United Airlines Flight 232 on July 19, 1989, was a DC-10 that suffered a catastrophic failure of turbine blades of its #2 (tail-mounted) engine, destroying the plane’s hydraulic flight control ssystems
Despite the inability to make any control surface changes, the crew kept the aircraft in controlled flight by using the speed controls of the good engine on each wing, brought it down and made an approach to the runway at Sioux City, Iowa’s Sioux Gateway Airport. Because of the aircraft’s instability, the absence of wing ailerons and flaps and tail elevators and rudder, and the need to maintain a relatively high speed, the landing resulted in a crash, but 185 persons survived, of 296 persons aboard.
Jim Gordon’s answer to Who are the commercial pilot heroes?
The accident stimulated improvements in engine design and redundancy/robustness of flight control systems, greatly advancing air transportation safety. The crew’s performance advanced the understanding of controlability through the use of engine power, which saved aircraft and lives on later occasions.
Pilot Captain Alfred C. Haynes, copilot First Officer William Records, flight engineer Second Officer Dudley Dvorak, and off-duty DC-10 flight instructor Captain Dennis E. Fitch.
Air Transat 236
Air Transat Flight 236 on August 24, 2001 was an Airbus A330 on the route between Toronto and Lisbon. The flight ran out of fuel while over the Mid-Atlantic with 306 people on board. The flight crew, Captain Robert Piche and First Officer Dirk de Jaeger managed to glide the unpowered aircraft to a successful emergency landing in Lajes in the Azores Islands with no loss of life.
The series of incidents that led to a gliding airliner nearly a hundred miles over the ocean started with an innocuous low oil temperature and high oil pressure alarm from Engine 2. Since none of these warnings had any direct relation with a fuel leak, the fight crew dismissed them as false warnings and continued on.
Soon after, when a second warning came on in the cockpit of fuel imbalance in the wing tanks, the pilots started transferring fuel from the port tank to the starboard side which at that time was standard procedure.
Unknown to them however the aircraft had developed a fuel leak in its starboard engine at a rate of about 1 gallon / min. The fuel transfer caused fuel from the operational side of the aircraft to be wasted through the leak in the engine on the other side.
The pilots, then decided to divert to Lajes Air Base in the Azores still unsure whether they had a fuel leak or not. As events would unfold this would prove to be a fortuitous decision.
Half an hour later the Starboard Engine flamed out due to fuel starvation and 13 minutes later the Port Engine failed as well. At that point the aircraft was 135 miles(217 km) from Lajes.
Without engine power, the aircraft not only lost all thrust, but also its primary source of electrical power. The emergency ram air turbine was deployed automatically to provide essential power for critical sensors and instruments to fly the aircraft. However the aircraft lost its main hydraulic power which operates the flaps, brakes, and spoilers, essential for safe landings.
Guided by air traffic controllers the aircraft then glided to Lajes and performed a hard touchdown on Runway 33. Without the emergency brakes, 8 tires burst and the aircraft came to a stop 700 metres from the runway end. The passengers and crew only suffered minor injuries.
The favorable outcome was partly attributable to the flight being rerouted at the last minute via a more southerly route across the Atlantic than initially planned, which brought the aircraft within range of the Azores.
The investigation revealed that the cause of the incident was a fuel leak in the number two engine, caused by an incorrect part installed in the hydraulics system by Air Transat maintenance staff. Air Transat maintenance staff had replaced the engine as part of routine maintenance, using a spare engine, lent by Rolls-Royce, from an older model. This engine did not include a hydraulic pump. Despite the lead mechanic’s concerns, Air Transat ordered the use of a part from a similar engine, an adaptation that did not maintain adequate clearance between the hydraulic lines and the fuel line. This lack of clearance — on the order of millimeters from the intended part — allowed vibration in the hydraulic lines to degrade the fuel line and cause the leak. Air Transat accepted responsibility for the incident and was fined CAD 250,000 by the Canadian government.
The incident also led to the French Directorate General for Civil Aviation (DGAC) and Federal Aviation Administration (FAA) issuing an Airworthiness Directive, forcing all operators of Airbus model A318-100, A319-100, A320-200, A321-100, A321-200, and A320-111 aeroplanes to change the flight manual, stressing that crews should check that any fuel imbalance is not caused by a fuel leak before opening the cross-feed valve. The French Airworthiness Directive (AD) required all airlines operating these Airbus models to make revisions to the Flight Manual before any further flights were allowed. The FAA gave a 15-day grace period before enforcing the AD. Airbus also modified its computer systems; the on-board computer now checks all fuel levels against the flight plan. It now gives a clear warning if more fuel is being lost than the engines can consume. Rolls-Royce also issued a bulletin advising of the incompatibility of the affected engine parts