What happened
On April 30, 2022, at approximately 0810 EDT, a Piper PA-32R-301, registration N4303P, was performing a personal flight from Huntingburg Airport (HNB) to Putnam County Regional Airport (GPC). About 10 minutes after departing Huntingburg, the aircraft was cruising at 3,000 feet MSL when the engine experienced a partial loss of power. The pilot executed a forced landing onto a gravel road. During the landing maneuver, the left wing of the aircraft struck a tree, causing substantial damage to the airplane. The pilot and passenger were not injured.
The investigation
Following the accident, an FAA inspector examined the engine. While no immediate anomalies were found during the initial inspection, a subsequent functional test run revealed that the engine could not reach full RPM. Upon removal and testing of the fuel servo, investigators determined it was unable to deliver more than 22 pounds of fuel per hour, which was below the required specifications.
Disassembly of the fuel servo revealed that a self-locking nut was stuck inside the top section of the plug. This obstruction prevented the head idle spring from properly allowing fuel to flow through the ball valve. Records indicated that the fuel servo had been overhauled in March 2002. At the time of the accident, the engine and fuel servo had both exceeded their established time between overhaul limits by 572 hours.