Raptor71
27th Feb 2016, 11:21
Hello guys,
I was just looking at the B737 perf especially on contaminated and slippery runway.
If someone has seen them, maybe he can answer me:
1- For the V1(MCG) limit weight table (Slush/standing water/max rev):
The limit weight will increase when the runway length increases (OK)
But I do not understand why the limit weight does not increase when altitude pressure increases.....I was thinking that the increase of altitude pressure will result in lower VMCG, V1 could be further reduced and limit weight would be increased. What's wrong with my reasoning?
The approx max TOW of the B737 800 being 80T, why bother putting such values as 102.8T in the table (2000m, 5000ft, 3mm)
2- V1 adjustment table (slush/standing water/max rev):
Values of V1 adjustment will decrease as the pressure altitude increases, I understand that as a loss of thrust due to the decreased pressure so we have to keep the TOD within TODA.
However I do not understand why the V1 adjustment decreases as the weight decreases (90T, SL, 3mm = -12kts ; 40T, SL, 3mm= -25kts)
3- V1(MCG) limit weight table ( slush/standing water/NO REV)
Figures are different depending on conditions, however there are only a few ones
At SL and for 3mm, for instance, you will find only 3 figures for all runway lenghts : 33.1, 66.9, 104.7. Figures are just offset when you change the pressure altitude
Why such similarities?
Thank you in advance
I was just looking at the B737 perf especially on contaminated and slippery runway.
If someone has seen them, maybe he can answer me:
1- For the V1(MCG) limit weight table (Slush/standing water/max rev):
The limit weight will increase when the runway length increases (OK)
But I do not understand why the limit weight does not increase when altitude pressure increases.....I was thinking that the increase of altitude pressure will result in lower VMCG, V1 could be further reduced and limit weight would be increased. What's wrong with my reasoning?
The approx max TOW of the B737 800 being 80T, why bother putting such values as 102.8T in the table (2000m, 5000ft, 3mm)
2- V1 adjustment table (slush/standing water/max rev):
Values of V1 adjustment will decrease as the pressure altitude increases, I understand that as a loss of thrust due to the decreased pressure so we have to keep the TOD within TODA.
However I do not understand why the V1 adjustment decreases as the weight decreases (90T, SL, 3mm = -12kts ; 40T, SL, 3mm= -25kts)
3- V1(MCG) limit weight table ( slush/standing water/NO REV)
Figures are different depending on conditions, however there are only a few ones
At SL and for 3mm, for instance, you will find only 3 figures for all runway lenghts : 33.1, 66.9, 104.7. Figures are just offset when you change the pressure altitude
Why such similarities?
Thank you in advance