Squawk Box

October 2015 Issue




Cessnas

The following information is derived from the FAA’s Service Difficulty Reports and Aviation Maintenance Alerts.

Cessna Model 172S Skyhawk SP

Frayed Control Cable

During an annual inspection, an aileron control cable (p/n 0510105-364) was found worn at the pulley cluster (p/n S378-4) in the center overhead ceiling area. Cable must be rotated so access can be gained where cable rests on the pulley at the six o’clock position. The cable wear is not easy to see and a strong magnifying device must be used.

Part Total Time: 1921.0 hours

Cessna Model 172S Skyhawk SP



Inoperative Starter

The aircraft failed to start. Inspection revealed the rear starter housing had twisted in relation to the front half of the assembly. We’ve seen this before; it’s possible for the power wire to break and short against the starter if the housing twists far enough. This did not happen in this case but the wire did have tension on it. The new starter failed a short time later.

Part Total Time: 13.0 hours


Cessna Model 182T Skylane

Stuck Exhaust Valve

Number 6 cylinder exhaust valve stuck during initial climb. Pilot landed uneventfully. Visual inspection revealed stuck exhaust valve plus push rod and push rod tube damage. The exhaust valve guide clearance was 0.019 inch, which is well within the acceptable limits.

Part Total Time: 1240.0 hours


Cessna Model 310L

Incorrectly Overhauled Heater

Combustion heater (p/n 96C62) received for overhaul. Upon inspection, heater had wrong combustion tube installed. Heater has FAA/PMA differential air pressure switch that was found broken when received. Heater failed pressure decay test required by AD 2004-21-05.

Part Total Time: 1000.0 hours


Cessna Model 402B

Cracked Wheel Half

While removing left main wheel assembly, the mechanic noticed the inner wheel half was split (cracked) approximately 4-5 inches on each side of the valve stem hole. The outer wheel half appeared okay but both wheel halves were replaced as a precaution.

Part Total Time: 4987 hours


Cessna Model U206G Stationair

Cracked Cylinder Head

Student pilot and instructor experienced strong engine vibration shortly after takeoff and returned for uneventful landing. Inspection revealed cracked cylinder head, which was replaced. Cylinder manufacturer referenced their service bulletin (SB) calling for crack inspections, which at first did not seem to apply. Further investigation revealed the head casting number was indicated in the SB and called for inspections beginning at 500 hours. The failed cylinder had slightly more than half the threshold time on it.

Part Total Time: 267.2 hours