Piper PA23 N14181 accident near San Juan, Puerto Rico

Probable cause

The pilot’s intentional operation of the airplane with known deficiencies of the left engine and subsequent in-flight loss of control after takeoff. Contributing to the loss of engine power was internal contamination of the left servo fuel injector. Contributing to the loss of control was the pilot’s intentional operation below the single engine rate of climb airspeed, and his failure to feather the left propeller.

NTSB analysis

The pilot-rated passenger reported that before takeoff, the pilot performed an engine run-up with no discrepancies noted. During takeoff, when full power was applied, the airplane yawed abruptly to the left and the left engine was not producing full power. The pilot elected to continue the takeoff and immediately applied right rudder, right aileron and back pressure, similar to a crosswind soft field takeoff. The airplane climbed about 100 ft-per-minute at an indicated airspeed below the published single engine rate of climb airspeed. When the pilot reached to retract the hydraulically controlled landing gear, it failed to retract. The airplane then rolled left and impacted the water adjacent to the airport in an inverted nose-low attitude.

The pilot-rated passenger, who was also a mechanic, stated that during a previous takeoff attempt, the pilot aborted the takeoff when the airplane yawed left after takeoff power was applied. While taxiing off the runway, the left engine quit. The pilot restarted the engine and taxied to the ramp. Following a visual inspection that revealed the left strut extension was more than the right, the pilot decided to attempt the takeoff again; it was during this subsequent takeoff that the accident occurred.

Postaccident examination of the flight controls, right engine and its systems, and the left engine powertrain, fuel supply, and ignition systems revealed no evidence of preimpact failure or malfunction. A missing nylon throttle stop of the left servo fuel injector (fuel servo) was the likely reason why the left engine quit at idle, and internal contamination of it resulted in a decreased fuel flow of about 31% of the minimum required value at full throttle and full rich mixture. Once the contamination was removed the left fuel servo flowed within limits at full throttle and full rich mixture; the contaminant was not analyzed.

Text from the NTSB. Open the NTSB docket for ERA20LA202 for the full record.