Their orders in the spring of 1942 were to transport tons of weapons, ammunition and fuel across some of the wildest and highest terrain on the planet, quickly christened "the hump" by the pilots, to supply nationalist forces in China after invading Japanese had cut the Burma Road that had been their logistics lifeline.

Hundreds of aircrew perished when their planes crashed into mountains in bad weather or were shot down over thick jungles where their remains have lain for more than 60 years.

Now the US military is determined to find them and bring them home.

One of the military's most remarkable units – the Joint Prisoners of War, Missing in Action Accounting Command (JPAC) – has begun the first of a series of missions to find the wreckage of Second World War aircraft and their crew in their last resting places scattered across the vast border region between India and China.

JPAC has worked in the jungles of South-East Asia and New Guinea and the battlefields of Europe locating the remains of thousands of servicemen to live up to the US military creed of leave no man behind.

This month a JPAC team located its first crash site on India's border with China, several days walk from the nearest road in dense forest.