History of Flight
On May 26, 2023, at 1118 eastern daylight time, a Cessna 172P, N3KV, was destroyed during an accident at Palm Beach County Park Airport (LNA), Lake Worth, Florida. The flight instructor and student pilot were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight.
According to airport security video, the airplane departed from runway 4, rotated and began to climb, descended, and then climbed again. The airplane then rolled right until it was in an approximate 90° right bank and continued in a right descending turn until it impacted the ground. A witness reported that the engine sounded like it was at full throttle throughout the flight.
Aircraft and Maintenance Information
The airplane was purchased on May 4, 2023, by the flight school owner. A prebuy inspection included opening panels to inspect attached connections of cables and checking free movement of flight controls. The airframe had accumulated 5,025.5 hours at the time of the accident. The most recent annual inspection was completed on September 19, 2022, at a tachometer time of 4,970.4 hours, during which the mechanic lubricated all flight control cables. No other remarks about flight control cables were recorded. The work was performed in accordance with the Cessna 172 service manual and Federal Aviation Regulations Part 43 Appendix D.
The previous owner provided an affidavit stating that the original maintenance logbooks were lost but would be forwarded if found. Manufacturer recommended inspections include checking aileron structure and cables at specified intervals, as well as inspecting for corrosion.
The service manual notes that corrosion on steel control cables should be checked during preventative maintenance. Corrosion on interior strands constitutes failure and requires cable replacement.
Wreckage and Impact Information
The airplane impacted the ground about 200 ft from runway 16/34. The debris path was oriented on a 006° heading, and the airplane came to rest about 140 ft from the initial impact point at an elevation of 16 ft mean sea level. All major components were located within the vicinity of the main wreckage.
The engine remained partially attached to the fuselage. Crankshaft and valvetrain continuity were confirmed, compression was present on all cylinders, and the magnetos produced spark. The carburetor and oil system showed no anomalies. The fixed-pitch propeller remained attached; one blade was bent forward at mid-span with chordwise scratching, and the other was twisted with similar scratching.
The cockpit was impact-crushed aft, with instruments separated from the panel. The empennage remained partially attached, and elevator and rudder control continuity was confirmed. The left wing was impact-separated, its outboard section crushed aft, and the wing tip separated. The right wing was also separated, with the outboard section bent and crushed aft.
Aileron control continuity was not confirmed. A separation was found in the aileron control system near the left upper door post right direct aileron cable pulley. The pulley showed corrosion and did not move freely. Another pulley on the right upper door post left direct aileron also exhibited corrosion and restricted movement. Several other breaks in the aileron system were consistent with tension overload failures.
Examination of the aileron control cables at the NTSB Materials Laboratory revealed uneven, localized thinning of wires, pockmarks consistent with corrosive attack, and woody appearance. Some wires showed cup-cone fractures from ductile overstress, while others had angled fractures.
Medical and Pathological Information
Autopsies of the flight instructor and student pilot were performed by the Office of the District Medical Examiner in West Palm Beach, Florida. Both reports stated the cause of death as blunt force injuries.