The bulletin
Text extracted from the PDF.
SPECIAL AIRWORTHINESS
INFORMATION BULLETIN
Aircraft Certification Service Washington, DC
U.S. Department of Transportation Federal Aviation Administration
CE-06-05 October 27, 2005 http://www.faa.gov/aircraft/safety/alerts/SAIB This is information only. Recommendations aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin advises you, registered owners and operators of aircraft equipped with NAS-649 series (superseded by MS21251M) turnbuckles with a manufacturing date of 1978 or earlier.
Background
We have discovered a safety issue with NAS- 649 series turnbuckles on primary flight controls through routine inspections of general aviation operators. We found cracks in turnbuckle barrels, both with and without “V” notches for installation of quick safety clips.
The MS21251M specification supersedes the NAS-649 series turnbuckle. This specification states “a turnbuckle with a manufacturing date of 1978 or older shall not be used for replacement repairs since stress relieving was not required prior to this date”.
Cracking of the turnbuckle barrel can result in failure of the cable system integrity. With a primary flight control, this can lead to loss of aircraft control resulting in an accident.
Recommendation
We recommend that all certified maintenance personnel:
1. Inspect and replace all turnbuckles that do not meet the requirements of MS21251M.
2. Replace any NAS-649 or MS21251M turnbuckle with a manufacturing date of 1978 or before.
3. Do not install any spare turnbuckles not meeting MS2125M requirements.
For Further Information Contact
Barry Ballenger, Aerospace Engineer, FAA, Continued Operational Safety Branch (ACE-
113), Small Airplane Directorate, 901 Locust Street, Room 301, Kansas City, Missouri, 64106; telephone: (816) 329-4152; fax: (816) 329-4090; e-mail: barry.ballenger@faa.gov