N9855S

HISTORY OF FLIGHTOn August 17, 2023, about 1202 eastern daylight time, a Piper PA28-161 airplane, N9855S, was destroyed when it was involved in an accident near Fort Pierce, Florida. One flight instructor was fatally injured and the other flight instructor sustained serious injuries. The airplane was operated by Aviator College under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91 as an instructional flight.

According to the flight instructor seated in the left seat, the purpose of the flight was to conduct a Title 14 CFR Part 141 proficiency check in order for the flight instructor seated in the right seat to begin instructing for the flight school. The pilots departed from Treasure Coast International Airport (FPR), Fort Pierce, Florida, and proceeded about 10 miles southwest to perform a variety of training maneuvers.

The left seat instructor administering the evaluation reported that the right seat instructor satisfactorily demonstrated maneuvers including chandelles, lazy eights, and slow flight. Subsequently, the right seat instructor asked him, “Can you show me something new?”

The left seat instructor responded that given he was already an instructor, there were no new maneuvers, but added, “I can show you an EASA maneuver.” He described that the maneuver involved a power-off aerodynamic stall and recovery without the use of engine power. The left seat instructor took control of the airplane and initiated the demonstration; he pitched the airplane up and entered a full aerodynamic stall with the engine power at idle. He recalled that after the airplane stalled, he pitched the airplane to “Vg” (glide airspeed, 73 knots) to recover from the stall. He stated that during the recovery, with power at idle, “the right wing came off” and there was an “abrupt banking tendency” to the right.

He recalled that he retracted the flaps, and added rudder and aileron application, but his “eyes were getting blurry,” he was starting to see “white,” and the airplane was “losing altitude like crazy.” He also noticed that a lot of wind was entering the cockpit. Subsequently, his next memory was awaking in the hospital. He did not recall observing any other components depart the airplane.

Multiple witnesses located near the accident site reported a similar circumstance in which booms or bangs were heard with variable fast-changing low- and high-power revving engine noises. Subsequently, the witnesses viewed the airplane as it descended in a near-vertical spinning descent, with both wings separated from the fuselage and numerous additional pieces of debris falling from the sky. A mobile phone video showed one wing falling to the ground.

National Transportation Safety Board (NTSB) Performance Study

The NTSB Office of Research and Engineering performed an ADS-B data-based airplane performance study to evaluate the maneuvers and approximate airplane loads, airspeeds, and pitch/bank angles sustained during the flight. The ADS-B system broadcasts an airplane’s GPS position and other data to ground stations where it is recorded. The GPS position has an accuracy of approximately 65 ft in both the horizontal and vertical dimensions.

The study found that four steep turns were made in the final few minutes of recorded data. At 1201:30, the airplane entered a climbing left turn while slowing below 50 knots calibrated airspeed. The airplane descended 800 ft while accelerating to over 120 knots while completing a 180° left turn. This maneuver looked like earlier 180° turns; however, the minimum speed was lower than the earlier maneuvers and was below the reported stall speed.

The airplane then flew level and straight for about 30 seconds before entering a climbing left turn while losing airspeed. The airplane reached a minimum airspeed of 47 knots at 1202:36 and began descending at 1202:39. The airplane accelerated as it descended. By 1202:41, the airspeed was calculated to be 90 knots and the corrected altitude was 4,820 ft. Just after 1202:41, the descent rate suddenly increased to over 10,000 ft/min and a second later the track turned to the right, likely due to the in-flight breakup of the airplane. Figure 1 provides an overview of the final few minutes of track data and the 4 steep turns.

Figure 1. ADS-B flight path with four turns of interest notated.

The final two 180° turns observed in the flight track data were of a significantly small radius as compared to previous maneuvers. The turn at 1201:45 had an estimated radius of 280 ft and the airplane accelerated to over 100 knots true airspeed while still in the turn, resulting in a calculated bank angle of at least 70° left wing down.

The final turn started with a radius of 200 ft that tightened as the airplane accelerated. At 1202:41, the airplane’s true airspeed was 99 knots, which for a 200 ft turn would result in a bank angle of at least 75° left wing down.

The pilot reported that the right wing departed the airplane first, which would result in a right rolling moment as the left wing continued to provide lift for an undetermined short period of time. Figure 2 provides an overview of the final recorded turn, subsequent descent into the building, and wreckage disposition.

Figure 2. ADS-B flight path for final turn and the subsequent in-flight break up. Locations of select wreckage are also annotated. PERSONNEL INFORMATIONFlight Instructor (Left Seat)

The flight instructor seated in the left seat, who was administering the proficiency check, survived the accident with serious injuries. According to the operator, he was employed as a flight instructor with Aviator College.

Flight Instructor (Right Seat)

The flight instructor seated in the right seat, who was undergoing the proficiency check, was fatally injured. According to an operator Employee Hiring Form, his official start date with the operator as a flight instructor was August 8, 2023 (nine days before the accident). AIRCRAFT INFORMATIONAirplane Information

According to FAA airworthiness records, the airplane was a Piper PA28-161, serial number 2842151, manufactured in 2002. The airplane was certificated in the normal and utility category.

The Pilot’s Operating Handbook stated that all acrobatic maneuvers, including spins, were prohibited while operating in the normal category. Turns exceeding 60° were prohibited in the normal category. The flight load factor limitations in the normal category were 3.8 g and 4.4 g for the utility category.

The airplane’s weight and balance were calculated based upon an operator-supplied basic empty weight and crew weights contained in FAA-maintained airman medical records. The fuel load and consumption were estimated based upon information submitted by the operator and ADS-B flight track data. The airplane was found to be in the normal category and within maximum weight and balance limitations at the time of the accident.

Maintenance Information

The airplane’s wing spars were subject to FAA Airworthiness Directive (AD) 2020-26-16, Wing Spar Integrity, which mandated bolt hole eddy current inspection at the 2 outboard holes for attaching the main spar lower cap on each wing.

According to the airplane’s maintenance records, the most recent 100-hour inspection was competed on June 29, 2023. The endorsement noted that FAA AD 2020-26-16 was complied with, and the factored hours were 1,199.1. The endorsement noted that no further action was required until 5,000 factored hours. The airplane had flown 87.4 hours since the last 100-hour inspection. Accounting for this additional flight time, at the time of the accident, the airplane had accumulated 1,286.5 factored hours.

The most recent annual inspection was completed on September 16, 2022. The endorsement noted that FAA AD 2020-26-16 was complied with.

On March 22, 2021, the FAA AD 2020-26-16 eddy current inspection was completed and both wings, and forward and aft spars, were marked as accepted. At this inspection, the airplane was noted to have a total time in service of 15,572.9 hours. The factored service hours for both wings were 15,405.02. The inspection was completed by S.E.A.L. Aviation LLC. The endorsement noted that during the testing no defects were found. According to the maintenance records, new wing spar bolts and nuts were installed on March 22, 2021, in accordance with the AD and Piper Aircraft Service Bulletin 1345.

The Operator

The operator was Aviator College of Aeronautical Science and Technology, based in Fort Pierce, Florida. The flight school held a Part 141 certificate.

According to the operator’s Chief Flight Instructor, they did not have a Safety Management System (SMS) or a Flight Data Monitoring (FDM) program. The operator did have an Aviation Safety Action Program (ASAP).

The operator provided 3 ASAP reports that involved the accident airplane or flight crew; all were found to be related to compliance with air traffic control instructions.

Part 141 Flight Instructor Proficiency Check

According to documentation provided by the operator, several items were to be evaluated by the left seat instructor during the check being conducted. The check was required for the right seat instructor to begin training Aviator College students.

The lesson objective was stated as: ‘Part 141 requires all flight instructors to be qualified to teach each course of training to which they are assigned, and prescribes certain knowledge and proficiency tests to be accomplished prior to being assigned to an approved training course.’

The lesson completion standard was stated as: ‘The instructor must satisfactorily accomplish a one-time proficiency test in each M/M [make and model] of aircraft (Piper PA28-161) before giving any flight instruction in the particular aircraft. The flight instructor shall meet or exceed the Commercial Pilot Airplane ACS [Airman Certification Standards].’

The proficiency check required multiple maneuvers to be completed and the examiner had the discretion to choose a selection of maneuver...