IGh,
It has always been a sensitive subject for Airbus. On top of the Flight Crew Training Manual, they have published no less than 3 FCOM Bulletins explaining how to avoid tailstrikes, hard landings, and more generally how to properly handle the aircraft in final approach. They are all very informative readings, and all of them have a paragraph dealing with the crucial adherence to the proper speed, being Vapp (either automatically calculated, or manually overridden)
Mainly, they recommend using the A/THR, but in the same time they don’t try to hide that in certain circumstances, the result may not be satisfactory as :
Originally Posted by FCOM BULLETIN
A/THR response to airspeed variations is the result of a design compromise between performance and comfort, and is optimized when the AP is engaged. Therefore, in turbulent conditions and when flying manually, the pilot may sometimes find it to be too slow or lagging.
This is probably what happened in DEN. Aircraft was following the glide slope but with a tail wind component + only CONF 3, engines were probably at idle for the latest stage of the approach including the early part of the flare. A/THR responded but not as promptly as desirable :
At the time of initial touchdown, the thrust levers were still in CLB, and engine N1 increased from approximately 54% to 64% over 3 seconds.
Manual THR could have been, maybe, a better option here ...
Chris Scott,
I read the same figure of 139 knots for VLS CONF 3 and 64T, but to me, unless it is applicable for the A330 but not the 320 (?) Vapp should have had an extra 5 knots as the approach was conducted under A/THR …
Zippy Monster,
If the captain is adding a nose-down input of his own while the first officer is PF, then he should push the take-over button to disconnect the F/O stick and take full control himself.
The sidestick/FBW system is not designed for 'corrections' to be made from the opposite sidestick, hence the 'dual input' warning being incorporated in the first place.
Fully agree with your comment, but I would call it Theory, it looks good in the books but is not supported by the facts as seen in the incident reports.
In the heat of the moment, the take-over button is usually forgotten.