Originally Posted by
HeliTester
The answer is: Not always for the reasons previously explained in this thread. You noted that you can operate in PC1 at 26,500 lb, at sea level, 32C, using the maximum TDP/Vtoss, but that you have to reduce the gross weight if the temperature goes above 32C. The only way to make the first segment climb requirement not limiting at temperatures above 32C is to increase the TDP/Vtoss. To satisfy your curiosity you should be able to see how much TDP/Vtoss would have to be increased (theoretically) by graphically extrapolating the performance charts.
I have been away and had limited inclination to tap away on my phone while on holiday! Sadly, I cannot locate my RFM copies right now, but will continue looking.
What I am reminded of, though, is an anomaly in the RFM performance graphs that I tried to correct some years ago. In fact, it was amended, but was subsequently restored in a later update, for some reason. Basically, the Cat A WAT graph states a maximum permitted Vtoss of 62/63 kts (can't recall exactly), with the associated maximum Vtdp which then, by definition, can be considered a limitation. However, the graphs used for calculating rejected and continued take off distances allow a Vtdp of 55 kts, with 70 kts Vtoss. Discussions at the time revealed that the maximum Vtoss stated was actually the speed above which no further increase in MTOM would be achieved, and so was the demarcation between 1st segment limiting and 2nd segment limiting performance. As I say, there was a period when this "maximum permitted" statement was removed, but it reappeared later. Regardless, when I set the criteria for our FATO upgrade, I stipulated a length of 810m as this was the nil wind rejected take off distance for a 55 kts TDP!