Cessna T337G N8594M accident near Homestead, Florida

Probable cause

The reported partial loss of engine power from the rear engine for reasons that could not be determined because postaccident examination of the engine did not reveal any anomalies that would have precluded normal operation.

NTSB analysis

The airplane was fueled before departure, and after fueling, the pilot reported that he checked the fuel tanks and fuel strainers and no contaminants were found. The facility that fueled the airplane reported no complaints or discrepancies related to the quality of fuel. The pilot departed and flew south along the coast at 900 feet above ground level when the rear engine suddenly lost power. The pilot was able to restart the rear engine, which regained only partial power, but not before losing 500 feet of altitude. Because of the low altitude, he did not want to troubleshoot the rear engine any further and opted to ditch the airplane with the landing gear extended. After touchdown, the airplane nosed over and all occupants exited the airplane and were rescued. The pilot further reported there was no issue related to the front engine.

Following recovery of the airplane, rear engine spark plugs tested satisfactorily. An alternate fuel supply was plumbed into the right wing root, and, after water and contaminants were removed from the internal portion of the rear engine, it was started but found to be only operating on the left magneto. The right magneto was replaced, and the engine was restarted and operated satisfactorily. A feather check of the rear propeller was performed during the engine run and no issues were noted.

The right magneto likely did not operate during the postaccident engine run because of internal moisture and corrosion due to salt water submersion. After cleaning the magneto, only the condenser tested outside its limits, most likely due to internal moisture. The magneto was placed on a test bench and it operated normally.

Postaccident testing of the rear engine did not reveal the reason for the reported loss of power.

Text from the NTSB. Open the NTSB docket for ERA13LA143 for the full record.