Squawk Box: 12/04


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


Beech Model 200 King Air
Rudder Boost Malfunction

During a rudder boost test, the right rudder pedal remained at full deflection, even with the engines at idle. When the system was turned off, both pedals returned to center. The rudder solenoid, p/n 717 was determined to be the culprit. The submitter stated if the system failed on final approach or during takeoff, the result could be devastating. Part total time: 1185.7 hours.

Cessna Model 150G
Windshield Departed In Flight

The pilot reported that a section of the windshield (P/N 0413419-200) departed the aircraft in flight. The aircraft records stated the windshield had been repaired on July 15, 2000. However, the technician did not find any evidence of reinforcement to the part remaining on the aircraft as called for in Advisory Circular AC 43.13-1B, Acceptable Methods, Techniques, and Practices – Aircraft Inspection and Repair, chapter 3, section 4.According to the submitter, this problem could have been prevented if the new windshield had been installed the way Advisory Circular AC 43.13-1B implies.Part total time: not reported.

Cessna Model 177 Cardinal
Loss of Aileron Control

While in flight, the pilot lost aileron control. He applied force to the control yoke and discovered that a total seizure of the ailerons had occurred. He landed the aircraft with rudder control only. The technician removed the tube assembly (P/N 1767030-13) from the firewall and discovered that the shaft and bearing (P/N 0760633-1) were severely worn. The submitter implied a dislodged needle bearing jammed the system, preventing yoke rotation for aileron control. A search of the FAA Service Difficulty Reporting System database revealed two reports of worn bearings; one reported with aileron control binding in flight.Part total time: 2598.6 hours.

Piper Model PA-28R-200 Arrow
Cracked NLG Downlock

During an inspection for an intermittent in a transit light, the technician discovered the nose landing gear downlock assembly (P/N 6715003) was cracked. Half the inboard perimeter of the actuator rod-attach point was broken off. The remaining half had several cracks emanating from the bolt hole. He replaced the broken assembly with a newly manufactured part, which has substantial structural improvements. The submitter reported that several more gear actuations would have resulted in complete separation. He recommended giving additional attention to this area (including drag-brace attach area). He also warned against ignoring intermittent landing gear indication lights by investigating the problem thoroughly.Part total time: 6854 hours.

Piper Model PA-34-200T Seneca
Inadvertent Master Switch

While washing the aircraft, the technician noticed that water went down the left side window into the switch panel. Accumulated water first energized the master switch circuit, then found connections in the left engine start circuit, resulting in prop rotation.Part total time: not reported.

Piper Model PA-46-350P Malibu
Flap Bellcrank Shaft Sheared

On the approach for landing, the right-hand inboard flap bellcrank shaft (P/N 82905-003) sheared and caused an asymmetrical flap condition. The bellcrank showed signs of being cracked for a long time. The flap system was severely out-of-rig. The out-of-rig problem was caused by the twisting of the bellcrank shaft and further adjustments of the rod-end causing an undue load. A search of the FAA Service Difficulty Reporting System database revealed five other aircraft with cracked, broken or failed bellcranks in the flap system. Part total time: 2538.1 hours.

Kelly/Janitrol Combustion Heaters
Combustion Tube

A new Airworthiness Directive (AD), AD 2004-21-05, supersedes 96-20-07, which applies to certain B-Series Combustion Heaters Models B1500, B2030, B3040, and B4050 that are installed on airplanes. AD 96-20-07 requires repetitive testing of the combustion tube and overhaul any heater that does not pass any test. A terminating action for the repetitive test requirements of the AD includes installing a new ceramic-coated combustion tube and an improved-design combustion air pressure switch.The new AD is the result of reports that the new ceramic-coated combustion tubes are subject to the same distress as the non-ceramic coated combustion tubes. Consequently, this AD retains the repetitive testing requirements of AD 96-20-07, removes the terminating action for the combustion tube, and adds Models B2500, B3500, and B4500 to the applicability section.The new AD, AD 2004-21-05, is effective on November 19, 2004; the FAA will accept comments from the public until December 20, 2004.


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