T-34 Mods Trouble?

FAA says some imported T-34s may have military mods that make them unairworthy


Some of the following information is derived from the FAAs Service Difficulty Reports. Click here to view “Airworthiness Directives.”


After the air combat simulation accident involving a Beech T-34, the FAA issued an AD limiting the airplanes aerobatic flight. As part of the investigation into the accident, the FAA has determined that a number of T-34s have been imported into the United States that have been sufficiently modified so that they no longer meet the original type design.

Over the years since the aircraft was originally produced, many of them have been exported and used by foreign governments for military missions or other special uses. The FAA is concerned that some of the modifications may compromise the structural integrity of the airplane.

Modifications to provide additional weapons hardpoints are a particular source of concern. They include additional holes in the wing or wing spars to allow wing pylons, holes in the structure for wiring and repairs made to the structure to compensate for the weaknesses created by those modifications.

The FAA says those modifications may be unapproved changes to the design of the airplanes that may make the airplanes unairworthy. In addition, the FAA reiterated that imported T-34 series airplanes are subject to AD 99-12-02, which limits aerobatic flight.

Bothersome Back Seats
Raytheon Aircraft Co. has reported to the FAA that, in the course of certain accidents, the rear seats of some Barons and Bonanzas have separated from their attach points to the aircraft. The company has issued a service bulletin to beef up the attachments for seats five and six to prevent the seats from pulling loose from their mounts in case of an accident. The service bulletin, SB 53-3159, applies to airplanes in the Bonanza 36 series, and Baron 55, 56 and 58 series.

Bellanca 8KCAB Super Decathlon
Engine Mount Failure

During a scheduled inspection, the technician discovered a broken engine mount tube.The engine mount cross tube broke above the magneto installation. The failure may have occurred when the engine mount flexed excessively due to sagging and worn out Lord mounts. The aircraft was used for aerobatic training.Part total time – 2,276 hours.

Beech F33A Bonanza
Elevator Trim System Failure

The pilot reported the elevator trim seized during flight.The technician discovered a broken elevator trim system tension bracket, which allowed the trim system to bind.Part total time – 1,019 hours.

Beech 58 Baron
Fuel Leak

The owner reported the fuel tank leaked.While inspecting the fuel system, the mechanic discovered the left outboard fuel cell nipples were broken. The technician identified the fuel cell as a Goodyear BTC-67. He remembered the same type of defects on BTC-39 fuel cells, which are covered by AD 78-05-06. For further information on this subject, refer to AD 78-05-06 and Beech Service Instruction 0895.Part age – 33 years.

Cessna 172G Skyhawk
Landing Gear Leg Failure

During landing, the right main landing gear leg sheared off above the axle.The technician discovered that the gear leg step was welded to the strut. The weld apparently created stress points and caused gear leg failure. The left gear leg step was also welded and failure was imminent. The manufacturer suggests bonding the gear leg steps instead of welding them.Part total time – 5,218 hours.

Cessna 172S Skyhawk
Cracked Wing and Flap Skins

During a scheduled inspection, the technician found a crack in the left upper wing trailing edge skin.The area around the third rivet from the inboard trailing edge had a 1-inch crack emanating from the rivet hole. The technician discovered cracks around two of the rivets on the right flap trailing edge skin. These cracks emanated from the 13th and 16th rivets from the inboard end. One crack was 0.5 inch long and the other crack was 0.25 inch long. Aircraft total time – 482 hours.

Cessna A185E Skywagon
Mixture Control Rod-End Failure

The pilot reported that the engine gradually lost power during flight, leading to an off-airport landing and an accident.The cause was traced to the threaded end of the mixture cable terminal, which had separated from the rod-end in the engine compartment.Aircraft total time – 5,890 hours.

Cessna 421C Golden Eagle III
Pilots Windscreen Failure

While flying at 17,000 feet, the windscreen failed and the airplane depressurized. The cause of the windscreen failure is unknown, but may have been due to a technician reworking it to remove scratches without following the manufacturers technical data for scratch removal limits.Aircraft total time – 4,449 hours.

Cessna 425 Conquest
Engine Oil Cooler Hose Failure

The right engine lost oil pressure and blew out oil during flight. The pilot shut down the engine and made a safe single engine landing. The side wall of the right engine oil cooler hose had ruptured at the point where the hose makes a sharp bend. It appeared that there were no signs of previous leakage prior to the hose failure. The installation of a longer hose would solve the problem, but would require an FAA field approval.Part total time – 117 hours.

Lear 35
Defective Pressurization System

Due to a recent aircraft accident involving a like aircraft, mechanics inspected the pressurization system. They determined that the safety valves installed in early versions of the aircraft may have unprotected pressurization system safety valves located in the aft baggage compartment. The location of the safety valves, and the fact that they are unprotected, can lead to damage when cargo is loaded or shifts during flight.In this case, technicians discovered the safety valve, installed in 1995, was cracked at the filter mounting nipple. The crack had traveled around three-quarters of the nipple circumference and had separated slightly. Flight crews and passengers should take care while securing baggage and cargo to avoid damaging the safety valve.

Maule MXT-7-180A
Flight Control Cable Damage

During a conformity inspection, the FAA Inspector discovered two frayed aileron control cables.The left and right lower aileron cables were severely frayed at the point where they exited the lower wing skin. Considering the small number of operating hours, this area deserves special attention during scheduled inspections and maintenance.Part total time – 88 hours.

Piper PA-28-161 Warrior II
Rough-Running Engine

The owner complained that the engine ran rough.Upon investigation, a mechanic discovered that the carburetor bowl was loose even though the fastener lock tabs were still in place. He replaced the entire carburetor assembly and ran a successful operational test. The mechanic stated this was the third such defect discovered in the past eight months.Part total time – 362 hours.

Piper PA 32R-300 Lance
Landing Gear Failure

The pilot reported the landing gear failed during a landing approach. The pilot used the manual gear extension system and made a safe landing.The technician discovered the landing gear hydraulic power pack motor would not operate because the electrical ground connection had failed. Part time since overhaul – 202 hours.

Piper PA 32-301T Turbo Saratoga
Aileron Control Failure

During a preflight inspection, the pilot heard a snapping sound while checking the flight control movement. The left aileron did not respond to control movements.The left aileron push-pull rod had broken flush with the rod-end jamnut. The mechanic could not determine if the failure was caused by intergranular corrosion or a manufacturing defect.The aircraft owner opted to replace the left and right ailerons, as well as the stabilator push-pull rods.

Piper PA 38-112 Tomahawk
Fuel Pressure Transducer Failure

The owner reported erratic fuel pressure indications.The fuel pressure transducer was found to have failed. The technician stated he had found two other occurrences of this problem in the previous five months. He speculated the original locations of the fuel pressure transducer and the oil pressure transducer expose them to excessive heat and vibration, which contributes to premature failure. The technician determined that moving the transducers to the firewall solves the premature failure problem. He reported using this method on a Beech 76 Duchess that now rarely experiences premature transducer failure. The modification requires an FAA field approval.Part total time – 65 hours.


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