THIS STORY goes back a quartercentury. Cleverer heads than mine may find the first part a bit obvious. But there is a twist in the tale. Quite literally a twist in the tail…
At this time GPS is still science-fiction, and aviators navigate by more earthy means.
Especially in a Pitts Special, in which any such fancy doo-dads as VOR and ADF are notably absent for reasons of weight, space, and the fact that they use up perfectly good electricity which might be required for other purposes, such as starting the engine and running the smoke system. (So much so that all the aerobatic tribe tend to have groundpower sockets so we can start on external power should it be available). Our nav-aids are roads, railways and rivers plus the dear old magnetic compass floating in its little goldfish bowl at the top of the panel.
On this day the weather is… well, trying. The solid overcast is about 900 feet above the ground – or to be more accurate, some of the ground, because beyond my left wingtip are the Pennines, which rise a lot higher than 900 feet and which I am therefore intent on flying around, not over. The visibility is sort of nearly VFR – well, say, about a mile-and-a-half – and I am flying down from a display in Manchester using one of the best nav-aids in Britain. It’s called the M6 motorway.
It is inadvisable to actually fly under the bridges – which is apt to cause comment – but as a Pitts nav-aid it is a comforting thing. It even has its own built-in weather Actuals – to wit, if all the oncoming cars have their headlights on in daylight, it is a reasonably safe bet that the weather ahead is even more crap than the weather you’re in right now.
Pity that doesn’t tell you much about the weather to the left. Because now is the time for me to prise myself away from the darling M6 and crank on to a heading of 080 to head for my next display in Nottinghamshire.
I duly do so, thumb on the map. Fifteen minutes later I am totally lost. I peer into the murk and nothing matches the bloody map. I am not yet fully-paid-up worried, but beginning to think this will do until “worried” comes along. So I call up a certain major airport and ask for a bearing from them…
“Lima Delta, bearing 320”. Two minutes later I ask again. “Lima Delta, bearing 005 degress”. That doesn’t make much sense. Unless… I bank sharply right. Even at this moment I am proud of the crispness of the Pitts S1- T’s roll-rate. I have been sporadically fiddling with the ailerons recently to make sure the rigging is really precise and that the ailerons move to the maker’s exact fulldeflection angles. On the next maintenance check I’ll even get my efforts signed-up by the engineers… I look down. Sliding directly below me is a runway. A very big and important runway.
Hell…!
I press the button rather slowly. “Aah, Lima Delta, I have my position fixed now”. For some reason my voice seems a bit strangled. “I regret to say I’m passing through your overhead…”
Which I’m painfully aware ain’t gonna go down big. And indeed there is a rather pregnant pause…
I proceed on my way, and carry out the next display. When I land there is a message awaiting me, and I pick up the phone like somebody putting a grenade to his ear with the pin pulled out.
“Why did you infringe our airspace?” I may – all right, do – have many personal faults. But I have a credo. Aviation is not an arena where anybody has the right to lie or present a false defence. And I’d screwed up. I said: “I screwed up. I thought I was well north of you. I don’t know how I came to do it, but there it is. You must report me if that’s what your rules say”.
The airport subsided with threats. (But here’s a thing. I never heard another word about it. That great big airport managed – to sort of lose the report. I don’t know who did it – but if you read this, this guilty pilot thanks you).
Early next morning finds me sitting in the Pitts, brooding at the map and trying to work out how I sinned so badly. I reached there down the M6, turned to 080… And ended up some 20 degrees out. Just how the hell did I manage that? With the map in my left hand I move the stick idly to the right to give myself more room. round 30 degrees.
I blink in astonishment. How can this be? I move the stick around all corners of the cockpit – and the compass swings dreamily through 40 degrees or more as I do it. Why? The compass was perfectly all right two days ago – well, as all right as any Pitts’ compass ever is. But now… Well, obviously the stick itself has become magnetised. But how? And when? And why?
I do not have the faintest idea. I have encountered many magnetic anomalies before. For example, I once had a rev-counter cable which mysteriously magnetised itself some of the time so that the compass pointed at the engine – but not all the time. Why? I still don’t know. With the Pitts in maintenance they say yes, the stick has become magnetised – and no, they don’t know why, either.
They take the stick out and degauss it – which means passing it through a very heavy stator ring which whacks a huge electric current through it which, as I understand it, bludgeons the molecules in the stick so that they no longer line up and create a magnetic field. The stick is de-magnetised, and after re-swinging the compass works fine. Except that ten days later it does exactly the same thing again. I clock it immediately since I am now thoroughly suspicious of the bloody compass and half expecting it to leap out of the panel and nip me painfully on the nose.
The stick is deguassed again.
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