Melbourne Tailstrike final report

[Mahatma Kote]

I made it more complex than required. The only figure required is runway length. The system can read ground speed and airspeed itself.

The system can also tell what the take-off mass is by measuring the accelleration vs thrust. This will allow it to call the rotates as well.

[Gulfstreamaviator]

RAAS

In Corporate this is the latest toy in our toybox.

We get distance remaining.

With a slight software enhancement, using the IRS acceleration, a GO NO GO point can be computed, withour reference to FMS computations.
Even give a warning TOGA NOW GUYS......

Say:100kt point from RAAS, compared to CAS 100k compared to FMS predicted 100k.

Just my 1 aed input....

[Denti]

Chu Chu,
In this event the erroneous weight was entered in the Electronic Flight Bag not in the Flight Management and Guidance System.

In that case my lowly 737 FMC would have alerted me to the issue. It shows computed QRH values for V1/Vr/V2, if the there is a big difference, especially to the negative, i certainly would question my own performance calculation. Only if i put in the wrong ZFM in both the EFB and FMC i would have a real problem.

[error_401]

1 cent worth:

First:
I'd like to have a "dry empty mass" sticker somewhere, even better as a basic figure in the FMGS. Would sometimes greatly help to have very basic figures. DRY + LOAD + FUEL = TOM

I do insist in separate calculations on EFB and never read the ZFM od TOM from the loadsheet or flight plan to the captain but hand him the paper to have him enter it himself. Then I crosscheck from FMGS to flight plan/load sheet and my calculation on EFB.

Has saved my day already couple times in 10 years...

Second:
Why not have mass sensors on the wheel legs? Could that work?

[Airbubba]

Why not have mass sensors on the wheel legs? Could that work?

This has been done several times in the past, here's one earlier example:

http://www.pprune.org/aviation-histo...mber-stan.html

Didn't some L1011's have a similar technology?

[Basil]

Both B747-200 and B747-400 freighters have the option of a total mass readout.
The -200 was allegedly troublesome to maintain but the -400 system worked well AFAIK.

[Ten-miles final]

Today's assumption is when error happened we try to invent new procedure or device to trap such errors in future. In this particular case i can hardly imagine what kind of further improvement may be found, and, the most important, why even we need it. There are enough predictions and crosscheks established to confirm grossweight - OFP (shows clearly 362 t TOW), loadsheet and previous experience. It was just error followed by inadequate crosscheck. Dramatic difference of 100t definitely should draw crew attention, but...
All of these were discussed above, don't see any appropriate remedial actions in general, such kind of mistakes will be done many times in future but hopefully without so severe consequences as 100t error is really very improbable.

[Akali Dal]

All the wonder ideas on how to trap such lack of airmanship and understanding of aircraft performance. All kinds of excuses for this screw up; why? Is he one of the skygod breed?

Any flex above your environmental envelope for a long haul flight should have raised all the red flags and warning bells. A cross check of your GMS gross weights against your loadsheet figures would have..........sigh

[nojwod]

To those who think the crew should have noticed the lack of acceleration:

I recently flew TG from BKK to SYD in an A340-600 and being a keen SLF observer of all aspects of my flight I was a little worried as the takeoff roll commenced without any appreciable g-force apparent.

However, the flight rotated well within the runway margins and off we flew, admittedly conservatively in the climb department.

Comparing that takeoff sensation to the previous A300 takeoff (moderate g-force) and the Dash8 Q400 departure (significant g-force) I can well understand crews who regularly experience flex takeoffs know better than to rely on apparent acceleration.

[canadair]

nojwod:
apparent acceceration may be a sensation or feeling not to be taken as a constant, but Thrust vs weight vsspeed vs distance ceratinly are fact.

And a very simple check which can be used as a gross error check is timing to speed.
30 seconds - 100 kts.
If after advancing the thrust levers and starting the clock at brake release this parameter is not met then it can be assumed something is incorrect,
ie not the correct thrust for weight, dragging brake, etc.
and it can then be taken that you may never reach V1 in the remaining distance.
Not to say if you reach 30 seconds and are not at 100 kts that you reject, but it is a guide, if you are at say 95 kts, accelerating, then the parameters have been met, but as in the MEL EK flt, they were so far beyond this from a timing point, that such a check would have been a huge wake up call.
why 100 Kts? have a look at brake energy charts, 100 kts is usually close to the top where wheels should stay intact at MTOW rejects.

Not to suggest this works for all types, but it seems to work quite well for most larger types. Boeing developed this very basic check over 40 years ago for the 747, and it is a great gross error check.

[Ten-miles final]

Canadair
...Boeing developed this very basic check over 40 years ago for the 747, and it is a great gross error check...

Is there any reference to original Boeing document or research papers available?
Would be great to read that.

[Capn Bloggs]

It's not totally clear in the report what the SOP response actually was, but to my way of thinking the Green Dot check should be a readout, from both pilots, of their GD speeds, not one read it and the other say "checked". If one is forced to read the number off somewhere, there is a much better chance of the check actually working. On more than one occasion I've said "checked" out of habit but not actually done it.

The other aspect/check that I thought was prone to failure was "both crewmembers to silently verify..." I would class that as a purely an airmanship check and not part of a robust procedure.

The other part of the report which was fascinating was that on Distraction Management. A huge threat, IMO, and hardly ever covered.

[patrickal]

This is a question, not a comment. After running off the end of the runway (although it appears the main gear had left the ground) and striking at least one ground object as they departed, was it wise for the crew to raise the gear, not being sure if anything had been damaged? Just asking.

[NigelOnDraft]

...was it wise for the crew to raise the gear, not being sure if anything had been damaged? Just asking.

With 20:20 hindsight, it might have been better to leave it down, in these exact circumstances.

However I (as a current airline Capt) cannot think of any circumstance, bar Windshear GA, where one is pre-briefed to leave gear down. To therefore "leave the gear down" in other situations requires:

1. 1 or more Flt Crew to suggest not raising the gear
2. The other Flt Crew to understand this interjection in time before gear is raised
3. The crew to interact (CRM, DODAR, analysis) as required and decide not to raise gear
4. All the above to occur at a flight critical phase of flight and delaying whatever else needs to be done

Bear in mind any "performance" issue assumes the gear is raised (typically engine failure).

So my view would be that yes, they were correct to raise gear, and I cannot see "how" a decision making process could work that would result in them not raising the gear that did not ask other "what ifs?".

[Akrapovic]

Does anyone know what happened to the crew involved?

I heard some rumour that the augment crew were reprimanded also?

[J.O.]

They were offered the opportunity to resign.

[TangoUniform]

Within 48 hours.......in order to receive their end of service benefits.

[fo4ever]

They were forced to resign with "gross negligence" charges from DSVP Flight operation (TCAS) 6 days after the accident.

The order came from the top (local owner of the airline)

End of story and problem solved.

[kinteafrokunta]

Poor sods were unlucky; with the right spin they could have been made heroes saving a crippled plane load of pax. Remember the Canadian Air Transat A330 crew who screwed up fuel leak management and got rewarded for dead stick landing at Lajes!

[Ten-miles final]

Is it described somewhere in manuals augmented crew must check performance calculations done by active crew? I suppose "Take off and landing crew" only is responsible for those calculations?