Flyaway

'Magnetic deviation,' he said. 'Remember what I told you at Assekrem about iron in the mountains causing trouble? Well, there's a lot of iron here. Up front there's a goddamn hunk of iron called an engine. That affects the compass reading. Now, that's a Wright Cyclone with nine cylinders and, in flight, all the spark plugs are busy sparking and sending out radiation. They tell you they can be screened but I've never seen anyone do a good job of screening yet. And there'll be other bits of iron about the airplane – the oleo struts, for instance.' He tapped the metal of the fuselage. 'This don't matter – it's aluminium.'

I said, 'What are you trying to tell me?'

'I'm getting to it.' Byrne stared thoughtfully at the compass. 'Now, you build an airplane, and you take a perfectly good compass and put it in that airplane and it gives you a wrong reading because of all the iron around. So you have to adjust it to bring it back to what it was before you put it in the airplane.' He pointed to the compass. 'Built in back of there are some small magnets put in just the right places to compensate for all the other iron.'

'And you think one of them fell off? Because of vibration, perhaps?

'Nope,' he said shortly. They're not built to fall off; they're screwed in real tight. And there's something else – any compass, no matter how good, will give a reading that's a bit off when you're flying on different courses. You see, the needle is always pointing in the same direction, to magnetic north; so when you change course you're swinging all your iron around the needle.'

'It's getting more complicated.'

This is the real point. Every compass in every airplane is tested individually because all airplanes have different magnetic characteristics – even the same models. The airplane is flown along different known courses arid the compass readings are checked. Then a compass adjuster does his bit with his magnets. It's a real skilled job, more of an art than a science. He works out his calculations and maybe adds in the date last Tuesday, then he makes out a deviation card for the residual errors he can't get rid of on various courses. I've been looking for Billson's deviation card and I can't find it.'

'Not surprising, after forty-two years. What are you really getting at, Luke?'

'You can bet your last cent that Billson would have had his compass checked out real good before the race. His life depended on it.'

'And it let him down.'

'Yeah; but only after Algiers. And compasses don't go fourteen degrees wrong that easy.'

I stared at him. 'Sabotage!'

'Could be. Can't think of anything else.'

My thoughts went back to English, the journalist who had set fire to Paul. 'That idea has come up before,' I said slowly. 'A German won the race – a Nazi. I don't suppose he could have done it personally, but a friend of his might.'

'I'd like to take this compass out,' said Byrne. 'There's a screwdriver in that kit of tools I brought.'

'I wondered about that,' I said. 'Were you expecting this?'

'I was expecting something. Don't forget there's a son of a bitch who is willing to kill to prevent this plane being found.'

'I'll get the screwdriver.'

As I dropped to the ground Byrne said, 'Don't tell Paul.'

Paul was sitting on the ground in front of Flyaway just looking at her. I walked away, got the screwdriver and came back, concealing it in the folds of my gandoura. Byrne attacked the first of the four screws which held the compass in place. It seemed locked solid but an extra effort moved it and then it rotated freely.

He took out all four screws and gently eased the compass out of place and turned it over in his hands. 'Yeah,' he said. 'You see these two brass tubes here? Inside those are small pole magnets. This screw here makes the tubes move like scissor blades – that's how the compass adjuster gets his results. And this is a locking nut to make sure the tubes can't move once they're set'

He tested it with his fingers. 'It's locked tight – which means…'

'… that if the compass is fourteen degrees out of true it was done deliberately?'

'That's right,' said Byrne.

CHAPTER TWENTY-EIGHT

Sabotage! An ugly word. An uglier deed.

I said, 'How long would it take to do it?'

'You saw how easy it was to take out this compass. To make the change and put bac k the compass wouldn't take long. A maximum of fifteen minutes for the whole job.'

'I'm taking that compass back to England with me,' I said. 'Just as it is. I'm beginning to develop peculiar ideas.'

'It only tells half the story,' said Byrne. 'We have to solve the other half – why did he come down? I have ideas on that. I want to look at the plumbing of this airplane.'

'I'll leave you to it.' I climbed down from the wing and joined Paul. 'Well, Paul, this is it – journey's end.'

'Yes,' he said softly. He looked up. 'He wasn't a cheat That South African was lying.'