Beech A23-24 N6945Q accident near Oklahoma City, Oklahoma

Probable cause

A total loss of engine power due to multiple connecting rod failures from oil starvation associated with an extensive before takeoff oil system leak, the source of which could not be identified due to postaccident fire damage.

NTSB analysis

The pilot and his passenger were conducting a personal flight when, about 1.5 minutes after takeoff, the airplane entered a left turn back toward the airport. The pilot told the tower controller that he was returning to land because the engine was losing power and subsequently declared an emergency. During the pilot’s transmissions, the engine was heard in the background running roughly. The tower controller cleared the pilot to land on any runway and issued the current surface wind condition. Witnesses reported that the engine was running roughly and there was smoke trailing from the airplane. The airplane impacted a concrete rubble pile at a concrete recycling facility about 0.4 nautical mile (nm) from the runway threshold. An extensive postimpact fire thermally damaged most of the airplane.

Postaccident examination of the pilot’s hangar revealed evidence of non-recent minor oil leaks often seen on hangar floors, and there was no evidence of an oil leak between the hangar and the asphalt taxiway. However, evidence of a significant oil leak and puddling was observed on the taxiway where the pilot likely started the airplane engine. The oil leak was consistent with the airplane being stationary for an extended period with the engine running. The nose landing gear subsequently deposited an easily discernible, dark black, oily tire track as the airplane began its taxi toward the runup pad and the runway.

Additional evidence of a significant oil leak and puddling was observed on the runup pad where the pilot likely completed his before takeoff engine runup checks. Finally, evidence of an oil leak was observed where the airplane came to stop before the hold short lines for the departure runway. Based on the available evidence, the engine oil system likely began leaking shortly after the engine was started and continued during the taxi, before engine runup, takeoff, and climb portions of the flight. The pilot was likely unaware of the significant engine oil system leak before takeoff.

Postaccident examination of the engine revealed evidence of multiple connecting rod separations due to a lack of oil lubrication. However, the extensive thermal damage to the engine and its oil system components precluded determination of the source of the oil leak.

FAA toxicological testing of postmortem samples taken during the pilot’s autopsy detected multiple impairing substances. However, these impairing substances likely were administered during the pilot’s postaccident medical care and therefore did not cause any impairment at the time of the accident. Additionally, toxicological testing conducted on a hospital blood draw obtained from the pilot about 37 minutes after the accident did not detect any tested-for substances, which included ethanol, opiates, fentanyl, and benzodiazepines.

Text from the NTSB. Open the NTSB docket for CEN24FA057 for the full record.