|Lead Page Photography by Wayne Glowacki|
If a Boeing 767 runs out of fuel at 41,000 feet, what do you have? Answer: A one hundred and thirty two ton glider with a sink rate of over 2000 fpm and barely enough hydraulic pressure to control the ailerons, elevator, and rudder. Put veteran pilots Bob Pearson and cool-as-a-cucumber Maurice Quintal in the cockpit and you've got the unbelievable but true story of Air Canada Flight 143 -- known ever since as the Gimli Glider.
Flight 143's problems began on the ground in Montreal. A computer system called the "Fuel Quantity Information System Processor" or "FQIS" manages the 767 fuel loading process. The FQIS controls all of the aircraft's fuel pumps and drives all the gauges, leaving little for the crew and refuelers to do but hook up the hoses and dial in the desired fuel load. The FQIS was not working properly on Flight 143 due to a poorly soldered sensor. An impossibly complex sequence of mistakes by Air Canada technicians investigating the FQIS problem (which took over a year to unravel) managed to defeat the redundancy built into the system. This left Quintal and Pearson without working fuel gauges.
In order to complete their flight from Montreal to Ottawa, and on to Edmonton, Flight 143's maintenance crew resorted to manually calculating the 767's fuel load using a procedure known as "dripping" the tanks. "Dripping" might be compared to calculating the amount of oil in a car based on the dipstick reading. Among other things, the specific gravity of jet fuel is needed to make the proper drip calculations.
The flight crew had never been trained how to perform the drip calculations. It was a job previously delegated to the flight engineer, before Air Canada and other airlines went to two-man cockpits. To be safe they and others re-ran the numbers three times to be absolutely sure the refuelers hadn't made any mistakes -- each time using 1.77 pounds/liter as the specific gravity factor. This factor was written on the refueler's slip and used on all of the other planes in Air Canada's fleet. The factor the refuelers and the crew should have used on the brand new, all-metric 767 was .8 kg/liter of kerosene.
After a brief hop Flight 143 landed in Ottawa, and Pearson had the 767 re-dripped. The refuelers reporting the plane as having 11,430 liters of fuel contained in the two wing tanks. Pearson and Quintal, using the same incorrect factor used in Montreal, calculated they had 20,400 kilos of fuel on board. In fact, they left for Ottawa with only 9144 kilos, roughly half what would be needed to reach Edmonton.
|Gimli from the air. Photography by Wade Nelson.|
According to Pearson, the crew and passengers had just finished dinner when the first fuel pressure light came on. Flight 143 was outbound over Red Lake Ontario at 41,000 feet and 469 knots at the time. The 767s "Engine Indicator and Crew Alerting System" (EICAS) beeped four times in quick succession, alerting them to the fuel pressure problem. "At that point" Pearson says "We believed we had a failed fuel pump in the left wing, and switched it off, and opened a crossfeed valve so the left engine could feed from the right tank. We considered the possibility we were having some kind of a computer problem. Onboard computers were pretty new back then, and we were still a bit suspicious of them. Our flight management computer showed more than adequate fuel remaining for the duration of the flight. We'd made fuel checks at two waypoints and had no other indication of a fuel shortage." When a second fuel pressure warning light came on, Pearson felt it was too much of a coincidence and made an instantaneous decision to divert to Winnipeg. Quintal keyed the mike and requested clearance in Apollo 13 fashion: "We have a problem." he said "We're going to, uh, requesting direct Winnipeg" Pearson throttled back the engines, and Flight 143 turned to the southwest and began a gradual descent to 28,000.
|Skid marks in runway left by 767. Photography by Maurice Quintal.|
Pearson and Quintal immediately began making preparations for a one engine landing. Two minutes later, just as preparations were being completed, the EICAS issued a sharp bong - indicating the complete and total loss of both engines. Says Quintal "It's a sound that Bob and I had never heard before. It's not even in the simulator." Things got quiet. Starved of fuel, both Pratt & Whitney engines had now flamed out. Pearson's response, recorded on the cockpit voice recorder for all eternity, was "Oh F___."
|767 "Glass Cockpit." Photography by Maurice Quintal|
The RAT is the 767's Ram Air Turbine, a propeller driven pump tucked under the belly of the aircraft. The RAT can supply enough hydraulic pressure to move the control surfaces and enable a dead-stick landing. The loss of both engines causes the RAT to automatically drop into the airstream and begin supplying hydraulic pressure.
As Pearson began gliding the big bird, Quintal "got busy" in the manuals looking for procedures for dealing with the loss of both engines. There was nothing. Neither he or Pearson had ever been trained on this contingency.
Pearson reports thinking "I wonder how it's all going to turn out." Controllers in Winnipeg began suggesting alternate landing spots, but none of the airports suggested, including Gimli, had the emergency equipment they would need for a crash landing. The 767's transponder had "Gone dark" as well, leaving controllers in Winnipeg scrambling, using a cardboard ruler on a standby radar screen to try and determine the 767's location and rate of descent. The more modern screens wouldn't display an aircraft without a functioning transponder.
Pearson glided the 767 at 220 knots, his best guess as to the optimum airspeed. There was nothing in the QRH manual about minimum sink. The windmilling engine fans were creating enormous drag, giving the 767 a sink rate of somewhere between 2000 and 2500 fpm. Co-pilot Quintal began making glide-slope calculations to see if they'd make Winnipeg. The 767 had lost 5000 feet of altitude over the prior ten nautical (11 statute) miles, giving a glide ratio of approximately 11:1. ATC controllers and Quintal both calculated that Winnipeg was going to be too far a glide-the 767 was sinking too fast. "We're not going to make Winnipeg" he told Pearson. Pearson trusted Quintal, and immediately turned north towards Gimli.
"For me it was a cold, unemotional experience.
It was the only time in my entire career I felt
like I was a computer. I had a job to do and I
stayed totally focused."
- Pilot Bob Pearson
To say that runway 32L was used for auto racing is perhaps an understatement. The inactive runways had been "carved up" into a variety of racing courses, including the aforementioned dragstrip. Drag races were the only racing event not taking place on April 23rd, 1983 since this was "Family Day" for the Winnipeg Sports Car Club. Go-cart races were being held on one portion of runway 32L, and just past the dragstrip a portion of the runway served as the final straightaway for a road course. Around the edges of the straightaway were cars, campers, kids and families in abundance. To try and land an airplane in the midst of all of this activity was certain disaster.
|The 767 shown with emergency slides on each side of the fuselage. A portable generator is shown at the nose of the airplane. Photography by Maurice Quintal.|
Six miles out Pearson began his final approach onto what was formerly RCAFB Gimli. Pearson says his attention was totally concentrated on the airspeed indicator from this point on. Approaching runway 32L he realized he was too high and too fast, and slowed to 180 knots. Lacking divebrakes, he did what any sailplane pilot would do: He crossed the controls and threw the 767 into a vicious sideslip. Slips are normally avoided on commercial flights because of the concern the buffeting creates in some of the passengers. Some of Flight 143's passengers ended up looking at nothing but blue sky, the others straight down at a golf course. Says Quintal, "It was an odd feeling. The left wing was down, so I was up compared to Bob. I sort of looked down at him, not sideways anymore.
|Fuselage of the 767 straddling a guard rail. Photography by Maurice Quintal.|
The "Amazing Coincidences" of Gimli:
The 767 silently leveled off and the main gear touched down as spectators, and kids on bicycles fled the runway. The gigantic Boeing 767 was about to become a 132 ton silver bulldozer. One member of the Winnipeg Sports Car Club was reportedly walking down the dragstrip, five gallon can full of hi-octane racing fuel in hand, when he looked up and saw the 767 headed right for him. Pearson stood on the brakes the instant the main gear touched down. An explosion rocked through the 767's cabin as two tires blew out. The nose gear hadn't locked down, and collapsed. The nose of the 767 slammed against the tarmac, bounced, and began throwing a hundred foot shower of sparks. The right engine nacelle struck the ground. The 767 reached the tail end of the dragstrip and the nose grazed a few of the guardrail's wooden support poles. (The dragstrip began in the middle of the runway with the guardrail extending out towards 32L's threshold.) Pearson applied extra right brake so the main gear would straddle the guardrail. Would all the sports car fans all be able to get out of the way, or would Pearson have to veer the big jet off the runway to avoid hitting stragglers?
"I've found myself that glider pilots make better
jet drivers. The guys who do the best deadstick
landings in the simulator are all glider pilots. It
definitely gives you an edge in managing the flight."
- Jeff Morris, Training Captain with Hunting Cargo Airlines, Ireland
The only injuries that resulted from Pearson's dead-stick landing
of Flight 143 came from passengers exiting the rear
emergency slide too fast and hitting the asphalt. None of the injuries
were life-threatening. The race fans had all managed to flee the path
of the 767. The fire in the aircraft's nose area was battled by
members of the Winnipeg Sports Car Club who reconverged on the
plane with dozens of hand-held fire extinguishers. Pearson had
touched down 800 feet from the threshold and used a mere 3000
feet of runway to stop. A general aviation pilot who viewed his
landing described it as "impeccable." The 767 was relatively
undamaged. Aircraft #604 was repaired sufficiently to be flown out
of Gimli by Air Canada's chief CFI two days later, and after
approximately $1M in repairs it re-entered the fleet. To this day
Aircraft #604 is known to insiders as "The Gimli Glider." The
avoidance of disaster was credited "To Capt. Pearson's knowledge
of gliding, which he applied in an emergency situation to the landing
of one of the most sophisticated aircraft ever built." Captain
Pearson credits Co-pilot Quintal strongly for his cockpit
management of "Everything but the actual flight controls," including
his recommendation of Gimli as an alternate landing spot. Captains
Pearson and Quintal spoke at the 1991 SSA Convention in
Albuquerque about their experience. Pearson was, at the time, still
employed and flying for Air Canada, and occasionally flying his
Blanik L-13 on the weekends; he has since retired to raise horses.
Maurice Quintal is now an A-320 Pilot for Air Canada, and will
soon be captaining 767's - including Aircraft #604, "The Gimli
An amusing side-note to the Gimli story is that after Flight 143 had landed safely, a group of Air Canada mechanics were dispatched to drive down and begin effecting repair. They piled into a van. They reportedly ran out of fuel en-route, finding themselves stranded somewhere in the backwoods of Manitoba.
Wade H. Nelson is a freelance writer living in Durango, Colorado, which he calls "The last of the great ski towns." He may be reached at: firstname.lastname@example.org
|Soaring Magazine||22 October 1997|