KEY POINTS:
You are standing in a queue to board your aircraft. The flight is full, the hour late and you are tired. Then you hear the call to board and head down the gangway, your path blocked by a crowd of other passengers.
Slowly you shuffle on to the aircraft, only to find your progress is held up by a scrum of people pushing luggage into overhead lockers, climbing over each other to reach windows and arguing over seats.
It is a typical start to a flight _ and, says American nuclear physicist Jason Steffen, it is also unnecessary.
Dr Steffen, who works at the giant particle accelerator laboratory Fermilab, in Illinois, has calculated that there is a far better _ and quicker _ way to get passengers aboard an aircraft than letting people wander on in groups.
Using his knowledge of atomic and molecular behaviour, he has worked out a way to slash boarding times by a factor of seven by carefully ordering passenger access to aircraft.
"I was heading back from a conference and I was kept waiting for almost half an hour after moving through the gate to getting to my seat.
I realised there had to be a better way. So I decided to find out the best method."
The Markov chain Monte Carlo algorithm gave him his answer. The journal Nature says the algorithm is widely used to investigate how atoms and molecules arrange themselves.
Dr Steffen used it to discover how passengers stacked themselves inside a plane. He assumed the main cause of delay is aisle-blocking caused by passengers pushing luggage into lockers.
Then he ran boarding options on his computer using the algorithm and found that one option was easily the best.
This requires that each passenger be given a specific place in the queue, that people in window seats board first, and that they do so with an empty row between them and the next passenger.
Thus, passengers entering at the back of a 40-row aircraft would board filling up seat 40A (window seat), then 38A, then 36A and so on to the front; then they fill 39F (window seat, other side), 37F, 35F, to the front; then 39A; 37A, 35A to the front; and so on, filling first window seats, then middle seats and finally aisle seats.
Boarding from the front, they would begin at 1A, then move to 3A. Either way, people loading luggage do not block progress.
"Sometimes you have to put families together if they have young children, but even then the system cuts down on boarding times significantly," says Dr Steffen, who has submitted his plan to the Journal of Air Transport Management.
"This is no simple back-of-an-envelope plan. It is a real solution for a real problem."
This last point is backed by air transport figures. Despite technical improvements, boarding times for aircraft have increased.
Other attempts to improve boarding have been made, with little success. But Dr Steffen is sure his method is the best.
"I have taken a patent out on the idea, so you can see I am very confident I have cracked this one.
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