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A senior Air Transat maintenance supervisor told concerned mechanics to proceed with an engine swap on one of the airline's Airbus A330s, despite missing parts, a senior company executive confirmed Tuesday.

The executive, in an interview arranged on condition that he not be identified, confirmed that the team's lead mechanic initially told his supervisor that he couldn't finish installing the engine because parts were missing. He was told to install the engine using the procedure for a slightly different model. That installation was improperly completed, resulting in chafing of parts and a major rupture of the fuel line on Air Transat Flight 236 to Lisbon on Aug. 24.

The aircraft lost power in both engines because of fuel starvation, forcing the pilots to glide the airliner to a safe landing at a Portuguese military air base in the Azores — the only land in any direction for more than 1,600 kilometres.

The senior Air Transat executive, while acknowledging that mistakes were made in maintenance, flatly rejected allegations published in The Globe and Mail this week that the company ignored the mechanic's concerns after the engine was installed. Rather, he said, the concerns were addressed, but the installation proceeded improperly.

"Everyone was acting in good faith," the senior executive said. He said that the lead mechanic who, according to a union official, had taped a telephone call with supervisors to substantiate a claim that his concerns were ignored, had raised no doubts about the installation after it was completed.

"We don't have that kind of working relationship," with employees, the executive said.

Jean Jallet, a union official who told The Globe and Mail on Sunday that a mechanic was so concerned about the installation that he taped a telephone conversation with the supervisor, did not return phone calls Tuesday. Other union officials have backed the company's denial that concerns were ignored. And sources close to the union told The Globe Tuesday that Mr. Jallet has been muzzled by senior union officials. The Globe and Mail has been unable to confirm the existence of the tape claimed to exist by Mr. Jallet.

Transport Canada, conducting a special audit of Air Transat's maintenance procedures, said Tuesday that it was "looking at the allegations."

"But nothing has been reported to us," said Peter Coyles, a spokesman for Transport Canada.

It is clear that the team of mechanics changing the engine on Aug. 19 — five days before the massive fuel leak — was dealing with an unfamiliar engine and was ordered to proceed with the swap by an Air Transat maintenance supervisor. The supervisor, since suspended with pay, apparently did not check the finished job. A different maintenance supervisor — the maintenance controller — signed off on the aircraft as serviceable.

The engine, lent to Air Transat by Rolls Royce to replace one of the airline's spares, was from an earlier model of the jet. When Air Transat workers uncrated it on Aug. 19 for a routine engine swap, they discovered it was a "premodification" engine. Furthermore, it was missing a hydraulic pump.

All of Air Transat's inventory of Rolls Royce engines for its three Airbus A330s were "postmodification" engines. Thus the members of the maintenance team were dealing with an engine they had never installed before, albeit one that could be safely installed as long as Rolls Royce special-service bulletins were carefully followed.

When the lead mechanic warned that he could not complete the swap because the part was missing, he was told to proceed using the installation outlined in a service bulletin issued by Rolls Royce. That bulletin details how to maintain the required clearances between the fuel line and the hydraulic lines to prevent chafing.

The Portuguese-led investigation is under way and neither Transport Canada nor the Canadian Transportation Safety Board has interviewed the team of mechanics who swapped the engine nor the suspended maintenance supervisor.

Safety-board investigators are assisting the Portuguese, who have authority to probe the incident because the aircraft landed on Portuguese territory.

Sources close to the investigation have said that a low-pressure, high-volume fuel line to the engine failed, apparently from chafing against a hydraulic line because the installation was improperly completed. At least eight tonnes of fuel leaked out before the pilots noticed. Investigators are examining whether the pilots mistakenly pumped more than 20 tonnes of fuel from the left-side tanks of the aircraft to the right-side engine.

Airbus design is also under close scrutiny.

Investigators suspect that the pilots initially — and wrongly — believed they were dealing with a fuel imbalance between the left and right wings, rather than a serious fuel leak. Sources close to the investigation suggested Tuesday that large amounts of fuel could leak before the sophisticated, computerized flight-management system warned the pilots that anything was amiss.

An imbalance warning is signalled when there is a difference of more than three tonnes in the fuel load in the two wings. But before that happens, another five tones — or about one hour of flying at high-altitude cruise — drains from the trim tank in the tail into the supposedly "lighter" side.

If this occurred, the Airbus lost eight tones of fuel before the first warning signal. The problem apparently was compounded when fuel was pumped from the left-side tanks through a cross feed.

The correct procedure for dealing with a massive fuel leak is to shut down the affected engine. The Airbus A330, like all modern twin-engine jetliners, can fly on one engine and make a routine landing. Although it would vary with routing and load, an Airbus A330 on a Toronto-to-Lisbon flight would take off with about 60 tonnes of fuel.

With engines windmilling on the A330, the pilot managed to guide the aircraft to a runway 85 naut. mi. away

The Aug. 24 shutdown of both 71,000-lb.-thrust Rolls-Royce Trent 700 engines on an Air Transat Airbus A330-200 transiting the Atlantic Ocean stunned industry--and promptly stirred regulators, airlines and manufacturers to action, initiating engine and fuel system inspections and probes of training and maintenance practices.

In the wake of the near-catastrophic event, flight safety experts can be expected to revisit all aspects of extended twin-engine overwater operations.

Just last week, Canadian Transport Minister David Collenette revealed Air Transat agreed to a request by Transport Canada to implement special ETOPS training sessions for all flight crew as well as to review proper procedures, which include fuel management and the need to divert to the nearest alternate airport at first sign of engine-related emergency. In addition, Air Transat initiated a comprehensive review of the safety of its maintenance and operations and has provided Transport Canada with a corrective action plan.

The Portuguese safety board, the Gabiente de Pevencao e Investigacao de Acidentes com Aeronaves (GPIAA), is leading the investigation, with assistance from the Transport Safety Board of Canada and DCGA, the French civil aviation authority. GPIAA's preliminary report determined that both engines failed as a result of fuel starvation, and that a low-pressure fuel line on the No. 2 engine, Rolls-Royce Trent 700 serial no. 41055, had failed "probably as a result of its coming into contact with an adjacent hydraulic line" (see p. 36).

180 and 120  minute ETOPS circles

Montreal-based Air Transat Flight TS236, an A330-200, C-GITS, departed Toronto Lester B. Pearson Airport as scheduled, at 8:10 p.m. (EST) on Aug. 23, en route to Lisbon, with 293 passengers and 13 crewmembers. The twin-engine aircraft is certified to operate under the ETOPS 120-min. rule, that is, permitted to divert with one operable engine to an airport that is up to 2 hr. away.

Flight TS236 was cruising at Flight Level 390 (39,000 ft.). At 0536Z, the flight crew became aware of a fuel imbalance between the left and right wing main fuel tanks. At about 0541Z, the crew, concerned about the lower-than-expected fuel quantity indication, elected to divert from the intended flight route to Lajes Field (LPLA), which is located on the northeast tip of Terceira Island in the Azores--850 mi. west of Lisbon.

At 0548Z, the crew ascertained a leak might be the cause of the fuel loss and declared an emergency to Santa Maria Oceanic Control. At 0613Z, with Flight 236 135 mi. distant from Lajes, the flight crew alerted air traffic control of the failure of the right Rolls-Royce Trent 772-211B engine.

About 13 min. later, about 85 naut. mi. from Lajes at an altitude of about FL345, the left engine failed. The flight crew advised ATC that ditching at sea was a possibility.

The aircraft, which has a range of 5,600 naut. mi., and can accommodate up to 406 passengers in high-density configuration, became a glider. Its fuel supply--tanks have a maximum capacity of 36,750 U.S. gal.--was apparently depleted.

The cabin crew prepared the passengers for ditching at sea and issued brace command. ATC provided radar vectors to the flight crew, who proceeded on an engines-out night visual approach in what the GPIAA described as good weather conditions--wind 330 deg. at 8 kt., visibility unlimited, few clouds at 2,500 ft. and 5,000 ft. and temperature at 19C.

When the A330 touched down on Lajes' 10,865 X 300-ft. Runway 33 at 0646Z, eight of 10 tires ruptured. The GPIAA report said small fires that started in the main gear wheels were extinguished by crash response vehicles in position at the field. "There was no evidence of fire on the engine or fuel system," an Air Transat official said.

The GPIAA said nine passengers and two cabin crewmembers received minor injuries in the emergency evacuation, which, according to Flight Director Meleni Tesic, was completed in 90 sec. Reportedly, there was no fire or smoke in the cabin.

Passengers described the landing as "brutal" and "hysterical" and some accused the cabin crew of panicking. Tesic said there "was absolutely no panic in the cabin." With no PA system, she explained, attendants must shout as loudly as possible so passengers can hear safety instructions. Some passengers may have misconstrued the shouting for panic behavior.

Capt. Robert Piche said at a press conference he was "fully confident" the aircraft was loaded with fuel when the flight departed Toronto Pearson. He said he had minimum power with which to control the aircraft on descent to Lajes.

Passengers and the public hailed the flight crew as heroes, but Piche dismissed this, saying, "I was only doing my job . . . . we train for the worst." First Officer Dirk DeJager agreed. Piche, 49, and with 30 years of airline experience has been employed by Air Transat for nearly five years. DeJager, 28, has been flying with Air Transat for about five years.

No one had to be reminded of possible endings for the TS236 story. Lajes, a U.S. air base from which air crews and support troops are deployed, has high terrain to 1,925 ft. 2.75 naut. mi. west, and 503 ft. 0.25 naut. mi. east. From October to May, strong winds create hazardous crosswinds.

Immediately following the incident, the Transportation Safety Board of Canada suspended that country's largest charter airline from operating 120-min. ETOPS for its three A330s in a fleet of 24 aircraft, and launched a special audit of the carrier's maintenance practices. It also increased surveillance of Air Transat's aviation program to ensure compliance with Canadian Aviation Regulations. "The issue is that a leak in a pipe should not result in two engine shutdowns. That is a serious concern," said TSB Chairman Benoit Bouchard.

Air Transat called the rule "normal" and "a usual procedure in this type of circumstance" and did not expect it to have more than a minor impact on day-to-day operations. The carrier is to continue to fly ETOPS under the 60-min. rule, that is, an engine-out aircraft must be no more than 1 hr. from an airport. This means Air Transat will fly routes closer to land masses.

As a precautionary measure, Air Transat completed inspections of its engines on its A330s. Air Canada, which operates eight A330s, all of which have Rolls-Royce Trent 700 engines, undertook and completed inspection of the powerplants to ensure no mechanical conditions existed of the type that may have contributed to the Air Transat emergency.

On Aug. 29, Airbus issued an AOT (All Operators Telex) to operators of Airbus aircraft equipped with Rolls-Royce Trent 700s, saying the source of Air Transat's fuel leak is "a damaged fuel feed pipe." Further, it says the damage is "due to interference with the hydraulic pipe from the aft hydraulic pump in the vicinity of the HP fuel pump inlet" and that the interference can result in "a significant fuel leak." It says the pipes are modified as part of Rolls-Royce service bulletin RB211-29-C625. Complete application of the SB would ensure adequate clearance, according to the AOT, adding that the SB appears to "be partially applied on the affected engine."

The aim of the AOT is to launch a one-time inspection of the A330/Trent 700 fleet and spare engines, to ensure there is no interference between the parts in question and to complete that inspection within 72 hr. of receipt of the AOT.

Air Transat late last week was trying to regain its equilibrium. The carrier, a subsidiary of a leading Canadian travel services company, Transat A.T., began operations in 1987. Air Transat operates charters from Canada and Europe to southern destinations. It has a total fleet of 24 aircraft, including three A330s (two -200s and one -300), four A310-300s, six Lockheed L-1011-500s, seven L-1011-10s and four Boeing 757-200s. The airline says it transported 3.5 million passengers last year.

The company has not had any accidents causing injury, nor has the aircraft involved in the Lajes occurrence been implicated in another incident. According to Air Transat President and CEO Denis Jacob, the carrier has had 54 minor events out of 2,800 listed for Canada's total air industry.

The Lajes incident, however, is the second emergency evacuation for the carrier within seven days. On Aug. 18, smoke issued from the cabin ceiling lights of an L-1011 as it taxied to the departure runway at Orlando, Fla., with 324 passengers and 14 crew on board, The pilot ordered an evacuation that resulted in a few minor injuries.

The crippled A330 sat on Lajes sole runway, forcing the airport to cease flight operations, stranding about 600 passengers, until Aug. 28, when repair crews arrived with equipment to move the aircraft.

Pierre Sparaco contributed to this report from Paris.

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