What a gas
The instances of a modern hi bi-pass jet engine failing in flight are now extremely rare. Therefore, the odds of all engines failing in flight are astronomical. Unless of course there is a common factor which affects all engines. It has happened. Perhaps the most well known incident was when a B.A. Boeing 747 flew through volcanic ash from an erupting Mount Galunggung in Java. All engines stopped and the aircraft glided for 12 minutes until a restart was possible at around 14,000 feet. But this incident is well known so I wont repeat the details here, but here are a couple of others that are, perhaps, less well known.
A big jet can glide quite well. During normal descent the throttles are closed, and the plane becomes, in effect, a giant glider. This is, of course, until the aircraft lowers its gear and gets down and dirty. Once this happens the big jet assumes the flight characteristics of a brick. it takes a pilot of rare ability (and luck) to dead stick a powerless big bird down safely.
In 1983, a Boeing 767 belonging to Air Canada took off from Montreal
to fly to Edmonton and Ottawa. Before take off the pilot noted that there
was no display of fuel load in the cockpit. Due to a number of extraordinary
incidents, coincidences and mistakes, the pilot thought that this was how
the plane was being flown at that time. A misunderstood conversation with
the previous pilot plus the misinterpretation of the engineering notes
lead him to believe that the situation was acceptable. The fuel load meters
had in fact been working (unreliably at the time) but due to attentions
of a well wishing but unqualified technician they weren’t any more. When
he entered the cockpit, he saw what he expected to see, no fuel load meters.
He also thought that it had been cleared to operate in this manner so long
as the fuel tanks were dipped. More problems. The fuel is pumped into the
crafts tanks in litres. It then has to be converted into kilograms via
a calculator so that fuel requirements can be worked out.
The fuel man, being used to conversions from litres to pounds for older
aircraft used the wrong conversion factor and in fact only half the amount
of fuel that should have been loaded was pumped into the tanks. The dip
stick was marked in centimetres which, through tables, was converted to
litres. This didn’t help as they already knew that from the pump readout.
No problem though, the pilot has to cross check the ‘fuelies’ calculations
and he will spot the problem. Unfortunately the pilot also used the same
wrong conversion factor and he arrived at the same wrong answer as the
fuelie. This answer (pounds of fuel) was then punched into the in flight
management computer as kilograms and it was happy. The plane took off from
Montreal with almost exactly half the fuel it should have had. One last
chance. The 767’s first short hop was to Ottawa where, as a precaution,
the tanks were dipped again.
By an amazing stroke of misfortune, the fuel man there again used the
same incorrect conversion factor and the 767 ran out of fuel at 41,000
feet. From here on in the pilots luck starts to change for the better.
A small ex airforce base called Gimli was within gliding range and while
no longer used by the Airforce, was still being used by light aircraft.
With no engines running, the flaps could not be lowered, but luckily the
landing gear could. He would get only one landing attempt. He touched down
at 175 knots in perfect position only to see that a car race meeting was
in progress at the far end of the runway. Children, cars, tents and caravans
were clustered around the area beyond the runway’s end. With no reverse
thrust or ground spoilers, plus a fast landing speed, the racers were in
a bit of bother. They were a bit surprised as well, a 767 was not one of
the days entries. But under braking, the nose gear of the plane which had
not locked, collapsed.
This proved a blessing as the extra friction caused by the fuselage
rubbing on the runway stopped the big Boeing well short of the meeting.
A few passengers received minor injuries during the emergency evacuation,
which was necessary as the front of the plane was smoking. The Winnepeg
Sports Car Club rushed up with their fire extinguishers and doused any
remnants of fire.