Originally Posted by
Arkwright
Many thanks for all the replies.
MU3001A, perfect, just the answer I needed! I won't have easy access to the performance manuals until two hours before the flight, and being new to operating at these altitudes, this issue was causing me some sleeplessness!
Genghis, in the manuals that I do have easy access to, the manufacturers state tyre limiting speed as groundspeed. After all, TAS only equals GS in zero wind conditions?? This a/c allows a maximum tailwind for take off of 10 kts, so that would have to be added to TAS to confirm GS was under max V tire.
The perf manual is still on the aircraft, its just that I'm nowhere near the aircraft!
Rainboe, sounds like a useful rule of thumb, and comparing it to MU3001A's calculations, fairly accurate!
Tyre limiting speed is in groundspeed of-course, which is TAS-headwind.
My point was that you need TAS, not IAS/CAS/EAS to determine safety.
As per both my, and MU3001A's calcs which, re-assuringly, come up with the same answer.
In passing, from my own very limited experience of high density altitude runways, the big issue is generally that the high TAS pushed both take-off and landing distances up substantially so if you aren't looking at a very large increase in TODR over standard conditions, then re-check your calcs, they're probably wrong!
G