In the darkened air cabin, passengers prayed and wept. But the mighty turbines of the Airbus A330
were silent. The plane was out of fuel with 75 miles (121 km) of ocean between it and land.
August 23, 2001 Air Transat Flight
236 departed from Toronto-Pearson International Airport (YYZ) in Ontario, Canada at 11:52 pm UTC,
bound for Humberto Delgado Airport (LIS) in Lisbon, Portugal. Piloting the Airbus A330
was 43-year-old Captain Robert Piché. He’s well experienced with 16,800 flight hours. His First
Officer, 28-year-old Dirk de Jager, had 4,800 hours of flight time. Between the two of them,
they had over 1,100 hours of flight time on the Airbus A330. Captain Piché was also
an experienced glider pilot, a fact that would play a key role in solving the life-threatening
situation that would soon occur. When leaving Toronto, the Airbus had
51.6 tons (46.9 tonnes) of fuel on board, 5 tons (4.5 tonnes) more than required by regulations,
and 6 tons (5.5 tonnes) more than they needed for the flight. Powering the plane were twin
Rolls Royce Trent 772B-60 engines. This particular plane had just over 2 years
of active service at the time of the flight. Not long after takeoff, air traffic directed
the pilots of Flight 236 to adjust the flight path 60 degrees south to avoid congestion
over the Atlantic Ocean. This minor deviation from the original flight plan would also play
a crucial role in the survival of the flight. The takeoff and first few hours of the flight
went smoothly. The night was calm with a clear sky. The passengers were a mix of
tourists and ex-pats looking forward to their early morning arrival in southern
Europe. The wide-body Airbus had 362 seats and only 293 passengers,
giving them space to spread out. Serving them was a cabin crew of 11.
At 4:38 am UTC, while they were high over the Atlantic, the fuel line servicing the
right engine sprung a massive leak. About 30 minutes later, the pilots received their
first sign that something was wrong--an alert warning of high oil pressure in the right engine
and also low oil temperature. This was an uncommon problem and the pilots couldn’t think of a reason
why it was happening. They assumed that the oil notification was a false alarm and there was
something wrong with the sensors aboard the plane. They reported the situation to the maintenance
control center in Montreal. Maintenance control advised them to continue to monitor the issue.
At 5:36 am UTC the pilots received another alert. This time, the plane warned them of a fuel
imbalance. The pilots still thought it might be a sensor issue, so they followed standard procedure
to remedy the imbalance by transferring fuel from the left wing tank to the right one. But because
of the leak, the pilots were actually dumping fuel through the fractured fuel line. By this point,
the leak had been occurring for about an hour and had only gotten worse. The aircraft was now losing
fuel at a rate of about a gallon per second. The oil pressure continued to drop and the oil
temperature continued to rise. At this point the pilots realized that the warning wasn’t a fluke,
something had gone terribly wrong. They called the lead steward to the cockpit and asked
her to go look through one of the passenger windows to see if fuel was leaking out from
under the right wing. However, the night was incredibly dark and she couldn’t see anything.
At 5:45 am UTC the pilots decided to initiate a diversion to Lajes Air Base on Terceira Island in
the Azores. Three minutes later, they radioed a fuel emergency with Santa Maria Oceanic air
traffic control. This message alerted the ground crew that an airplane had less than the needed
amount of fuel to finish the flight. The ground crew began to prepare for an emergency landing.
Meanwhile, the majority of passengers were peacefully dozing or watching the movie
Chocolat on the retractable television monitors above the aisles. Newlywed Margaret McKinnon
went to use the tiny airplane restroom. When she tried to turn on the faucet no water came out.
She had no idea that the bathroom’s plumbing system depended on air pressure generated by
the plane’s engines. The non functioning tap was also a symptom of the fuel leak.
Margaret assumed the tap was broken and returned to her seat next to John,
her husband. Passengers began to stir as the movie ended. An episode of Seinfeld started playing and
then suddenly cut off. The cabin lights flickered. An announcement was made over the loudspeaker in
Portuguese. Margaret and John didn’t understand but passengers around them became alarmed,
some even broke into tears. Then the message was repeated in English--The
pilot was experiencing difficulties and they should prepare for a water landing.
The cabin crew directed the passengers to pull their life jackets from beneath their seats.
They also told everyone to take off their shoes. This was in case the passengers had shoes with
sharp heels that could damage the inflatable slide. The cabin crew spread out repeating
instructions in three languages--English, French and Portuguese making sure the passengers were
properly securing their life jackets. One of the flight attendants broke down and began to cry.
At 6:13 am UTC, the right engine on Air Transat Flight 236 flamed out due to lack of fuel. The
plane was flying at 39,000 feet (11,880 m) and was 170 miles (280 km) from Lajes.
Captain Piché immediately began a descent to 33,000 feet (10,000 m), which was the proper
single-engine altitude for the Airbus at that time. The plane could actually fly on
one engine and the pilots were going to do all that they could to keep the plane in the sky.
They also shut off the fuel transfer pump. Over the intercom, Captain Piché announced
that an engine had gone out. Many passengers heard a loud click as if part of the plane
had shut down. The roar of the engine began to fade away. By now, the lights in the cabin were
out. Over and over the crew warned that when they said “Brace!” the passengers should lean
forward and put their hands behind their heads. Ten minutes after the right engine flamed out,
the pilot sent a mayday to Santa Maria Oceanic air traffic control. Three
minutes after the mayday call, at 6:26 am UTC, the left engine also flamed out.
The plane was now about 75 miles (120 km) from Lajes. To make a terrible situation worse,
without engine power, the plane’s flaps, brakes, and spoilers lost hydraulic power. Thankfully,
the RAT (ram air turbine) properly deployed to provide essential power for critical sensors,
flight instruments as well as enough hydraulic pressure to operate the primary flight controls.
Still the plane was falling at a rate of 2,000 feet a minute (610 m/min). The pilots
estimated that they had about 15 minutes or so before they would have to ditch in the ocean.
Suddenly the only thing those aboard flight 236 heard was the eerie whistling of air against
the fuselage. By now many of the passengers were praying and weeping. Some pleaded in
Portuguese calling out the name of Our Lady of Fatima. Others said goodbye to their families.
The plane floated swiftly downward,
much like a paper plane drifting in the wind. At 6:31 am UTC, the oxygen masks
dropped down in the passenger cabin. The pilots grimly prepared for a water landing.
Minutes later one of the pilots yelled “We have a runway! We have a runway!”. They had
sighted Lajes air base. Military air traffic controllers and radar vectors from Lajes ATC,
communicated with the pilots, guiding their approach to the island. Leaning
into his experience as a glider pilot, Captain Piché executed one 360° turn,
and then a series of “S” turns, to dissipate excess altitude during the engine-out glide.
Passengers huddled in darkness as the plane shuddered and jolted as it
corkscrewed down. Many were sick and vomited. It was beginning to grow light outside. The
plane made a final turn and then the pilots aimed it at the runway.
At 6:45 am UTC the plane’s landing gear slammed down hard around 1,030 feet (310 m) past the
threshold of runway 33, at a speed of around 230 mph (370 km/h). The aircraft bounced before
touching down again roughly 2,800 feet (850 m) from the threshold. The passengers could hear the
plane scraping and grinding as it slid against the tarmac. Maximum emergency braking was applied and
retained, finally the plane came to a stop. With limited brakes, the 8 main tires had locked up,
and the landing gear as well as the lower fuselage experienced massive damage from the impact. Some
small fires started in the area of the left main-gear wheels, but they were immediately
extinguished by rescue response vehicles. The runway itself was also severely damaged.
But Flight 236 had landed safely after gliding for nearly 75 miles (121 km) without engines. It
must have seemed like an eternity to the terrified passengers, but it was only about 18 minutes from
the second engine failure to when they landed. When the plane finally came to a stop,
the passengers began to cheer, but the crew rushed them toward the exits. Captain Piché
had ordered an emergency evacuation for fear that the aircraft would explode due to the damage it
sustained during landing. Passengers slid down the emergency slides and ran for their lives into
a field of dewy grass next to the runway. Buses soon arrived and took the shaken,
bruised survivors to the small terminal. Ultimately, fourteen passengers and two crew
members experienced minor injuries from the rough landing. Another two passengers received serious
injuries during the evacuation of the aircraft. The passengers waited several hours in the
terminal before taking a boat to another airport, where they caught a second plane that took them
to Lisbon early Saturday. The injured were treated at the local hospital on the island.
Captain Piché and First Officer de Jager were hailed as heroes.
A few years later the subsequent accident report both blamed and praised the pilots. Investigators
listed pilot error as one of the leading causes of the accident because the Air Transat crew failed
to identify the plane's fuel loss. They actually further fed the leak instead of isolating it.
The high oil pressure, low oil temperature notification indirectly diagnosed the leak.
Engine fuel is used to cool oil. But because of the leak, cold fuel was flowing through
the fuel-oil heat exchanger much faster than normal, resulting in the oil cooling rapidly
and increasing in viscosity thereby raising the oil pressure. However, once the pilots
thought the issue was with the sensors, they didn’t consider anything else. As a result,
they failed to follow standard operating procedures in possibly more than one instance.
The case of Flight 236 and this example of confirmation bias is now studied in flight school.
The accident report also praised the pilots, concluding that Captain Piché’s skill in gliding
the aircraft to a successful landing averted a catastrophic accident and saved the lives of those
on board. First Officer de Jager provided complete and effective support to the Captain during the
engine failure and subsequent glide to landing. The report also discussed the main cause of the
accident; an incorrect part installed on the plane. Four days before Flight 236,
the Airbus underwent routine maintenance. In the oil filter on the right-hand engine,
the mechanics found tiny metal chips. This was a sign that an engine component was about to fail.
Unfortunately, the mechanics couldn’t figure out what was causing the metal shedding. So
they decided to swap the engine out and send it for separate maintenance. But they didn’t have
any spare engines available in North America. So they had a spare engine flown in from Hong Kong.
When the maintenance crew started installing the loaner engine, they realized that it was
similar, but not a perfect fit. After some research, they found a
technical service bulletin issued by Rolls Royce. The company had made a slight modification to the
engine to improve hydraulic pump efficiency. The plane had been using engines from after
Rolls Royce’s change, but the loaner engine was from before the changes. This meant that in
addition to swapping the engine, the maintenance crew should have changed the hydraulic pumps,
the hydraulic lines and fuel line to match the engine they were installing into the
plane. The service bulletin explained how to do this maintenance work and exactly
what components should be changed. However, due to a computer failure in the maintenance
control unit, they couldn’t access this information. Rolls Royce was called for advice.
Ultimately, the setup was checked by the maintenance engineers and
it was decided that there was enough clearance between the fuel and hydraulic lines. However,
they didn’t take into account that when they were installing the engine setup there was no pressure
in the lines. As hydraulic pressure was applied to the hydraulic line, the line stiffened and
the tiny clearance between the hydraulic line and the fuel line was lost. Per servicing rules, the
engine was put through a ground run and passed. The aircraft looked fine but after about 4 hours
of flight where the right engine fuel and hydraulic lines chafed each other,
the fuel line ruptured and sprang a big leak. The report estimated that Flight 236 lost about
12 -15 tons of fuel per hour. Meanwhile the engine continued to work fine as there
was nothing wrong with the engine itself. The report on Airsat Flight 236 triggered
an in-depth review of the part, the removal and installation instructions as well as the testing
procedures in the authorized technical manual. Several countries also began requiring new
airplane flight manuals to include procedures in the event of a fuel leak.
The Airbus 330 was repaired and returned to service in December 2001, with the nickname
“Azores Glider”. It was in regular service with Air Transat until March 2020, when it was put in
storage due to the COVID-19 pandemic. On October 18, 2021, the aircraft operated its last flight
with Air Transat and was subsequently returned to the owner AerCap. Its future use is unknown.
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