Flare height illusions when landing in fog
I have just had the pleasure of reading the book "Yellow Belly" by John Newton Chance. It was first published in Great Britain in 1959. It is the personal story of a novelist who went to War to fly but it is also the story of every man who learnt to fly in the last Great Air war that we shall know. The author became a flying instructor throughout the war.
In the book he describes being in an accident in which he was landing an Airspeed Oxford at night in a shallow layer of fog. The year was 1942. He was doing a check flight on a student when fog rolled in over the Lincolnshire aerodrome where they had been practicing night circuits. They flew a circuit by timing and turned in on final.
This is what he wrote: Quote:
"We turned in, keeping the dim line of little lights ahead. They disappeared in sudden patches where the fog was thicker, but we were on the line and were not going to let go, or we would have to go up again. So it had to be this time or perhaps not at all.
We came down very steadily. It could have been a model exercise - because everything depended on this one being right. The method of landing by flares was to sink down towards the second flare until it appeared to be a little way up the port window, then you throttled back and the aircraft stalled gently on to the ground. We came in a bit high over the first flare but dropped down till the second glowed through the white gloom just in the right position up the side window. I throttled back.
The bottom dropped out of the world. There was an appalling sensation of falling miles and miles through impenetrable blackness, and during the fall I saw what had happened as the actual flares, smoky red ghosts through the fog, showed their true light. There was a layer of fog four yards high over the flare path and, through refraction, the flares were shining as light bubbles on top of this blanket. I did not see the real flares until we stalled into the fog.
There was one hell of a crash and we were flat on our belly. I remember using the disaster to demonstrate crash action, but what reflex caused this I have no idea. "Petrol off! Switches off! Out!" The aircraft did not catch fire though we got well away from it as the fire engine and ambulance came rumbling on through fog." Unquote.
During my own flying career on aircraft from Tiger Moths to Boeing 737's I have landed in foggy conditions a few times. But I was never aware of the existence of false illusions of runway lighting at night when landing in shallow fog and which can fool the pilot into rounding out prematurely. I certainly have experienced false visual horizons caused by heavy concentrations of water on the windshield but what I read in this book of fog illusions caught me by surprise.
Have an Pprune readers struck this phenomena particularly in Cat 3 landings in fog?