On July 12, 1985, a Gates Learjet 35A (registration N613RR) operated by Million Air was involved in an aviation accident near Fort Worth, TX. Investigators recorded the probable cause as: The brake lines on the left main landing gear were reversed, causing errant command signals to the anti-skid control unit during heavy brake application, negating the anti-skid function. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 4 related events involving the same aircraft type or operator are linked below.
An aircraft veered right after landing, departed the runway, and sustained damage after brake lines were reversed during a prior overhaul, negating anti-skid function.
Accident Description
During a landing on a 4001-foot runway, the aircraft experienced a normal approach, touchdown, and initial braking. After approximately 1000 feet of normal braking, the aircraft began to drift to the right. The pilot applied full left rudder and asymmetrical braking, which partially corrected the drift. However, the aircraft departed the departure end of the runway, encountering down-sloping terrain. This terrain caused the nose gear to collapse and the right wing to buckle.
Investigation Findings
Post-accident investigation revealed that the brake lines on the left main landing gear had been reversed. This mis-installation occurred during the previous brake overhaul. The reversed lines caused errant command signals to be transmitted to the anti-skid control unit during heavy brake application, which negated the anti-skid function. The maintenance manual used during the overhaul did not address the criticality of proper hose installation, and either hose could be installed in the inboard or outboard brake housing ports. The aircraft was not equipped with thrust reversers.
Probable cause
The brake lines on the left main landing gear were reversed, causing errant command signals to the anti-skid control unit during heavy brake application, negating the anti-skid function.