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#11
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Density altitude strikes again
On Wednesday, August 15, 2012 6:21:10 AM UTC-4, Dylan Smith wrote:
On 2012-08-15, Dudley Henriques wrote: What has piqued our interest isn't what's obvious but rather how this pilot ignored so many visual cues and performance cues during the takeoff run, all of which should have been telling him to abort. Never underestimate the power of denial. Quite to the contrary, our interest lies more on the REASONS a pilot accepts flight into error. DH |
#12
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Density altitude strikes again
On 2012-08-20, Dudley Henriques wrote:
On Wednesday, August 15, 2012 6:21:10 AM UTC-4, Dylan Smith wrote: Never underestimate the power of denial. Quite to the contrary, our interest lies more on the REASONS a pilot accepts flight into error. As I said: never underestimate the power of denial. I don't know the experience or history of this pilot, but for a moment if we assume he's taken off with this load and at this density altitude plenty of times. He knows performance is bad, but he's climbed out fine but slowly. But this time he forgot to set the mixture for best power, and never realises it. After he takes off and then settles back down to the ground, the power of denial is this. "Oh, I've done this before, I must have just tried to lift off too early". Then he's off the end of the airfield but still over flat land. "It'll climb soon, it always has". His mind is powerfully telling the possibly more sensible part of him in a loud voice that it'll all come out OK in the end if we just press on a little further, and to ignore all the signs that in fact things will not turn out well, in other words, the power of denial. There's probably some pschological term for this, but every day I see people unable to resist the power of denial, that it happens to pilots too is not unusual and we need to recognise it to stop it from flying us into the trees. |
#13
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Density altitude strikes again
Dylan Smith wrote:
On 2012-08-20, Dudley Henriques wrote: On Wednesday, August 15, 2012 6:21:10 AM UTC-4, Dylan Smith wrote: Never underestimate the power of denial. Quite to the contrary, our interest lies more on the REASONS a pilot accepts flight into error. As I said: never underestimate the power of denial. I don't know the experience or history of this pilot, but for a moment if we assume he's taken off with this load and at this density altitude plenty of times. He knows performance is bad, but he's climbed out fine but slowly. But this time he forgot to set the mixture for best power, and never realises it. After he takes off and then settles back down to the ground, the power of denial is this. "Oh, I've done this before, I must have just tried to lift off too early". Then he's off the end of the airfield but still over flat land. "It'll climb soon, it always has". His mind is powerfully telling the possibly more sensible part of him in a loud voice that it'll all come out OK in the end if we just press on a little further, and to ignore all the signs that in fact things will not turn out well, in other words, the power of denial. There's probably some pschological term for this, but every day I see people unable to resist the power of denial, that it happens to pilots too is not unusual and we need to recognise it to stop it from flying us into the trees. It is quite simple. You identify a point on the runway where you quit if not off the ground. This should not be before each flight, but selected before your first use of the airstrip and adhered to come what may. Ideally a board at the side of the strip marked with the distance in yards from the threshold. I have aborted many take-offs in this way, and the great thing is you don't even have to think about it. |
#14
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Density altitude strikes again
On 2012-08-20, Gilbert Smith wrote:
It is quite simple. You identify a point on the runway where you quit if not off the ground. It can be more complex than this. About four years ago I witnessed a serious stall/spin crash. It was a rather marginal microlight being tested at gross weight by an experienced pilot and the owner. Where I live it's not much above sea level, but this aircraft didn't have great climb performance. Off the end of the runway in use are some low hills (actually, a glacial terminal moraine left by the last Ice Age) probably only 150 feet high at most. They don't look in any way imposing from the airfield, they are a good 3/4 mile off the end of a runway that's the best part of a mile long, and probably not really high in the thoughts of the pilot. However, the "clutching hand" from these hills goes way above their tops and can require good climb performance to escape. The hills are much more sheer sided than they look from the far end of the runway, and the sink can be very strong. I was actually on downwind at the time and watching his position as I was planning a stop-and-go landing, and he broke ground well before the halfway point of the runway. After doing my stop-and-go, I lowered the nose just to check on his progress - knowing I would probably be faster - only to see the wreckage on top of the hill. (Fortunately they both survived, the owner was just bashed and bruised but the pilot was more seriously injured. Another thing in their favour was that there happened to be a Royal Navy Sea King in the air on routine exercises only 20 minutes flying time away, fully crewed and equipped for transporting casualties) From his point of view, the takeoff was nominal, he was off before the halfway point and climbing, apparently enough to clear the hills. |
#15
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Density altitude strikes again
Dylan Smith writes:
As I said: never underestimate the power of denial. I don't know the experience or history of this pilot, but for a moment if we assume he's taken off with this load and at this density altitude plenty of times. Or, I assume he probably sensed something wrong on the takeoff run but felt social pressure to make the flight with has pax. I've always believed the best pilot has some asshole in him or her: the ability to say "we're not flying today" regardless of the hopes of others for the flight. -- Before I travelled my road I was my road. --Antonio Porchia, Voces, 1943, translated from Spanish by W.S. Merwin |
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