Airworthiness finding — cracked spar cap, Cessna 172 fleet

Summary

During routine annual inspection at a Bankstown MRO, an inspection of the left main spar cap on a Piper PA-28-161 Warrior III revealed a 7 mm fatigue crack at the inboard lower spar cap. The aircraft was immediately grounded and CASA notified. The aircraft had accumulated 10,240 hours TIS.

Investigation Findings (4)

1. 01Crack was identified via dye-penetrant inspection at the wing root attachment.
2. 02The crack originated at a surface corrosion pit on the aluminium alloy spar cap.
3. 03Piper Aircraft was notified and confirmed this finding was within the known scatter of spar cap fatigue life on high-cycle aircraft.
4. 04CASA requested a fleet survey of Piper PA-28 aircraft with greater than 8,000 hours TIS.