MH134

[drpixie]

See www.facebook.com/AIRLINESECRETS/posts/2210636529209353 and Investigation: AO-2018-053 - Airspeed indication failure on take-off involving Airbus A330, 9M-MTK, Brisbane Airport, Queensland, 18 July 2018 (http://www.atsb.gov.au/publications/investigation_reports/2018/aair/ao-2018-053/)

How did that crew make any kind of V1 abort/continue decision, with no airspeed indications? WTF

[Icarus2001]

With guidance from their deity of choice.

[hoss]

Time to get a new deity of choice. What about his fellow countryman from the opposition who was going to dead reckon back to KLIA.

[ampclamp]

Anything the Brissy wasps can do, humans can do better! :eek:

All jokes aside, it is a serious incident where several inspections failed to pick up the presence of the covers.

One would think airspeed anomalies, or lack of indicated airspeed may have been picked up earlier, but I'll leave all judgement to the investigators.

[ozziekiwi]

https://www.pprune.org/rumours-news/611306-mas-a330-bne-leaves-pitot-covers.html

[packapoo]

I learned my lesson some time back. This serves to remind me NEVER be tempted to fly Malaysian.

[A320skoda]

Pitot covers installed are made of fabric so they don’t melt if pitot heat comes on with them installed. This fabric let’s a small amount of air through like a very dense filter. It’s possible airspeed did register up to a certain point as there would still have been some pressure getting to the probe.

[The Bullwinkle]

All jokes aside, it is a serious incident where several inspections failed to pick up the presence of the covers.
Have heard from a fairly reliable source that no Flightcrew were observed conducting a pre-flight walk around.

Also, the ground handling agents apparently installed Boeing pitot covers instead of Airbus pitot covers. Apparently the Airbus covers are designed to disintegrate when the Probe heat is turned on.
Finally, the decision was made to continue even though they did not have accurate airspeed indications and once airborne, Airbus being Airbus, the screens all went blank because the ADIRU’s couldn’t work out what was going on.

It’s amazing that they even got it back on the ground in one piece, albeit with a heavy landing.

[Australopithecus]

. We conduct external pre-flight inspections all the time with the covers on as they are removed by Mx personnel closer to departure time.

Our (Airbus) covers are woven from kevlar, and I don't get the sense that anything short of an oven would compromise them. In fact they are made specifically not to melt; perhaps there is something about their construction that makes them unravel?

The screens don't go blank during an unreliable airspeed event....in fact pilots are expected to fly attitude and power to a safe conclusion.

There is also a back-up speed scale that, when selected by turning off air data, displays fast/slow cues based on alpha. That system (BUSS) may in fact be a a factory option, and if so, MH may not have it installed* (see below)

Unreliable airspeed in an A330 is a non-trivial, but manageable event. That said, its pretty unlikely to cross the fence at exactly the optimum speed, and a heavy, slow aircraft bleeds energy quickly. Its not difficult to see how either a hard or long landing might result, especially with rarely used manual thrust.

On edit...I was curious about the BUSS. Deeper research reveals that BUSS might be optional even on later build aircraft.

[DutchRoll]

Have heard from a fairly reliable source that no Flightcrew were observed conducting a pre-flight walk around.

Also, the ground handling agents apparently installed Boeing pitot covers instead of Airbus pitot covers. Apparently the Airbus covers are designed to disintegrate when the Probe heat is turned on.
Finally, the decision was made to continue even though they did not have accurate airspeed indications and once airborne, Airbus being Airbus, the screens all went blank because the ADIRU’s couldn’t work out what was going on.

It’s amazing that they even got it back on the ground in one piece, albeit with a heavy landing.

I'm not sure that simply not noticing a pilot doing a walk-around is concrete evidence that none was done (they don't take long, and there's often a fairly big time window in which they can be done), but as Australopithecus above alludes to, it is SOP at YBBN to do a pilot preflight with the covers still on due to the mud wasp issue. What's not SOP is actually getting through the A330 Before Start checklist item of "Gear pins and covers - Removed" with the covers still on! Also, at least in our "large iconic aussie airline", the tech log must have an open coupon stating that covers are installed and everyone I know keeps the tech log highly visible until the ground engineer comes up, shows us the covers, and signs off the open coupon as "covers removed". So it would seem there are multiple pretty poor procedural breaches there. Dunno about the pitot cover design thing. I had a look at our Airbus covers the other day in YBBN and they look pretty robust to me. I would've thought if they disintegrated or melted, a partial blockage might be likely. That could be even more confusing than a simple reversion to the BUSS.

When the air data side of the system decides that all its pitot-static data is unreliable it automatically displays the BUSS on both PFDs in the A330. The BUSS uses only data from the AOA vanes on the airspeed tape side of the display. That's a "normal" reversionary mode on the aircraft built into the system software.

How & why they got airborne, I have no idea.

Dutchy
Current A330 pilot

[Snakecharma]

Dutchy - one thing I dont know is how old the malaysian 330's are - the older aeroplanes don't have BUSS

[Bravohotel]

I listened to the ATC conversation they kept asking for groundspeed reports and asked for vectors for a 20 mile final runway 01

[Altimeters]

From another forum. But apparently these pics are what the crew had.

https://cimg9.ibsrv.net/gimg/www.gmforum.com-vbulletin/1080x810/6a9b5185_1783_4ab8_b058_7d072bc2d0d2_41116ad05f574fac7a63ae4 5053311f53a05da7f.jpeg
https://cimg0.ibsrv.net/gimg/www.gmforum.com-vbulletin/1080x810/c6bd8a5e_c363_4118_9ed3_f8268c143c21_99b9c05011e34e6019ddf63 737c379262b4f4e2d.jpeg

[maggot]

Eng 2 inop?
maybe a frivolous pic there
But the BUSS is accurate what you're looking at instead of a speed tape

[BuzzBox]

When the air data side of the system decides that all its pitot-static data is unreliable it automatically displays the BUSS on both PFDs in the A330. The BUSS uses only data from the AOA vanes on the airspeed tape side of the display. That's a "normal" reversionary mode on the aircraft built into the system software.

That's not how it works on our A330s that have BUSS; it's not displayed until the flight crew turn off all three ADRs. In the case of unreliable speed, the pilot decides the airspeed is unreliable and then applies the UNRELIABLE SPEED INDICATION procedure. That procedure leads the flight crew to select all three ADRs off when below FL250, which causes the BUSS to be displayed.

[morno]

I guess other newer Airbus’ are the same, but new A320’s have a simple push button on the panel to display the BUSS.

[Australopithecus]

Dutchy - one thing I dont know is how old the malaysian 330's are - the older aeroplanes don't have BUSS

The aircrft serial number in the report reveals a 2012 build date.

A flight Global article from 2007 announced the developement of the BUSS, but I just found this Airbus article from 2007 which states that the BUSS is OPTIONAL on the A330
https://static.mediapart.fr/files/Joelle_Barthe.pdf

[Altimeters]

Eng 2 inop?

I'm not the bus but why would it say that Eng 2 inop and have an N1 and N2 reading? Or is that part of the photoshop?

[Australopithecus]

Further to my last, Airbus has a free app for their “Safety First” magazine. In the archive section, edition 3 is an article on blocked pitot tubes on the ground, and an earlier 330 incident is cited. Recommended reading.

[swh]

From another forum. But apparently these pics are what the crew had.

https://cimg9.ibsrv.net/gimg/www.gmforum.com-vbulletin/1080x810/6a9b5185_1783_4ab8_b058_7d072bc2d0d2_41116ad05f574fac7a63ae4 5053311f53a05da7f.jpeg
https://cimg0.ibsrv.net/gimg/www.gmforum.com-vbulletin/1080x810/c6bd8a5e_c363_4118_9ed3_f8268c143c21_99b9c05011e34e6019ddf63 737c379262b4f4e2d.jpeg

Those photos are not from the event, never got that high as displayed in the top photo, and the second photo does not have enough fuel loaded for the trip.

To mevthey look more like something taken for or during a simulator exercise.