Go Back  PPRuNe Forums > Flight Deck Forums > Rumours & News
Reload this Page >

AirAsia flies to Melb instead of KL . Navigation error

Rumours & News Reporting Points that may affect our jobs or lives as professional pilots. Also, items that may be of interest to professional pilots.

AirAsia flies to Melb instead of KL . Navigation error

Old 8th Sep 2016, 00:52
  #41 (permalink)  
Join Date: Mar 2002
Location: Moved beyond
Posts: 1,243
Received 123 Likes on 72 Posts
Originally posted by NSEU
Also, the magnetic heading data fed into the VOR systems is based on IRU present position (which appears to have been wrong). I'm surprised the aircraft reached Melbourne with vectors (unless they were using their whiskey compass).
The report says the FO subsequently carried out the IRS ALIGNMENT IN ATT MODE checklist from the QRH. That would have restored attitude and heading information once the aircraft's magnetic heading (from the standby compass) was entered into the MCDU. The heading would then need to be updated periodically, just like an old-fashioned gyro compass.
BuzzBox is offline  
Old 8th Sep 2016, 01:14
  #42 (permalink)  
Join Date: Feb 2004
Location: Australia
Posts: 1,307
Likes: 0
Received 0 Likes on 0 Posts
Thanks, BuzzBox... I should probably read the report (*^ ^*). From the initial posts, I didn't get the impression that the F/O knew what he was doing. I recall that on the 744, if you have one IRU in NAV and the others in ATT, the IRU in NAV will feed magnetic heading data to the IRUs in ATTitude (I can't recall if the HDG entry boxes still appear with one IRU still in NAV).

Of course, we are talking about an Airbus....
NSEU is offline  
Old 8th Sep 2016, 05:48
  #43 (permalink)  
Join Date: Jan 1999
Posts: 275
Likes: 0
Received 0 Likes on 0 Posts
Buzzbox and Curtain twitcher, thanks for the link to the report, I hadn't seen it before questioning ATC's actions. The OP only put up the Guardian article which seemed to say the crew were left blindly flying around and found their own way to Melbourne. Happy to withdraw any criticism of ATC, they helped enormously.

Now regarding the criticisms of this crew. Some on this thread have lambasted them for lack of systems knowledge. I think its also rather unfair. My own decades long experience and knowledge of INS systems wouldn't have anticipated the behaviour seen in this event. Its perplexing.

Several yonks ago when I did my ATPL I remember the instructor telling us that an INS will NOT align if you input a grossly inaccurate position. The reason being that the INS platform compares the input position to the local 'vertical' and this would not resolve if the 'expected' vertical didn't match the 'sensed' vertical within narrow limits.

A decade later I flew INS equipped B747's (before the days of GPS) and those INS's behaved exactly as was taught. They were twitchy buggers and would fail to align even if a wind was making the aircraft move around, or the loaders were being a bit boisterous. A few degrees disagreement to the sensed vertical was enough to fail the process.
In this AK case the difference between 'input position vertical' and the real 'sensed vertical' was huge - 136deg - and yet it seems the INS accepted the error and aligned to the wrong location. A very 'robust' INS, no doubt. Is that such a good thing?

When I went on to my first Airbus there was no GPS. The first commercial GPS system was only set up around 1995. Before that it all relied on INS (IRS).
In those days we had to confirm a valid 'Position Update' of the aircraft symbol on the ND to the runway on start of the take off roll. It would happen automatically when thrust levers were advanced. It was reliable. I never saw it 'not work'.

In this AK event the report says the Position Update did not happen at start of take-off, because "the error was too great". Seriously!? You mean Airbus designed a navigation system that simply goes 'idle' when you've created a massive error - exactly when you most need it to work? Or at least WARN you that it isn't working?

When GPS was introduced we were told this would (when available) prevent any more gross errors in Nav, as the GPS would automatically update the 'mix POSN' and eliminate gross errors. Surely a pair og GPS's in agreement are more reliable than even 3 INS's?
But no. Now we discover that if the GPS doesn't agree with the INS's it will effectively vote itself out of the system, and the only warning you'll get is one single chime after it has thought about it for ten minutes (or more)! Incredible.
By the way, its not at all unusual to have 'mystery chimes' go off which never reveal themselves. Perhaps a flicker on the ECAM which you can't read, and which can't be recalled. So what do you do? Stop everything? Go back for engineering inspection? Not likely in the real world.
The lack of a proper clear warning of a primary navigation failure is again unbelievable.

Airbus aircraft seem to regularly do this to their crews - they fail, and dump everything in the crews lap with little hint as to what's really going on. This incident reminds me so much of the Air France AF447 accident - another crew let down by hard to diagnose Airbus systems failures, with obscure (out of normal envelope) systems behaviour contributing to their confusion. They were extremely lucky this didn't end up the same way. Perhaps if it had been night time?
Those saying there was an obvious action - what is it? When the EGPWS starts shouting at you at 400' after liftoff you know you've got problems - but when you realise now your ND compass is giving you erronoeous information (because ATC tell you) what would be expected except confusion and shock?
Reverting to raw data sounds an obvious first step - but the ND is still wrong, and you can't steer unless you realise it and focus on that micky mouse compass. All very easy to describe from the comfort of an armchair. Ever steered by a magnetic compass? If so you'll know its not that simple.

Did the AK crew screw up? The Captain input the position manually. Is that Air Asia procedure? If so - why? If that's what they train them to do, who's at fault really?
In my INS days the position entry had to be done together with a second crewmember, and double checked. This didn't happen here - is that how they're trained?
Why weren't they trained to use the slew buttons? We were trained to use them and we all much preferred it - its so much easier than struggling with conversion of Lat/Long to Airbus formats.
Why were they even required to insert the Gate rather than just accept the ARP (which will be updated anyhow at take-off)?
Why wasn't the maintenance mod done by AK? The Align would have been automatic - as it is in the Airbus I fly now. Human error is largely removed entirely.

What I'm saying is that the armchair heroes are good at boasting about their own knowledge of the systems - after the fact.
The keyboard warriors get some self satisfaction from slating their fellow pilots - inferring to the rest of us how 'skilled' they themselves are? They let the manufacturers and regulators and the airlines entirely off the hook. Haven't you learned by now that the next guy to swing is you!?

Last edited by Algol; 8th Sep 2016 at 06:00.
Algol is offline  
Old 8th Sep 2016, 05:53
  #44 (permalink)  
Join Date: Nov 2013
Location: Earth
Posts: 332
Likes: 0
Received 5 Likes on 2 Posts
Algol i don't know all the details of the report but it seems that only the Longitude was incorrectly entered. If I remember correctly from ATPL studies an INS platform will happily accept any Longitude entered as long as the Latitude is correct. Latitude is used to level the platform. So in this situation the INS will happily align itself and believe its position to be correct
TurningFinalRWY36 is offline  
Old 8th Sep 2016, 06:18
  #45 (permalink)  
Join Date: Jun 2005
Location: UAE
Posts: 210
Likes: 0
Received 0 Likes on 0 Posts
To OLDPAX et al

As an ATC working in the Middle East for many years, you would be staggered at the number of times we had to ask pilots "Where are you tracking to"

It was mandatory for ATC to issue a route clearance, and obtain a correct readback, for EVERY aircraft that entered the FIR. On many occasions the readback was correct but they then flew a different route. Go figure.

Last edited by Rule3; 8th Sep 2016 at 06:20. Reason: Grammar
Rule3 is offline  
Old 8th Sep 2016, 06:26
  #46 (permalink)  
Join Date: Feb 2001
Location: The Winchester
Posts: 6,586
Received 17 Likes on 14 Posts
Originally Posted by TurningFinalRWY36
If I remember correctly from ATPL studies an INS platform will happily accept any Longitude entered as long as the Latitude is correct. Latitude is used to level the platform.
That's pretty much how I recall it as an end user of early platforms. An incorrect latitude entry will, I think, manifest itself at the levelling and/or gyro compassing stage. An incorrect longitude causes no such problem.
wiggy is online now  
Old 8th Sep 2016, 06:55
  #47 (permalink)  
Join Date: Jul 2007
Location: Germany
Posts: 1,035
Likes: 0
Received 8 Likes on 3 Posts
Very similar incident happened to LOT with a 737 at Heathrow some years ago. They entered east instead of west and flew round not very convincingly on the standby instruments before landing back. It is fairly basic system knowledge that you can force the IRS to accept a wrong position (by repeating the false data entry) for reasons explained above. What is not so simple is to fix the problem once in the air. The captain in the Sydney incident had 22000 hours so rather than filing this under children of the magenta line I think the CRM and problem solving aspects are the interesting bit. The idea that you are going to fly a long haul leg without the primary instrumentation and autopilot is a bit out of touch with reality and indeed regulation. Problem solving and recovering the systems (as far as was possible) is the bit that went seriously wrong.
lederhosen is offline  
Old 8th Sep 2016, 07:06
  #48 (permalink)  
Join Date: Jan 2008
Location: Reading, UK
Posts: 15,986
Received 307 Likes on 158 Posts
If it's not a silly question, why can't FMS data providers include airport gate coordinates in their data packages?

Even if crews were still required to input the lat/lon manually from the coordinates displayed at the gate, at least the system could verify that they corresponded to a known location rather than being in the sea 300km from the nearest airport.

In fact even a simple automated check that the input coordinates are within a couple of miles of the flight plan origin would do, at a pinch.

In an era where the aircraft is increasingly expected to protect itself from the actions of the crew, it's not rocket science.
DaveReidUK is offline  
Old 8th Sep 2016, 07:08
  #49 (permalink)  
Join Date: Dec 2008
Location: uk
Posts: 913
Received 0 Likes on 0 Posts
Sounds like a simple failure to follow company SOP's, which are almost certainly the same as or very close to Airbus SOP's. This error should have been easily trapped before departure, during either the briefing or running the checks.
Poor tech knowledge by both pilots explains the rest.
Had they managed to turn off all three ADRIRU, gulp!!
macdo is offline  
Old 8th Sep 2016, 07:54
  #50 (permalink)  
Join Date: Feb 2001
Location: The Winchester
Posts: 6,586
Received 17 Likes on 14 Posts
Originally Posted by DaveReidUK
If it's not a silly question, why can't FMS data providers include airport gate coordinates in their data packages? .
Some (many?) do, or failing that at least hold the lat/long of the airport reference point. FWIW our preferred option is to align using the current GPS position but as there's still a verification process.

On some types/SOPs the manual longhand entry of Lat/long for alignment is seen as something to be avoided if at all possible( for obvious reasons). If that it has to be done then there's usually the need for extra checks to trap errors.
wiggy is online now  
Old 8th Sep 2016, 07:58
  #51 (permalink)  
Join Date: Sep 2008
Location: 41S174E
Age: 57
Posts: 3,144
Received 540 Likes on 152 Posts
If it's not a silly question, why can't FMS data providers include airport gate coordinates in their data packages?
At my outfit you check the actual position coordinates against the airport coordinates as part of the preflight checks. The airport coordinates are part of the data package obviously.
I think this is a case of there being multiple chances to trap the error but none of the opportunities were taken to do so.
framer is offline  
Old 8th Sep 2016, 08:12
  #52 (permalink)  
Join Date: Jul 2007
Location: uk
Posts: 781
Received 0 Likes on 0 Posts
Surely the map could have been corrected by overflying a known VOR and entering the co-ordinates into the Fix Info page. This was taught by Airbus back in the early '90s.

Last edited by Meikleour; 8th Sep 2016 at 08:34. Reason: typo
Meikleour is offline  
Old 8th Sep 2016, 08:38
  #53 (permalink)  
Join Date: Sep 2009
Location: Australia
Posts: 228
Received 9 Likes on 4 Posts
Meikleour - Airservices Australia has just spent a fair bit of time and money removing lots of navaids to leave only the Backup Navigation Network, so this might have been practical in early 2015 but it is less practical now. The nearest VOR to Sydney looks to be Canberra, roughly 130NM away, and almost exactly halfway to Melbourne where they ended up. The idea behind the Backup Navigation Network is that all IFR aircraft will primarily rely on GPS for navigation, with only a skeleton network of ground based aids left. Luckily all the GPS-based navigation systems as seen here are so robust!!
De_flieger is offline  
Old 8th Sep 2016, 09:06
  #54 (permalink)  
Join Date: Feb 2001
Location: The Winchester
Posts: 6,586
Received 17 Likes on 14 Posts
Luckily all the GPS-based navigation systems as seen here are so robust!!!

Maybe, but perhaps a better description of modern airliner nav systems would be "computer based with inertial/GPS/Air data/radio input, blah blah..etc etc".

In this incident's case it looks to me as if the GPS side of the nav system was robust enough, but it's data was being disgarded because of system logic.

If the crew had been using a pure GPS nav system I somewhat doubt the incident would have happened.

Last edited by wiggy; 8th Sep 2016 at 09:56.
wiggy is online now  
Old 8th Sep 2016, 09:17
  #55 (permalink)  
Join Date: Jun 2000
Location: last time I looked I was still here.
Posts: 4,507
Likes: 0
Received 0 Likes on 0 Posts
From early comments on here it would seem they still had No.2 ADIRU. Will someone say if this is enough to give correct info to either PFD, or whatever ABus call it.
RAT 5 is offline  
Old 8th Sep 2016, 10:25
  #56 (permalink)  
Join Date: Dec 2010
Age: 72
Posts: 896
Received 33 Likes on 17 Posts
What has my attention right now is, what EXACTLY did they tell the passengers when they landed in Melbourne.

I can imagine that the first advice would have been wrapped in "technical problems". But at some point the truth must have become obvious to the flight crew. Did they at that time fess up and give those who might have wanted to get off the damned aircraft the opportunity to do so, or did they then continue to conceal the real nature of the diversion and in so doing stamp their behaviour as dishonest and misleading?

Keeping the customers calm is not an excuse for feeding them bullsh...t. Not when you're already on the ground.

Last edited by WingNut60; 8th Sep 2016 at 10:36.
WingNut60 is offline  
Old 8th Sep 2016, 11:07
  #57 (permalink)  
Join Date: Nov 2008
Location: Flyin' low and feeling mean
Posts: 194
Likes: 0
Received 0 Likes on 0 Posts
How many cockups is this for AAX in Aussie airspace in the past few years??

I would hope CASA would be taking a very close look at them and soon.
Hogger60 is offline  
Old 8th Sep 2016, 11:19
  #58 (permalink)  
Join Date: Apr 2008
Location: Nearer home than before!
Posts: 524
Likes: 0
Received 0 Likes on 0 Posts
Of course, if their ND HDG was so far out, didn't they query it on line up? I certainly would with a 30 degree error on the runway....
RVF750 is offline  
Old 8th Sep 2016, 11:31
  #59 (permalink)  
Join Date: Apr 2010
Location: London
Posts: 7,072
Likes: 0
Received 0 Likes on 0 Posts
It's easier than you'd think to enter/copy the wrong co-ordinates into any spreasdsheet/computer/ whatever - has happened since the year dot..... (I always worried about Christopher Columbus's booze cruise to Morocco....)

You'd be better off if you just typed in the FULL name (not a set of letters like MEL) of your destination
Heathrow Harry is offline  
Old 8th Sep 2016, 13:04
  #60 (permalink)  
Join Date: Jul 2007
Location: uk
Posts: 781
Received 0 Likes on 0 Posts
Der fleiger: thanks for your update. The procedure I mentioned also works if you simply type in the GPS co-ordinates!! Perhaps the crew here disbelieved their GPS as well as their FM data?
Meikleour is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.