PPRuNe Forums - A-320 V Speeds

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Hi All
Have noticed A-320 V speeds at certain weights /temp/PA that VI=VR=V2
Any explanation ?
Thanks

Quote:

Any explanation ?

If the runway is very long, then the theoretical maximum V1 can be very big.
V1 can't be > VR,
VR can't be > V2,
Therefore V1 = VR = V2.

According to CS/FAR 25.107(c)(2):

Quote:

(c) V2, in terms of calibrated airspeed, (...) may not be less than –
(1) (...);
(2) VR plus the speed increment attained (in accordance with CS 25.111(c)(2)) before reaching a height of 11 m (35 ft) above the take-off surface;

So how can V2 be equal to VR?

Hifly, hello. Briefly:
Airbus typically base T/O speeds on an Optimum V2/VS Ratio.
For 4 eng a/c there will be a range of ratios. For 2 eng a/c there is only one optimum ratio.
V2 is a factored value of VS which in itself is a function of weight.
Long runway, low weight high probability of unity for V1/R/2

Suggest read notes in FCOM2 (as was) or current Book 4 in the Perf/TO section.

Out of interest: Did you notice the speeds on the output from an automated T/O calculation program, or from inspection of a RTOW page. (I'm guessing the former:))

P.S. Just read yr profile. Sympatico on losing yr Cat. When I lost mine, felt like me legs 'ad gorn!