School children caught up in Qantas plane weight drama Part 2

[Prince Niccolo M]

I am intrigued that at no point has anyone mentioned that Cobham crews had been raising this problem and the potential outcome for at least 5 years, clearly without the risk being confirmed and mitigated.


There is a much bigger systemic failure being buried here....

[Sarcs]

Covered here by SMH: Schoolkids tip balance of Qantas plane (http://www.smh.com.au/business/schoolkids-tip-balance-of-qantas-plane-20140903-10bv5i.html)
And this is the Short Investigation report: AO-2014-088 (http://atsb.gov.au/media/5092920/ao-2014-088_final.pdf)

Cheers...:ok:

[Fris B. Fairing]

On 9 May 2014, the group was checked in by two CSAs at Canberra Airport. They recorded the actual weight of each bag to speed up the check-in process and then attempted to convert the pre-checked baggage weight from 20 kg per bag to the actual weight, in the customer management (CM) module.

I believe this should read;

They recorded the standard weight of each bag

i.e. 20kg

UPDATE:

I referred this to the ATSB and they confirm that the original wording is correct. In case I'm not the only one to find this wording confusing, this is what happened.
Two days before the flight, the group was pre-checked into the departure control system with a standard baggage weight of 20kg per passenger.
When the group arrived at CBR Airport, the actual baggage weights were tallied, but outside the departure control system. This total actual weight was then used to update the standard weights previously stored in the DCS. All perfectly normal procedure.

[framer]

What also intrigues me about this is that this is the third thread to be started and will no doubt be closed in short order. What are the mods thinking?
There has been no Qantas bashing or poor behaviour by members posting, so why close it? It is a very interesting systemic failure and one worth discussing in order to make some safety learnings.
For example, I think there was a chance that this event could have resulted in a high speed RTO if there was a different crew onboard (because I have read a report of that very thing happening on a 737 in Europe) but others think that is highly unlikely and that the event is not at all serious. Who is right? I don't know and it doesn't matter but I do know I would have learnt something that I could taken to the line if the conversation hadn't been stopped.

[Kharon]

The mildly intriguing thing is Tiger, Virgin and now Qantas have had ground paper work systems at the root of later 'trouble', is this becoming a 'trend?. Couple or three stuff ups a year would be about par for the course. If more than three have slipped through to the keeper, how many have slid by un-remarked. Understaffed?, under-trained?, computer glitches or plain old fashioned 'stuff-ups' and finger trouble: perhaps a combination.

Not a research project – passing interest only – wouldn't bother except the threads were shut down. Passing strange. Comments – anyone??

[rammel]

In regards to QF this is not the first time this has happened, maybe just the first time the ATSB has reported it.

This goes back to when the Amadeus Flight Management system was implemented. It was overcome by training the people who looked after the group check-in to recognize this and it was sorted out during the check-in process.

My theory as to why this may have happened is to do with the staffing levels at airports, being that they have to do more with less. If it was someone who doesn't normally do group check-in they may not have been aware of this.

I've got no doubt that unfortunately this will occur again at some time in the future.

[rob_ginger]

Just an inquisitive SLF here, trying to get in before the thread is closed *again*..

What does the PF feel when a 737 is nose-heavy ? I would imagine there's heaps of elevator authority available, so it would be possible to just keep pulling back to get the nose to come up to the right "rotate" attitude. But is there a SOP that mandates an RTO if the amount of back stick required is abnormal ? Definitely a moment when the PF earns his wage !

[travelator]

Rob, rotate speed is higher than V1 so reject at rotate = off the end of the runway and likely death/fire/paperwork etc.

Not familiar with the 737 but on my aircraft the stab is set using CoG, weight and flap setting. If this setting is off then extra (or less) control input is required and trim accordingly.

I am doubtful that the pilots would have noticed before rotation so fail to see how a high speed reject may be a consequence. The acceleration may have been faster than anticipated but thanks to flex/derate, every takeoff is different and would be very hard to pick.

[Capn Bloggs]

I am doubtful that the pilots would have noticed before rotation so fail to see how a high speed reject may be a consequence.
Eh? If you pulled near to full back stick (then used trim??) and the nose doesn't come up, you fail to see that at least the thought would go thru the PFs mind that "this thing isn't going to fly, can/should I stop?"?

On a 3500m+ runway (admittedly not at CBR) the "unflyable" reject criteria would flash thru my mind...

Another good scenario for the Sim...

[framer]

so reject at rotate = off the end of the runway and likely death/fire/paperwork etc.
Sometimes yes, sometimes no.
I fly the 737 and sometimes with a long runway using the Boeing OPT you could stop from VR with a kilometre to spare.
V1 and VR are often within one or two knots of each other in the NG.
This from a 737 RTO report;
. At VR, the copilot applied normal rotation force on the control column. “He doubled his effort after his first attempt had no effect,” the report said. “The captain was aware that there was no rotation and decided to stop the aircraft.”
Airspeed was 155 kt when the pilots brought the throttles to idle and proceeded with the re- jected takeoff procedure. “The speed was under control with 900 m [2,953 ft] of runway remain- ing, which allowed braking to be reduced, and the aircraft vacated the runway at the upwind end,” the report said.
So how different is that from the situation we are discussing? I think it is fairly similar and can think of two more where the RTO was initiated after VR because the nose was very heavy and the Captain determined that the aircraft was "unsafe to fly".

Unsure of aircraft type for this one;
During a takeoff from Frankfurt airport, just before reaching V2 there was a loud bang followed by severe vibration. The Captain concluded that the aircraft was not safe to fly and rejected the takeoff. The aircraft stopped in the remaining runway available. The vibrations were caused by a tire failure.

This one is also 737;
The takeoff was rejected after the decision speed V1 and while the nose wheel was off the ground for approximately two seconds. The aircraft stopped with 500m to spare.
There are plenty more. The takeoff safety training aid points out that of the 74 RTO overruns studied from the western built jet transport fleet, the RTO was initiated after V1 58% of the time. The problem I see with getting false load data is that the problem is often hidden until the high speed regime where the flight crew have to make a decision very quickly with incomplete information.
I don't think it is an area where we can accept declining standards and cross our fingers.

[Oakape]

The report stated that the stab trim was 1 unit out when the correct figures were used. That is not a large difference & wouldn't require excessive control input. I regularly have to apply back trim when getting airborne in the NG. The actual weight was less then thought, so the speeds were higher than needed, so no problems there. If the actual weight had been higher than what was used to calculate the take-off data, then that would have been a more serious issue.

The matter does need to be investigated & addressed, particularly so that systemic issues can be corrected. But to imply that there were serious safety issues with regard to the actual take-off & flight is a bit of a stretch.

[Jay Arr]

Unsure of aircraft type for this one;
Quote:
During a takeoff from Frankfurt airport, just before reaching V2 there was a loud bang followed by severe vibration. The Captain concluded that the aircraft was not safe to fly and rejected the takeoff. The aircraft stopped in the remaining runway available. The vibrations were caused by a tire failure.

Well, that would have been REALLY interesting......! :hmm:

[travelator]

At 120 knots, the flight crew noted the onset of a vibration. When the vibration increased, the captain elected to reject and assumed control. Four to eight seconds elapsed between the point where the vibration was first noted and when the RTO was initiated (just after V1). Subsequent investigation showed two tires had failed. The maximum speed reached was 158 knots. The airplane overran the end of the runway at a speed of 35 knots and finally stopped with the nose in a swamp. The airplane was destroyed.

At 154 knots, four knots after V1, the copilot’s side window opened, and the takeoff was rejected. The aircraft overran, hitting a blast fence, tearing open the left wing and catching fire.

According to an FAA study of high speed rto accidents (120kt and above) 18% were unavoidable and 52% would not have occurred if the takeoff was continued.

Not excusing the systemic stuff up that led to this but strongly cautioning the idea of v1 + rejects. It may work out ok sometimes (45%) but the when it doesn't people can die.

[framer]

but strongly cautioning the idea of v1 + rejects.

I agree. I certainly didn't mean to champion the idea. I was just trying to show that it does happen and by introducing the need for a go/no go decision at VR ( by having incorrect load data) , we are making it more likely.