Sharing her challenge and route is Colin Bodill from Nottingham, who hopes to become the first person to fly around the world in a 100-horsepower Microlight aircraft, two years after setting the world record for a Microlight journey from London to Sydney.

Any adventure is a risk - it's such a small helicopter and it doesn't have autopilot

Jennifer Murray

Both pilots begin the first legs of their record-setting trips from Brooklands Airfield in Surrey on Wednesday.

Jennifer, who has three children and two grandchildren, will turn 60 on the 11th day of her adventure, when she is expected to be somewhere over the Jordanian desert.

"Of course there are risks if I find myself in severe turbulence or storms, or have mechanical failure in the wrong place," she said.

Weather risk

"Any adventure is a risk. One of the biggest challenges is that it's such a small helicopter and it doesn't have autopilot."

Bad weather could cause problems as her Robinson R44 helicopter cannot be flown above 8,000 feet, and she has rehearsed escaping from a submerged aircraft at a military base, in case she has to ditch in the sea.

Colin Bodill will be at the mercy of the elements

"I'm doing it for the great adventure and to raise money for charity," added Jennifer, who has homes near Frome in Somerset and in South Kensington, London.

The grandmother said she learned to fly helicopters in 1994 after her venture capitalist husband Simon bought a half-share in one.

"He said `I haven't got time to learn to fly it, so you'd better'.

"Since then he has learned too. We both love it, and it's a great way to travel."

Flying instructor Colin, 49, said: "My family is used to me going off on adventures, but I'm a bit nervous about the weather forecasts.

Good cause

My family is used to me going off on adventures, but I'm a bit nervous about the weather forecasts

Colin Bodill

"Northern Europe is experiencing bad weather at the moment and then there's the monsoon season in India and Burma to contend with, and 100mph winds over Greenland on the return leg."

His Rochdale-built Microlight is "completely open to the elements" and cruises at around 60 knots.

The pair hope to raise US$1m for Operation Smile, a charity which provides reconstructive facial surgery for young people in 16 developing countries.

New Internet company now.com and fashion designer Tommy Hilfiger are sponsoring the challenge.

A report on their progress will be updated every 20 minutes on now.com's website, and the pilots are due back at Brooklands on August 24.

The route both pilots intend to follow