Lemurian,
Thanks a lot for your input and your educated guesses about landing distances and stopping margins. Very intriguing, I'm curious to see how this one comes out in the end.
I have enquired and I don't know of an airline with a *decel* call-out based on the PFD speed trend.
Strictly
based on the PFD speed trend is perhaps saying too much, but EASA published a temporary revision to the Airbus A320 family FCOM in
SIN 2008-10, which can be found on
this page.
NVPilot, yes, quite a recent revision to the procedure, that may not yet have been incorporated into all operators' manuals.
There may or may not be a similar revision for Latin American operators, but the cited revision states in the LANDING SOP:
Originally Posted by EASA Safety Information Notice 2008-10
[...]
DECELERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . CHECK/ANNOUNCE
The deceleration is felt by the flight crew, and confirmed by the speed trend on the PFD.
The deceleration may also be confirmed by the DECEL light (if autobrake is on).
[...]
So the Decel call is based on, in this order:
- Seat-of-the-pants
- Speed Trend Arrow on PFD
- DECEL light
The revision also includes a reversionary procedure for "No Spoilers", which was sorely missing from the FCOM, namely to ...
- Verify and confirm that both thrust levers are set to IDLE or REV detent.
[...]
Together with the following ...
Note: If one or more thrust levers remain above the IDLE detent, ground spoilers extension is inhibited.
... this marks it clearly as a consequence of the runway overrun accident of a TAM A320 at Sao Paulo Congonhas in July 2007.
Common to both accidents may be a failure to assess deceleration correctly in a critical phase (at Congonhas: after touchdown, at Toncontin: after "70kts").
Bernd