Aviation Safety Letter 3/2003

Recreational Aviation: Missing bolt fatal

(This article was originally published in Aviation Safety Ultralight and Balloon, Issue 2/95)

Beaver ultralight
There are numerous models of the Beaver ultralight available on the used market. Since the Beaver factory is no longer in business, it is difficult for the Beaver owners to obtain ongoing maintenance information and spare parts.

The Beaver ultralight was on a local practice flight with an instructor and student on board. At about 500 feet altitude the wing was observed to detach from the aircraft and the occupants lost their lives in the ensuing crash. Findings during the preliminary investigation were that the bolt on the left wing rear attachment point was missing. Reasons for the missing bolt have not been determined. Unless the bolt is found, the exact cause may never be determined.

The following three points on safety are suggested as a result of this tragedy:

  1. Prior to installation, inspect bolts and safety devices that attach wings and tail components to ensure that they match the manufacturer's material specifications.
  2. Prior to any flight, inspect visible high-stress points such as wings, spars, struts, tail assembly and flight controls for security and correct bolts, lock nuts, safety pins, cotter keys and lockwire as specified by the manufacturer.
  3. If the wings or other major flight components have been removed for repair or transport, then have a second knowledgeable person inspect the reassembled ultralight for security and properly installed locking devices prior to flight.

There have been a number of very serious ultralight accidents and incidents resulting from carelessness or ignorance of basic mechanical assembly details of these machines. The ultralight community can learn from these occurrences and become more safety conscious as a result.

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