T/O thrust reduction and speeds
Guest
Posts: n/a
Some thoughts ..
(a) it makes more sense (to me) to adjust the VR/V2 speeds to suit actual RTOW data with several considerations
(i) if you keep the V2 around V2min plus 20 or so, then the improved gradient is good value
(ii) if the procedure involves a turn for terrain, then make sure that your V2 rescheduling is compatible with whatever the ops engineers designed into the procedure from the point of turn radius.
(iii) I would be cautious about playing with V1 unless you have some quantitative data to hand upon which to base any changes. It would be normal for the performance manual to have some sort of guidance in this regard. In addition, be wary of reducing V1 to V1min values in conditions of strong crosswind.
(iv) the question of derating to a limiting condition has been well canvassed in other threads
(b) alternatively, keeping with the speeds for the higher RTOW data ought not to present a problem unless
(i) the bird has a desire to lift up its skirts and fly below those higher speeds.
(ii) the operator prefers to keep the shake rattle and roll wear and tear down during the ground roll operations - and we ought to keep in mind that, as pilots, we owe a duty to our employers in respect of desired standards and methods of operation.
(c) noise (sound pressure level) is a distance squared animal, so height is most important. With a significant derate operation, the SPL meter ought to record a difference in sound energy.
(d) BFL is not an a priori consideration. BFL often is a convenient calculation basis, but generally doesn't offer the best RTOW figures.
(e) if your preference is to increase thrust with a failure, then do so steadily rather than abruptly and after the rotation flare is completed, gear selected up, and the aircraft in stabilised climb conditions - why make an awkward situation even more critical ?
I know of at least one fatal where throttle advance was implicated. The normal limit speed boundaries ought to protect against directional control problems presuming that the pilot is appropriately competent.
From my observations in simulator exercises, I would earnestly suggest that you practise such exercises in sim free time so that you are comfortable with the sometimes surprising handling effects.
(a) it makes more sense (to me) to adjust the VR/V2 speeds to suit actual RTOW data with several considerations
(i) if you keep the V2 around V2min plus 20 or so, then the improved gradient is good value
(ii) if the procedure involves a turn for terrain, then make sure that your V2 rescheduling is compatible with whatever the ops engineers designed into the procedure from the point of turn radius.
(iii) I would be cautious about playing with V1 unless you have some quantitative data to hand upon which to base any changes. It would be normal for the performance manual to have some sort of guidance in this regard. In addition, be wary of reducing V1 to V1min values in conditions of strong crosswind.
(iv) the question of derating to a limiting condition has been well canvassed in other threads
(b) alternatively, keeping with the speeds for the higher RTOW data ought not to present a problem unless
(i) the bird has a desire to lift up its skirts and fly below those higher speeds.
(ii) the operator prefers to keep the shake rattle and roll wear and tear down during the ground roll operations - and we ought to keep in mind that, as pilots, we owe a duty to our employers in respect of desired standards and methods of operation.
(c) noise (sound pressure level) is a distance squared animal, so height is most important. With a significant derate operation, the SPL meter ought to record a difference in sound energy.
(d) BFL is not an a priori consideration. BFL often is a convenient calculation basis, but generally doesn't offer the best RTOW figures.
(e) if your preference is to increase thrust with a failure, then do so steadily rather than abruptly and after the rotation flare is completed, gear selected up, and the aircraft in stabilised climb conditions - why make an awkward situation even more critical ?
I know of at least one fatal where throttle advance was implicated. The normal limit speed boundaries ought to protect against directional control problems presuming that the pilot is appropriately competent.
From my observations in simulator exercises, I would earnestly suggest that you practise such exercises in sim free time so that you are comfortable with the sometimes surprising handling effects.
