Emergency Qantas landing?

[NM]

I was just thinking that. Rather high for a 744 even when empty.

I believe the service ceiling for 744 is just over 45,000 ft (FL451 to be exact). Obviously the aircraft would have been light, and I wonder if they were wanting to test out the repaid job or just found the most favourable conditions up there??

 

[straitman]

I believe the service ceiling for 744 is just over 45,000 ft (FL451 to be exact). Obviously the aircraft would have been light, and I wonder if they were wanting to test out the repaid job or just found the most favourable conditions up there??

I'll make some enquires about the service ceiling.

NM was that a typo or... :?:

The FL's always correspond to the altitudes with the last two zeros dropped. ie FL450 equates to 45,000 ft.

 

[NM]

I'll make some enquires about the service ceiling.

NM was that a typo or... :?:

The FL's always correspond to the altitudes with the last two zeros dropped. ie FL450 equates to 45,000 ft.

Yes, my research reveals the service ceiling for 744 is 45,100 feet. Hence FL451. Note I said "just over 45,000 feet" and "FL451 to be exact". And FL451 is just over 45,000 feet (by a whopping 100 feet .

Now its not very common for a 744 to make it up to that height except perhaps on a ferry flight such as this one.

 

[straitman]

Yes, my research reveals the service ceiling for 744 is 45,100 feet. Hence FL451. Note I said "just over 45,000 feet" and "FL451 to be exact". And FL451 is just over 45,000 feet (by a whopping 100 feet .

Now its not very common for a 744 to make it up to that height except perhaps on a ferry flight such as this one.

NM,

I've just checked with a couple of 744 captains and essentially they agree with your post with minor variations.

The maximum altitude for a 744 is 45,100ft but the service ceiling is slightly lower at 43,000ft.

There are two problems with flying the 744 at those altitudes.
The first is that the maneuvering margin at those altitudes is very small. ie the difference between the cruising Mach No and IAS/EAS is so small there is little margin for error. The comment made was that this trip at FL430 was unnecessarily high and that QF were a mob of wxx_ers for doing it.
The second is to do with the pressurization differential which is the ability to keep the cabin pressure at normal levels. Remembering that most aircraft run cabin pressure at 8-9,000ft and you need oxygen above 10,000ft there is little margin available. Any higher and it's possible to blow out the pressurization valve.

 

[simongr]

And I guess with a newly repaired gaping hole in the side - additional pressure differentials may not be the greatest plan?

 

[NM]

NM,

I've just checked with a couple of 744 captains and essentially they agree with your post with minor variations.

The maximum altitude for a 744 is 45,100ft but the service ceiling is slightly lower at 43,000ft.

There are two problems with flying the 744 at those altitudes.
The first is that the maneuvering margin at those altitudes is very small. ie the difference between the cruising Mach No and IAS/EAS is so small there is little margin for error. The comment made was that this trip at FL430 was unnecessarily high and that QF were a mob of wxx_ers for doing it.
The second is to do with the pressurization differential which is the ability to keep the cabin pressure at normal levels. Remembering that most aircraft run cabin pressure at 8-9,000ft and you need oxygen above 10,000ft there is little margin available. Any higher and it's possible to blow out the pressurization valve.

Thanks Bill. All good insight. Perhaps they decided flying at FL430 was a god test for the new repairs and the overall pressurisation system? Or perhaps they flew up there just because they could (light)? Who knows?? Probably only the pilots. Another little bit of trivia - apparently the Captain and FO of the original MNL emergency landing were on board the ferry flight, though the PIC for teh ferry flight was the Captain that flew the initial validation test flight after the repairs were completed in MNL.

 

[docjames]

IIRC the 747 than had a short holiday on the golf course at BKK (!) flew back with Geoff Dixon on board, along the lines of proving it's been repaired properly and it's safe for everyone including the CEO to fly on.

perhaps going to max service altitude (yes i know it can do FL451 but it'd never go >FL430 in the "real world") was along similar thought lines ("look, it's been fixed properly and is safe to fly on"

 

[mannej]

Maybe the significant negative G (descent) will make this aircraft a writeoff?

I know this is a tad old, but VH-QPA is back in the air. Flew back from HKG on the 12th of Feb and if it wasn't for checking up on the rego details on the net after my return, you would not have known that it was involved in the QF72 incident it was involved in a few months. Was very smooth so not complaining at all

 

[Evan]

They repair them well
Some say they are never the same like VH-OJH after the QF incident in 99 but generally they are good as new.

 

[Nigelinoz]

They repair them well
Some say they are never the same like VH-OJH after the QF incident in 99 but generally they are good as new.

I hope so,considering the dire consequences if they don't,remembering specifically the crash of JAL 123 which crashed after a faulty repair on a bulkhead after a tail strike.

 

[Evan]

I hope so,considering the dire consequences if they don't,remembering specifically the crash of JAL 123 which crashed after a faulty repair on a bulkhead after a tail strike.

I sure do remember that one ! a tragic story of a bad repair and poor inspection of the repair.
Like a car its always better to have one that has not been crashed.... but it is sometimes unaviodable.

Its probably very false logic but i always feel much safer on a repaired 747-400 than say a 737-200.... and thankfully i have not had recently and 737-200 rides.

 

[oz_mark]

Second report coming

On Wednesday, 18 November 2009, the Australian Transport Safety Bureau (ATSB) will be holding a media conference to accompany the release of its second interim factual report into the in-flight upset involving Airbus A330-303 aircraft, registered VH-QPA that occurred 154 km west of Learmonth, WA on 7 October 2008

MEDIA ALERT : 16 November 2009 - 2009/14: Second Interim Factual Report into the Qantas Airbus A330-303 in-flight upset, 154 km west of Learmonth WA, on 7 October 2008

 

[Nigelinoz]

The second report will no doubt make interesting reading,especially if it contains anything that is in any way critical of QF-will be interesting to see how the media handle it-especially our friends at New Ltd.

 

[markis10]

News have released a story blaming a Neutron

Tiny neutron may have forced down jet | Breaking News | News.com.au

Quite a bit of the article is dedicated to the inevitable comparisons being made with the Air France Incident and how it would appear to be unrelated.

 

[medhead]

Cosmic Rays may have hit Qantas plane

Not sure if this should be in the thread about the original incident, but...

Seems that they are grasping at straws to find the cause of the sudden plunge of a Qantas aircraft of the WA coast.

AdelaideNow... 'Cosmic rays' may have hit Qantas plane off Australia's northwest coast

COSMIC rays may have been responsible for a near disaster involving a Qantas jet off Australia's northwest coast.

Safety investigators have isolated the cause of two terrifying dives by the Airbus A330-303 to an onboard computer.

But the computer itself, fitted to about 900 aircraft worldwide, was found to be in perfect working order, the Herald Sun reports.

This is from Adelaide Now, but there was a better write up in The Australian (I just can't find a link). Basically they are trying to say that a neutron from cosmic ray interactions in the upper atmosphere, hit the memory in the ADIRU and might have changed a memory bit. That invalid data then resulting in invalid data to the flight computer.

That's one hell of a lucky memory bit.

 

[Mal]

The link to the second interim report is here:

http://www.atsb.gov.au/media/748444/ao2008070_ifr_2.pdf

And once again people still don't wear seat belts while on planes:

Based on data from all the available sources, there were 147 passengers reported to be seated at the time of the first upset, with 87 wearing their seatbelts and 60 not wearing their seatbelts (a seatbelt use rate for this group of passengers of 59%). Twenty-three passengers were reported to be not seated at the time of the first upset.

And suffer the inevitable consequences when something goes wrong:

The injury rate for passengers reportedly wearing seatbelts (36%) was significantly lower than for those seated but not wearing seatbelts (92%) or for those who were not seated (100%) at the time of the first upset.
The proportion of seated passengers wearing seatbelts who received hospital medical treatment (11%) was significantly lower than for those seated but not wearing seatbelts (33%) or for those who were not seated (61%).

 

[oz_mark]

The thing I found most interesting about the seatbelts, were the inadvertant release scenarios.

For this to occur, the seatbelt had to be loosely fastened and the buckle had to be positioned in a vertical orientation underneath the right armrest prior to an upward force being applied. The lift-latch could then catch on the armrest and the buckle release.

The ATSB has conducted further examinations of this inadvertent release scenario on one of the operator’s A330 aircraft. Those examinations found that, for this scenario to occur on those aircraft, the seatbelt had to be adjusted so that there was at least 25 cm of slack in the belt

I wonder if,down the track, there are some recommendations about design/certification of seatbelts coming out.

 

[medhead]

The thing I found most interesting about the seatbelts, were the inadvertant release scenarios.



I wonder if,down the track, there are some recommendations about design/certification of seatbelts coming out.

I'm not sure how they could change the design. The critical point is the need to have 25 cm of slack. There has to be the ability to have slack in the belt because people are all of different sizes. That slack also means that belt buckle has no force applied to it until the person has moved the full length of the slack, with the buckle held in place by the arm rest. Then at the point that the slack is taken up the full force of 80 kg or 100 kg is applied to the buckle. It is a sudden loading, that probably caused the belt to realise. IMO this is a different loading situation to ift eh belt was adjusted to length correctly where the force would be evenly and smoothly applied to the buckle. It is also due to people not using the belt as instructed.

BTW I've taken a frame of reference from inside the aircraft when saying that the people move up and away from the seat. That doesn't mean I don't realise that the aircraft actually moved down.

 

[straitman]

I'm not sure how they could change the design.

There are quite a few other designs of aircraft seat belt buckles around though one appears to be the standard for RPT passenger aircraft.

In any case I agree with you that there is probably no need to change.

 

[oz_mark]

I am not sure what they could do either. However, given that they have identified a failure mode for a seatbelt, I would think that there would be some work going on to solve the problem.