What happened
During a pushback maneuver, the left side nose wheel tire of an aircraft was damaged after the tow bar failed. Following this incident, the damaged tire was replaced. While the mechanic was in the process of servicing the new tire on the aircraft, the tire rim suffered a structural failure. This event resulted in 1 fatality.
The investigation
Investigators examined the high-pressure bottle used to service the tire, which featured dual pressure scales displaying bars on the exterior and PSI on the interior. The scale had a maximum capacity of 10,000 PSI, and the bottle was pressurized to 4,000 PSI at the time of the incident; the target service pressure for the tire was 150 PSI. A post-accident inspection of the regulator confirmed it was properly calibrated.
According to the FAA, the tire rim had been subjected to a stress of 580 PSI. An examination of the fracture surface revealed no manufacturing or material defects, and the failure pattern was consistent with a tensile overload type of failure. Additionally, the company reported that no low-pressure regulators were available for use at the time, as such equipment is kept under lock when not in use and the authorized personnel had already departed for the day.