Accident Details
On July 12, 2023, at approximately 1400 eastern daylight time, a McDonnell Douglas A-4K, registration N143EM, was substantially damaged during an accident at Cherry Point Marine Corps Air Station (Cunningham Field) Airport (NKT), Cherry Point, North Carolina. The commercial pilot, who was the sole occupant, sustained serious injuries. The airplane was operating as a Title 49 of the United States Code public aircraft.
The aircraft was a light attack airplane formerly owned and operated by the Royal New Zealand Air Force. This variant was equipped with both a tailhook and a drag chute, the latter intended to assist in slowing the airplane after landing or during an aborted takeoff due to the lack of anti-skid braking capability.
Preflight and Takeoff
The pilot reported no irregularities during the flight briefing approximately 40 minutes before takeoff. The most recent maintenance documented was the installation of a heads-up display (HUD). The walk-around and preflight inspection were normal, with all panels opened to inspect internal components and systems, including hydraulic pressures, hoses, connections, and flight control actuation systems.
Start-up and ground operations were normal, with no anomalies in flight control checks. Wing flaps were set to 25° (half-flaps), and horizontal stabilizer trim and manual trim override were set appropriately. The trim actuator was operationally tested on the rudder, ailerons, and elevator. A pilot in an adjacent airplane observed the accident airplane’s configuration before takeoff and noted no anomalies.
Weather at NKT at 1356 included wind from 220° magnetic at 6 knots gusting to 15 knots. Special observations at 1346 and 1411 reported winds from 270° at 7 knots and from 310° at 16 knots gusting to 24 knots, respectively.
Three runways were available: Runway 5L (8,491 ft long), Runway 23L (8,188 ft long), and Runway 32R (8,979 ft long). All were equipped with E-28 arresting gear, but the gear on Runway 5L, located 2,438 ft from the departure end, was unavailable at the time of the accident.
The pilot stated that the takeoff roll was smooth with sufficient engine power and no warnings or cautions. As the airplane approached 145 knots, the pilot neutralized the control stick and felt the nose strut extend, but the nose landing gear remained on the runway and rotation did not occur. With the control stick full aft and nose-up trim applied, the airplane passed 156 knots without rotating. Realizing insufficient runway remained, the pilot elected to eject.
Aftermath and Examination
The airplane departed the paved runway and traveled approximately 3,000 ft through the overrun area, impacting several runway and threshold lights before coming to rest as fire enveloped the aircraft. It sustained substantial impact and thermal damage.
During recovery, the horizontal stabilizer pitch trim was found at 0°, whereas the normal takeoff setting was between 6° and 8° nose up—a setting confirmed before takeoff by ground maintenance personnel, the flight lead, and the pilot. Additionally, the flaps were found in the up (retracted) position, despite witnesses reporting them down before takeoff and the normal takeoff setting being 25°.
Examination of the horizontal stabilizer actuator limit switches and wiring revealed no anomalies. Operational testing showed the horizontal stabilizer trim moved nose-up and nose-down as directed. The trim switch and manual override stab switches were electrically neutral and not stuck. According to the operator, a runaway nose-down trim was a known anomaly for this make and model, with several incidents in US Navy and US Marine Corps fleet history. A runaway nose-down trim could be either mechanical or electrical in nature.
Further examination found that the front left throttle quadrant air-to-air refueling store control head cannon plug was loose. The cannon plug rested against the horizontal stabilizer manual override push-pull rod end in a way that could limit operation and showed evidence of severe chafing consistent with contact with the rod end.
Performance and Procedure
According to the airplane’s takeoff performance chart, with a weight of 21,500 lbs, a 6-knot tailwind, temperature of 32°C, and barometric pressure of 30.02 inHg, the takeoff ground roll would be about 4,800 ft. The airplane operating handbook (page 5-4, section 5.18) listed circumstances that may require aborting a takeoff, including runaway nose-down trim and slower than normal acceleration. The decision to abort or continue depended on factors such as speed, runway remaining, and arresting gear availability. For a runaway nose-down trim scenario, the checklist included aborting if below refusal speed (108 knots); above that, the pilot should select flaps up, manual trim override nose up, jettison external stores, and deploy the ram air turbine.