100 Tonnes of Error

It was the closest we have ever come to a major aviation catastrophe in Australia.

A simple error of entering 262.9 instead of 362.9 into the aircraft’s computer almost resulted in the loss of 275 passengers and crew. When the aircraft reached rotation speed it remained firmly stuck to the runway, full power was applied & when it finally rotated, the rear of the aircraft hit the runway, dragged across 265m of bitumen, the grass overrun, hitting 2 localiser antennas & missing a concrete building by 30cm. The tail section had damage down to the pressure bulkhead & missing panels.

How did this happen?

It was 20 March 2009. Emirates Flight 407 was an A340-500 flying from Melbourne to Dubai. The copilot calculated a take off weight of 362.9 tonnes for the 14 hour flight. During the busy pre-flight he made a simple typo & entered a figure that was 100 tonnes lighter. During the start & taxi sequence, the opportunity to fix the error through checklist action was missed 4 times by the 2 pilots & the 2 augmenting pilots.

As the crew accelerated down the runway, they failed to notice the aircraft’s sluggish acceleration. At the point of calculated rotation the first officer pulled back on his side stick…nothing happened. He pulled harder…still nothing. The aircraft had rotated but still remained heavily on the bitumen. The pilot increased thrust to the TOGA detent. The tail section struck the runway hard with only 265 metres of runway remaining. There was still not enough lift to get airborne until 3 seconds later. It hit a 30cm high strobe light, a 60cm high localiser antenna & finally a 3m high antenna. As the jet slowly climbed away the crew received a tail strike warning, it was not pressurising & the Flight attendants told the front end that smoke was entering the aircraft.

The crew dumped fuel & returned to land. The smoke in the cabin was found to be dust from the tail scraping as the pressurisation bulkhead had been damaged.

How is it possible that the 4 crew were able to miss such a simple typo that almost resulted in a tragic crash with 275 POB.

Pretty simple really. A typo is such a simple error. The fact that that number was on a page surrounded by dozens of other numbers made it easy to miss. Windspeed, wind direction, outside air temp, altimeter setting, flap configuration, runway conditions, anti-ice selection, air conditioning status. Who’s going to pick up a single incorrect digit that is not out of normal operating weight limits? Maybe if it was an extra digit such as 3262.9 it might have stood out as odd, but a 262.9 tonne aircraft is completely normal.

The crew wasn’t even running behind schedule, they were relatively well rested & as they went through their check lists, their were no time, fatigue or external pressures.

For those of you thinking how easily this could happen to you, may I offer these simple mind tricks. Assess the gravity of this story. Imagine how lucky they were to survive, how close they were to a fireball at 200kts. Know that this crew has since been fired by Emirates. Imagine how much of a pain in the ass it would have been for the crew that eventually had to fly this aircraft to Airbus in France at 12000ft the entire way to get it repaired. Then determine which tasks you carry out on the daily that have the potential to kill you, or worse, make you famous if you stuff it up well enough! Then when it comes time to do these tasks, figure out a system that works for you to check it once, twice, ten times to ensure that it is correct.

If you’re feeling out of your normal groove through fatigue or stress or your dog died or whatever, have a system to know your critical steps & check them. A simple checklist in your notebook, an acronym, use your crew & back each other up. Use what you have at your disposal because we all make multiple mistakes every day. Own them, take responsibility for them, learn from them, grow into a better you because of them.

Just like running though a red light, the same error can have multiple outcomes. This Emirates crew got lucky, make sure your luck doesn’t run out when you need it most.

Have a safe day with your Crew!

Further information on automation and FMS systems that you may find beneficial.

https://www.iata.org/whatwedo/safety/runway-safety/Documents/FMS-Data-Entry-Error-Prevention-ed-1-2015.pdf

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