The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts. Click here to view “Airworthiness Directives.”
The Greensboro, N.C., Flight Standards District Office has issued a warning to owners and operators of Beech 58P Barons after a gear-up landing. The normal landing gear extension system failed and the pilot was unable to extend the landing gear with the emergency gear crank handle because it was jammed.The inspector discovered that the emergency landing gear extension crank handle jammed under the spar carry-through cover. The crank handle had been improperly stowed under the spar carry-through cover during a recent inspection.The manufacturers technical data provides instructions for removing the spar cover; however, instructions for reinstalling the cover are not given. The spar cover has an access cutout for the emergency crank handle but the manufacturers data does not contain any warnings addressing the possibility of the spar cover jamming the emergency crank handle if the spar cover is installed improperly.This problem exists in most Beech Baron and Bonanza series aircraft. Beech has agreed to update the technical data to include the possibility of the emergency gear crank handle being jammed by improper installation of the spar carry-through cover. A service bulletin or airworthiness directive is also a possibility.
Beech K35 Bonanza
During a flight, the aircraft experienced engine failure requiring an off-airport landing. The aircraft sustained substantial damage during the emergency landing.The pilot switched fuel tanks approximately 12 minutes prior to engine failure and did not notice a positive detent when he moved the selector valve handle. When the engine quit, he attempted to switch fuel tanks, and the fuel selector valve handle came off the valve shaft. During an investigation, the inspector discovered both roll pins missing from the fuel selector valve shaft. Part total time – 3,600 hours.
Beech A-36 Bonanza
Autopilot Electrical Short
During a flight, the pilot detected a burning odor in the cockpit. The autopilot disengaged and would not re-engage; however, the pilot landed the aircraft safely.The technician discovered a shorted transistor and lifted traces in the printed circuit for the servo-engage section of the autopilot computer. Further inspection revealed an electrical short in the autopilot servo-engage wiring in the aircraft wiring harness caused the transistor failure. A wire chafed and shorted approximately 3 inches from the autopilot computer connector where the pitch-and-roll wires splice together. The splice chafed against a step in the control column cover and was found by physically shaking the instrument panel. Other wire chafing damage was found in the trim circuit wiring harness, which had chafed against the yaw servo bracket causing an additional autopilot computer failure.Part total time – 542 hours.
Beech 56TC Baron
Flight Control Column Failure
During flight, the pilot made an abrupt movement of the control yoke, and the yoke separated from the control column. He made a safe landing and delivered the aircraft to a maintenance shop.The technician found the control yoke failed at the adapter assembly. AD 71-24-10 incorporates, by reference, Beech Service Instruction 0254-156, which deals with this subject. The AD applies to aircraft altered to incorporate control wheels that have provisions for a clock and light.Part total time – 1,981 hours.
Cessna 172R Skyhawk
Defective Shock Mounts
During an annual inspection, the technician found three of the eleven engine cowling shock mounts severely damaged.The technician found one shock mount torn through approximately half its diameter. He reported finding more than 20 defective cowling mounts on new Cessna 172 aircraft. The new cowling shock mounts are much thinner than those used on older 172s. Part total time – 243 hours.
Cessna 210B Centurion
Nose Landing Gear Failure
While rolling out after landing, the pilot encountered severe nose gear shimmy. Immediately, the nose gear wheel assembly separated from the aircraft.The nose gear fork assembly broke where it attached to the strut. Airworthiness Directive AD 71-22-02 deals with this subject but is not applicable to the Cessna 210-series aircraft. AD 71-22-02 references Cessna Service Letter 63-31, which does include the Cessna 210-series aircraft.Part total time – 3,083 hours.
Piper PA 23-250 Aztec
Electrical System Failure
During a 100-hour inspection, the technician discovered battery electrical power was not available even though the battery was fully charged.While investigating the cause of this defect, the technician discovered electrical power would not pass through the battery contactor. When he disassembled the contactor, he discovered a large amount of corrosion debris. The debris prevented the contactor from conducting electrical current.Part total time – 1,795 hours.
Piper PA 28R-201 Arrow
Broken Engine Mount
During a scheduled inspection, the technician discovered a broken engine mount.The right side engine mount broke where the drag brace attached. A previous pilot reported the gear unsafe light came on only during descent. The microswitch for the gear unsafe light is mounted above the broken engine mount. Apparently, when the pilot reduced engine power, torque caused mount movement, and prevented the switch from maintaining contact. The broken mount may have been the culmination of previous damage suffered during a hard landing. The FAA database contains reports of five additional failures of this part number.Part total time – 7,476 hours.
Piper PA 31-350 Chieftain
Defective Firewall Shutoff Valve
During a scheduled inspection, the technician found the right engine fuel firewall shutoff valve did not function properly.With the shutoff valve in the off position, the fuel continued to flow. He removed the shutoff valve, and determined it failed internally. Airworthiness Directive AD 80-18-10 deals with this subject and incorporates Piper Service Bulletins 507 and 648. However, these documents do not apply to this aircrafts serial number. He replaced the questionable shutoff valves with shutoff valves having an improved design.Part total time – 3,542 hours.
Piper PA-32-301T Turbo Saratoga
Hydraulic System Failure
During cruise flight, the pilot noticed the loss of hydraulic pressure and the landing gear extended without command.The technician determined the left main landing gear actuator leaked severely from the actuator shaft. He also discovered the hydraulic pump seal was defective. Also, the nose gear actuator leaked internally and allowed air to be drawn into the system. The air introduced into the hydraulic system caused the pump to cycle continuously until it failed.Part total time – 143 hours.
Piper PA-32R-301 Saratoga
Fuel Starvation Accident
During flight, the student pilot inadvertently moved the fuel selector valve to the off position. This action resulted in an emergency, off-airport landing and substantial damage to the aircraft.During the accident investigation, the inspector discovered he could move the fuel tank selector valve to the off position with very little resistance. The stop is attached to the center fuel panel and the spring steel arm was bent, which allowed the selector handle to bypass the stop.Part total time – 1,800 hours.
Piper PA-60-601P Aerostar
During a scheduled inspection, the technician discovered several areas throughout the airframe displayed the early stages of surface corrosion. One area displayed advanced stages of severe intergranular corrosion on the right main landing gear aft side brace support fitting.The technician removed the trunnion fitting. Prior to installing a new trunnion fitting, he treated the damaged areas and the new part with a corrosion-preventive compound.This aircraft operates approximately 4 months of each year in a salt air environment. Since it is not always possible to avoid salt air environments, it should be a standard practice to wash these aircraft using fresh water as quickly after exposure as possible.Part total time – 2,065 hours.
Stinson 108-2 Voyager
The aircraft was in an accident due to engine fuel starvation. Investigators determined the fuel hose running from the fuel strainer to the carburetor did not supply sufficient fuel to sustain engine operation.The half-inch hose was manufactured in the third quarter of 1985 and had a fire sleeve installed over the outside for protection.The hose was found to have a small piece of the interior liner curled up near one end, which obstructed the flow of fuel from the strainer to the carburetor. The aircraft was being operated using auto fuel.The inspector speculated exposure to auto fuel over an extended period of time might have contributed to the hose deterioration.