Vmcg and V1
Hi friends,
I am new here, and read this interesting conversation on Vmcg and V1 started by IDG.
1.If you look at the factors affecting Vmcg using Vmcg tables, the values are put against two variables that is Temp and Press Altitude. These 2 variables only change the thrust and Vmcg is directly proportional to Thurst. More thrust more the Vmcg and vice a versa. Xwind has no affect on Vmcg.
2. Vmcg testing: xwind of 7kts from the worse direction is considered. Pilot should be able to control using aerodynamic controls only. Initial force applied could be 180lbs, but later the force on leg should not be more than 150lbs. The aircraft should not drift more than 30 ft from centre line + certain restriction on change of heading that I dont remember offhand. A lot more variables are used to determine like bleeds off takeoff, Minimum weight and Max aft cg. So enough built-in safety.
3. V1mcg. We all know that V1 cannot be lower than Vmcg. So the lowest V1 is always higher to cater for the max x-wind component allowed for the aircraft.
IDG has noted that using LPC the speeds have gone down quite a lot. The operation/performance engineering department of the airlines can choose between three V1. Minimum V1, Maximum V1 and Optimum V1. May be IDGs airline has chosen a V1 that is lower than Optimum V1. Minimum V1 gives better safety margin and Maximum gives better takeoff performance. In my airliner this kind of revision has taken place many a times.
Thanks for bearing such a long one.
Moch
A330-200