Piper PA23 — San Juan, PR, 2020

Piper PA23 — San Juan, PR

2 fatal High-time pilot

Date	June 2, 2020
Location	San Juan, PR
Aircraft	Piper PA23
Purpose of flight	Flight Test
Conditions	Day · Visual Meteorological Cond
Phase / occurrence	Initial climb Miscellaneous/other
Pilot age	51
Pilot total time	9,504 hrs · High time
Time in type	Unknown
Fatalities	2, 1 serious

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 findings

Aircraft-Aircraft power plant-Engine fuel and control-Fuel control/carburetor-Damaged/degraded
Personnel issues-Action/decision-Info processing/decision-Decision making/judgment-Pilot
Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Engine out control-Not attained/maintained
Personnel issues-Task performance-Use of equip/info-Use of equip/system-Pilot
Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Airspeed-Not attained/maintained
Aircraft-Aircraft systems-Landing gear system-Main landing gear-Incorrect use/operation
Aircraft-Aircraft propeller/rotor-Propeller system-Propeller feather/reversing-Not used/operated

What happened

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.

An editorial "what led to it / how to avoid it" analysis for this accident is generated separately and will appear here.