Gainesville, TX, USA
N456AG
Piper PA34
The flight instructor and pilot receiving instruction were conducting a training flight in the multi-engine airplane, which included several takeoffs and landings. Flight track data indicated that, just before the accident, the airplane was on a 1/2-mile final approach for landing about 250 ft above ground level. The airplane subsequently impacted the ground about 1,500 ft left of the approach end of the runway in a left-wing low attitude. A post-impact fire ensued. Examination of the left engine propeller showed indications of low or no power; the right engine propeller displayed evidence of moderate or higher power at the time of impact. The left engine No. 2 cylinder fuel injector nozzle was plugged with an unknown substance. Fire damage precluded further determination of mechanical factors related to the asymmetric engine power at the time of impact. The accident airplane’s engines had been recently replaced and since replacement, both engines had experienced loss of power events during ground operations. Maintenance actions included adjusting the fuel mixture idle setting and a ground test run, during which the problem could not be duplicated. A witness stated that, immediately before departing on the accident flight, the airplane’s left engine lost power and was restarted. Several flight instructors voiced concerns with the company’s inadequate maintenance practices and stated that there were self-induced pressures to complete training flights. Review of the pilot’s training records indicated difficulty with maintaining airplane control during simulated one engine inoperative flight, and deficient language skills that resulted in a previous event during which another flight instructor experienced difficulty taking control of the airplane from the pilot. Evidence at the accident site was consistent with asymmetric engine power at the time of the accident, but whether there was an actual loss of left engine power or if the approach was being conducted with a simulated loss of left engine power could not be determined. The position of the wreckage left of the runway and the airplane’s impact in a left-wing-low attitude is consistent with a loss of control due to a failure to maintain minimum control airspeed (Vmc) during the landing approach.
HISTORY OF FLIGHTOn July 28, 2019, about 1609 central daylight time, a Piper PA-34, N456AG, was destroyed when it was involved in an accident near Gainesville, Texas. The flight instructor and pilot receiving instruction were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. According to Automatic Dependent Surveillance-Broadcast (ADS-B) flight tracking data, the airplane departed Denton Enterprise Airport (DTO), Denton, Texas, at 1440, flew two visual approaches at DTO, then climbed to the northwest and maneuvered between 4,000 and 5,000 ft mean sea level (msl). The airplane then descended toward GLE from the west, then entered a left downwind to Runway 18, and completed several takeoffs and landings. (See Figure 1.) Figure 1. ADS-B Flight Track of Airplane The last recorded ADS-B data showed the airplane about 3,200 ft north of the Runway 18 threshold at 75 knots ground speed and about 250 ft above ground level. The airplane subsequently impacted the ground about 1,500 ft left of Runway 18. (See Figure 2.) A post impact fire ensued. Figure 2. Aerial View of Accident Site and Runway 18 PERSONNEL INFORMATIONThe pilot receiving instruction failed the training company’s Stage 1 flight check for his commercial rating two times before the accident flight. According to company records, the pilot struggled with basic aircraft control and had a lack of situational awareness. During both flight checks, the pilot did not maintain positive control of the airplane during simulated engine failures in the traffic pattern. English was not the pilot’s native language, and according to a flight instructor, the pilot was not a proficient English speaker. Another flight instructor reported that, during a flight, the pilot continued to apply pressure on the rudder pedals after he had verbally been directed to relinquish the flight controls. A forceful command from the flight instructor was required to correct the pilot’s deficient transfer of control. The company submitted a request to the pilot’s sponsoring airline for 5 additional hours of training to address deficiencies; however, according to the company director of training, the submission of the request was delayed because it “fell between the cracks.” The pilot did not fly for about five weeks. During that time, he practiced solo in an aviation training device (ATD) 26 times between June 14 and July 24, 2019, as well as once each on July 26 and 27, 2019. The pilot’s last flight occurred on July 25, 2019, with the accident flight instructor. Company training records for this flight indicated that the pilot required constant reminders to maintain heading during all maneuvers, especially engine-out maneuvers. The flight instructor was hired by the company on November 29, 2018, and completed an instructor proficiency check for the PA-34-200 on March 1, 2019. According to the company chief pilot, the flight instructor completed a proficiency check to be a company check airman in single-engine airplanes. AIRCRAFT INFORMATIONThe airplane’s engines were both replaced on July 12, 2019, with overhauled engines due to a propeller strike incident. At the time of the accident, each engine had accumulated about 22 hours of flight time. On July 24, 2019, an instructor reported a power loss on the right engine during taxi. The instructor restarted the right engine and pulled the throttle to idle, which resulted in a second power loss. Maintenance arrived at the airplane and adjusted the right engine to a higher idle speed. Due to training time constraints, the instructor aborted the planned flight. After the aborted flight, another instructor flew the airplane on July 24, 2019, and observed the left engine sputter and lose power about 2 to 3 seconds after landing at GLE. The instructor restarted the left engine on the fourth attempt and flew back to DTO uneventfully, then informed company dispatch of the power loss. A mechanic stated that an engine run was conducted from idle to full power, including rapid throttle movements. No engine hesitations or other anomalies occurred, and the airplane was returned to service. On July 25, 2019, the accident flight instructor flew the airplane and reported “after landing left engine lost power on the runway after idling…able to restart it on the taxiway.” As a corrective action, a mechanic increased the left engine idle power setting. This maintenance action was not recorded in the engine maintenance log. During engine runup at DTO immediately before the accident flight, a witness heard an abnormal noise similar to a rough running engine. The witness subsequently noticed the left engine was shut down and then restarted. The airplane departed DTO and flew two visual approaches, during which the witness did not hear any abnormal noises. AIRPORT INFORMATIONThe airplane’s engines were both replaced on July 12, 2019, with overhauled engines due to a propeller strike incident. At the time of the accident, each engine had accumulated about 22 hours of flight time. On July 24, 2019, an instructor reported a power loss on the right engine during taxi. The instructor restarted the right engine and pulled the throttle to idle, which resulted in a second power loss. Maintenance arrived at the airplane and adjusted the right engine to a higher idle speed. Due to training time constraints, the instructor aborted the planned flight. After the aborted flight, another instructor flew the airplane on July 24, 2019, and observed the left engine sputter and lose power about 2 to 3 seconds after landing at GLE. The instructor restarted the left engine on the fourth attempt and flew back to DTO uneventfully, then informed company dispatch of the power loss. A mechanic stated that an engine run was conducted from idle to full power, including rapid throttle movements. No engine hesitations or other anomalies occurred, and the airplane was returned to service. On July 25, 2019, the accident flight instructor flew the airplane and reported “after landing left engine lost power on the runway after idling…able to restart it on the taxiway.” As a corrective action, a mechanic increased the left engine idle power setting. This maintenance action was not recorded in the engine maintenance log. During engine runup at DTO immediately before the accident flight, a witness heard an abnormal noise similar to a rough running engine. The witness subsequently noticed the left engine was shut down and then restarted. The airplane departed DTO and flew two visual approaches, during which the witness did not hear any abnormal noises. WRECKAGE AND IMPACT INFORMATIONThe airplane impacted a mowed field in a left-wing low attitude; the debris path was oriented to the northeast. The fuselage was consumed by fire from the forward bulkhead to the aft tail cone. Figure 3. Airplane at Accident Site Flight control cable continuity was established from the cockpit to each of the control surfaces. The main landing gear was in the retracted position and the flap position could not be determined. Cockpit switches and fuel selector levers had no usable information due to fire damage. The left and right wing fuel selector valves were in the on position. The stabilator trim jackscrew position corresponded to a partial nose-up stabilator trim setting and the rudder trim jackscrew position corresponded to a partial right rudder trim tab deflection. The left and right engine propellers remained attached to their respective crankshaft propeller flanges. The left propeller blades were at a low pitch setting, with no scoring on the blade faces. The right propeller blades were at an intermediate pitch setting, with leading edge polishing and chordwise scoring on the blade faces. Crankshaft, camshaft, and valve train continuity was confirmed for both engines. Both engine ignition harnesses and magnetos were significantly fire damaged. The fuel inlet screens of both engines were free of debris. The left engine No. 2 cylinder fuel injector nozzle was plugged with an unknown substance. The remaining left engine fuel injector nozzles, as well as all of the right engine fuel injector nozzles, were clear and free of debris. ADDITIONAL INFORMATIONMinimum control speed (Vmc) is the calibrated airspeed at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the airplane with that engine inoperative. Vmc for the accident airplane was 80 miles per hour (mph), and company guidance directed a minimum of 105 mph during an engine-out visual approach. MEDICAL AND PATHOLOGICAL INFORMATIONToxicology tests performed on the flight instructor were positive for medications used in the resuscitative efforts after the accident including ketamine, norketamine, midazolam, lorazepam, morphine, fentanyl, norfentanyl, and etomidate. Toxicology tests performed on the pilot receiving instruction were positive for carboxyhemoglobin which is consistent with a post-accident fire. ORGANIZATIONAL AND MANAGEMENT INFORMATIONMost flight instructors stated that there was no pressure from the company to take a flight, but there was pressure for students to complete training within the hours allotted for the curriculum. Some student pilots felt pressure to fly and thought the flight instructors felt pressure to fly an unsafe aircraft. Several flight instructors commented that the school was short on airplanes and multi-engine flight instructors. The company director of training stated that “there obviously is pressure…to give the student training” and that flight instructors might also feel pressure when there are only a few aircraft available. He viewed those pressures as internal to the flight instructors, noting that in addition to wanting to obtain training for their students, flight instructors could feel pressure to fly because pay was based on flight hours and also wanting to log the flight hours.
The pilots’ failure to maintain airspeed while on final approach with asymmetric engine power, which resulted in a loss of control.
Source: NTSB Aviation Accident Database
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