Squawk Box: 12/05


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


Cessna 172S
Stall Warning Horn Failure

During the students first stall practice, the warning horn failed to operate through the full stall and the CFI halted the maneuver. Troubleshooting confirmed the warning horn assembly (p/n 0713348-1) was defective. The failed unit was replaced with a new (assembly), and a maintenance operational check and test flight were completed. A second 172 aircraft (of three) had the identical problem…at 491.5 hours. The part was replaced twice because the first new part failed during testing. A third aircraft has 417.6 hours TSN and has been recently checked; it is okay at this time. (The) probable cause (for these failures) has not been determined.Part Total Time: 311.7 hours.

Cessna 206H
Crew Flood Lights

A customer complained the overhead floodlights for the crew seats fail to attain full and/or similar brilliance as those found over passenger seating. Cessnas engineering department reported this (reduced illumination) is the way the system was intended to operate. Neither the maintenance manual nor the aircraft flight manual addresses this issue.Part Total Time: (n/a)

Cirrus SR22
Inadvertent Door Opening

The submitter states, Both doors will pop open in flight, causing a safety distraction…. This still happens, (despite) several trips to a Cirrus authorized repair center and the factory for repairs. Cirrus response is the doors are within specifications and should not come open. (I) have heard from other owners; they too have the same problems with the new door design. This entry is the only Cirrus door discrepancy found in the SDR data base.Part Total Time: 250.0 hours.

Piper PA-31T
Cracked Bearing Support

A pilot reported unusual yaw characteristics in flight. Having previously adjusted the rudder cable tension, the submitting mechanic was very surprised to find it loose. Subsequent inspection found the rudder torque tube bearing support flange cracked at the aft bolt on the pilots side. The mechanic speculates excess rudder pedal force with the aircraft on the ground (and not moving) may have been the cause of this failure.Part Total Time: 3539.0 hours.

Raytheon/Beech 58 Baron
Cracked Forward Spar Web

Cracks were noted in the forward carry-though spar web (p/n 002-430018-5) at the l/h upper, outboard-most Huck bolt holes (two each) on the forward side of the carry-through assembly. The web skin around the Huck bolts was removed down to the underlying web tie plate. The plate was then eddy current inspected-no cracks were detected.AD 90-08-14 addresses cracks in the carry-through webs, and limits cracking at the Huck bolts to one per side. This aircraft had two bolt areas cracked on one side, thus the need for DER involvement. High aircraft time and damage history are believed to have contributed to the cracking in this area.Part Total Time: 12,474.4 hours.


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