C-GITS, the Airbus A330 involved in the incident, seen in 1999
|Date||August 24, 2001|
|Summary||Fuel exhaustion caused by fuel leak due to improper maintenance|
|Site||Lajes Airport/Air Force Base,|
Terceira Island, Azores, Portugal
|Aircraft type||Airbus A330-243|
|IATA flight No.||TS236|
|ICAO flight No.||TSC236|
|Call sign||TRANSAT 236 HEAVY|
|Flight origin||Toronto Pearson Int'l Airport|
Toronto, Ontario, Canada
|Injuries||18 (16 minor; 2 serious)|
Air Transat Flight 236 was a transatlantic flight bound for Lisbon, Portugal, from Toronto, Canada, that lost all engine power while flying over the Atlantic Ocean on August 24, 2001. The Airbus A330 ran out of fuel due to a fuel leak caused by improper maintenance. Captain Robert Piché, 48, an experienced glider pilot, and First Officer Dirk de Jager, 28, flew the plane to a successful emergency landing in the Azores, saving all 306 people (293 passengers and 13 crew) on board. Most of the passengers on the flight were Canadians visiting Europe or Portuguese expatriates returning to visit family in Portugal.
Flight TS 236 took off from Toronto at 00:52 (UTC) on Friday, August 24, 2001 (local time: 20:52 (ET) on Thursday, August 23), bound for Lisbon, Portugal. There were 293 passengers and thirteen crew members on board. The aircraft was a two-year-old Airbus A330-243 registered as C-GITS that first flew on March 17, 1999, configured with 362 seats and placed in service by Air Transat on April 28, 1999. It was powered by two Rolls-Royce Trent 772B-60 engines capable of delivering 71,100 lbf (316 kN) thrust each. Leaving the gate in Toronto, the aircraft had 46.9 tonnes of fuel on board, 4.5 tonnes more than required by regulations.[Note 1]
Unbeknownst to the pilots, at 04:38, the aircraft began to leak fuel through a fracture which had developed in a fuel line to the No 2 (right) engine.:23 At 05:03 UTC, more than 4 hours into the flight, the pilots noticed low oil temperature and high oil pressure on engine No 2.:7,23 Although these readings were an indirect result of the fuel leak, there was no reason for the pilots to consider that as a cause. Consequently, Captain Piché, who had 16,800 hours of flight experience (with 796 of them on the Airbus A330),:12 and First Officer Dirk DeJager, who had 4,800 flight hours (including 386 hours on the Airbus A330),:12 suspected they were false warnings and shared that opinion with their maintenance control center, who advised them to monitor the situation.:56
At 05:36 UTC, the pilots received a warning of fuel imbalance. Still unaware of the fuel leak, they followed a standard procedure to remedy the imbalance by transferring fuel from the left wing tank to the right wing tank. The transferred fuel was lost through the fractured fuel line, which was leaking at about one gallon per second. This caused a higher than normal fuel flow through the fuel-oil heat exchanger (FOHE), which in turn led to a drop in oil temperature and a rise in oil pressure for the No 2 engine.
At 06:13 UTC, while still 150 nautical miles (280 km; 170 mi) from Lajes and at 39,000 feet (12,000 m), engine No 2 flamed out due to fuel starvation. Captain Piché then initiated a descent to 33,000 feet (10,000 m), which was the proper single-engine altitude for the weight of the plane at that time. Ten minutes later, the crew sent a Mayday to Santa Maria Oceanic air traffic control.
Thirteen minutes later, at 06:26 UTC and approximately 65 nautical miles (120 km; 75 mi) from Lajes Air Base, engine No 1 also flamed out, requiring the plane to glide the remaining distance.:8 Without engine power, the plane lost its primary source of electrical power. The emergency ram air turbine 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, alternate brakes, and spoilers. The slats would still be powered, however, when the flaps No 1 position was selected. Five minutes later, at 6:31 UTC, the oxygen masks dropped down in the passenger cabin.:9
Military air traffic controllers guided the aircraft to the airport with their radar system. The descent rate of the plane was about 2,000 feet (600 metres) per minute. They calculated they had about 15 to 20 minutes left before they would be forced to ditch in the ocean. The air base was sighted a few minutes later. Captain Piché had to execute one 360-degree turn, and then a series of "S" turns, to dissipate excess altitude.
At 06:45 UTC, the plane touched down hard, approximately 1,030 feet (310 m) past the threshold of Runway 33, at a speed of approximately 200 knots (370 km/h; 230 mph), bounced once and then touched down again, approximately 2,800 feet (850 m) from the threshold. Maximum emergency braking was applied and retained, and the plane came to a stop after a landing run that consumed 7,600 feet (2,300 m) of the 10,000-foot (3,000 m) runway. Because the anti-skid and brake modulation systems were inoperative, the eight main wheels locked up; the tires abraded and fully deflated within 450 feet (140 m).:11 Fourteen passengers and two crew members suffered minor injuries, while two passengers suffered serious injuries during the evacuation of the aircraft. The plane suffered structural damage to the main landing gear and the lower fuselage.
The Portuguese Aviation Accidents Prevention and Investigation Department (GPIAA) investigated the accident along with Canadian and French authorities.
The investigation revealed that the cause of the accident was a fuel leak in the #2 engine, caused by an incorrect part installed in the hydraulics system by Air Transat maintenance staff as part of routine maintenance. The engine had been replaced with a spare engine, lent by Rolls-Royce, from an older model which did not include a hydraulic pump. Despite the lead mechanic's concerns, Air Transat authorized 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 millimetres from the intended part, allowed chafing between the lines to rupture the fuel line, causing the leak. Air Transat accepted responsibility for the accident and was fined 250,000 Canadian dollars by the Canadian government, which as of 2009 was the largest fine in Canadian history.
Pilot error was also listed as one of the lead causes of the accident (for failing to identify the fuel leak, for neglecting to shut down crossfeed after first engine flame out, as well as for failing to follow standard operating procedure in possibly more than one case). Nevertheless, the pilots returned to a heroes' welcome from the Canadian press as a result of their successful unpowered landing. In 2002, Captain Piché was awarded the Superior Airmanship Award by the Air Line Pilots' Association.
Following the accident investigation, the French Directorate General for Civil Aviation (DGCA) issued F-2002-548B, requiring a detailed fuel leak procedure in the flight manual and the need for crews to be aware of this. This was later cancelled and replaced by F-2005-195. The Federal Aviation Administration (FAA) issued AD 2006-02-01, effective February 3, 2006, requiring new airplane flight manual procedures to follow in the event of a fuel leak for Airbus Model A330 and A340 aircraft.
The accident led to the French Directorate General for Civil Aviation (DGCA) and Federal Aviation Administration (FAA) issuing an Airworthiness Directive (AD), requiring all operators of Airbus models A318, A319, A320 and A321 narrow body aircraft to revise 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 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 fuel is being expended beyond the specified fuel consumption rate of the engines. Rolls-Royce also issued a bulletin advising of the incompatibility of the relevant engine parts.
The aircraft was repaired and returned to service with Air Transat in December 2001, with the nickname "Azores glider". The aircraft was placed into storage in March 2020.
Margaret McKinnon, a postdoctoral psychology student at Baycrest Health Sciences in Toronto at the time, was a passenger on her honeymoon on Flight 236. She and colleagues recruited fifteen other passengers in a study of posttraumatic stress disorder (PTSD), published in August 2014 in the academic journal Clinical Psychological Science, which compared details recalled by passengers suffering from PTSD with those recalled by passengers without PTSD and with a control group.