Ask The Pilot

[jb747]

Hi JB . The following ATSB report is about a A330 and it is interesting that the captain took a break between the event and before they landed. A330 engine malfunction incident detailed in ATSB preliminary report | ATSB

It was stable, and I'm sure they were prepared for things to get worse. QF long haul FO's are legally allowed to be acting in command in the cruise, so you could reasonably expect the FO/SO to be able to handle things. It becomes an assessment of whether having that break will make a difference later on, and that's something that can only be decided at the time, by the people there.

What is much more interesting, from the ATSB report, is the behaviour of the engineering staff. They had a visual indication that there were major issues with the engine, but chose to write it off.

During the turnaround in Los Angeles, two maintenance engineers troubleshooted the N2 vibration issue, during which they observed particles in the right engine exhaust. The troubleshooting culminated in the aircraft being released to service with its N2 vibration sensor inoperative in line with minimum equipment list (MEL) requirements, meaning N2 vibration readings were not available to the flight crew on the incident flight.

That is just appalling. They could see particles, but did not follow up on them, but chose to MEL a system that was working correctly. I'll bet that if "particles" had been mentioned to the Captain, that he would not have accepted the MEL. I know that I wouldn't have.

I was wondering how the issue of fatigue is address in training after an incident has happened and there is a long period of time before landing to ensure that both pilots are as fresh as possible for the critical parts of the flight?

There's nothing specific. It's all up to the Captain on the day.

Also with QF 30 did pilot fatigue become an issue with the extra work load ?

No. It was only about an hour from the time it went bang, to when we landed. If I had to have an incident, the timing of this one, was almost perfect. Daytime. Body clock midday, after a decent night's sleep.

 

[mjt57]

The troubleshooting culminated in the aircraft being released to service with its N2 vibration sensor inoperative in line with minimum equipment list (MEL) requirements,

This, to me at least, is confusing. Is it OK to lift the protection on an engine thus removing from service a safety device?

In my former job, shaft vibration sensors (or accelerometers) were a critical part of a turbine's protection system. To disable them would've resulted in somewhat unpleasant results for those responsible.

That engine pretty much self-destructed at idle. Imagine the catastrophic failure that would've occured at cruise power and the crew would've been unaware of it unless the vibes could be felt in the cabin/flight deck prior to it going kaboom.

 

[cambriamarsh]

This, to me at least, is confusing. Is it OK to lift the protection on an engine thus removing from service a safety device?

In my former job, shaft vibration sensors (or accelerometers) were a critical part of a turbine's protection system. To disable them would've resulted in somewhat unpleasant results for those responsible.

That engine pretty much self-destructed at idle. Imagine the catastrophic failure that would've occured at cruise power and the crew would've been unaware of it unless the vibes could be felt in the cabin/flight deck prior to it going kaboom.

Thanks JB, are the LAX maintenance engineers QF staff or outsourced?

 

[jb747]

This, to me at least, is confusing. Is it OK to lift the protection on an engine thus removing from service a safety device?

What is very much forbidden is making any serviceable system unserviceable, just so that you can apply an MEL. And in this case, making a working warning system U/S, because you don't like the readings, is beyond dumb. I can see that an MEL may be appropriate for a vibration monitoring system that is either not working at all, or is giving intermittent readings, but I'd expect that to be extremely limited in its scope, and to come with many caveats. The fact that they found any particles in the engine should have stopped them in their tracks.

In my former job, shaft vibration sensors (or accelerometers) were a critical part of a turbine's protection system. To disable them would've resulted in somewhat unpleasant results for those responsible.

That engine pretty much self-destructed at idle. Imagine the catastrophic failure that would've occured at cruise power and the crew would've been unaware of it unless the vibes could be felt in the cabin/flight deck prior to it going kaboom.

It compressor stalled. You'd notice that. There are other vibration monitors on the the other spool, so you'd get some sort of indication from that system. I cannot see that you'd be able to deactivate both. And once it stalled, the rest of the engine display would have plenty to say, in particular, the EGT.

Thanks JB, are the LAX maintenance engineers QF staff or outsourced?

I expect that in keeping with QF's way of doing things, that they'd have created a subsidiary company in LA employing local engineers. So QF, but not really. I don't recall seeing an Australian engineer there since around 2008 or so.