Sad Realization

ppragman said:
In that case, isn't it kind of silly to even think about V1 then because basically if you've started your rotation you're past your abort point and if you haven't you can abort, no?
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Definitely not silly. Not to beat the horse to death further, but I'll just add that if you're really light, Vmcg comes into play (and V1 cannot be lower than Vmcg). Also, rotation can be delayed if windshear is encountered after V1. You can safely take the aircraft in the air with a delayed rotation, but rejecting past V1 would put you off the end.

Random anecdote, but a couple weeks ago we had really gusty winds departing out of MSP where we did exactly the above: I was PF, and we took the runway right behind a Delta jet that'd gone around a second time. Even though V1 and Vr didn't have much of a split on paper, I kept the airplane on the ground until roughly Vr+20, which is appropriate practice for most airplanes in that situation to protect against shear.

(Sorry for the ninja edits)
 
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dasleben said:
Definitely not silly. Not to beat the horse to death further, but I'll just add that if you're really light, Vmcg comes into play (and V1 cannot be lower than Vmcg). Also, rotation can be delayed if windshear is encountered after V1. You can safely take the aircraft in the air with a delayed rotation, but rejecting past V1 would put you off the end.

Random anecdote, but a couple weeks ago we had really gusty winds departing out of MSP where we did exactly the above: I was PF, and we took the runway right behind a Delta jet that'd gone around a second time. Even though V1 and Vr didn't have much of a split on paper, I kept the airplane on the ground until roughly Vr+20, which is appropriate practice for most airplanes in that situation to protect against shear.

(Sorry for the ninja edits)
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Same with us. If we select windshear in our Aerodata it commands max blast and delayed rotation.
 
PhilosopherPilot said:
On an icy or otherwise contaminated runway, I've seen V1 at 95 knots, and VR at 125 (flaps 4).
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Even the Saab would go down to the 100's when it was wet or slushy and VR was 120ish. Of course we had to stop using speed cards and start using REAL WB+performance software.

I wonder what @ppragman would see on a 1900 that had a real performance software rather than cards.
 
mshunter said:
You're completely missing the point. Our speeds are already based of of weight. If we factored in one more bit of data(runway length), that is literally all that would change. Most part25 airplanes have a v1/vr that's do close, it wouldn't even matter. But I still see no reason to do it the way hacker is suggesting. Set V1 according to runway length. As far as brake energy is concerned, that's what testing an aircraft is for. The numbers that we would get, would obviously include that.
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What point am I missing?
 
Dugie8 said:
What point am I missing?
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Boop.gif
 
PhilosopherPilot said:
Same with us. If we select windshear in our Aerodata it commands max blast and delayed rotation.
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T/O-1 and Flaps 1, field length permitting, will be used in that situation, with appropriate numbers sent for. I'm not sure if our performance software adjusts for delayed rotation (I'll ask — I've never had ACARS performance, so there's that).
mshunter said:
You're completely missing the point. Our speeds are already based of of weight. If we factored in one more bit of data(runway length), that is literally all that would change. Most part25 airplanes have a v1/vr that's do close, it wouldn't even matter. But I still see no reason to do it the way hacker is suggesting. Set V1 according to runway length. As far as brake energy is concerned, that's what testing an aircraft is for. The numbers that we would get, would obviously include that.
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I'm not sure how we do things at the "other" airline, but the Bro takeoff data looks something like this:
Code: 
APT  PRWY        POAT PWIND  PQNH  PMRTW FLP MAXV1 PTOW MFPTW
CLD  24          20.0 000T00 29.91 2544  15  110   2408 26192

RMKS NONE

-------- ---- ------ ----- ------- --- ----- --- --------------------
RWY      OAT  WIND   QNH   MRTW    FLP MAXV1 PWR CONFIG/CONDITION

----------------------- BLEEDS OPEN - STATIC ------------------------
            06             24
            4897 FT        4897 FT
            SPECIAL        DT H247
  OAT TRQ   FLAP 15        FLAP 15
   26  100  2501 O 09      2503 F 09
   24  100  2507 O 09      2519 F 10
   22  100  2514 O 09      2533 F 10
 / 20  100  2521 O 09    / 2544 F 10
   18  100  2526 O 09      2553 F 11
   16  100  2532 O 09      2562 F 11
   14  100  2537 O 09      2571 F 11
HW/10KT       41    2        47    3
TW/10KT     -299   -6      -341   -7
ROLLING      -58   -2       -70   -2

----------------------- BLEEDS CLSD - STATIC ------------------------
            06             24
  OAT TRQ   FLAP 15        FLAP 15
   26  100  2501 O 09      2503 F 09
   24  100  2507 O 09      2519 F 10
   22  100  2514 O 09      2533 F 10
 / 20  100  2521 O 09    / 2544 F 10
   18  100  2526 O 09      2553 F 11
   16  100  2532 O 09      2562 F 11
   14  100  2537 O 09      2571 F 11
HW/10KT       41    2        47    3
TW/10KT     -299   -6      -341   -7
ROLLING      -58   -2       -70   -2
The "09" or "10" on each line is a field-length adjusted max V1, as that is, how do you say, a very short runway down that way. V1 is selected as performance chart V1 or Max V1, whichever's lower. (In this case, a 25,400-lb airplane has a performance card V1/Vr of roughly 114 knots if memory serves; V1 therefore equals 110 knots and Vr is still off the card of 114 knots.) We're already doing this behind the scenes.
 
Autothrust Blue said:
T/O-1 and Flaps 1, field length permitting, will be used in that situation, with appropriate numbers sent for. I'm not sure if our performance software adjusts for delayed rotation (I'll ask — I've never had ACARS performance, so there's that).

I'm not sure how we do things at the "other" airline, but the Bro takeoff data looks something like this:
Code: 
APT  PRWY        POAT PWIND  PQNH  PMRTW FLP MAXV1 PTOW MFPTW
CLD  24          20.0 000T00 29.91 2544  15  110   2408 26192

RMKS NONE

-------- ---- ------ ----- ------- --- ----- --- --------------------
RWY      OAT  WIND   QNH   MRTW    FLP MAXV1 PWR CONFIG/CONDITION

----------------------- BLEEDS OPEN - STATIC ------------------------
            06             24
            4897 FT        4897 FT
            SPECIAL        DT H247
  OAT TRQ   FLAP 15        FLAP 15
   26  100  2501 O 09      2503 F 09
   24  100  2507 O 09      2519 F 10
   22  100  2514 O 09      2533 F 10
/ 20  100  2521 O 09    / 2544 F 10
   18  100  2526 O 09      2553 F 11
   16  100  2532 O 09      2562 F 11
   14  100  2537 O 09      2571 F 11
HW/10KT       41    2        47    3
TW/10KT     -299   -6      -341   -7
ROLLING      -58   -2       -70   -2

----------------------- BLEEDS CLSD - STATIC ------------------------
            06             24
  OAT TRQ   FLAP 15        FLAP 15
   26  100  2501 O 09      2503 F 09
   24  100  2507 O 09      2519 F 10
   22  100  2514 O 09      2533 F 10
/ 20  100  2521 O 09    / 2544 F 10
   18  100  2526 O 09      2553 F 11
   16  100  2532 O 09      2562 F 11
   14  100  2537 O 09      2571 F 11
HW/10KT       41    2        47    3
TW/10KT     -299   -6      -341   -7
ROLLING      -58   -2       -70   -2
The "09" or "10" on each line is a field-length adjusted max V1, as that is, how do you say, a very short runway down that way. V1 is selected as performance chart V1 or Max V1, whichever's lower. (In this case, a 25,400-lb airplane has a performance card V1/Vr of roughly 114 knots if memory serves; V1 therefore equals 110 knots and Vr is still off the card of 114 knots.) We're already doing this behind the scenes.
Click to expand...

I'll take a pic when I get to the jet in a little while, but that's our exact format for takeoff data in the non-ACARS machines.

EDIT: Actually, here you go. From a past flight. Domestic 767-200.

Screen Shot 2014-11-11 at 8.03.18 PM.png
 
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Autothrust Blue said:
T/O-1 and Flaps 1, field length permitting, will be used in that situation, with appropriate numbers sent for. I'm not sure if our performance software adjusts for delayed rotation (I'll ask — I've never had ACARS performance, so there's that).
Click to expand...

You guys use flaps 1, no flex T/O for LLWS?
 
PhilosopherPilot said:
We use flaps 1 for almost every takeoff.
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On the 170 flaps 2 is generally optimum (1 hot and high, 4 short). I'm guessing 1 is optimum on the 190? At my operator we send off for optimum #s and select no flex if LLWS present, contamination etc. Just wondering if the previous poster selected flaps 1 for LLWS scenarios specifically on the 170.
 
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