A330 / A340 Best Rate of Climb

[luvmuhud]

Hi,

My company's ops manual has little guidance and explanation for calculating a max rate of climb speed for the Airbus 330/340. It provides a rule of thumb only, which is to fly at 285kt/0.78M for max rate.

Another method I have seen is to set Cost Index to 0, and check the managed climb speed.....the theory being that the jet will use max rate climb speed in its max range flight profile (CI=0). This method gives speeds of around 310-315kts.......quite a bit different from the rule of thumb stated earlier.

Any Airbus test pilots / perf gurus care to shed some light??

lmh

[mcdhu]

Although I'm none of the above, my copy of Airbus 'Getting to Grips with Aircraft Performance' Page p157 says:

"CI=0 gives IASecon = Max rate of climb speed.

Try it - it works.

mcdhu

[luvmuhud]

Thanks mate....just downloaded that manual....lots of good gouge.

Cheers,

lmh

[HazelNuts39]

Hi luvmuhud;

I agree with mcdhu. When I looked into this on another thread, I found in general that the speed for max rate of climb reduces with reducing thrust-to-weight ratio. So if you found these speeds at low altitude, maybe you'll find lower speeds as you get closer to cruise FL's. The question is also discussed in Boeing's JT Performance Methods.

regards,
HN39

[divinehover]

Try use turbulence penetration speed