Mooney M20R N13LV accident near Southport, North Carolina

Probable cause

The pilot’s improper decision to fly a known unairworthy airplane, which resulted in a total loss of engine power due to oil starvation.

NTSB analysis

The pilot was picking up his airplane following unfinished maintenance. Witnesses reported excessive white exhaust smoke and oil leaking from the airplane onto the ground as the pilot taxied it from the mechanic’s hangar to the runway for takeoff. Shortly after takeoff, the pilot reported an engine failure on the common traffic advisory frequency and that he was returning to the runway; however, the airplane impacted a residential area about 1/2-mile before the runway threshold and a postimpact fire ensued.

The airplane had been in for maintenance for 8 months. The private pilot/owner had requested that the mechanic troubleshoot interior lighting, service the brakes, attach a standby vacuum hose, and repair an exhaust leak. The mechanic could not complete the work as he could not start and run up the engine due to dead batteries. When he inspected the batteries, he realized that they were unairworthy. Specifically, the airplane was designed with a 24-volt electrical system that utilized two 24-volt batteries; however, the mechanic found four 12-volt batteries installed. When the mechanic contacted the pilot about the discrepancy, the pilot instructed him to reinstall the four 12-volt batteries. The mechanic refused, as it would have been an unapproved and unairworthy installation. The pilot then stated that he wanted his airplane back. The mechanic told him that the airplane was unairworthy, as he had not completed repairs on it; he also noted that it was unairworthy on the invoice.

The wreckage came to rest on its right side and oil streaks were noted on the underside of the empennage. The engine came to rest inverted, and the propeller remained attached to the engine. An oil sump accessory port plug was observed loose, with oily blue stained baffling material resting below it. Additionally, the No. 4 connecting rod had protruded through the top of the engine case. A check of the oil dipstick revealed no measurable oil in the engine. The engine likely failed due to oil starvation as the oil leaked from a loose oil sump accessory port plug as a result of uncompleted maintenance work.

Text from the NTSB. Open the NTSB docket for ERA23FA273 for the full record.