Accident Overview
On September 12, 2020, at approximately 1143 mountain daylight time, a Piper PA-30 airplane, registration N7602Y, was substantially damaged when it was involved in an accident near Billings Logan International Airport (BIL), Billings, Montana. The airline transport pilot was seriously injured. The airplane was being operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
Sequence of Events
The pilot does not recall the accident but remembers experiencing an issue with the right engine and shutting it down. The flight originated from Lake Elmo Airport (21D), St. Paul, Minnesota, with a destination of BIL. According to the Federal Aviation Administration (FAA), the pilot contacted the BIL air traffic control tower requesting clearance to land on runway 28. The pilot mentioned that one engine was "out" but did not provide details and did not declare an emergency. While on short final, the pilot made another radio call indicating loss of the second engine. The airplane subsequently landed short of the runway, impacting a cliffside. On-scene law enforcement reported no smell of fuel at the accident site and no fuel present in the fuel tanks.
Postaccident Examination
Examination of the airframe revealed no anomalies that would have precluded normal operations. Flight control continuity was confirmed throughout. All fuel caps were loose in their filler necks, but the cap seals were pliable and undamaged. No fuel was present in any of the fuel bladders. A small amount of uncontaminated fuel was drained from the fuel strainers. The strainer bowls were removed and showed no anomalies. The fuel selector valve hands were undamaged, moved freely by hand, and exhibited normal detents. The auxiliary pumps would not operate when the switch was in the ON position. The airplane structure near the pumps showed extensive damage, preventing examination of the pumps.
Engine and Propeller Findings
Both engines were examined and revealed no anomalies that would have precluded normal operations. All upper spark plugs were removed and exhibited normal wear. Cylinder rocker covers were removed, and the valves were lubricated with a light brown oil. The crankshaft was rotated by hand on both engines, with thumb compression obtained on all cylinders and proper valve movement. Spark was obtained from each ignition lead.
The right engine propeller assembly was found in the feathered position, with the spinner showing impact damage on one side. One blade was bent about midspan with multidirectional scuffing near its leading edge; the other blade had damage consistent with recovery. The left engine propeller assembly was found in the low pitch position. One blade was bent aft near the shank with scuff marks on its cambered side near the leading edge; the other blade was unremarkable.
Fuel Estimation
Estimated fuel calculations were performed assuming full tanks. The flight duration was approximately 4 hours and 31 minutes. According to the Piper Twin Comanche Owner’s Handbook, the airplane's usable fuel capacity is 84 gallons, and at 75% power it would consume about 77.4 gallons. The calculations did not account for variables such as engine leaning, wind, climb, or descent.