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Old 24th Oct 2011, 23:11
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cosmo kramer
 
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Thrust reduction during the flare:

It's apparently a wide spread technique to initiate the thrust reduction at 10 feet or less with the goal of achieving a smooth landing. In my opinion this technique is wrong (and not in line with the FCTM).

In my opinion it's more than often counter productive and the direct result is a firm touchdown. I believe the cause is two fold. First, it's more difficulty to judge the required input to counter the pitch down moment due to the thrust reduction which happens within a relatively short timespan and at the most critical part of the flare, where you want the most precise control. Second, the extra thrust carried causes the speed to be too high (wind correction should be bled off during the flare) and the aircraft to continue flying, which obviously is counter productive as well, when the goal is to land.

Then there is the aspect of flaring distance. The above will certainly result in a landing in the last part of the touchdown zone, and those that regularly uses this technique may do so quite consistently. However, once in a while they have to "drop it", for a very firm touchdown, when it becomes clear that it would otherwise result in a long landing.

With correct technique, it's no problem to close the thrust levers by 30' and obtain a perfectly smooth landing. With the added bonus of being in the beginning of the touchdown zone. Again the reason is two fold and the opposite of above. First, it's easier to adjust the control input required to counter the pitch down. Even if you use either of two techniques: 1) Slowly closing the throttles give more time and better feel to keep nose where it should be. 2) Slamming the throttles shut at 20-30 feet may not give the same accurate feel, but it then gives more time (feet) to get the adjustment right. In any case the adjustment is complete before the final critical few feet of the flare and all control input can be concentrated about path control, instead of thrust compensation, for the most precise control. Second the engines are at idle and the speed is correct and decreasing when touching down - the aircraft is ready to land by itself more of less with very little input.

Of course there are circumstances that may warrant to keep the thrust in or even adding thrust in the flare, likewise sometimes thrust reduction should be initiated higher than 30 feet as well. But either should be done as a deliberate action when required. Reducing by 10 feet as the norm should not.

Immediate rush to select start switches to CONT in slight turbulence.
...and reduce speed to .76 during cruise. Even when there are no recommendations in the manuals to set this speed for cruise phase of flight at any turbulence intensity.

Re: Bleeds off takeoff:
It's far too easy to forget but having an open sup manual is another fail safe on a vital system.
If one knows his C pattern and read the after take off checklist afterwards he is covered.
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