B738 one pack off takeoff N1 diffrentce?
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Joined: Mar 2009
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From: SH
B738 one pack off takeoff N1 diffrentce?
B738 with left pack off takeoff N1 diffrentce?
V1 if biger than the V1 with two packs nornal.
when takeoff with left Pack off ,Reduced thrust assume temp 45`C
fmc caculate N1 L95.3/ R94.0 ?
why left N1 is higher?
how much diffrence N1 is not acceptable for take off ?
Thanks!
V1 if biger than the V1 with two packs nornal.
when takeoff with left Pack off ,Reduced thrust assume temp 45`C
fmc caculate N1 L95.3/ R94.0 ?
why left N1 is higher?
how much diffrence N1 is not acceptable for take off ?
Thanks!
Joined: Jun 2000
Posts: 4,507
Likes: 4
From: last time I looked I was still here.
FMC calculates balanced field speeds. No idea why V1's should be different. Do you use de-rates or only assumed temp's from max thurst; and from what max N1%, 22k, 24k or 26k? If you look at V1 for different derates, this could be an answer.
For difference in N1% the reason is the left N1% is showing Bleeds Off values and thus is higher than the Bleeds On value of right engine. However, the difference on our a/c is only 8%, so your numbers are curious.
For difference in N1% the reason is the left N1% is showing Bleeds Off values and thus is higher than the Bleeds On value of right engine. However, the difference on our a/c is only 8%, so your numbers are curious.
Joined: Jun 2007
Posts: 71
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From: FL350
It should be the other way around...ie with left pack off, the left N1 should be lower. This is because a slightly higher N1 is required to sustain the airplane and the bleed air/pneumatics etc.
The second part, are you talking about a packs off take off?
The second part, are you talking about a packs off take off?
