Cracks And Corrosion

The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts.


Cessna 172RG

Cracked Main Gear Actuator

The pilot reported a loud “pop” just before entering the pattern. When he extended the gear, the green “gear down” light would not come on. A fly-by revealed the left main gear was in transit. A gear-up landing ensued. Inspection revealed the left main gear actuator (p/n 9882015-2) housing was cracked across the forward attach bolt hole. The cracked housing allowed the piston rack to jump gears on the pinion gear attached to the main gear leg. This area is inspected each 100 hours for cracks and defects very carefully, (using) lights and inspection mirrors. Time since last inspection: 25.0 hours.

Part Total Time: 6917.0 hours.

Cessna 172/180/185 (all models)

Control Yoke Corrosion

The FAA recently proposed an Airworthiness Directive mandating compliance with Cessna SEB01-3R1, regarding control yoke internal corrosion. The recommendation was issued after reported failure of a control yoke discovered while complying with


the service bulletin on a 1985 Cessna 172P. The yokes drain hole appears to be larger than -inch diameter and is mislocated. The FAA determined the alteration from the service bulletin weakened the tube structure, and may have contributed to the failure.

Part Total Time: Unknown.

Teledyne Continental Motors TSIO-360-F

Broken Impulse Coupling Spring

This engines magneto impulse coupling spring was found broken. The components displayed evidence of a pre-existing crack and corrosion, even with very low time in service. Magneto-to-engine timing was lost. Both mags experienced the same failure almost simultaneously.

Part Total Time: Unknown.

Mooney M20B

Failed Gear Lever Downlock

The airplanes landing gear lever became disengaged from the downlock latching assembly on the lower center instrument panel. Aircraft was on the ground during landing rollout. This allowed the gear to collapse. Mooney service bulletin SB M20-88B, dated 5-10-94, addresses this failure.

Part Total Time: Unknown.

Cirrus SR22

Corroded Flap Hinges

Flap hinges-all positions, both left and right wings-were found at annual inspection with intergranular corrosion and near the point of failure. Part numbers: 13431-003, 13431-004, 13432-002, 13433-006, 13433-005.

Part Total Times: Unknown.


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