Human error

Passengers knew they were flying into the setting sun and told stewardesses to notify the pilots but that sort of stuff does not happen in Latin American airlines.

the fuel situation is common on every flight: if the pilots learn actual flying skills by climbing or descending on the own, their ham fisted operation of the throttle costs several hundred dollars of fuel on a financially marginal flight, whereas if the computer operates the throttle it can do so perfectly and save fuel. so every flight pilots lose skills and computers gain them. so when air france had a computer that suddenly cut out, the pilots didn't know what to do.

The zero-fuel weight of a 747-8 is 330,00kg. It's maximum take off weight is 448,000kg. So about 25% of a fully loaded 747 is fuel.

Quote: Nareed

There were additional errors in both cases, but those stand out and were the main causes of the accidents.

What is fascinating about that Gimli Glider story is that the same error was made so many times. They calculated how much was in the plane, then they calculated how much they had to add, then an independent person checked both calculations. Then they made a stopover and a dipstick measurement was made, but once again they repeated the calculation with the same error.

One liter of water weighs 1 kilogram. Jet fuel floats on water (everyone knows that) so one liter of jet fuel weighs less than 1 kilogram.

Quote: Pacomartin

What is fascinating about that Gimli Glider story is that the same error was made so many times.

This is reminiscent of the Hubble's flawed mirror. They all made the same calculation with the wrong conversion factor, so they all got the same wrong result they thought it was right. The Hubble mirror was precisely ground to the wrong specification.

Just as the pilots in south america kept flying for hours into the setting sun and never realized that it meant they were flying west rather than north east.

In gimli glider, the crew really didn't consider the tanks were running dry it was the on board cockpit visitor who re-inforced the concept of the tank actually being low in fuel as the reason for the low fuel pressure, low fuel flow, engine out sequence they were about to experience.

One plane took off without being able to find its fuel receipt and so asked for the data to be radioed to them when the paperwork was found. Of course it turned out that no one could find the fuel receipt because it didn't exist, the plane never having been refueled at all.

Quote: Nareed

They all made the same calculation with the wrong conversion factor, so they all got the same wrong result they thought it was right.

Yes, but some conversion factors are fundamental to measuring system. The plane had 7700 liters of fuel. So now 7700 liters of water weighs 7700 kilograms by definition. Everyone knows that fuel floats on water so 7700 liters of fuel most weigh less than 7700 kg. The specific gravity of fuel is 80.3% so the correct calculation is 80.3%*7700. Now most people will not remember 80.3% for fuel, but they all did 177%*7700 which they should have recognized as incorrect because it was bigger than 100%. Jet fuel doesn't sink in water. It is just basic definitions in metric.

For instance I know that the degree in a quarter circle are 90. I know that there are 60 minutes in a degree, and that a nautical mile is the same a minute. So the equator to the North Pole is 90 degrees * 60 minutes = 5400 nautical miles. I know BY DEFINITION that the distance is also 10,000 kilometers.
So I know that 5400 nautical miles = 10,000 kilometers. It is impossible for me to forget that conversion since I will never forget that there are 60 degrees in a minute.

If you ask me how many kilowatt hours are in a horsepower I may forget and have to look it up. But it is not conversion based on a definition. There is nothing obvious about it.

Quote: Fleastiff

I think it is ryan air that aggressively punishes pilots who land with too much fuel and controllers get sick of ryan air planes squaking about 'sucking fumes' as they ask priority for landing.

Allegiant Air has been busted for this a couple times. The FAA mandates taht they must have enough fuel for an extra 45 minutes of flying, but on July 23rd Allegiant flight 426 (Vegas to Fargo) only had 42 minutes worth.

Quote: Las Vegas Review Journal

Flight 426: "Our company has been trying to call and we're down circling Fargo. We don't have enough fuel to go anywhere else. Our guys are trying to get in touch with the tower manager to coordinate our landing or I'm going to have to declare an emergency and come in and land."

Fargo tower: "There'll be a window opening in about 20 minutes for a landing."

Flight 426: "Yeah, I don't have 20 minutes."

Fargo tower: "Roger, unless there is an emergency, there's Grand Forks Airport which is 70 miles to the north."

Flight 426: "Yeah, listen we're at bingo fuel here in about three to four minutes. I've got to come in and land."

("Bingo fuel" is a military slang term meaning "running on empty.")

Fargo tower: "You'll have to declare an emergency for that and we would coordinate to get you in."

The controller then told the pilots they should have known the airport was going to be closed (so the Navy's Blue Angels could practice) before they left Las Vegas. That flight was piloted by 2 executives at Allegiant "because the airline is short of qualified pilots."

the fuel truck operators do not do conversions... they read the chart taped to the work area of their truck and go down one column and across to another column. they do not think. they are not in "math mode".

Quote: Pacomartin

So now 7700 liters of water weighs 7700 kilograms by definition. Everyone knows that fuel floats on water so 7700 liters of fuel most weigh less than 7700 kg. The specific gravity of fuel is 80.3% so the correct calculation is 80.3%*7700. Now most people will not remember 80.3% for fuel, but they all did 177%*7700 which they should have recognized as incorrect because it was bigger than 100%. Jet fuel doesn't sink in water. It is just basic definitions in metric.

there's knowing, and then there's thinking about what you know.

I think I can more clearly illustrate this with a joke. Someone in a panic asks "What's the number for 911?"

A person in a panic can be easily understood not to be thinking. But thinking is a conscious, deliberate act. It doesn't just happen. You can see it all the time, like people saying "good morning" at 3 pm, or turning left after being told to turn right, or passing the salt when you ask for the pepper, or, in the case of flight 143, using the wrong conversion factor.

You're right that two seconds of thought would have avoided the entire debacle. That can also be said for many other air disasters, even when there was some kind of mechanical failure or weather event involved.

It's worth noting that after the FUBAR fuel situation, the pilots at least kept their focus on flying their crippled jet effectively. They were thinking then.

Remember the Air Florida crash in DC due to icing on a snowy day? The CVR tapes are unclear whether on the checklist one of the pilots answered "on" or "off" in response to "anti-icing." One documentary labeled the answer as "onf," meaning the pilot answered on and off in the same word. I find that completely plausible. Pilots unused to flying in icy conditions could easily overlook the importance of anti-ice gear even in the middle of a snow storm. Habits are habits for a reason.

In fact, I'll go as far as to say some pilot training protocols and flight procedures are set, at least in part, to compensate for a failure to think. the reason is more likely that in an emergency there may not be time to figure things out. That is to say, no time to think. But the effect is the same.

It was clearly "off" and I doubt that during their 43 second flight the pilots even realized their error, though the copilot's doubts were confirmed about insufficient power, he never realized the reason for it, he just realized they were going down.

Its the same thing with the small 19 seater, the pilot called for "gear up" the co pilot did it, as the nose wheel traveled aft, the center of gravity shifted just too far rearward and in all their maneuverings in trying to regain control, they never thought to lower the gear.