA42 series airplanes. This AD action will require inspecting for improperly manufactured hydraulic hoses replaced during a specific time frame and replacing all affected hydraulic hoses. An incorrect designation of a Piper Model PA31-310 and a Piper Model PA23-150 airplane prompted the proposed AD action. The actions specified by this AD are intended to prevent hydraulic hose failure which could cause loss of hydraulic capabilities resulting in a gear-up landing and possible loss of the airplane.

Airworthiness Directives; The New Piper Aircraft, Inc. PA31, PA31P, PA31T, and PA42 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to The New Piper Aircraft, Inc. (Piper) PA31, PA31P, PA31T, and PA42 series airplanes. This action requires inspecting for cracks beneath and in the area of the inboard aileron hinge bracket on the aileron spar and rib using dye penetrant methods, replacing any cracked aileron spar or rib, and replacing the inboard aileron hinge bracket with a hinge bracket of improved design. Several reports of cracks in the vicinity of the inboard aileron hinge bracket, aileron spar, and aileron rib prompted this proposed action. The actions specified by the proposed AD are intended to prevent structural failure of the aileron caused by cracks in the area of the inboard aileron hinge bracket, which, if not detected and corrected, could result in loss of control of the airplane.

Airworthiness Directives; The New Piper Aircraft, Inc. (Formerly Piper Aircraft Corporation) Models PA31, PA31-300, PA31-325, and PA31- 350 Airplanes

This amendment supersedes Airworthiness Directive (AD) 80-14- 06, which currently requires the following on The New Piper Aircraft, Inc. (Piper) Models PA31, PA31-300, PA31-325, and PA31-350 airplanes: repetitively inspecting the outboard flap tracks, wing rib flanges, and the rear spar web at Wing Station (WS) 147.5 on each wing, and modifying the area at WS 147.5 on both wings if any cracks are found as terminating action for the repetitive inspection requirement. The Federal Aviation Administration's policy on aging commuter-class aircraft is to eliminate or, in certain instances, reduce the number of certain repetitive short-interval inspections when improved parts or modifications are available. This action retains the repetitive inspection requirement of AD 80-14-06, and requires modifying the area at WS 147.5 on both wings as terminating action for the repetitive inspection requirement. The actions specified in this AD are intended to prevent structural failure under certain load conditions caused by cracked areas at WS 147.5, which, if not detected and corrected, could result in loss of control of the airplane.

Airworthiness Directives; The New Piper Aircraft, Inc. (Formerly Piper Aircraft Corporation) PA31, PA31P, and PA31T Series Airplanes

This amendment supersedes Airworthiness Directive (AD) 88-05- 05, which currently requires the following on certain The New Piper Aircraft, Inc. (Piper) PA31, PA31P, and PA31T series airplanes: repetitively inspecting both the left and right main landing gear (MLG) forward sidebrace, and replacing any cracked MLG forward sidebrace. The Federal Aviation Administration's policy on aging commuter-class aircraft is to eliminate or, in certain instances, reduce the number of certain repetitive short-interval inspections when improved parts or modifications are available. This action retains the current repetitive inspection and necessary replacement requirements contained in AD 88- 05-05, and requires incorporating both a left and right MLG forward sidebrace of improved design as terminating action for the repetitive inspection requirement. The actions specified in this AD are intended to prevent the MLG from retracting because of a cracked MLG forward side brace, which, if not detected and corrected, could result in gear collapse and loss of control of the airplane during landing operations.

Airworthiness Directives; the New Piper Aircraft, Inc. (Formerly Piper Aircraft Corporation) Models PA31T, PA31T1, PA31T2, and PA31T3 Airplanes

This amendment supersedes Airworthiness Directive (AD) 84-08- 06, which currently requires the following on certain The New Piper Aircraft, Inc. (Piper) Models PA31T, PA31T1, PA31T2, and PA31T3 airplanes: repetitively inspecting the fuselage station (FS) 332 bulkhead for cracks, and reinforcing or replacing the FS 332 bulkhead if cracks are found. The Federal Aviation Administration's policy on aging commuter-class aircraft is to eliminate or, in certain instances, reduce the number of certain repetitive short-interval inspections when improved parts or modifications are available. This action retains the current repetitive inspections contained in AD 84-08-06, and requires incorporating a stabilizer forward spar attachment bulkhead reinforcement kit or installing a reinforced bulkhead assembly as terminating action for the repetitive inspection requirement. The actions specified in this AD are intended to prevent structural failure of the horizontal stabilizer and the aft fuselage attachment caused by cracks in the FS 332 bulkhead, which, if not detected and corrected, could result in loss of control of the airplane.