There ain't no petrol – no gasoline – in here, Paul. Not after forty-two years. It'll have evaporated.'

'From a sealed tank?' said Paul sceptically.

'No fuel tank is sealed,' said Byrne. There's a venting system. You try to pull gas from a tank without letting air hi and you'll get nowhere. It's okay, Paul; there's no fuel in here now.'

There was a clang as he struck the head of the chisel. He struck again and again and presently I went to help him by holding the chisel so he could strike a harder blow. But first I cautioned him to make sure he hit the chisel and not my hand. Slowly we cut a hole into the side of Flyaway and, oddly, I thought it an act of desecration.

The hole was about a foot by six inches and at last Byrne was able to bend back the flap of aluminium so that he could look inside. As he did so some brown powder dropped out to lie on the sand. 'Yeah,' he said. 'An integral fuel tank.'

'What's the powder?'

'You always get gunk in the bottom of a tank no matter what you do. The gasoline is filtered going in and filtered coming out but no gas is pure anyway, and you have chemical instabilities and changes.' He put his hand inside and withdrew it holding a handful of the powder. 'More in here than I would have thought, though. If I was Billson and entering a race I'd have the tanks scoured and steam-cleaned before starting.'

I looked at the handful of dried sludge as he put it to his nose. 'More than you would have thought,' I repeated.

'Don't put too much into that,' he advised. 'This is the first time I've looked inside a fuel tank. It ain't a job that's come my way before. There were over three hundred gallons in this tank and God knows what was happening to it while it was evaporating. Constant changes of temperature like you get here could have started all kinds of reaction.'

'All the same,' I said, 'I'd like to have a sample of that stuff.'

Then find something to put it in.'

I'm old-fashioned enough to use a soap shaving-stick and mine came in a plastic case. It hadn't seen much use in the desert and I'd grown a respectable beard which, Byrne told me, was flecked with grey. 'Pretty soon you'll look as distinguished as me,' he had said. I broke off the column of soap and we filled the case with the brown powder and I screwed the cap back on and, for safety, secured it with an adhesive dressing from Byrne's first aid kit.

By that time it was past midday so we prepared a meal. As we ate Paul said, 'When are we leaving?'

Byrne glanced at me and I knew the same thought was in both our minds – we had a burial detail to attend to. He said, 'Early tomorrow.'

I said nothing to Paul until we had finished eating and had drunk our tea. Then I put a new film in my camera because I wanted a full record. I said, 'Paul, brace yourself; there's something I must tell you.'

His head jerked and he stared at me wide-eyed, and I knew he'd guessed. 'You've found him. You've found my father.'

'Yes.'

He got to his feet. 'Where?'

'Not far from here. Are you sure you want to see him? Luke and I can do what's necessary.'

He shook his head slowly. 'No – I must see him.'

'All right. I'll take you.'

The three of us went to the cave and the tears streamed down Paul's face as he looked down at what was left of his father. There were still scraps of flesh and skin left attached to the bones but it was brown and mummified, and a few tendrils of hair clung to the skull which otherwise was picked clean.

I took some photographs and then we began to brush the sand from the skeleton. Underneath the thin layer of sand was rock so we could not bury Peter Billson. Instead we piled a cairn of stones over the remains, Paul sobbing all the time. Then we went back to Flyaway, Byrne carrying under his arm the tin box which had been next to the body. There were a couple of other things we had buried with Billson; two packets bearing the name of Brock, the pyrotechnic company. One contained flares, the other smoke signals. Neither had been used because a rescue plane had neither been seen nor heard.

Standing next to Flyaway Byrne held out the box to Paul. 'Yours,' he said simply.

He took it and then sat down on the sand and laid the box in front of him. He looked at it for a long time in silence before he stretched out with trembling fingers to open it. This was nothing like opening a Christmas present. There were a lot of papers inside.

In his last days Peter Billson had kept a diary, written in his log-book. I don't propose to go into this in detail because it is most harrowing. A proposal has been made that it be published in a future edition of the Journal of the Royal Aeronautical Society. I'm against the idea. A man's mental agonies when facing death ought to be private.

There was Billson's flying licence, a sealed envelope addressed To my darling, Helen', a worn leather wallet, a pipe and an empty tobacco pouch, a Shell petrol carnet, a sheaf of bank notes – British, French and Nigerian, and it was strange to see the old big British five-pound note – and a few other small odds and ends.

Paul picked up the letter addressed to his mother. His lower lip trembled. 'I ought to have treated her better,' he whispered, then handed it to me. 'Will you burn that, please?

Don't open it.'

I nodded. Byrne stooped and picked up a card. 'The compass deviation card,' he said. 'Not more than a degree and a half out on any course.' He handed it to me. 'It don't matter if a compass has deviation as long as you know what it is.'

Printed on the card was a compass rose around which were written figures in ink. It was signed by the compass adjuster and dated the 4th of January, 1936. I turned it over and saw something scrawled on the back. / wonder how bloody true this damn thing is? I nudged Byrne and showed it to him, and said in a low voice, 'He was beginning to guess in the end.'

The diary told Byrne what he wanted to know about the landing. 'He was a good flier, Paul,' he said. This is how he got down. His engine had quit and he was coming down in a glide with an airspeed of fifty-five knots. There was a low moon and suddenly he saw rocks between him and the moon, so he stalled her. He pulled her nose right up and that lost his speed and his lift at the same time, so he fell out of the sky damn near vertically. What he called a pancake landing. Never heard it called that before. He says, 'The old girl pancaked beautifully but I'm afraid both oleo legs are broken – one badly. Never mind, she wouldn't take off from here anyway.'

I read the diary. He had lasted twelve days on two and a half gallons of water. At first the handwriting was firm and decisive but towards the end it degenerated into a scrawl.' During the last few days he was apparently feverish and had hallucinations, communing with the painted men on the wall of the cave. The last entry was in a surprisingly firm hand and was a plea that his wife and young son be well looked after. The thought of the?100,000 insurance on his life seemed to comfort him a lot.

Byrne grunted and stood up. 'A guy like that deserves better than a heap of stones. He needs a marker.' He strode to Flyaway and jumped up on to the wing, then made his way up the fuselage until he was astride the cowling of the big radial engine. There was a banging and I saw he was unshipping the propeller.

That gave me an idea. I found the piece of aluminium we had cut from the side of the fuselage and, using the chisel and a small hammer began to incise letters. Paul came over to see what I was going and stayed to help. When I thought we had finished I said, 'That's it, Paul.'

'No – there's something I want to add.'

So he guided the blade of the chisel while I thumped with the hammer and we added the fourth line so that our rough plaque read:

PETER BILLSON AIRMAN 1903-1936 Fly away, Peter