Piper PA 28RT-201 N8162S accident near Russell Springs, Kentucky

Probable cause

Maintenance personnel’s inadequate fuel injection servo maintenance due to an out-of-date AD list, which resulted in the fuel injection servo plug backing out of the threaded plug hole on the regulator cover of the fuel injection servo and subsequent total loss of engine power.

NTSB analysis

While the airline transport pilot was flying a practice instrument approach in visual meteorological conditions, the airplane incurred a total loss of engine power. During the forced landing, the fuselage and wings were substantially damaged.

Postaccident examination of the engine revealed that the brass fuel injection servo plug had backed out of the threaded plug hole on the regulator cover of the fuel injection servo and was hanging below the fuel servo by a piece of safety wire. The missing plug likely resulted in the engine running excessively lean and losing power.

In the 7 years between the manufacturer’s discovery that the fuel injection servo plug could back out of the regulator cover hole, and the accident, the manufacturer had published a safety alert, a mandatory service bulletin, and two service information letters (SILs) advising of the issue and recommending corrective actions to prevent a loss of engine power, all of which were applicable to the accident airplane. The Federal Aviation Administration had also published three airworthiness directives (ADs) mandating the specified changes developed by the manufacturer.

Review of the maintenance records for the airplane and engine revealed no entries that indicated when the fuel injection servo had been last overhauled; if any of the actions published in the safety alert, mandatory service bulletin, SILs had been accomplished; or if any maintenance had occurred that would have required removal and reinstallation of the plug.

Further review of the maintenance records also indicated that the mechanic who had been maintaining the airplane for about 10 years used a service provider to provide him with ADs; however, the AD list was not current, and none of the three ADs were included in the published AD list. Thus, the ADs had not been accomplished for the airplane.

Text from the NTSB. Open the NTSB docket for ERA15LA341 for the full record.