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Picture this: you are piloting a brand new Boeing 767-200, making a regular flight from Montreal to Edmonton. Over Red Lake, Ontario, the aircraft's cockpit warning system sounds, indicating a fuel pressure problem on the aircraft's left tank pump.
You read the manual. It says it will be a failing fuel pump. The recommended action: as there are two pumps by engine, turn off the failing one. A few moments later, the second fuel pump of the port engine starts to fail. At this point, you begin to worry if you have enough fuel: when you boarded the plane, the Fuel Quantity Indicator System was off. This device says how much fuel you have. But the ground crew dipped the tanks, and tested the fuel quantity with a dipstick incorporated in the wing fuel tanks. Then, you as the pilot, your copilot, and the ground crew, checked and rechecked the numbers. So, there must be enough fuel... or not?
Well, this is not a theoretical question. All this happened on 23 July 1983, when the Boeing 767-200 registration C-GAUN, c/n 22520/47, Air Canada flight 143, was making this route with Captain Robert (Bob) Pearson and First Officer Maurice Quintal at the controls.
At this point, they requested a diverted landing on Winnipeg. Not much later, the left engine ran out of fuel. The captain leveled the plane, expecting that anything that happened inside the left wing will be happening in the right one, and trying to squeeze any drop of fuel into the right engine. Their last hopes of pump malfunctions died when the "low pressure bell" sounded again with the right pumps, and a "bong" (a sound never heard in the simulations) indicated a total loss of fuel.
If you are pretending to emulate this flight, and that's my intention, you must be sweating about the perspective of landing a 767 with 61 passengers, plus a crew of 8, inside any nearer airport, without a second chance. So, to do it real, turn off the avionics now.
It's no joke. The 767-200 avionics are powered by the engines' generators, or by the APU. Without fuel, there are no engines, no APU, no electricity, no instruments. There was, of course, a heading indicator, an altimeter, a radio and an artificial horizon, all battery operated, or just mechanical.
Not hard enough? Well, the engines' electricity feeds the hydraulic pumps too. You can't handle manually any plane with a span greater than 75 feet. Without hydraulics, the controls freeze. You'll be unable to move the control surfaces in a few seconds. But all the great airliners have a RAM inside. This is a a generator driven by a small propeller, usually hidden but ready to emerge in an emergency like this. Two problems with the RAM: the faster you go, the better it works. And, it induces drag. As I said, two problems when you are gliding slowly.
Of course, you'll want to know what is the better gliding speed in a 767. Well, the copilot checked the manual, and the answer is... nothing. There was no "out of fuel" section in the plane's manual. Nobody ever tried or calculated the gliding speed. To make things worse (yes, Murphy's Law happens) the VSI indicator was not one of the battery powered instruments. Getting funny?
To reproduce this daunting scene, we flightsimmers need a Boeing 767-200. We can find many 767s in the FlightSim.Com library, but there is a copy of the Gimli Glider called P762GIML.ZIP. When I installed this file, I made the usual test: moving surfaces, texture quality, take off speed... and here I found a big problem. The takeoff run was too long, and the climb angle too low. Then, when I tried to make a landing circuit, the ailerons where too heavy. Of course, I couldn't make the full turn to the airport, so the plane crashed halfway.
The problem is that this simulation has all the tanks filled up, and all the passenger seats occupied. Of course, the total weight goes over the maximum takeoff weight. In our case, we need to change the passenger weight as follows:
| First class | 1700 | |
| Business class | 1700 | |
| Economy class | 3400 |
(I prefer tourist; economy sounds like something like expendable.)
The fuel weight, of course, depends of the moment you start the simulation, but I will use zero. If you wish to start right in the moment when the engines turn off, the available data is: altitude: 26,000 feet. Location: roughly over Red Lake, Ontario, heading 250 to Winnipeg. Speed: as the plane was descending, it may have been 300 knots. If you want to start on the tarmac, I'll give you later the real and estimated fuel data.
But it doesn't finish the tuning of our model. It turns as fast as a Flash Gordon black and white spaceship. So, I edited the aircraft.cfg file and increased the aileron_effectiveness and rudder_effectiveness numbers to 1.200. It gives me a turn rate similar to the default 777, maybe a bit more agile. Maybe they are not the right numbers, but I'm a repainter, not an aerodynamics engineer. The original numbers are not a mistake, but the ones that emulated the handling of the plane with the loss of energy and only the RAM working.
Once our plane is flying, engines out, without avionics, and assuming we dropped the RAM turbine, we will start to have good news. The first one is that Rob, the captain, was a glider pilot in his free time. He estimated the best gliding speed at 220 knots. They had another lucky shot: the Winnipeg airport had an old fashioned radar. How can that be lucky? Well, the modern traffic control towers don't use radar, they use transponders. The tower sends a pulse "interrogating" all the planes, and the plane's transponder sends its ID and position back. It's cheaper than a radar, and can't be jammed by ground buildings or clouds... but if you are a drug carrier with the transponder shut down, or a 767 without engines, the control tower can't see you.
So the First Officer Maurice Quintal began making calculations to see if they could reach Winnipeg. He used the altitude from the mechanical altimeter, while the distance traveled was supplied by the air traffic controllers in Winnipeg, measuring the distance the aircraft's echo moved on their radar screens. The aircraft had lost 5,000 feet in 10 nautical miles (1.5 km in 18.5 km), giving a glide ratio of approximately 12:1. The controllers and Quintal both calculated that Flight 143 would not make it to Winnipeg. There wasn't any airport nearer where the 767 can be landed... and here they were lucky again. The copilot was a military pilot, and he served in the Royal Canadian Air Force at Gimli airbase. It was closed, but not destroyed. The calculations showed that they will make it, so they diverted to Gimli as they were twelve miles out, so we must wait to be at this distance before turning right.
As they aproached, Captain Pearson lowered the landing gear by a gravity drop. Due to the airflow, the nose wheel failed to lock into position. It is a very common design failure and I'm still wondering why so many planes are designed like this. Even so, the drag reduced the speed, the RAM supplied less power and the controls started to become heavy again. If we want to make it real, then we must stop the simulation, edit the aircraft.cfg and reinsert the original, heavy numbers for aileron_effectiveness and rudder_effectiveness. Going back to the simulation, and like the real flight, all starts to happen faster now. The captain saw that he was too high from the landing point. In a normal landing, you can deploy the airbrakes and flaps or make a go-around. In this case, there is only a glider maneuver that could be made, a maneuver that a passenger captain never does.
Pearson tried a side slip. Turning the wheel for a left turn and pushing the rudder for a right turn, the plane fought with itself and descended faster. It made the left wing start to point down, carrying the plane so near to a golf field that one of the passengers said that he could almost see the number of the clubs.
Unknown to him, however, the base had become a dragstrip and had decommissioned one of its runways. As a result of the runway's conversion to use as a dragstrip, the runway had been converted into two lanes with a guard rail running down the middle of it. Furthermore, a "Family Day" was underway at the dragstrip that particular day and the area around the decommissioned runway was covered with cars and campers. The decommissioned runway itself was being used to stage a race. If he had know that, he would have diverted to the active one... but he could see only the wrong runway, the color of the another one merged with the background.
The side slip was prolonged almost at the crashing point. Forty feet above the ground--mere seconds before contact--Captain Pearson managed to wrestle Flight 143 back to a straight and level approach. The plane leveled, quietly. So quietly that none of the campers heard it. The alarm came from a boy mounting a bicycle, who started to shout. Quickly, everybody dove to get out of the path of the rapidly descending plane. At 8:38 pm central time, the rear landing gear grabbed the tarmac at Gimli airport, just 800 feet from the start of the runway but blew out two tires and threatened to skid off the runway. Ahead was a steel barricade that had been erected across the runway. Suddenly, the front landing gear collapsed. The nose of the plane scraped along the runway throwing dangerous sparks but dragging the plane slower. The plane slammed into a guard rail which made the plane lose a bit more speed to stop it from flying off the runway.
As the simulation ends at this point, I would stop talking about the plane right now, but I prefer to continue. A minor fire in the nose area was soon put out by racers and course workers armed with fire extinguishers. As the aircraft's nose had collapsed onto the ground, its tail was elevated and there were some minor injuries when passengers exited the aircraft via the rear slides. These were tended by a doctor who had been about to take off in an aircraft on Gimli's remaining runway. The pilot, copilot and ground crew were found guilty by the company, due to mistakes in the fueling process, but a pilot strike and the public opinion restored him to the job and awarded with the Federation Aeronautique Internationale Diploma for Outstanding Airmanship. The plane was repaired and put back into service until January 24, 2008, when he was retired and used for parts. But, funny, the mechanics sent out to Gimli from Winnipeg Airport were left stranded when their van ran out of fuel.
If you want to make the flight just flom the start, these are the fuel weights as the wikipedia says:
At the time of the incident, Canada was converting to the metric system. As part of this process, the new 767s being acquired by Air Canada were the first to be calibrated for the new system, using litres and kilograms instead of gallons and pounds. All other aircraft were still operating with United States customary units. For the trip to Edmonton, the pilot calculated a fuel requirement of 22,300 kg. A dripstick check indicated that there were 7,682 litres already in the tanks. In order to calculate how much more fuel had to be added, the crew needed to convert the quantity in the tanks to a weight, subtract that figure from 22,300 and convert the result back into a quantity. (In previous times, this task would have been completed by a flight engineer, but the 767 was the first of a new generation of airliners which made this position redundant.) A litre of jet fuel weighs 0.803 kg, so the correct calculation was:
7682 litres x 0.803 = 6169 kg
22300 kg - 6169 kg = 16131 kg
16131 kg - 0.803 = 20088 litres
Between the ground crew and flight crew, however, they arrived at an incorrect conversion factor of 1.77, the weight of a litre of fuel in pounds. This was the conversion factor provided on the refueller's paperwork and which had always been used for the rest of the airline's imperial calibrated fleet. Their calculation produced:
7682 litres x 1.77 = 13597 'kg'
22300 kg - 13597 'kg' = 8703 kg
8703 kg - 1.77 = 4916 litres
Instead of 22,300 kg of fuel, they had 22,300 pounds on board -- only a little over 10,000 kg, or less than half the amount required to reach their destination. Knowing the problems with the FQIS, Captain Pearson double-checked their calculations but was given the same incorrect conversion factor. All he did was check their arithmetic, inevitably coming up with the same erroneous figures.
I want to thank to:
http://www.damninteresting.com/?p=744My previous reviews:
Looking for a Warhawk
Looking for a Tiger
Looking for a Tinmouse
Looking for a Spad VII
Looking for a Mosquito
Alejandro Hurtado
dracosist2@cantv.net
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