The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts.
The FAA continues to receive service difficulty reports regarding leaks in the landing gear down hydraulic line in the cockpit on Cessna 210s.
In one case the leak resulted in the loss of all hydraulic fluid while in flight. The nature of the failure rendered the emergency gear hand pump inoperative as well and the aircraft was forced to land gear up.
An investigation revealed the movement of the aileron control cable from the pilots control wheel had worn a hole into the landing gear down hydraulic line, which is located in the area of the pilots right rudder pedal.
It was found that the gear down hydraulic line was not adequately supported and was repositioned against the aileron cable. Since the hydraulic line is located close to the pilots feet, the hydraulic line could have been inadvertently repositioned against the aileron cable by the foot of the pilot. This situation would then allow the aileron cable to wear into the hydraulic line and cause the failure of the landing gear system.
Owners, operators, and maintenance personnel should inspect the landing gear hydraulic lines of Cessna 210 aircraft in the forward cockpit area near the rudder pedals for wear damage or leaks. If the hydraulic lines are in close proximity to the aileron cables, the lines should be repositioned to provide adequate clearance to prevent interference between the hydraulic lines and the aileron control cables.
Make sure there is sufficient clearance for the pilots feet. The FAA recommends making this inspection within the next 10 hours of operation and be repeated annually or after every 100 hours of operation.
American General AA-1
Separated Oil Line
The pilot reported the cabin filled with smoke just after takeoff.Inspection revealed the 111-6 hose fitting blew off the hose. The hose assembly originally manufactured in 1996 had been modified in July 2002 by persons unknown. Apparently the hose itself had been replaced using the old fittings and the nipple of one of the fittings was not inserted properly into the inside of the hose.
Beech A36 Turbine Bonanza
Sheared Nose Gear Bolt
During a preflight inspection, the pilot found a nut lying on the ground that should have been attached to the lower nose gear bolt. The bolt attaches the inner shock strut tube to the nose gear fork and retains the inner sleeve plug.The bolt was sheared off flush with the nut. There were indications of corrosion at the fracture line.
Beech 95-58 Baron
Aileron Trim Tab Link
During an annual inspection, the technician found the aileron trim tab link rubbing on the leading edge of the aileron.Inspection found the trim tab linkage arm had been installed 180 degrees out, with the short end hooked to the actuator linkage rather than the long end.
Beech 95 Travel Air
Nose Gear Actuator Arm
During the landing rollout, the nose gear collapsed.The technician discovered the nose gear actuating arm that attaches to the gear transmission box had cracked, allowing the arm to flex and rotate on the splines of the transmission shaft. The same actuator arm is installed on several Beech models.
A technician reported that, after complying with AD 2000-20R1, the new stop bolts would bind with the rudder structure. The new stop bolts are larger.The technician reported the binding only occurred if pressure was applied simultaneously to both rudder pedals.
The pilot reported the throttle jammed with the engine at 2,000 rpm. The engine was shut down and the airplane glided to a safe landing. After landing, the engine restarted and ran normally.Inspection found the accelerator discharge tube in the carburetor venturi broke off and got sucked up to the throttle plate. When the engine was shut down, the tube fell down into the intake air box and the throttle plate worked normally. The tube was found lying in the air box.
Loose Firewall Junction Box
A technician found the brackets for the electrical junction box were loose. Upon further inspection, the 12 rivets that hold the brackets to the box were loose, with six having either popped heads, cracks or fractures. Cessna recommended the B-style rivets be replaced with AN rivets, which required disassembly of the entire box.
Failed Seat Lock
The pilot was practicing forced landings. As he applied full throttle to abort the landing, the seat back suddenly reclined. The pilot managed to use the electric trim to reduce nose angle and regain control. He then moved the seat back upright. The problem could not be replicated on the ground, but the seat recline cylinder lock assembly was replaced as a precaution.
During a phase inspection, the technician discovered the flame retardant on the aft carpet was crumbling.The fire block had settled into the overlapping seams of the floorboard and structure, causing corrosion where it accumulated.
Broken Elevator Brackets
During a scheduled inspection, the technician noticed excessive play in the elevators. Further investigation revealed that the brackets that support the elevator bellcrank in the tail were each missing three rivets. The parts were not even drilled to have the rivets installed when the aircraft was manufactured in 1984, yet the airplane had been through18 previous annual inspections.
Cracked Engine Crankcase
Technicians discovered two one-inch cracks on the forward right side of the engine case, around the front alternator mounting bracket. The submitter reported this was the third such aircraft found to have the same discrepancy, which requires an engine change.
Diamond DA20-A1 Katana
The airplane was on a training flight when the two pilots noticed a sudden decline in engine power. The airplane was landed in a field, dismantled and trucked back to its base.Investigation revealed the No. 3 cylinder intake valve had separated, causing significant damage to the cylinder head and piston.
Corroded Wing Skin
After the leading edge of the right wing was damaged during taxi, technicians found extensive corrosion on the right wing spar cap stiffener behind the right seat.The corrosion had eaten through about 90 percent of the spar cap stiffener. Furthermore, the wing inspection panels were riveted on with cherry max rivets instead of being attached by screws, making proper annual inspections impossible.
Piper PA-20 Pacer
During an annual inspection, the inspector discovered that the original manufacturers data tag was not found in its normal position on the floorboard near the battery box.Instead, a handmade tag was found riveted to the firewall. The handmade tag contained apparently accurate information, but a new tag was ordered from the manufacturer.
Piper PA-28R-201 Arrow
Loose Nose Gear Actuator
During a routine inspection, the technician discovered the nose gear actuator attach bracket was loose and the actuator attach bolt was bent.All of the rivets were tight and the mechanism worked properly.
Piper PA-31-350 Chieftain
Boost Pump Wiring Fault
The pilot reported the left fuel boost pump circuit breaker popped in flight.Further inspection revealed evidence of a brief electrical fire in the area. The plastic spiral wrap around the fuel line had melted, the pneumatic line to the deice boot was melted and the area contained soot.The fire apparently started because the wire to the low-pressure boost pump chafed against the fuel line to the boost pump warning pressure switch. When the wire arced, it created a fold in the fuel line, which then leaked.
Piper PA-46-350P Malibu Mirage
Broken Flap Bellcrank
The pilot reported the aircraft rolled left when the flaps were extended for landing. He retracted the flaps and noted the left flap remained extended about 10 degrees.Investigation revealed the left flap bellcrank was twisted in two at its midpoint. The bellcrank was in compliance with Piper SB 1062 and it did not break at a weld. Inspection of the right flap bellcrank revealed it had begun to fail in the same manner.