The 70 knot call was 7 seconds before hitting the fence and going off the cliff. He was reducing reverse before the 70 knot call so must have thought all was well at that time.
That's also what I think.
Why at 70 knots couldn't he stop in that 7 seconds or go back to max reverse thrust if rubber deposits reduced his braking? I know nothing except what I have learned here on Airbus 320 logic but it seems he lost all braking shortly after that call of 70 knots.
That's the big question.
I said it before but that last 1000 feet should be for emergency stopping only. Once slowed down to a safe speed use it to save brake wear and temp.
Basic airmanship.
One of the reasons why this transcript is galling is that most of the cockpit preparation is not there : For instance, the crew referrred to a *MEMO* that they cancelled. What was on that memo pad ? Some posters have also noticed that the discrepancy between *Manual braking* and *Decel* is at least very puzzling.
What is left for us to ponder about is that the deceleration from the touch-down speed and 70 kt was normal, even stronger than we'd expect from a medium autobrake setting (I stick to my figures)...
There is also the *Single Chime* recorded which is very probabbly related to a
minor failure showing after 80 kt (phase 8 inhibition)...what was it ? Was it related to the braking system ? In which case the "Cancel the..." makes sense as in "Switch the Anti-skid off..." (But here I digress and there is nothing to back that theory up, especially when they seemed to have had some effective braking prior to that point).
rwa,
As far as I can work out (such technical knowledge as I have is in another field) at that time any problem with the 'Anti-Skid and Nosewheel Steering' showed up only as a 'STEERING' warning. Cycling the switch removed the warning; but it ALSO cancelled the autobrake setting, and there was no warning message about that.
The usual mudding up of any discussion on an Airbus related subject...
That incident comes from 1/- some very flippant conceptions of SOPs, and 2/- an incomplete knowledge of the airplane systems and emergency procedures. I might add that 1 and 2 generally go in pairs.
Why ?
1/-Where in their manual have they found that *switch cycling procedure* ?
Not on the FCOMS I've used.
2/- *LOSS OF BRAKING* is one of the 9 memory drills on the 320. They are :
- Emergency descent
- Unreliable IAS
- Oxygen masks
- Loss of braking
- Engine surge
- Pull up TOGA
- Aborted T/O
- TCAS resolution
- Windshear TOGA
If one considers that some of them are so obvious as to be rather insulting to us pilots like aborted T/O, we are left with a very few number of specific procedures, among which *Loss of Braking*.
The crew in the incident you referred to did not know their drills. Final.