Qantas B744 Total electrical failure?

[NSEU]

If one generator was operating, was it feeding all busses? If not, there may have been a slight degradation of proper flight control. Lower Yaw Damper? Speedbrake Flight Detent? Aileron Lockout? (overcontrol at higher speeds)

Edit: re Aileron Lockout... In the (latest) BKK incident, this would mean undercontrol at lower speeds if DC Bus #2 had no power.

[LeadSled]

Hot Dog,

The Crikey journalist is one of Australia's most respected aviation journo's, he seems to often have better sources of information than ATSB, he most certainly has many long standing friends amongst the QF pilot and maintenance fraternity.

Have a look at the ATSB report re. flight controls, or get a -744 electrical diagram and have a look what is left with just one generator, and the split system breaker open. Have a look at which busses were still powered, and there seems to be less than 100% certainty about that , given the QAR and FDR lost power. Have a look at the FCC power sources.

Down to one generator is still bloody serious, even without the other electrical malfunctions listed.

Tootle pip!!

[Teal]

NSEU - always enjoy your posts. I gather this problem is only applicable to the 400 series, and given that there are over 600 in service, I would trust () that all other operators would be undertaking their own checks rather than wait for a service bulletin to be promulgated in May.

Can I bounce a few questions off you?

• Do you know how the earlier versions are different, so as to not suffer the same affliction?
• Why would these drip shields be made of fibreglass (simply low cost/weight?). To quote Wikipedia - "Moisture is easily adsorbed, and can worsen microscopic cracks and surface defects, and lessen tenacity"
• What's your take on the event being 'less serious' than first reported?

Apologies if already covered in previous posts.

Rgds

[HotDog]

LeadSled, there is no reference to degraded flight contols on the ATSB reports to date.

Between approximately 0840 and 0852, cockpit indications showed a number of electrical bus and system failures that indicated alternating current (AC) buses 2, 1 and 3 were not powered. The status of AC bus 4 appeared normal and some systems were powered by batteries.
The captain’s primary flight display, navigation display, and some other instruments were available in a degraded mode. Standby instruments and the aircraft’s instrument landing system were also available. The crew conducted an approach to runway 01 Right in day visual meteorological conditions and the aircraft landed at 0907.

The crew elected to proceed on the approach to VTSB without any further trouble shooting which could have theoretically, regained some further bus power after the initial trip off because they had sufficient instrumentation, including ILS and adequate flight control capability to execute a safe approach and landing.

Apart from that fact, for your most reputable aviation journalist to bring forth other totally irrelevant Qantas mishaps, REX engine loss and the attack on ATSB; smacks of journalistic sensationalism. Must admit, it sells paper and impresses the uninitiated. Have a good day, mate.

[Teal]

Some required levity...

[NSEU]

Have a look at the FCC power sources.

What was the actual quote regarding flight controls in this article? The FCC's are only going to affect the autopilot. They won't change the way the aircraft is flown manually. The 744 is not fly-by-wire (apart from the throttles).

Can I bounce a few questions off you?

Hmmm... sounds too much like WORK

Do you know how the earlier versions are different, so as to not suffer the same affliction?

I can't really say that earlier versions are that much different in this area (other than the later aircraft being more automated with regards to electrical bus control). This event was what you really would call rather unusual. Perhaps the holes in the slices of swiss cheese were always there... It just took 35+ years of flying the 747 series for the holes to line up.... Just as the holes in the swiss cheese lined up for the BA 777 last month.

Please note.... There have been faulty drip trays on older 747's and there have always been faulty drain mast heaters.... and faulty drip trays in other areas have even caused electrical problems, but, as far as I know, nothing on the scale of this latest incident. System redundancy in earlier cases has probably prevented this. Unfortunately, such was the volume of water in this latest case, that not even system redundancy could help. Note that modifications were made to drip trays in these other areas and, as far as I know, are now no longer a problem.

As mentioned previously, there is a series of safeguards which prevents water in the galleys from reaching the equipment on the lower deck... and the drip tray is only one of them. I still don't know how the water got through all of them (I'm still waiting for the final report to come out).

What's your take on the event being 'less serious' than first reported?

It is difficult to comment on this without knowing all the details. However, some busses are less important than others. AC Bus 4, from memory, doesn't have a great deal of vital items on it*. Better than nothing, of course

Airplane design has always had an element of "evolution"... Designers learn from their (and other people's) mistakes. But, with so many components in the average aircraft, there will always be some unforseen interreaction between them. Flying will never be 100% safe.. only 99.999.. % safe

Anyway, excuse me.. I have to go bandage up a fingernail which I broke on the fireproof flapper door of a toilet waste bin...

Cheers.
NSEU

*Other than probe heat (RH side), heat for one of the Captain's windows, a few assorted fuel pumps and Pack Temp Control "B".

[Teal]

Thanks. Didn't mean to overwork you..

Rgds

[qfflyer]

Incidets Within Australian Airlines

I Am Wondering Wether There Are Official Reports Published Anywhere Regarding Incidents Specifically Regarding Qantas That I Could Have A Look At Them ,

Wheres Best To Look ?

Thanks

[NSEU]

Can't say I've seen anything substantial on this incident. Usually CASA has reports on these kinds of event events, but couldn't find anything in their Flight Safety magazine or on their website (using the search function).

Civil Aviation Safety Authority

As coincidence would have it, there was a drain mast heating problem only a few days ago on one of Qantas' 747-400's. An internal heating element failed on the Centre Drain Mast and it iced up, causing flooding in the door #4 galley and surrounding areas (well away from the Main Equipment Centre). Thankfully, there were no other side effects other than wet floors/carpets.

It was just one of those everyday events of components failing (like lightbulbs), but caused a substantial delay... despite QF Engineering's intense efforts to get the problem rectified. Engineering was most insulted to see Qantas management distrubuting a printed document amongst the inconvenienced passengers, saying the delay was due to an industrial dispute over wages! This sort of misinformation only paints management in a worse light. If it wasn't for Engineering's efforts, the aircraft, in theory, could have been delayed 24 hours (the Boeing Maintenance Manual's procedure for drain mast removal/installation calls for sealant which has a 24 hour curing time).

Rgds.
NSEU

[rmm]

qfflyer,

All reports are here, although the site appears to be down at the moment.

http://www.atsb.gov.au/

[flynerd]

NSEU

I do not doubt your report...

I am not surprised by the report (but it sickens me) in the recent incident. Even though I am a staunch regular SLF on QF AND a US based stockholder, I am regularly pee'd off with the way their managment work. Looks like this should invoke a probing question to the board at the next AGM

[NSEU]

http://www.atsb.gov.au/publications/...003_prelim.pdf