Bound To Fail

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


Diamond DA20-C1

Cracked Nose Gear Fork

Several reports of cracked nose landing gear forks (p/n: 20-3220-08-00) on both left and right sides have been received by the FAAs Service Difficulty Reporting System (SDRS). The SDRS database records at least five such discrepancies, with in-service times ranging from 1926.7 to 573.6 hours.

Part Total Time: various

Learjet 60

Binding Aileron Controls

The pilot in command reported difficulty moving the aileron to the starboard position while levelling off after initial climb. The aircraft made an uneventful landing. Upon inspection, the chart holder extension arms attached to the co-pilots yoke were extended forward, and became caught in the yoke cover, increasing turning resistance. The extensions were retracted and subsequent tests of the aileron movement revealed no further discrepancies.

Part Total Time: 1728.0 hours

Piper: PA-46-350P

Loose Landing Light Power Supply

The pilot could not reduce engine power during landing but landed without incident. Investigation revealed the aircraft had been modified with STC SA02279AT by installing a high intensity landing light. The lights power supply was mounted on the forward engine firewall above and behind the fuel control unit and secured adhesive per the STC. The adhesive mounting failed; the power supply fell from the firewall and became lodged in the FCU linkage, preventing power reduction and full engine control. The power supply was relocated to the engine mount and secured to an aluminum plate.

Part Total Time: (unknown)

Continental IO-470-K

Improper Fuel Fittings

A technician performed the factory-recommended fuel injection setup but the flow was below specifications. Inspection revealed inlet elbow fittings (p/n 631658 and 628437) had been reversed, probably 12 years earlier when installing an electronic fuel flow transducer. Part 631658 has a restrictor orifice, while 628437 does not. The parts look identical externally. A very careful observation is required to see the internal difference. The TCM parts manual shows the different part numbers, but does not describe the differences.

(According to the FAA, this airplane had five cylinder changes during the 12 years, most likely caused by lean operation at full power and resulting from restricted fuel flow.)

Part Total Time: (unknown)


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