AL 1999-04
13 August 1999
Cracked Elevator Spring
A recent SDR reported the failure of the elevator down spring which led the pilot to state that he virtually lost all elevator back pressure "feel" while landing his aircraft. This aircraft was using the new elevator down spring (P/N 71056-03) with only 421 hr on it.
Piper has been aware that there have been some elevator down spring failures to their Navajo and Navajo Chieftain Aircraft (Models PA31, 31-300, 31-325, 31-350, 31-350 T1020, 31P). In order to remedy this they have issued Service Bulletins (SB) 626C & 1002. Both service bulletins place a 100-hr repetitive inspection on these springs (P/N 71056-02) and a life limit of 1000 hr. At 1000 hr the 71056-02 springs, if replaced with the 71056-03 springs, are no longer subject to the 100-hr repetitive inspection. Transport Canada's SDR database shows two aircraft with failures to the replacement 71056-03 springs, one at 421 hr and the other at 302 hr.
The Continuing Airworthiness Division has received samples of broken springs which have been sent to the Transportation Safety Board lab for analysis. The consequences of failure are significant enough to warrant a recommendation to all owners who have complied with SBs 626C & 1002 to continue with the 100-hr repetitive inspection until the cause of failure has been determined.
For more information, please contact a Transport Canada Centre, or call Mr. Robert Dixon, Continuing Airworthiness, Ottawa, telephone (613) 952-4308, facsimile (613) 996-9178 or e-mail dixonro@tc.gc.ca.
For Director, National Aircraft Certification
B. Goyaniuk
Chef, Maintien de la navigabilité aérienne