I read with interest the Embraer Legacy flight test "Family values" (Flight International, 11-17 March). As always with your flight tests it was informative and very readable.
However, I noticed that in the section "stall tests", the author mentions deliberately disabling the stick pusher to reach a higher angle of attack (lower airspeed). While I am sure that this would have been carefully briefed before flight, I would caution your wider readership against attempting any repetition of this practice on any aeroplane fitted with a stick pusher.
Stick pushers are fitted as stall identification devices and, as such, mark the end of the usable aerodynamic envelope for the aeroplane. Pilots must understand that the airworthiness authorities have no requirements for flight beyond the stall (stick pusher) and the aircraft's characteristics in that area will, therefore, be largely unknown.
Flight at greater angles of attack may lead on some types to an irrecoverable "deep stall" or to some other adverse or catastrophic aerodynamic characteristic. Although this was clearly not the case on the Legacy, I would implore all pilots not to attempt to "beat" or resist the stick pusher - it must be respected at all times.
G G Reid Chief test pilot, UK Civil Aviation Authority, Gatwick Airport, UK
Editor's reply: Flight evaluations are performed by a fully qualifed test pilot, Mike Gerzanics. In our flight tests, we endeavour to test as much of the flight envelope as possible, including an aircraft's stall. Flight International does not condone a pilot operating an aircraft beyond the prescribed limits.
Source: Flight International
