SAIB CE-03-35

SPECIAL

AIRWORTHINESS

INFORMATION

BULLETIN Aircraft Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration No. CE-03-35 April 16, 2003 We post SAIBs on the internet at "av-info.faa.gov" This is information only. Recommendations are not mandatory.

Introduction This Special Airworthiness Information Bulletin (SAIB) alerts you, an owner or operator, of the following Piper PA-31 models, of potential failure of elevator bungee spring P/N 71056-2 or P/N 71056-

3. The failure of the elevator bungee spring may result in loss of elevator down spring tension, which will cause a variation in longitudinal control input force requirements.

Model Serial Numbers PA-31, PA-31-300, and PA-31-325 31-2 through 31-8312019 PA-31-350 31-5001 through 31-8553002 PA-31P 31P-1 through 31P-7730012 Background The FAA has received several reports of premature failures of elevator bungee spring P/N 71056-2 or P/N 71056-3. Note that this spring is the subject of Airworthiness Directive AD 98-08-18, and it is to be repetitively replaced at 1000 Hrs. time-in-service interval.

Some of the reports indicated that failures occurred in flight. Evaluation of one failed spring showed that failure was due to a torsional fatigue crack that initiated at the inside position of an active coil.

Recommendation After reviewing available data, we recommend that you have a heightened awareness of elevator bungee spring failure. The failure of the elevator bungee spring can be recognized by the loss of elevator down spring tension, and is best noted during controls check accomplished as part of the Before Starting Engines check.

If you suspect or note spring failure, you should take the appropriate maintenance action to inspect, remove, replace, and adjust the elevator control system. In an event of spring failure, we request that you notify the FAA at the address listed below. Include as much information as possible, including model number, serial number, part number, part’s time-in-service, and physical description of the failure. We also request that you retain the failed spring for further review.

Note: Based on current information we, the FAA, only recommend these actions. We will continue this investigation and analyze any added information. We may require additional actions, such as the issuance of an Airworthiness Directive based on this analysis.

For Further Information Contact Samuel Belete, Aerospace Engineer, FAA, Central Region, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, Suite 450, Atlanta, GA 30349; phone (770)-703-6048; fax

(770) 703-6097; email: samuel.belete@faa.gov