The original thread disappeared about 5 minutes ago, I can only guess that the original poster deleted it. Anyway, I've spent ages writing this response, so i'm going to post it anyway! I have removed any reference to the original poster.
the charts are true and correct
Are you sure? Whilst we all like to think that they are correct, this may not be the case.
Would you agree that if an aircraft required X distance at a certain weight to get to the screen height, if a headwind exists that distance would be shorter or the weight higher. Conversely, if a tailwind exists, that distance would be longer or the weight lower.
I set out to prove this by using the
B777 AFM-DPI, this is the electronic version of the Airplane Flight Manual and is a certified program. I was surprised to see the following:
Zero Wind
CRITICAL: Field Length Limit 263549 KG
CRITICAL: Climb Limit 263549 KG
10 kt Head Wind
CRITICAL: Field Length Limit 265606 KG
CRITICAL: Climb Limit 265606 KG
(This makes sense, headwind gives more weight for same distance)
10kt Tail Wind
CRITICAL: Field Length Limit 265606 KG
CRITICAL: Climb Limit 265606 KG
The 10kt HW and 10kt TW weight/speed/distance data is identical up to the screen height. I can take a greater weight with a 10kt tailwind that with 0kts!
Guess that this goes back to Mr Boeing.
Ironwalt
I don’t totally agree with you, the runway gives the weight, the weight gives the speeds. Therefore for totally difference runway lengths with a fixed weight you will have the same speeds. Kinda like what comes first the chicken or the egg
Mutt