The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts. Click here to view “Airworthiness Directives.”
After an accident in which a helicopter crashed and burned, NTSB investigators discovered that the hose used to refuel the aircraft had decomposed internally and leached a gummy resin into the fuel. The contaminated fuel clogged the carburetor jets and the helicopter lost power on takeoff.
The truck-mounted fuel hose was a 30-foot terra-cotta colored hose labeled Versicon which the owner had acquired as a replacement hose from a local supplier in August 1997. The owner reported that the supplier of the Versicon hose had advised him that the hose was acceptable for use with aviation fuels.
The owner reported previously noticing a clear sticky substance weeping from the cut ends of the hose where it attached to the filters and nozzle. He also noted that fuel held within the 30 foot length of hose had changed to a green-yellow color.
Examination of the green-yellow fuel sample and gum revealed that the fuel contained a Benzenedicarboxylic compound, and that this was the primary component making up the fuel soluble gum.
It is important to remember that any operator acquiring hose for the purpose of transporting aviation fuels should ensure that the hose is approved and marked in accordance with API standards. Failure to do so may result in contaminants entering the aircrafts fuel system.
Beech A-36 Bonanza
Defective Pitch Trim
During flight, the pilot experienced an abrupt pitch down and elevator trim runaway, which resulted in a rapid descent. When he disengaged the autopilot, another abrupt pitch change occurred.The system ground tests were satisfactory, but the pitch trim runaway occurred again when the autopilot was engaged. After the pitch servo was replaced, the system functioned normally.The problem apparently was tied to the trim sensor in the pitch servo.Part total time – 20 hours.
Beech 56TC Baron
Flight Control Failure
During flight, the pilot experienced severe turbulence and the flight control column broke. The pilot maintained control of the aircraft by using the autopilot and made a safe landing.The weld broke where the shaft was attached to the flange of the control column adapter assembly. AD 71-24-10 addresses this subject, and this aircraft was in compliance with the AD.Part total time – 1,981 hours.
Empennage Structural Damage
During an annual inspection, the technician found the elevator control cable tension low. Several attempts to adjust the cable tension failed, and the technician determined the pulley did not move when the cable was pulled. Since there are no access panels in the tail section, he removed the entire tail group structure and found the cables stretched and the aft horizontal bulkhead cracked at several locations.Part total time – 4,006 hours.
Defective Elevator Spar
The technician removed a damaged elevator spar assembly and ordered a new one.The technician conducted a receiving inspection on the new part and discovered the new assembly came with the outboard hinge bracket already installed (unlike the original assembly). The hinge bracket was not installed properly and would have made the outboard hinge bolt misaligned. He ordered a second assembly and rejected it due to the same defect. He ordered a third assembly, found it serviceable, and installed it.Part total time – 0 hours.
Cessna 172R Skyhawk
After removing the engine cowling for a 100-hour inspection, the technician discovered firewall cracks adjacent to the cowling shock mounts.The aircraft had been inspected according to Cessna SB 98-53-02, which deals with this subject, less than 200 hours earlier. The technician also found cracked firewalls on three of four like aircraft. Part total time – 389 hours.
During a takeoff roll, the pilot noticed all of the radio lights flickering and the voltmeter indicated 21 volts. He aborted the takeoff but could not identify the problem. When the pilot attempted another takeoff, he experienced the same problem.A mechanic found the starter inoperative due to an internal failure. The starter solenoid may have been stuck in the engaged position, causing the starter to be driven by the engine.Part total time – 87 hours.
Damaged Pitot Tubing
This aircraft was involved in a landing accident that destroyed the aircraft. During the accident investigation, the pitot system tubing was found crushed. The tubing was improperly routed between the fuselage frame and the skin on the left side. This resulted in restricted flow to the airspeed indicator and lower than actual airspeed indications and may have contributed to the accident.Part total time – 397 hours.
Exhaust System Component Cracking
Two Mooney M20Ks that incorporated Continental TSIO-520-NB engines under STC SA5691NM suffered exhaust system component failures. One aircraft had cracked left lower rear and right front turbocharger mount brackets. The other aircraft had cracks adjacent to welds and where the engine baffling rubbed against the tailpipes, headers, and transition pipes.Part total time – 212 hours and 584 hours.
Piper PA-24-180 Comanche
The technician removed both stabilators to replace the bearings and found corrosion on the stabilator torque tube. The corroded area was not visible until the stabilators were removed. Part total time – 3,763 hours.
Piper PA-28-161 Warrior
After returning from a flight, the pilot reported engine vibration during engine starting and shutdown procedures.Mechanics found a loose right lower engine mount-to-firewall bolt. In addition, the bolt grip length was too long and allowed the nut to bottom out on the threads. The maintenance records revealed the bolt had not been replaced since the aircraft was new.Part total time – 837 hours.
Piper PA-32R-301T Turbo Saratoga
Vertical Stabilizer Attachment
During an annual inspection, the technician noticed movement when he exerted hand pressure against the top of the vertical stabilizer. The technician removed the four rear spar attachment bolts and discovered wear marks made by movement of the attachment point surfaces. The torque on the attachment bolts was less than the required 100-inch pounds. The mechanic recommended that the manufacturer replace the stabilizer attachment bolts with ream-to-fit AN-174-series close tolerance bolts.Part total time – 2,278 hours.
Piper PA-34-200 Seneca
Rudder Control Failure
During ground operation, the rudder went to full left deflection and could not be returned to the neutral position.Mechanics found that the rudder arm assembly failed at the point where it is welded to the cross-bar assembly. This aircraft was used for flight instruction and used to demonstrate single-engine operation, which requires full rudder travel to maintain control of the aircraft. Part total time – 5,200 hours.
Teledyne Continental GTSIO-520-H
Sudden Loss of Engine Power
During flight, the pilot experienced a sudden loss of engine power and made a dead stick landing. Mechanics found that the idler gear-support pin was loose and had backed out of the crankcase. That allowed the idler gear to move out of position and disconnect the magneto drive train. Also, there was extensive damage to the teeth of the crankshaft gear, starter drive adapter gear, and the camshaft gear. Part time since overhaul – 838 hours.