What happened
The flight proceeded normally until the aircraft reached the landing roll phase. During the rollout, the first officer felt the antiskid system releasing, prompting the captain to take control of the aircraft. While braking action was initially present, all braking effectiveness was subsequently lost. As a result, the aircraft departed the end of the runway and came to a stop in the grass approximately 200 feet past the departure end. The aircraft sustained a blown left outboard main tire during the excursion.
The investigation
An examination of the aircraft identified several mechanical discrepancies involving the antiskid system. Investigators found that the brake and return lines for the left inboard antiskid valve had been crossed. Additionally, the left inboard skid detect circuit was inoperative. Further inspection revealed that the wiring for the left inboard and left outboard wheel speed transducers had also been crossed. Evidence indicated that the aircraft had experienced hydroplaning near the departure end of the runway. These discrepancies had not been identified during antiskid system testing conducted approximately two weeks before the accident.