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

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.

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.

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.

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