The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts.
The FAA published a Special Airworthiness Information Bulletin (SAIB) reminding owners of single or multi-engine piston airplanes of the need to properly maintain pneumatic system components that power air-driven gyro instruments. Specifically, the SAIB recommends following the applicable maintenance, inspection and replacement instructions published by Parker Hannifin for their Airborne-brand vacuum pumps and components. The companys service letters are available on the Internet at www.parker.com/ag/nad/sl.asp.The recent SAIB also references SAIB CE-01-29R1, published on July 10, 2001, which provides a recommended method to preflight check the proper operation of the pneumatic system.
Another SAIB published by the FAA notes the agency has received reports that a small number of United Instruments, Inc. altimeters have failed, or have been miss-assembled during maintenance. The effect of the failures is to allow the barometric dial and the altitude pointers to become desynchronized. This condition could result in the altimeter indicating an incorrect altitude. The FAA recommends ensuring sure that the altitude indication pointers and the barometric pressure dial remain synchronized when the altimeter setting is adjusted. If they do not remain synchronized, the altimeter should be repaired prior to further flight.
Mooney M20M Airplanes
Turbocharger V-Band Clamp
The FAA also published a SAIB advising Mooney M20M owners and operators of an Alternative Method of Compliance (AMOC) to Airworthiness Directive (AD) 91-03-15. The AMOC results from revisions to factory service bulletin SB M20-283A, which is incorporated by reference into AD 91-03-15. According to the FAA, the AMOC provides an improved part number to comply with mandatory replacement of the V-band clamp used on the turbocharger outlet to tail pipe connection. Additionally, the FA notes it is considering mandating the requirements of the service bulletin through additional rulemaking action.
Cessna Model 206 Airplanes
The FAA is notifying owners of Cessna Model 206 airplanes equipped with an S-TEC autopilot of possible cracking at the right wing rear spar shear web, and requests inspection of the roll servo mounting location at the shear web. During routine inspections on two Cessna 206 airplanes modified with floats and tip tanks, operators discovered cracks at the fasteners holes of the right wing rear spar shear web where the roll servo was installed. S-TEC service letter SL 03-003 was issued in response. Subsequently, the company issued service bulletin SB 03-001, Revision 4 to include all Cessna 206 configurations (not just float and tip tanks) equipped with S-TEC autopilots.