THE GIMLI GLIDER

In command was Captain Robert “Bob” Pearson, 48, with roughly 15,000 flight hours. Beside him sat First Officer Maurice Quintal, 36, a former Royal Canadian Air Force pilot. Behind them, six cabin crew looked after 61 passengers, 69 people aboard in total. The aircraft was a Boeing 767-233, registration C-GAUN, fin number 604, one of Air Canada's first 767s and the first aircraft in the airline's fleet to measure its fuel in kilograms and litres instead of the pounds every other aircraft Air Canada flew still used. Canada's aviation industry was only partway through switching to metric, and the 767 was the leading edge of that change.

The trouble had actually started the night before, in Edmonton, when a fault made the aircraft's electronic Fuel Quantity Indicator System (FQIS) go blank. A technician did exactly what procedure called for: pulled and tagged the circuit breaker feeding the failed channel, formally deferring the repair. In Montreal the next day, a second technician briefly reactivated that same channel to test it, then got called away before restoring the tag properly. Nobody who came after him could be entirely sure, from the paperwork alone, whether the gauges might actually still work. Rather than risk it, the flight crew and ground staff fell back on the aircraft's oldest, least automated backup: measuring the fuel by hand.

With both engines gone, Pearson had only a handful of battery- and RAT-powered instruments to work with: airspeed, altitude, basic attitude information, nothing resembling the normal, fully computerized 767 flight deck. There was no power for autothrottle and no meaningful autopilot, and no guidance at all for the one flight condition the aircraft had never been designed around.

He targeted roughly 220 knots by feel, faster than a sailplane's usual minimum-sink speed, because a 132-ton jet gliding “dirty,” with its landing gear and airframe drag factored in, behaves nothing like a sailplane. In one measured ten-nautical-mile stretch of the descent, the aircraft lost about 5,000 feet: a glide ratio of roughly 12-to-1, well short of the 767's theoretical best of around 20-to-1 under ideal conditions, but still enough distance to reach a runway they weren't at all sure, on paper, they could reach.

Facing a landing without engines and without hydraulically powered flaps or speed brakes, Pearson flew a forward slip: rudder deflected one way, ailerons the other, deliberately increasing drag to bleed off the extra altitude and speed the approach had left him. It's a maneuver every glider pilot learns and one that almost no airline training program teaches, since it's rarely if ever needed on a powered jet.

A teenager watching from the ground, Art Zuke, described what he saw to AOPA Pilot magazine years later, in about as plain a description of a 132-ton aircraft in a sideslip as exists.

In the immediate aftermath, Air Canada disciplined the people closest to the error: Captain Pearson was demoted for six months, First Officer Quintal was suspended for two weeks, and three maintenance staff were also disciplined, all for operating an aircraft without functioning fuel gauges. Appeals later reversed or reduced most of those penalties, and both pilots returned to flying for Air Canada. In 1985, Pearson and Quintal received the first-ever Fédération Aéronautique Internationale Diploma for Outstanding Airmanship, aviation's own acknowledgment that the same flight had been both a corporate failure and a genuine feat of flying.