Incident Overview
The pilot of an airplane radioed that they were experiencing a loss of power and were attempting to land on a highway.
Witness Account
A witness who observed the airplane as it approached an overpass reported that the pilot appeared to have pulled up to avoid power lines. The airplane then collided with a telephone line before impacting onto a median strip.
Post-Incident Examination
Examination of the airplane after the incident found that the induction air box door spring had worn completely through the attach hole of the air box door arm. The total spring length measured 2.50 inches, whereas the engineering drawing specified a spring length of 3.66 inches. Additionally, the thickness of the arm itself was less than 50% of that specified by the drawing.
The bracket to which the other end of the spring attaches was mislocated by approximately 0.50 inch from the drawing dimension. Furthermore, the air box was fastened together mostly by blind fastener rivets, which are not called for on the drawing. The air box was also caulked with a soft sealant, also not specified in the drawing.