View Full Version : Interesting reading for A330 pilots

13th Sep 2021, 20:48

13th Sep 2021, 21:10
Taiwan's CAA reported the root cause of the occurrence is still under investigation and advises all A330 operators to take countermeasures:

- prior to dispatch consider possible deceleration deficiencies with the conditions mentioned above on wet runways.
- required landing distance shall be predetermined for a wet runway, if the distance is a concern consider an alternate aerodrome
- operators should enhance crew awareness of wet runway operations, if automatic braking is out of function promptly change to the alternate system or apply manual braking

Very helpful advice... :rolleyes:

Loose rivets
13th Sep 2021, 22:11
Gasp. The computers were like folk rejecting a hot potato.

I get the feeling there wasn't a lot of ABS-ing going on. That was a loooong time with very low - g forces.

I assume that high hydraulic pressure recorded latterly doesn't actually reach the brake hubs? IIRC, ~ 2,600psi.

Big Pistons Forever
13th Sep 2021, 23:16
The crew were given a :mad: sandwich at a very bad time. It look's like good CRM and prompt crew action prevented an over run for what should have been an impossible fail mode.

Kind of makes you wonder how this would have gone in a "single pilot" version of the aircraft........

14th Sep 2021, 00:23
After that, the nose gear flipped between air mode and ground mode for nearly 7 seconds.

There might be a very good reason for having Air/Ground Logic installed in the nose gear.

Just can't see which one is it ...

14th Sep 2021, 06:21
Could this be a very soft bounce/skip with an 11.5 kt tailwind?

Bill Harris
15th Sep 2021, 18:11
Big Pistons Forever

And how many over runs attributed to pilot error actually weren't.

Loose rivets
15th Sep 2021, 22:14
Also, I'm not at all sure this was prompt action. As a dinosaur, I'm very hesitant to criticise younger crews that know so much more, but that prolonged low negative g was making me ache as I counted the seconds.

I recall getting into the habit of testing the brakes while the kinetic energy was still high. Hardly enough for the passengers to feel, but that short moment was very comforting and all-telling. I imagine these days the system would tell on me for non SOP actions.

Rt Hon Jim Hacker MP
16th Sep 2021, 16:48

Seem to recall some strange logic on the 330 that gave a better stopping distance once the nose strut was compressed when using max manual braking. One of our techies found it and it was his pet "how clever am I" subjects.

16th Sep 2021, 17:14
I hope the people at Airbus are taking a long hard at what caused the computers to all fail at pretty much the same time - that's probably not a coincidence - there is some unknown common failure going on.
We had an issue several years ago with the CF6-80C2 FADEC. There was an in-flight shutdown - and when I looked at the data it very much appeared that both FADEC channel CPUs failed at the same time (or within one second, since that was the data recorder frequency). Now, while that is theoretically possible, the odds are astronomical - in fact our engine controls Tech Fellow went so far as to say it was impossible. But with nothing else to go on I figured it was a freak occurrence. But then there were several other shutdowns with the same symptoms (IIRC we ended up with 7 total shutdowns due to that cause). GE was finally able to track it down - it was an Electro Magnetic Interference (EMI) effect when continuous ignition was commanded on. Turns out there had been several hardware changes and a software change over the previous 10 years that combined to give the susceptibility :eek:.
The real concern was it was a potential common cause failure since continuous ignition is commanded when the flaps are lowered during approach. Fortunately the actual probability of Con Ignition 'ON' causing a shutdown was quite low so the odds of a multiple engine event were in the 10-9/flight range, but it was still worrisome (and you know what they say about statistics :rolleyes:). The FAA quickly issue an AD that dictated 'depairing' of suspect FADECs (i.e. you could only have one FADEC with that particular combination of software and hardware configuration per aircraft), and I slept better after we got a fix certified and retrofit into the fleet.

16th Sep 2021, 18:55
Quite a while back. We lost 5 of the 6 screens whilst climbing out of Tenerife. Only for 15 seconds or so. I flew the same aircraft a few days later & had a look at the relevant tech log page. Defect was cleared as “Not Possible” I suspect that their is a bit of a mind set when it comes to these very very very rare events. Glad the FADEC issue was followed up with more enthusiasm.