Chafed, Cracked, Seized

Cessna 180J

Chafed Fuel Line

A mechanic writes, “Two aileron cables, one flap cable, and the fuel line are all routed through the l/h lower aft door post area. This fuel line is protected by a plastic sleeve, but an (aileron) cable wore through the sleeve (and began cutting) into the fuel line. This line (p/n 0500106-326) is approximately 20 inches long with four bends. I suggest a one-time inspection in case other aircraft might have this problem.”

Part Total Time: 2365.0 hours.

Failed Main Gear Castings

Two of these broken components were found on different aircraft. One of them is operated on mostly unimproved airstrips in South Africa. The part is the same as

found on 206F and G models, and was installed at the time of aircraft manufacture (p/n 1211601-3).

The casting cracked and failed upon landing. The aft bolt was also cracked and sheared. This aircraft had a normal approach and landing resulting in the l/h gear leg breaking loose from the outboard casting and pushing backwards, pinching the brake line and locking up the left brake.

Part(s) Total Times: 1776.0 and 1250.0 hours, respectively.

Cylinders Cracked Heads

(The same mechanic discovered eight cracked cylinders installed on Continental IO-520 engines in four separate aircraft. This report is representative.)

The TISN71.2ACA cylinder was found cracked behind the injector between the first and third fins. The defect is the same as all the others in this group.

In-service times for the eight cracked cylinders: 295.1; 531.8 x 2 each; 785.9; 811.2 x 3 each; and 901.4 hours, respectively. The group average is 684.95 hours. According to the FAA, a search of the agencys Service Difficulty Reporting System database reveals at least 37 reports on this part number.

Seized Exhaust Valve

During the Cessna 172s flight, the engine started running rough and lost power. An emergency landing was completed without damage or injury. The number three exhaust valve had seized in the valve guide. Further investigation found the guide (p/n 74230) broken in the cylinder head.

This operator has 17 aircraft with the new roller tappet engines. Inspection of the rest of the fleet found the majority of exhaust valves for all cylinders to be tight in the guides. The operators fleet has between 650 and 900 hours total time per aircraft.

Part Total Time: 888.7 hours.