ERA23FA340

The left seat instructor’s intentional maneuvering of the airplane in an aerobatic steep turn for which it was not approved, which resulted in an exceedance of the structural limitations of the airplane and an inflight breakup.

Two flight instructors were taking part in a flight school proficiency check. The instructor seated in the left seat was employed by the flight school and was administering the check to the newly-hired instructor in the right seat. The left seat instructor stated that he was demonstrating an EASA [European Union Aviation Safety Agency] maneuver at the time of the accident. He described that the maneuver involved a power-off aerodynamic stall and recovery without the use of engine power. The left seat instructor described that he pitched the airplane up and entered a full aerodynamic stall with the engine power at idle. After the airplane stalled, he recalled pitching to a glide airspeed of 73 knots to recover from the stall. He stated that during the recovery, with power at idle, the right wing departed the airplane, and the airplane banked abruptly to the right. The airplane then descended and impacted a small building that housed a recreational vehicle (RV). Both wings and the horizontal stabilator separated from the airplane in flight and were located about 600 to 700 ft away from the fuselage. A performance study using ADS-B data and a forensic metallurgical examination of the fractured wing surfaces were conducted following the accident. The performance study found that the airplane made four steep turns in the final few minutes of recorded data before the inflight breakup. The final two 180° turns observed in the flight track data had a significantly smaller turn radius compared to previous maneuvers. The second to last steep turn had a radius of 280 ft and the airplane accelerated to over 100 knots airspeed while still in the turn, resulting in a calculated bank angle of over 70° left wing down. The final turn started with a radius of 200 ft that tightened as the airplane accelerated. With the airplane’s true airspeed at 99 knots, for a 200-ft turn radius, the resulting bank angle was over 75° left wing down. These calculated bank angles, and thus the calculation of any resulting load factors, derived from ADS-B data were approximate values that were dependent upon the accuracy of the recorded GPS data. The Federal Aviation Administration (FAA) Airplane Flying Handbook stated in part that steep turn maneuvers consisted of single to multiple 360° and 720° turns, in either or both directions, using a bank angle between 45° and 60°. The chapter specifically provided guidance pertaining to the dangers of exceeding those bank angles and the structural limitations of general aviation airplanes. The forensic metallurgical examination found that the left and right main spars fractured in ductile overstress following wing loads that exceeded the design capability of the airplane. The right wing likely fractured first, and the local deformation associated with the spar fracture was consistent with the upward loading on the wing. The left wing failure was secondary, showing local downward deformation at the fracture location. The left wing failure likely occurred due to a sudden elastic relaxation of the overloaded left wing in response to the rapid load change from the right wing failure, combined with downward air loads on the left wing associated with a subsequent roll to the right from the loss of lift on the right side of the airplane. Further metallurgical examination of both the right and left wing main spar lower caps found that fatigue cracks initiated in areas of fretting damage. The cracks were not yet large enough to impact the strength of the spar under the accident loading conditions since none of the fractures initiated at or intersected any fatigue cracks. Therefore, although fatigue cracks were present, they did not contribute to the in-flight breakup. The uniform deformation and upward bending on both sides of the spar box was indicative of a steep turn maneuver that grossly exceeded the structural limitations of the airplane. The airplane was operating in the normal category at the time of the accident. The airplane’s pilot operating handbook prohibited aerobatic maneuvers, which included turns beyond 60° of bank, and included a load limit of 3.8g while operating in the normal category. The airplane was operated by a large flight school. The “EASA” maneuver the left seat flight instructor stated that he was demonstrating was not a part of the operator’s Instructor Briefing Sheet Test for the proficiency check being administered. In summary, the analysis of the airplane’s flight path based on the recorded data and the postaccident metallurgical examination findings were indicative of the pilots performing a series of increasingly aggressive, aerobatic steep turns, which ultimately exceeded the design capability of the airplane, resulting in its inflight breakup. The surviving instructor reported that he was flying the airplane at the time of the inflight breakup, but his recollection of the last moments of flight and the maneuver being demonstrated was not consistent with the steep turns identified in the ADS-B performance study. The flight school did not have a safety management system (SMS) or a flight data monitoring (FDM) program, nor were they required to have such programs. The operator did have an Aviation Safety Action Program (ASAP). A review of the ASAP database by the operator found no relevant reports involving the accident pilots or accident airplane. If the flight school had a flight data monitoring program (FDM) and safety management system (SMS), they could have had additional methods of identifying and monitoring flight data for exceedances of normal flight envelope parameters. Without SMS or FDM, flight schools have limited tools to assure that standard operating procedures are being followed.

Flight 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). Airplane 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 maneuvers within certain categories. The left seat instructor, who was administering the evaluation, reported that the other instructor had demonstrated chandelles, lazy eights, slow flight, and aerodynamic stalls satisfactorily. The left seat instructor described that at the time of the accident he was demonstrating the “EASA” maneuver, as described in the history of flight section above. This maneuver was not a part of the operator’s formal training program. The Operator’s Flight Operations Manual, Performance Maneuvers The operator’s PA28-161, Flight Operations Manual (FOM), provided detailed guidance on the performance of Steep Turns. The manual stated in part: DEFINITION(S) The steep turn maneuver consists of two consecutive 360° turns in either direction (usually first to the left and then to the right), using a bank angle between 45 to 60° (45° bank angle at the Private Pilot level and 50° at the Commercial Pilot level). This will cause an overbanking tendency during which maximum turning performance is attained and relatively high load factors are imposed. According to the autopsy report issued by the Florida Medical Examiner Department – District 19, the cause of death for the right seat instructor was blunt impact injuries of the head, torso, and extremities, and the manner of death was an accident. Toxicology testing performed by the FAA’s Forensic Sciences Laboratory was negative for ethanol and positive for acetaminophen and salicylic acid in both blood and urine samples for the right seat instructor. The left seat instructor was not drug tested following the accident. On 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,