Investigation Summary
On the early morning of February 1, 1990, a Federal Express Boeing 727 was parked and chocked at Indianapolis International Airport, awaiting a tug for movement. A ramp employee, acting as the tug operator, brought a tug and tow bar to the aircraft. He initially stopped to disconnect the tow bar from the tug and attach it to the aircraft's nose gear. The operator then re-boarded the tug to reposition it closer to the tow bar for final attachment. As the tug moved forward, it failed to stop, striking the tow bar and continuing until it made contact with the underside of the aircraft's nose. The operator was fatally crushed between the moving tug and the stationary airframe as he attempted to exit or was caught in the impact. Investigators focused on the operator's footwear, a built-up steel-toe boot on the right foot. Mechanical testing demonstrated that if this specific boot was positioned under the brake pedal, it physically restricted the pedal's travel, rendering the brakes ineffective. Scuff marks were found on the toe of the boot, although their origin could not be definitively linked to the brake assembly.
Final Conclusions
The National Transportation Safety Board determined the probable cause was the tug operator's failure to maintain control of the vehicle. This loss of control was likely caused by the operator's built-up, steel-toe boot inadvertently becoming caught under the brake pedal, which prevented the application of sufficient braking force to stop the tug before impact.
Video Analysis
No video analysis linked for this case file yet.
Crew Experience
Captain
Aged 37 at the time of the accident.
Systems & Failure Modes
Tug Braking System
The mechanical braking system of the ground tug, which was found to be obstructed by the operator's specialized footwear during post-accident testing.
Tow Bar
The connection device between the tug and the aircraft nose gear; during the accident, the tug struck the bar, which then slid off the face of the tug.
Interesting Facts
- 01The accident occurred at night under visual meteorological conditions (VMC).
- 02The tug operator was wearing a built-in built-up shoe on his right foot.
- 03Post-accident tests confirmed that the shoe could obstruct the brake pedal's range of motion.
- 04The aircraft sustained minor damage to the nose section.
- 05All six occupants on board the aircraft (three crew and three passengers) were uninjured.
Safety Actions & Advisories
Footwear Inspection and Policy
Source ↗Following the investigation, emphasis was placed on the suitability of specialized or orthopedic footwear for ground equipment operators to ensure such gear does not interfere with vehicle control systems like brake pedals.
Location
NO VERIFIED COORDINATES · Coordinates are the estimate published in the ntsb final report. No map is shown, because a marker here would imply a precision the record does not have.
Reported location: Indianapolis, Indiana, United States