Casualties unknown

1993-05-21: Piper PA-25 (N6453Z) — Shenandoah Flight Services,inc — Essex, IA

Essex, IA, US

On May 21, 1993, a Piper PA-25 (registration N6453Z) operated by Shenandoah Flight Services,inc was involved in an aviation accident near Essex, IA. Investigators recorded the probable cause as: The forward spar fuselage attachment assembly for the right wing failed from fatigue at the clevis ears. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

An airplane on a swath run experienced right wing buckling and crashed. Post-accident examination revealed fatigue failure of the forward spar attachment assembly at the clevis ears. A similar failure occurred in a Piper PA-25 in 1991, prompting an NTSB recommendation for inspections, but no AD was in effect at the time of this accident.

Accident Overview

The airplane was conducting a swath run when the right wing buckled, causing the aircraft to roll into a descent and subsequently crash.

Post-Accident Findings

A post-accident examination of the airplane determined that the forward spar fuselage attachment assembly for the right wing had failed. The failure was attributed to fatigue at the clevis ears.

Previous Similar Incident

On September 21, 1991, a Piper PA-25 experienced a similar failure of the wing attachment assembly.

Regulatory Action

On May 13, 1992, the National Transportation Safety Board (NTSB) issued an urgent recommendation to the Federal Aviation Administration (FAA). The recommendation called for an Airworthiness Directive (AD) to require immediate inspections of Piper PA-25 airplanes for corrosion and cracking of the clevis ears. It also mandated repairs if such conditions were found and established periodic inspection requirements to detect cracks before they become critical.

On July 16, 1992, the FAA agreed with the intent of the NTSB recommendation. However, as of the date of this accident, no inspection procedure had been implemented.

Conclusion

No further causal factors were identified beyond the fatigue failure. The accident highlights the structural vulnerability of the wing attachment components, but no additional analysis is provided in the source.

Probable cause

The forward spar fuselage attachment assembly for the right wing failed from fatigue at the clevis ears.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X12330. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.