B737 QRH Questions
i have several, but will do one subject at a time:
QRH
B737:300 CFM56-3 22K
Performance Inflight-General:
Advisory information:
Slush/Standing Water Takeoff:
page PI.20.4
Weight adjustment table: i can understand.
V1(MCG) Limit Weight table: ??? (question 1)
V1 Adjustment (KIAS) ??? (question 2)
1. example:
7000 ft available length: at sea level:
3mm= 59.6
6mm= 62.6
13mm= 66.9
an increase of contamination allows a higher V1(MCG) limit weight on a given runway distance.
2. example:
Weight: 60K at sea level:
3mm= -16
6mm= -10
13mm= 2
also with an increase of contamination, less reduction to V1 and even a increase of 2 knots if it is 13mm!
i could sit here in a dark room and surmize as to the reasons behind this, or simply ask if there is someone out there with some "endorsed" reasons why this is so?
i can think of the increase of slush on runway will increase time to accelerate to any certain V1. but since V1 is a speed (and not a distance) at which one should stop or continue, i can't quite see how the increased slush will cause an increase in V1(MCG) weight or V1 adjustment unless the slush actually helps you to stop.
i first heard that suggestion in Korea, but find it hard to swallow.
then on top of that, do we then go to the slippery runway chart and do some more adjustments, since it should perhaps be considered slippery if there is slush on it, where the V1 adjustment (KIAS) chart makes more since with a decrease of speed with a decrease in braking action.
any help will be greatly appreciated.
more later