History of Flight
On March 6, 2008, at about 1630 eastern standard time, a Rockwell International 112TCA, registration N4623W, was substantially damaged when it overran runway 27 during an aborted takeoff from Brandywine Airport (OQN) in West Chester, Pennsylvania. The pilot, who was the sole occupant, was not injured. The flight was conducted under 14 Code of Federal Regulations Part 91, and visual meteorological conditions prevailed. No flight plan was filed.
The pilot had flown the airplane to OQN earlier that morning for maintenance on the weather data-link avionics and to address an autopilot issue from a previous upgrade. The airplane was released to him about 1600.
Aircraft and Maintenance
The aircraft, a 1977 Rockwell International 112TCA, had accumulated about 2,052 total hours in service. Its most recent annual inspection was in May 2006, and it had flown about 39 hours since then. The airplane was equipped with a Century III two-axis autopilot.
Maintenance records and a technician's statement indicated that the autopilot electrical connector for glideslope coupling had been incorrectly paralleled at the altitude transducer. The technician rewired the assembly to match the manufacturer's drawing and performed functional checks, confirming correct operation. The technician then instructed the pilot to check the trim before departure, as it runs during ground checks.
Takeoff Attempt and Overrun
Before engine start, the pilot noticed the pitch trim was near its full airplane nose down (AND) position and manually adjusted it to the takeoff setting. The airplane had about 37 gallons of fuel. The pilot reported light and variable winds. After a normal engine start and runup, he ensured the autopilot was off and the trim master breaker was on. Flaps were retracted. He initiated a full-length takeoff, releasing brakes at 30 inches manifold pressure (MP). At about 65 knots indicated airspeed and 40 inches MP, the pilot applied aft control column pressure to lift off, but the airplane did not feel right. By 75 knots, he had moved the column significantly aft, but pitch attitude increased only slightly, and the airplane did not become airborne. He rejected the takeoff by reducing throttle and applying brakes. The airplane overran the runway at an estimated 20 to 30 knots, traveled down an embankment, and came to rest about 150 feet from the runway end in a shallow ditch. The pilot was uninjured, and there was no fire.
A witness reported pulling the airplane from the maintenance hangar around 1630; the pilot returned on foot to report the accident about 1640.
Post-Accident Examination
FAA inspectors arrived about two hours after the accident. They observed impact damage to the propeller, engine cowling, left wing, nose landing gear, and left main landing gear. The pitch trim cockpit indicator and elevator trim tab were both in their full AND positions. A skid mark began at the painted runway number and extended about 375 feet to the pavement end. Beyond the embankment, three furrows consistent with the landing gear spacing were found about 100 feet past the runway end.
Post-accident testing confirmed elevator and manual pitch trim control continuity, functionality, and directional correctness. The electric pitch trim and indicator also functioned correctly. The autopilot ON/OFF switch was spring-loaded to OFF and held on by a solenoid energized only when the avionics master switch was on. A test showed that with electrical power off and trim set to takeoff, applying power and turning on the autopilot caused the trim to run to full AND. Turning off the autopilot left the trim in that position.
Two checklists were recovered from the airplane: a manufacturer's Normal Procedures Checklist and a laminated checklist. Neither had explicit autopilot references, but both contained items for elevator trim and avionics master switch. The autopilot Pilot's Operating Handbook, which included a preflight procedure noting that prolonged ground checks could cause automatic trim to run to limits, was not found in the airplane.