Engine failure and water ditching of aircraft

No fatalities • Marathon, United States of America • Takeoff (climb)

An aircraft experienced a total loss of engine power shortly after takeoff, necessitating an emergency ditching in open water.

What happened

Following takeoff, the aircraft experienced a complete loss of power from its engine. Due to the loss of propulsion, the pilot was forced to perform an emergency ditching in open water. All occupants were able to exit the aircraft after the impact and were later recovered by a nearby recreational boat.

Findings

An inspection of the engine identified a fracture hole located near the number two cylinder. Investigators determined that the number two cylinder connecting rod had suffered a fatigue fracture. This failure was attributed to high levels of stress and heat, which were triggered by the failure of the number two bearing.

Analysis of the fatigue fracture showed multiple points of origin, which is characteristic of high cyclic stress. This condition likely arose because excessive clearances had formed between the bearing and the crankshaft journal. The investigation noted that the failure of the bearing could have been caused by either a material defect within the bearing or a disruption in the lubrication oil supply to the bearing and journal interface. Both potential scenarios would result in the observed damage patterns, specifically the excessive heating that led to the ultimate mechanical failure.

Probable cause

The engine failure was caused by a fatigue fracture of the number two cylinder connecting rod resulting from bearing failure.

Frequently asked questions

What happened in the 2021-12-29 Cessna 207 Skywagon/Stationair accident near Marathon, United States of America?

An aircraft experienced a total loss of engine power shortly after takeoff, necessitating an emergency ditching in open water.

Were there any fatalities in the 2021-12-29 Cessna 207 Skywagon/Stationair accident?

No fatalities were recorded in this accident.

What aircraft was involved and where did it happen?

The accident on 2021-12-29 involved a Cessna 207 Skywagon/Stationair, registration N1596U, operated by ExecAir of Naples, at Marathon, United States of America.

What was the probable cause of the accident?

The engine failure was caused by a fatigue fracture of the number two cylinder connecting rod resulting from bearing failure.

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