Aircraft: Piper Navajo. Injuries: 1 Fatal. Location: Dalton, Ga. Aircraft damage: Destroyed.
What reportedly happened: According to a friend, the pilot was taking the airplane to have an annual inspection completed. The friend said the airplane’s take off was normal.
A witness in the vicinity of the accident stated the airplane flew over his house at an altitude of about 200 feet and descended toward the trees. He said the right propeller was not turning, and the right engine was not running. He stated that the left engine sounded as if it was running at full power. The airplane pitched up to avoid a power line, then rolled to the right, descending below the tree line. A plume of smoke and an explosion followed.
Examination of the right propeller assembly revealed evidence of significant frontal impact. Due to fire and impact damage of the right engine and related system components, the reason for the loss of power could not be determined.
An examination of the airframe and left engine revealed no mechanical malfunctions or failures that would have precluded normal operation.
A review of the airplane maintenance logbooks revealed that the annual inspection was 12 days overdue. According to Lycoming Service Instruction No. 1009AS, the recommended time between engine overhaul is 1,200 hours or 12 years, whichever occurs first. A review of the right engine maintenance logbook revealed that the engine had accumulated 1,435 hours since major overhaul and that neither engine had been overhauled within the preceding 12 years.
Although the propeller manufacturer recommends that the propeller be feathered before the engine rpm drops below 1,000 rpm, a review of the latest revision of the pilot operating handbook revealed that the feathering procedure for engine failure did not specify this.
Investigators determined that it was likely that the pilot did not feather the right propeller before the engine reached the critical 1,000 rpm, which prevented the propeller from engaging in the feathered position.
Probable cause: The pilot’s failure to maintain control following loss of power in the right engine for reasons that could not be determined. Contributing to the accident was the pilot’s delayed feathering of the right propeller following the loss of engine power and the lack of specific emergency procedures in the pilot operating handbook indicating the need to feather the propellers before engine rpm falls below 1,000 rpm.
NTSB Identification: ERA12FA423
This June 2012 accident report is are provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.