A320 Thrust LIM Penalty

[hans brinker]

Originally Posted by Lantirn

2) Add the additional weight penalty to your actual weight to find the driftdown altitude. E.g GW 70T. Penalty on single engine driftdown is -4200ft (OAT>15C) according to MEL. Calculate driftdown values for GW 65.8

It looks like you subtracted the penalty from the GW. If it was a penalty on the GW it would be an addition not a subtraction. The reason it is a subtraction is that is not a weight penalty but an altitude penalty. What you calculate do is calculate the the driftdown for your GW of 70T, and you subtract the penalty of 4200 feet from that number to find the corrected driftdown. Your method would give a higher driftdown after a penalty, because of the lower GW, so obviously wrong. And you are subtracting feet from tonnes.... (sorry if harsh, but if you take the time to comment, at least do a gross error check)