Solution: four Year 12 science and technology students from King Edward VI school in Northumberland and two small pieces of black rubber.
Today, those four pupils will find out how their work compares with that of 60 other finalists in The BA Crest national science fair awards. But to the 22 RAFsearch and rescue chopper crews, they are already winners.
One of the four, Angharad Porteous, 18, has been awarded a pound;22,000 RAF scholarship to study engineering at Cambridge, after which she will enlist. The other three - Ella Vogel, Scott Mulcahy and Robert Franks - are also off to some of Britain's top universities to study science.
Dr Tim Hughes, the science teacher who coached them through more than 100 hours working on the project, said: "I feel immensely proud of them for coming up with such complex solutions, at such a young age while studying AS-levels It's quite astounding."
Dr Hughes, who has put hundreds of unpaid hours into the school's engineering education scheme, is now overseeing another four students on a further helicopter design quest.
The RAF has an established engineering education scheme: it commissions crack science students to find fresh ideas for some of its more intractable problems.
Put simply, the problem facing Angharad and her team-mates was that the lever controlling the helicopter's elevation is prone to jam. If the Sea King was climbing, it would continue doing so; and if rapidly descending - well, the consequences do not bear thinking about.
"What they've had to do every time it's happened - and it's happened quite regularly - is get the winchman in from the back to force the lever so they can make an emergency landing," said Angharad (pictured, left, with Ella).
"There haven't been any accidents, but it was inevitable if they hadn't fixed it."
The pupils proposed four solutions, one closely resembling the version RAF engineers were already working on. But the fourth - two rubber strips that stopped the lever jamming - was simpler, cheaper, and arguably better.
RAF engineers have commended that solution to Augusta Westland, the helicopters' manufacturers. It was impressed and is considering introducing it.
Flight lieutenant Mick Wood, an engineer at RAF Boulmer, said "The senior engineers were impressed. The air force had created an emergency recovery fix but the students came up with a cheap fix to stop the problem."
'Scientists are weird', page 10