Investigation Summary
During the initial climb from Newark, the flight crew noticed abnormal vibrations in the number 2 engine, specifically high N2 rotor readings. Although the vibration warning light briefly illuminated and then extinguished, the crew continued the climb while monitoring the instruments. As the aircraft reached 10,000 feet, the number 2 engine suffered a catastrophic uncontained failure. The failure was later traced to a lack of oil flow to the Low Pressure Location Bearing (LPB). This was caused by worn seals and a leak introduced during a recent overhaul, which led to the bearing's eventual seizure and the subsequent disintegration of the low-pressure turbine. Debris from the failure exited the engine casing and penetrated the fuselage, severing hydraulic lines for three of the four redundant systems (A, B, and D). This left the crew with only hydraulic system C operational. The damage also caused the s-duct walls to deform, physically jamming the rudder cables and rendering the rudder immovable. The crew managed the descent by using the remaining flight controls in conjunction with differential thrust from the two wing-mounted engines. To ensure a safe landing weight, the crew jettisoned approximately 48,000 pounds of fuel before executing a successful landing on Runway 22L at JFK.
Final Conclusions
The accident was caused by an uncontained failure of the number 2 engine, which led to the simultaneous loss of three hydraulic systems. The crew's successful recovery of the aircraft demonstrated the importance of redundant systems and effective emergency handling, as the remaining hydraulic system and differential thrust allowed for sufficient control to land the aircraft.
Video Analysis
Eastern Air Lines Flight 935 - Catastrophic Leaks — A detailed look at the uncontained engine failure of an L-1011 TriStar and the subsequent loss of three hydraulic systems.
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Airframe & Maintenance
Systems & Failure Modes
Hydraulic Systems
The L-1011 features four independent hydraulic systems (A, B, C, and D). The uncontained engine failure severed lines for three of these systems, leaving only system C to power limited flight controls.
Rolls-Royce RB211-22B
The turbofan engines powering the aircraft; the No. 2 engine suffered a catastrophic uncontained failure.
Airborne Vibration Monitor (AVM)
A cockpit instrument that alerted the crew to abnormal internal engine vibrations during the initial climb.
Interesting Facts
- 01The aircraft was a Lockheed L-1011 TriStar delivered in July 1972.
- 02The uncontained failure occurred in the No. 2 (center/tail) engine.
- 03Three out of four hydraulic systems (A, B, and D) were completely lost.
- 04The crew jettisoned approximately 48,000 pounds of fuel to reach a safe landing weight.
- 05The crew used differential engine power and the remaining hydraulic system (C) to control the aircraft.
- 06The aircraft was later repaired, returned to service, and eventually sold to Air Transat in 1989.
Safety Actions & Advisories
Hydraulic Redundancy Review
The incident highlighted the vulnerability of co-located hydraulic lines to uncontained engine failures, leading to further industry emphasis on physical separation of redundant systems.
Location
ACCIDENT SITE · Coordinates taken from the airport reference point.