Investigation Summary
The accident was rooted in a maintenance error during a recent overhaul of the elevator control system. The DC-8 uses a control tab system where pilot inputs move a tab, which then aerodynamically moves the larger elevator surface. During the takeoff roll, as the aircraft reached rotation speed, the right elevator control tab's geared tab pushrod disconnected because an attachment bolt had not been properly secured with a cotter pin or had been incorrectly torqued. This caused the right elevator to shift to a full trailing-edge-up position, creating an extreme nose-up pitching moment. The crew's flight data recorder showed they were applying continuous nose-down pressure, but the mechanical jam overrode their inputs. The captain's report of an 'extreme CG problem' reflected the crew's perception of the aircraft's behavior, though investigators confirmed the cargo was properly loaded. The aircraft reached a peak altitude of 987 feet before stalling and crashing into a salvage yard approximately 1.5 miles from the airport.
Final Conclusions
The National Transportation Safety Board (NTSB) determined the probable cause was a loss of pitch control resulting from the disconnection of the right elevator control tab. This disconnection was caused by the failure to properly secure and inspect the attachment bolt during maintenance. Contributing to the accident was the design of the DC-8 elevator control tab, which did not account for the possibility of a single-point failure leading to a jam, and the inadequacy of the airline's maintenance work cards regarding required inspection items.
Photographic Evidence (1)
Video Analysis
Nuts and Bolts | Emery Worldwide Flight 17 — On February 16, 2000, the DC-8 crashed onto a salvage yard shortly after taking off from Sacramento Mather Airport, killing all three crew members.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
Kevin Stables
First Officer
George Land
Flight Engineer
Russell Hicks
Systems & Failure Modes
Elevator Control Tab
A small auxiliary surface on the trailing edge of the elevator. On the DC-8, pilot inputs move the tab, which uses aerodynamic force to move the main elevator surface.
Ground Proximity Warning System (GPWS)
The system alerted the crew multiple times with 'PULL UP' warnings as the aircraft lost altitude during its erratic flight path.
Stick Shaker
A mechanical device that vibrates the control yoke to warn the pilots of an impending aerodynamic stall, which activated several times during the flight.
Interesting Facts
- 01The aircraft was a 32-year-old Douglas DC-8-71F (MSN 45947) that had been converted from a passenger configuration to a freighter.
- 02The aircraft was originally built as a DC-8-61 in 1968 and was converted to the -71 series in July 1983 through the installation of CFM56-2 engines.
- 03The right elevator control tab was found detached at the crash site, with the attachment bolt missing.
- 04The NTSB investigation found that the airline's maintenance procedures failed to ensure the elevator control rod bolts were properly torqued and locked.
- 05Following the accident and subsequent FAA inspections, Emery Worldwide was found to have over 100 maintenance violations.
- 06Emery Worldwide Airlines permanently ceased all flight operations in December 2001.
Safety Actions & Advisories
DC-8 Fleet Inspection
The NTSB recommended that the FAA evaluate every DC-8 operating in the U.S. to ensure the elevator control tab attachment bolts were properly secured.
Maintenance Work Card Revision
Recommendations were made to improve the adequacy of DC-8 maintenance work cards, specifically regarding 'Required Inspection Items' (RII) for critical flight controls.