
Why did AirAsia fly a crippled jet away from a nearby airport yesterday? - CPAhem
https://blogs.crikey.com.au/planetalking/2017/06/26/airasiax-fly-crippled-jet-away-nearby-airport-wa-yesterday/
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sitharus
At at guess, because the maximum landing weight of a A330 is 187,000 kg but
the maximum takeoff weight is 242,000 kg. They'd have to burn off fuel before
landing or risk crushing the landing gear.

The A330 doesn't have fuel dumping nozzles as standard equipment so that may
not have been an option.

Edit:

From a slightly dodgy source [http://www.pprune.org/tech-log/117765-a330-fuel-
consumption....](http://www.pprune.org/tech-log/117765-a330-fuel-
consumption.html) they'd burn 6 tonnes on takeoff and another ~7 in the 1.5
hours before the engine failed, and approx another 7 before landing but I
don't know what the consumption would be like for a single engine return.

That gives 20 tonnes total fuel burn. At those figures the 5:40 flight would
take 41.5 tonnes of fuel, plus a bit extra.

~~~
ubernostrum
You are almost certainly correct. Getting rid of fuel to get down to max
landing weight is a concern any time there's a problem this early in a long
flight.

And needing to sometimes fly a bit before you can land safely is, well, the
whole idea behind ETOPS. For those unfamiliar with the acronym (officially:
"ExTended OPerationS", sarcastically: "Engines Turn Or Passengers Swim"), it
refers to a certification process for twin-engine aircraft, to demonstrate
that they can safely operate far from any airport, since their engine
reliability is sufficient to allow extended periods of single-engine flight if
and when necessary.

An ETOPS rating is given in minutes. For example, ETOPS-60 would mean the
plane is approved to fly routes that might require up to 60 minutes of single-
engine flying in order to reach a landing site after one engine fails. The
Airbus A330 is approved (depending on the exact variant and configuration the
airline buys) for either ETOPS-180 or ETOPS-240.

~~~
nayuki
ETOPS is covered in this easy-to-digest video by Wendover Productions:
[https://www.youtube.com/watch?v=HSxSgbNQi-g](https://www.youtube.com/watch?v=HSxSgbNQi-g)

~~~
ubernostrum
I haven't watched that one, but the ones I have watched have been... a bit
spotty/incomplete about aviation stuff.

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uhnuhnuhn
It's too early to tell what factors went into the decision to divert to Perth.
Aviation is incredibly complex and armchair speculation by people outside the
industry is almost always going to get it wrong.

As per usual, more well-founded technical discussion on this incident is
ongoing over at AV Herald:
[http://avherald.com/h?comment=4aac9f14&opt=0](http://avherald.com/h?comment=4aac9f14&opt=0)

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jw2k
Al Jazzera has a great exposé on the issues of quality and supply / demand for
pilots in Asia.
[https://www.youtube.com/watch?v=qSZ-R5HdPQU](https://www.youtube.com/watch?v=qSZ-R5HdPQU)

It's truly frightening, and makes me think twice when any of these airlines
come up when I'm searching for flight deals.

~~~
jpatokal
Grain of salt time: Air Asia has one of the better safety records in Asia,
with one accident since they started, despite being one of the region's
largest carriers and flying into a lot of minor airports.

But since we're making generalisations about "Asia", it's worth noting that
pilot hiring is screwed up all over the world. Did you know the pilot flying
your regional jet in the good old USA is likely barely making minimum wage?

[https://www.google.com.au/amp/s/skift.com/2013/08/28/the-
u-s...](https://www.google.com.au/amp/s/skift.com/2013/08/28/the-u-s-airline-
pilots-who-barely-make-minimum-wage/amp/)

But regardless of how predatory airlines get, pilots have pretty strong
incentives not to crash!

~~~
chrismeller
That article is specifically about _co-pilots_ , not the captain. For better
or worse the airline pilot market is _heavily_ seniority based, so you're
expected to do your time before making anything significant.

None of that inherently makes anything more or less safe. Statistically it's
still significantly safer than the taxi driving you to the airport.

~~~
FabHK
> it's still significantly safer than the taxi driving you to the airport.

That's a bit of a myth, or a misunderstanding at any rate, as far as I can
tell.

Jets are much safer than cars _per passenger kilometre_ \- so for a given
distance, you're better off to go by airliner than by car.

However, per _vehicle hour_ , fatality rates are the same order of magnitude
(plane is actually 3x worse). So, if you take a 1/2 hr cab ride to a several-
hour flight, you're more likely to die on the flight.

Source: [https://www.uber.com/elevate.pdf](https://www.uber.com/elevate.pdf),
p. 17

~~~
YeGoblynQueenne
I'd like a better source for that information than Uber, as I'd like a better
source for the information on the safety of air travel than air carriers.

Btw, neither measure is very good for comparing cars to planes. Airliners
carry many times more passengers per kilometer, on average, than cars do; and
cars take many times longer to complete a route than airlineres do. If we are
to assume that the probability of dying rises the longer you travel then
obviously the vehicle that goes faster will have a better record... except of
course for the fact that going faster may kill you faster too. Then again, it
doesn't make much sense that the probability that a given person will be
killed in an accident should vary with the number of people in the same
vehicle as them!

Overall, what you really need to know to decide whether one or the other type
of vehicle is safest is the probability to be involved in a serious accident
given that you board a vehicle of that type. I don't think there's a good way
to measure that, so measures like the ones above are just proxies, I guess.
Which leaves them open to some degree of exploitation from industry bodies,
that can claim that their vehicle type is the safest, even if it's really just
a matter of perspective.

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anatari
Why didn't they turn off the engine to stop the vibration? To a layman that
would seem safer than having an engine violently shake the wing!

~~~
sifex
They did, assumedly as soon as they could've. The shaking came from the plane
having effectively a giant scoop for the air to catch below one of the wings.

Source:
[http://avherald.com/h?article=4aac9f14&opt=0](http://avherald.com/h?article=4aac9f14&opt=0)

------
ithinkinstereo
The captain apparently informed the passengers he was praying for their
survival and asked that they pray too[1]. This tells you everything you need
to know about the quality of AirAsia pilots.

Anytime I fly in that area of the world, I make it a point to avoid Malaysian
and Indonesian airlines at all costs. Fly Cathay or SingAir and their
affiliates if you can. The cost premium is well worth it.

1)[http://www.smh.com.au/business/aviation/a-boom-in-midair--
th...](http://www.smh.com.au/business/aviation/a-boom-in-midair--
then-90-scary-minutes-on-airasia-plane-that-shook-like-a-washing-
machine-20170625-gwycan.html)

~~~
coffeevradar
Some AirAsia pilots are religious!?

My word!

~~~
ithinkinstereo
You're missing the point; it's completely unprofessional.

~~~
kijin
It depends on the religion and the culture. In some parts of the world, it is
considered perfectly normal for people to make religious statements to one
another, especially when something dangerous is happening.

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KyeRussell
I can't even fully grasp what you're getting at. It really feels like you're
grasping at straws.

~~~
ithinkinstereo
How so? It's perfectly okay for pilots to be spiritual/religious. It's not
okay for pilots to take time, in the middle of dealing with an engine failure,
to ask passengers to "pray" for a safe resolution.

The golden rule for pilots when dealing with an in-flight emergency is to
"Aviate, Navigate, Communicate" [1], not "Pray".

[https://www.faasafety.gov/gslac/ALC/course_content.aspx?cID=...](https://www.faasafety.gov/gslac/ALC/course_content.aspx?cID=40)

~~~
dingaling
Just as an aside, that's not technically a rule but a guideline.

For example at a busy airport, failing to communicate during an emergency
might prove more dangerous ( to self and others ) than failing to navigate.

~~~
jimmywanger
Communicating panic and lack of control to your passengers is never safe. You
will be absolutely honest and clear with ATC and any escorts/emergency
vehicles regarding your current status, but you cannot ever let that bleed
into your communications with the passengers.

In all communication with passengers, you need to be about as calm as if
you're just taking a walk in the park. "Folks, we're making an unexpected
detour to check out some technical issues that came up. We might be delayed a
few hours, but the ground crew will book you on the next flight available, and
work with you on rescheduling your transfers."

~~~
lb1lf
To quote Eric Moody, captain of what was at the time the world's largest
commercial glider after a quadruple engine failure:

"Ladies and gentlemen, this is your captain speaking. We have a small problem.
All four engines have stopped. We are doing our damnedest to get them going
again. I trust you are not in too much distress."

[https://en.m.wikipedia.org/wiki/British_Airways_Flight_9](https://en.m.wikipedia.org/wiki/British_Airways_Flight_9)

