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Old 3rd May 2019, 16:31
  #7 (permalink)  
FlightDetent

Only half a speed-brake
 
Join Date: Apr 2003
Location: Commuting not home
Age: 46
Posts: 4,319
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Mine:-
(1) -> 26x 3 = 7500 (approx) + 6000 G/S intercept =>> 3 deg profile is 13500'
(2) -> the A/C is 1500' above
(3) -> 370 /20 = 1900 fpm is required to keep a 3 deg descent
(4) -> with present sink of 2200 we're slowly regaining the profile from above.

This arithmetic gives a good understanding of
- where you are (2)
- where you will be (4) based on GS, the effect of wind is already accounted for.

Obviously, with deceleration towards 250 knots coming soon that nice, steeper-than-3° trajectory won't last for long.

Personally, I do not make any mental calculation adjustments for the decel segments (250 / 210). I just run the (2) and (4) again and again, as many times as required. Anticipation notwithstanding!

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The above example is quite critical, me thinks.
- With platform at 3000' and 270, it would be "rather efficient"
- With platform at 3000' and 290, I'd say daring,
- With platform at 6000 and 270, it looks borderline,
But 6000 and 290, with 1500 above already? The (vertical) room to slow down, which needs to be done soon to 250 and then almost immediately to 210ish, is just not there.


Choice of weapons depends. My present operator requires 250 below 10k AFE, so A/P off and full speed-brake for us
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