Investigation Summary
The accident occurred during a functional evaluation flight (FEF) following a 'D' check and Stage III noise compliance modifications. The crew was tasked with identifying the speeds at which the stick shaker activated and the aircraft stalled. As they decelerated at approximately 1 knot per second, the aircraft encountered a buffet at 151 knots, which the crew noted was 'pretty early.' At 145 knots, the aircraft entered a full stall without the stick shaker activating. The pilot flying (PF) called for maximum power, but the abrupt throttle movement caused a compressor stall in the number 2 engine, producing loud popping sounds and asymmetric thrust. The PF then made a critical error by pulling back on the control column by five to ten degrees instead of maintaining a nose-down attitude to regain airspeed. The pilot in command (PIC), seated in the right seat, failed to take control or provide corrective guidance, partly due to a lack of defined command authority between the two captains. The aircraft entered a series of violent rolls and a steep descent, impacting the southeast side of a 4,200-foot mountain (identified as East River Mountain) at an elevation of 3,400 feet, approximately 6.5 km west of Narrows, Virginia.
Final Conclusions
The NTSB determined the probable causes were the inappropriate control inputs by the flying pilot during stall recovery, the failure of the non-flying pilot-in-command to correct those inputs, and the airline's failure to establish a formal FEF program with adequate training. Contributing factors included the inoperative stick shaker stall warning system and the inadequate fidelity of the ABX DC-8 flight simulator in reproducing stall characteristics. The investigation also noted that the crew lacked a visual horizon due to darkness and cloud cover, and were distracted by the engine compressor stall.
Video Analysis
A Small Failure. A Huge Mistake. A Tragedy That Shouldn’t Have Happened. — A detailed look at the 1996 Airborne Express Flight 827 accident, examining how a routine test flight ended in disaster due to mechanical failure and pilot error.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain (Pilot Monitoring / PIC)
Seated in right seat; Boeing 767 flight manager and instructor. Garth Avery, 48.
Captain (Pilot Flying)
Seated in left seat; Manager of DC-8 flight standards. William 'Keith' Leming, 37.
Flight Engineer
FAA designated examiner. Terry Waelti, 52.
Systems & Failure Modes
Stick Shaker
A mechanical system designed to vibrate the control column to provide a tactile warning of an impending aerodynamic stall; it failed to activate during the accident flight.
Horizontal Stabilizer Trim
The crew trimmed the aircraft for 175 knots instead of the intended 184 knots, though investigators determined this was not a primary factor in the crash.
JT3D-7 Engines
Equipped with 'hush kits' for noise reduction; the number 2 engine suffered a compressor stall due to high angle of attack and rapid power application.
Interesting Facts
- 01The aircraft had just completed a major 'D' check and Stage III engine modifications.
- 02The flight was a 'round-robin' evaluation intended to return to Greensboro.
- 03The stick shaker stall warning system failed to activate during the test maneuver.
- 04The pilot flying pulled back on the control column during the stall, deepening the stall.
- 05The crew encountered a compressor stall on the number 2 engine during the recovery attempt.
- 06The flight was conducted at night in instrument meteorological conditions (IMC).
- 07The airline's simulator did not accurately replicate the DC-8's actual stall behavior.
Safety Actions & Advisories
Angle of Attack Indicators
The NTSB reiterated the need for transport-category aircraft to present pilots with visual angle of attack (AOA) information to aid in maximum climb performance and stall recovery.
FEF Program Formalization
Recommendations were made to the FAA to require air carriers to establish formal functional evaluation flight programs with specific pilot training and guidelines.
Simulator Fidelity Improvements
The investigation led to calls for improving the fidelity of flight simulators to ensure they accurately represent aircraft handling at the edges of the flight envelope, such as deep stalls.
Location
ACCIDENT SITE · Coordinates taken from the official investigation report.