Date & Time:
Dec 30, 1989 at 1910 LT
Type of aircraft:
Boeing 737-200
Operator:
Registration:
N198AW
Flight Phase:
Landing (descent or approach)
Flight Type:
Scheduled Revenue Flight
Survivors:
Yes
Schedule:
Phoenix - Tucson
MSN:
19710
YOM:
1968
Country:
United States of America
Region:
North America
Crew on board:
5
Crew fatalities:
0
Pax on board:
125
Pax fatalities:
0
Other fatalities:
0
Total fatalities:
0
Captain / Total hours on type:
3970
Aircraft flight hours:
62466
Aircraft flight cycles:
38827
Circumstances:
During approach, a fire erupted in the wheel well of the 22-year old airplane. The fire burned thru the hydraulic lines rendering the a, b, and standby hydraulic systems inoperative. The crew landed the airplane using the emergency manual reversion flight control system. However, the airplane was unable to stop on the runway because of the previous failures of the check valves in the backup hydraulic accumulator pressure systems for the #2 thrust reverser and the inboard pair of wheel brakes. During the 2 minutes rollout, the airplane traversed 14,000 feet, overran the runway end, and collided with a concrete structure which collapsed the nose gear. The airplane had recently undergone a 'C' check during which the operator's mechanics failed to observe and repair an electric wire which had been chafing against a hydraulic line. On the accident flight the energized wire arced, punctured the line, and ignited the escaping hydraulic fluid. The hydraulic check valves had failed earlier due to mechanical wear.
Probable cause:
Failure of the operator's maintenance personnel to detect an electrical wire which had chafed against a hydraulic line and which eventually arced causing a leak in the hydraulic line and subsequent fire and hydraulic system failure. In addition, previous wear of check valves in the backup hydraulic systems prevented the airplane from stopping on the runway. A contributing factor was the airplane manufacturer's inadequate guidance for maintaining the hydraulic components.
Final Report:
N198AW.pdf91.57 KB
