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Old 13th Jan 2014, 16:40
  #326 (permalink)  
HazelNuts39
 
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Originally Posted by rudderrudderrat in post#228
Vs1g was demonstrated in flight test in ALT LAW.
In your post #266 you quoted from the preamble of the FAA Special Conditions for the US type certification of the A320. Development testing is not certification testing. In the Special Conditions it is evident that certification tests to determine Vs1g are conducted in normal law, the AoA protection system operating normally, except that alpha-floor must be disengaged.

Special Condition 6. Flight Envelope protection, (b) Angle-of-Attack Limiting, under (1)(i), states: Conditions associated with the determination of the stalling speed are those provided in § 25.103 of the FAR.

Relevant sections of FAR § 25.103 as amended by the special conditions read:

(a) VS is the reference stalling speed with--
(1) Stalling speed determined at not greater than IDLE thrust (NOTE: automatic go-around thrust application feature must be disengaged);
(2) (...)
(b) The stalling speed VS is the minimum speed obtained as follows:
(1) From a stabilized straight flight condition at any speed not less than 1.16 Vs (or speed at AOA protection onset, if greater) nor more than 1,30 Vs, apply elevator control to decelerate the airplane so that the speed reduction at the stall does not exceed one knot per second.
(2) (...)

In short: Vs is the speed obtained in normal law when the sidestick reaches the aft stop, i.e. Vs = V(alpha-max)

Last edited by HazelNuts39; 23rd Jan 2014 at 10:36. Reason: To add 'normal law' in the last sentence
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