WPR18FA119

The flight instructor's failure to maintain airplane control during the initial climb as a result of the airplane being loaded above its maximum gross weight and beyond its aft center of gravity limits. Contributing to the accident was a degraded engine power output due to a preexisting engine cylinder intake valve spring failure, which further reduced the airplane's climb capability.

The airline transport pilot, student pilot, and four passengers departed on a cross-country fight with the airline transport pilot occupying the front right seat, the student pilot occupying the front left seat, and the four passengers occupying the two middle row and two aft row seats. Even though the student pilot was seated in the left seat, the investigation could not determine who was manipulating the flight controls when the accident occurred. Witnesses and airport surveillance camera video indicated that the airplane's wings were rocking during the departure and shortly after rotation. The controller asked if the airplane was experiencing any difficulties; according to the controller, the pilot responded, "we're good. We're just in training mode." One witness reported that the engine sounded as if it was not developing enough power. The last recorded radar data point indicated that the airplane's altitude was about 200 ft above ground level. A traffic camera, located about 0.5-mile northwest of the end of the runway, showed the airplane in a left bank turning left. As the turn progressed, the bank angle increased, and the airplane started to descend. The airplane's wings were nearly vertical before the airplane impacted terrain. A postcrash fire ensued.  Evidence indicated that, at the time of departure, the airplane was 135 pounds over its maximum gross weight and was loaded 2.22 inches beyond its aft center of gravity (CG) limit. The CG is an important factor in flight performance. If the CG is too far aft, the airplane could rotate prematurely on takeoff, and longitudinal stability could be reduced. It is likely that during the initial climb, the pilot was unable to maintain airspeed which resulted in a loss of control. Postaccident examination of the engine revealed that the No. 3 cylinder intake outer valve spring was broken. The fracture surfaces had signatures consistent with fatigue growth before failure. The surface damage observed on the springs indicated that the failure had likely occurred at some point before the accident and had gone undetected. It is likely that the failure reduced the available engine power that, although not detectable during previous flights, was more critical with the overloaded condition of the accident flight. No other preimpact anomalies were noted that would have precluded normal operation of the engine and airframe. The inactive cocaine metabolite benzoylecgonine was found in the student pilot's blood specimens at fairly low or nondetectable concentrations and without any detection of cocaine, which indicated past and not immediate cocaine use. Although the timing of the student pilot's cocaine use could not be determined, cocaine has a very short half-life, so, unless the student pilot was a chronic user, this drug would have a negligible effect after 6 hours. Similarly, the detection of methylenedioxymethamphetamine (ecstasy) in the student pilot's urine but not blood specimens indicated past and not immediate use of this drug. Thus, the student pilot's cocaine and ecstasy use were not a factor in this accident.

HISTORY OF FLIGHT On April 9, 2018, about 2048 mountain standard time, a Piper PA-24-260 airplane, N9456P, was destroyed when it impacted terrain shortly after takeoff from Scottsdale Airport (SDL), Scottsdale, Arizona. The airline transport pilot, the student pilot, and four passengers were fatally injured. The airplane was registered to N9456P LLC and was operated by the pilots as a Title 14 Code of Federal Regulations Part 91 personal flight. Nighttime visual meteorological conditions prevailed, and no flight plan was filed for the cross-country flight, which was destined for North Las Vegas Airport (VGT), Las Vegas, Nevada. Earlier that evening, the airline transport pilot flew the airplane from VGT to SDL to pick up the student pilot and the passengers and fly them to VGT. The inbound flight, which was the airline transport pilot's first flight in the airplane, departed from VGT at 1842 mst and landed at SDL at 2018. A video surveillance camera at SDL located on the ramp where the airplane was parked captured the occupants as they began to board the airplane about 2028. The surveillance video, along with photographs and videos posted to social media by one of the occupants, revealed that the student pilot occupied the front left seat and that the airline transport pilot occupied the front right seat. A video surveillance camera located midfield on the west side of the runway captured the airplane's departure from runway 03. The video showed that the airplane's wings were rocking during and shortly after rotation. The tower controller reported that, as the airplane began the departure roll, the lights on the wings were alternating up and down as if the pilot was rocking the wings. The controller also reported that, as the airplane passed the tower, the wings appeared to be stable but that the engine sounded as if it was not producing enough power. At that time, the controller asked the pilot if the airplane was experiencing any difficulty. According to the controller, the pilot responded, "we're good. We're just in training mode." The controller observed the airplane continue straight out but noted that it did not appear to be climbing. Over the departure end of the runway, the airplane made a left turn. A review of radar data revealed that the airplane's last depicted altitude, between 2046:18 and 2046:28, was about 200 ft above ground level, which occurred during the left turn. As the airplane continued in the left turn, the controller observed the airplane enter a nose-down attitude. A traffic camera located about 0.5-mile northwest of the end of the departure runway recorded the airplane in a left bank. The bank angle continued to increase as the airplane descended, and its wings were nearly vertical. The camera then depicted the airplane's impact with terrain and a fireball. Video captured by the traffic camera and the airport tower camera were used to estimate the trajectory and speed of the airplane. The airplane's ground speed was estimated at 75 ± 4 knots shortly after takeoff, and its climb rate was 270 ft per minute (fpm). Twelve seconds later, as the airplane entered the left turn near the end of the runway, its ground speed decayed to 50 ± 4 knots. The airplane began to descend and impacted the ground several seconds later. The airplane was airborne for about 70 seconds. A witness located near the departure end of the runway was listening to the tower frequency and overheard the controller asking the pilot if the airplane was experiencing any difficulties. The witness looked down the runway and observed the airplane proceeding toward him. As the airplane flew by, the witness noted that the airplane appeared to drift toward the west side of the runway safety area while at low altitude and that the engine sounded as if it was not developing full power. The witness stated that the airplane, before reaching the end of the runway, started "an early left crosswind turn." The witness also stated that the airplane continued in the turn and started to descend just before disappearing from sight behind buildings and trees. Seconds later, the witness heard an explosion and saw a plume of smoke and fire. Another witness located on the ramp observed the boarding process and watched the airplane taxi toward the runway. The witness lost sight of the airplane but was able to hear what sounded like a typical preflight engine run-up. The witness then observed the airplane accelerate down the runway and stated that, about midway, the wings began to roll in an "extreme" motion. The witness reported that the oscillations eventually diminished, and that the airplane began to climb, reaching an altitude that was about level with the top of the adjacent airport buildings. The airplane continued at an altitude that was about the same altitude and then began a climbing left turn, which appeared similar but lower than most aircraft departing the traffic pattern. As the turn progressed, the airplane's attitude changed to pitch down, and the airplane disappeared from sight. A fireball ensued. The witness did not hear any unusual sounds or see the airplane emitting smoke, fire, or vapors, and she stated that the engine sounded similar to the airplanes that she observes. PERSONNEL INFORMATION The pilot held an airline transport pilot certificate with airplane single-engine land and multiengine land ratings. He also held a flight instructor certificate with ratings for airplane single engine, airplane multiengine, and instrument airplane. On February 7, 2018, the pilot received a special issuance first-class medical certificate with the following limitation: "Not valid for any class after 08/31/2018." At the time of his most recent medical application, the pilot reported that he had 5,200 hours of total flight experience, 500 hours of which were in the previous 6 months. The pilot's employer reported that, from August 24, 2017 (his start date with the company), to April 8, 2018 (the day before the accident), the pilot had accumulated 161 hours of flight time, 69 hours of which were in 2018. The pilot had accumulated about 2 hours of flight time in the accident airplane. The student pilot had been receiving lessons from another flight instructor. He did not possess a student pilot or airman medical certificate. The student pilot's total flight experience could not be determined. AIRCRAFT INFORMATION The single-engine, retractable gear airplane was manufactured in 1970 and was powered by a 260-horsepower, 6-cylinder, fuel-injected Lycoming IO-540-N1A5 engine and a two-blade constant-speed Hartzell propeller. The airplane was equipped with six seats. The last entry in the airframe logbook indicated that the airplane received an annual inspection on December 1, 2017, at a total airframe time of 6,158 hours. According to a logbook entry dated August 1, 1973, the airplane's empty weight was 2,007 pounds, the useful load was 1,193 pounds, and the empty weight center of gravity (CG) was 87.22 inches. No additional weight and balance data were located. The airplane flight manual listed a maximum allowable gross weight of 3,200 pounds and a CG range between 80.5 and 93.0 inches aft of datum. The last obtained fuel receipt was dated April 3, 2018, from VGT. A search of commercially available flight software indicated that the flight from VGT to SDL on the day of the accident was the first flight after the last refueling. The combined weight of the pilot and the student pilot was about 375 pounds, the combined weight of the two passengers (a male and female) located in the middle row was about 320 pounds, and the combined weight of the two passengers (both female) in the aft row was about 252 pounds. All of the estimated weights included 15 pounds of carry-on baggage per person. An estimated fuel load of 63.44 gallons was calculated based on the maximum usable fuel (86 gallons) subtracted by the fuel burned during