01-31-2017, 09:25 AM
Two questions:
1. Do we know, or have a map/chart of "the box" and the "display line".
2. Do we know, or have, the precise wind speed / direction at the "precise time" of the incident.
Having watched all the videos that I can find on the net, and taking "steep turn's" comments on board, I am inclined to think that he was suckered into attempting to "tighten" the turn, "primarily" to prevent breaching "the far end of the box".
Possible reasons could be:
(a) a slightly late initiation of the turn from the downwind leg, and / or combined with:
(b) a stronger tail wind component than he thought he had, resulting in a greater effective turn radius than planned.
BUT, I have a "secondary worry".
Either or both effects, would produce an optical illusion (heightened at low level and low speed) of "apparent skidding" when in fact he was not (aerodynamically) actually skidding, thus initially subconsciously calling for "more bank" to both "stop skidding" and "stay within the downwind boundary of the box".
I fear that the "stop the skidding optical illusion" effect may have been the "silent killer" here.
As a glider pilot, (we fly SLOW - where "apparent wind effects" are magnified) since our speeds in circuit (downwind - base - final) are slow), "significant" wind "transients" at low level, keep us very much on our toes, because even a not very strong wind is such a significant percentage of our air speed, and especially so from the beginning of the turn from downwind onto base.
Apparent "downwind wind drift" on base, often makes a complete mess / meal of the "planned / intended" base ground track, with the result that there is a need to "crab in" quite often (in even moderate, let alone strong and / or gusty wind conditions).
The point of this ramble is this:.
Power pilots, as a rule, are flying higher and faster and on much wider circuits than we do.
When a power pilot suddenly is flying lower, slower, and with a "tighter base leg, tightened to virtually no "leg" but a continuous 180 degree turn", than he "normally would" fly, his "mental map" of what he is doing is "different" to begin with, then, throw in a surprise factor, like the optical effect above, and ............ tragedy.
Thoughts ?
1. Do we know, or have a map/chart of "the box" and the "display line".
2. Do we know, or have, the precise wind speed / direction at the "precise time" of the incident.
Having watched all the videos that I can find on the net, and taking "steep turn's" comments on board, I am inclined to think that he was suckered into attempting to "tighten" the turn, "primarily" to prevent breaching "the far end of the box".
Possible reasons could be:
(a) a slightly late initiation of the turn from the downwind leg, and / or combined with:
(b) a stronger tail wind component than he thought he had, resulting in a greater effective turn radius than planned.
BUT, I have a "secondary worry".
Either or both effects, would produce an optical illusion (heightened at low level and low speed) of "apparent skidding" when in fact he was not (aerodynamically) actually skidding, thus initially subconsciously calling for "more bank" to both "stop skidding" and "stay within the downwind boundary of the box".
I fear that the "stop the skidding optical illusion" effect may have been the "silent killer" here.
As a glider pilot, (we fly SLOW - where "apparent wind effects" are magnified) since our speeds in circuit (downwind - base - final) are slow), "significant" wind "transients" at low level, keep us very much on our toes, because even a not very strong wind is such a significant percentage of our air speed, and especially so from the beginning of the turn from downwind onto base.
Apparent "downwind wind drift" on base, often makes a complete mess / meal of the "planned / intended" base ground track, with the result that there is a need to "crab in" quite often (in even moderate, let alone strong and / or gusty wind conditions).
The point of this ramble is this:.
Power pilots, as a rule, are flying higher and faster and on much wider circuits than we do.
When a power pilot suddenly is flying lower, slower, and with a "tighter base leg, tightened to virtually no "leg" but a continuous 180 degree turn", than he "normally would" fly, his "mental map" of what he is doing is "different" to begin with, then, throw in a surprise factor, like the optical effect above, and ............ tragedy.
Thoughts ?