Incident: Westjet B736 at Abbotsford on Jan 20th 2009, navigation system flies different route than pilots
The crew of a Westjet Boeing 737-600, registration C-GWSB performing flight WS-456 from Abbotsford,BC to Calgary,AB (Canada) with 104 people on board, noticed during an RNP (Required Navigation Procedure, precision RNAV navigation) departure, that the airplane was not following the programmed standard instrument departure route. The airplane was below minimum safe altitude. The crew contacted Victoria Terminal and was issued radar vectors away from high terrain. The airplane continued to the destination for a safe landing.
Subsequently it was established, that the engine out procedure had been inadvertently activated in the flight management system.
Now you see why a pilot might want to shoot the FMS?
12 comments:
Whenever I read about research towards pilot-less planes, I don't feel too comfortable. Did they think about integrating and connecting a gun to the FMS that can shoot the FMS in case of failure when no pilot is around? HAL?
Oh I see now, thanks for the news. Very interesting! :)
Hahaha they must change the name FMS to HAL :P
Good day, bye.
Automation is always a two-edged sword. And it'll cut you up baaaad if you don't pay attention. Good thing they were.
The more I work with cockpit automation systems, the more I realise that the pilots are essential (even if just to monitor things). The number of times we're saying "What the frak is it doing now?" and "Why is / isn't it doing that?" :)
One of our more recent sessions in a fixed-base 737-800 sim was particularly filled with WTF moments (and some dumb mistakes on my part). I wrote it up on my blog along with a few other fun sessions :)
Great to have you back and blogging again. Glad you had a good break - I'm looking forward to reading your ongoing adventures :)
Gordon Baxter used to write that someday, there will only be a man and a dog in airline cockpits. The man is there to feed the dog. The dog is there to bite the man if he tries to touch any of the controls.
Shudder. :)
Can somebody enlighten a non-pilot aviation geek? Why would the plane be below MSA because the FMS was doing an engine out procedure?
I thought the point behind predefined engine out departures/EOSIDs was to keep aircraft away from terra firma even though single engine climb performance is negligible?
Re: Why below MSA?
Without having all the details... FMS can provide actual flight guidance to the Auto-Pilot laterally (i.e. make the required turns over specified waypoints), but Vnav-guided climbs or descents are seldom used. I presume this is because of the need to coordinate these in a real-time basis with ATC, etc..
I'm guessing that the aircraft was being flown at an acceptable altitude for the planned routing, but this wasn't adequate for the route it was actually following.
The article says the correction was to immediately turn the aircraft (towards the original routing I presume) away from the higher terrain.
@Aluwings:
Am I right to assume that company EOSIDs provide an escape route over the lowest possible terrain while the (stepped) MSA on normal SIDs will be higher?
Assuming this is right, then if the FMS flew the LNAV component of the EOSID but the pilots flew the (higher) altitudes on the SID, the aircraft ought to be safely above the MSA for the EOSID.
Ha. It probably was right next to that button. I'm happy to not have to deal with FMS buttons. Or PMS buttons for that matter. I've heard too many stories containing "why's it doing that?!". All operator error, but no wonder given the arcane user interface and forest of badly labelled buttons. Here is a typical "if something doesn't seem right..." example, with minor consequences. I guess the ultimate operator error in Nav/FMS programming is KAL 007.
@Sarah I would think American Airlines flight 965 would be up there too.
@nec timide
Oh yes, I forgot about that one. Not a good time and place to be head-down fooling with the FMS waypoints. Language difficulties apparently had a role too, as the controllers "did not have enough non-aviation english to communicate their uneasiness with the crew's course & location" (paraphrased from memory).
I'm amazed how fascinated pilots are with accident and incident reporting. Me too. I read the ones remotely related to what & how I fly with the view that "that is not happen to me if I can help it".
To further that, here is a recent series from the US FAA I just ran across. Interesting and often less fatal incidents: FAA SAFOS
anonymous: single-engine climb may be 'negligible' in your light twin. It is not so in transport-category aircraft, by definition, (and certification). On my airplane, at mid-weights, single-engine climb performance is generally around 2100FPM. Oh, and full rudder!
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