Gimli Glider Incident Gimli Glider Incident InvestigationInvestigation

By Lee Xuan Hong By Lee Xuan Hong

OverviewOverview

In this investigation, we will find out what the In this investigation, we will find out what the incident is about and why the incident incident is about and why the incident occurred.occurred.

Summary of Incident(1)Summary of Incident(1)

Gimli glider is the nickname of the Air Gimli glider is the nickname of the Air Canada aircraft, which was involved in an Canada aircraft, which was involved in an incident due to maintenance errors.incident due to maintenance errors.

Air Canada Flight 143, a Boeing 767-200 jet Air Canada Flight 143, a Boeing 767-200 jet (Gimli glider), ran out of fuel at 26 000 feet (Gimli glider), ran out of fuel at 26 000 feet high when it was halfway through its journey high when it was halfway through its journey to Edmonton via Ottawa from Montreal.to Edmonton via Ottawa from Montreal.

Summary of Incident(2)Summary of Incident(2)

However, the flight crew successfully glided However, the flight crew successfully glided the aircraft to an emergency landing safely.the aircraft to an emergency landing safely.

The aircraft was nicknamed Gimli glider The aircraft was nicknamed Gimli glider because it glided to a landing at Gimli because it glided to a landing at Gimli Industrial Park Airport.Industrial Park Airport.

Date of IncidentDate of Incident

July 23 1983July 23 1983

TimelineTimeline

Day before Incident Day of IncidentDay before Incident Day of Incident

Aircraft flew from Toronto to Edmonton Aircraft flew from Aircraft flew from Toronto to Edmonton Aircraft flew from

A pre-flight inspection was Edmonton to Montreal,A pre-flight inspection was Edmonton to Montreal,

made by a maintenance then from Montreal to made by a maintenance then from Montreal to

engineer for the next flight Edmonton. (incident engineer for the next flight Edmonton. (incident

the next day occurred) the next day occurred)

Day before IncidentDay before Incident

The aircraft flew from Toronto to Edmonton where The aircraft flew from Toronto to Edmonton where it underwent routine checks. it underwent routine checks.

The engineer there noticed that the Fuel Quantity The engineer there noticed that the Fuel Quantity Indicator System (FQIS) was not working unless Indicator System (FQIS) was not working unless he disabled one of the 2 measuring sensors. By he disabled one of the 2 measuring sensors. By doing so, the fuel gauges in the cockpit were doing so, the fuel gauges in the cockpit were restored to working order but with only 1 FQIS restored to working order but with only 1 FQIS measuring sensor operative.measuring sensor operative.

Day of Incident(1)Day of Incident(1)

The aircraft flew to Montreal from Edmonton. Before The aircraft flew to Montreal from Edmonton. Before the plane departed, the engineer informed the pilot of the plane departed, the engineer informed the pilot of the problem with the FQIS and that the fuel in the the problem with the FQIS and that the fuel in the tanks would have to be checked with the tanks would have to be checked with the floatstickfloatstick (an (an instrument used to measure fuel for aircrafts).instrument used to measure fuel for aircrafts).

The pilot however, misunderstood and thought that the The pilot however, misunderstood and thought that the plane had been flown with the fault the previous day.plane had been flown with the fault the previous day.

Day of Incident(2)Day of Incident(2)

On arriving at Montreal, there was a crew change for the return On arriving at Montreal, there was a crew change for the return flight back to Edmonton. The outgoing pilot informed Captain flight back to Edmonton. The outgoing pilot informed Captain Pearson and First Officer Quintal of the problem with the FQIS Pearson and First Officer Quintal of the problem with the FQIS and passed on his mistaken belief that the plane was flown the and passed on his mistaken belief that the plane was flown the previous day with this problem. In a further misunderstanding, previous day with this problem. In a further misunderstanding, Captain Pearson believed that the FQIS had been totally Captain Pearson believed that the FQIS had been totally unserviceable.unserviceable.

An engineer who was investigating the problem with the FQIS An engineer who was investigating the problem with the FQIS re-enabled the measuring sensor which was originally disabled re-enabled the measuring sensor which was originally disabled in order to test the system. As a result, the fuel gauges in the in order to test the system. As a result, the fuel gauges in the cockpit went blank. It was then when the engineer was called cockpit went blank. It was then when the engineer was called away, forgetting to disable the measuring sensor.away, forgetting to disable the measuring sensor.

Day of Incident(3)Day of Incident(3)

As a result, Captain Pearson wasn’t As a result, Captain Pearson wasn’t surprised to see blank fuel gauges when he surprised to see blank fuel gauges when he entered the cockpit. Thus, they measured entered the cockpit. Thus, they measured the fuel via floatstick. It was then when they the fuel via floatstick. It was then when they made a made a criticalcritical error… error…

Conversion ErrorConversion Error

As fuel was added to the aircraft, a conversion error was made. As fuel was added to the aircraft, a conversion error was made. Correct CalculationCorrect Calculation Wrong CalculationWrong Calculation (A litre of fuel was 0.803kg) (A litre of fuel was 0.803kg) Weight of 1 litre of fuel in poundsWeight of 1 litre of fuel in pounds

7682 litres × 0.803 = 6169 kg 7682 litres × 0.803 = 6169 kg Weight of fuelWeight of fuel 7682 litres x 1.77 = 13597 kg 7682 litres x 1.77 = 13597 kg 22300 kg − 6169 kg = 16131 kg 22300 kg − 6169 kg = 16131 kg already in planealready in plane 22300 kg – 13597 kg = 8703kg 22300 kg – 13597 kg = 8703kg16131 kg ÷ 0.803 = 20088 litres 8703 kg ÷ 1.77 kg = 4916 litres of fuel 16131 kg ÷ 0.803 = 20088 litres 8703 kg ÷ 1.77 kg = 4916 litres of fuel of fuel to be transferred to be transferred of fuel to be transferred to be transferred

Fuel requirement of 22300 kg for the plane. 7682 litres of fuelFuel requirement of 22300 kg for the plane. 7682 litres of fuel already in the tanks already in the tanks

Weight Required Weight Required

Instead, of 20088 litres, 4916 litres of fuel was Instead, of 20088 litres, 4916 litres of fuel was transferred. The same error was made when the plane transferred. The same error was made when the plane stopped for refueling at Ottawa. Thus, the plane left for stopped for refueling at Ottawa. Thus, the plane left for Edmonton with no chance of reaching there. Edmonton with no chance of reaching there.

Running out of Fuel and LandingRunning out of Fuel and Landing

Therefore, the plane ran out of fuel at 26000 feet Therefore, the plane ran out of fuel at 26000 feet altitude.altitude.

Fortunately, Captain Pearson was an experienced Fortunately, Captain Pearson was an experienced glider pilot and he executed a forward slip to increase glider pilot and he executed a forward slip to increase drag and lose altitude so that the aircraft will descend drag and lose altitude so that the aircraft will descend more quickly. He “stood” on the brakes as soon as the more quickly. He “stood” on the brakes as soon as the wheels touched the runway.wheels touched the runway.

The nose of the aircraft scraped against the runway as The nose of the aircraft scraped against the runway as the nose wheel was forced back into its well.the nose wheel was forced back into its well.

None of the passengers were seriously hurt.None of the passengers were seriously hurt.

ConclusionConclusion

After investigation, the reasons of the air After investigation, the reasons of the air crash were found to be:crash were found to be:-Wrong conversion factor used-Wrong conversion factor used-Carelessness of the engineers-Carelessness of the engineers-Misunderstanding between the previous -Misunderstanding between the previous pilot and Captain Pearsonpilot and Captain Pearson

In other words, a chain of minor human In other words, a chain of minor human errors led to this incident.errors led to this incident.

The EndThe End

Sources: Wikipedia, Google, http://mattstodayinhistory.blogspot.com/2010/07/gimli-glider-july-23-1983.html