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Author Topic: ACA429 IFE - Flaps Failure  (Read 17819 times)

Offline bcradio

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ACA429 IFE - Flaps Failure
« on: July 21, 2008, 04:26:20 PM »
ACA429 had a flaps/slats failure on approach to Pearson a couple weeks ago.. Here's the audio I managed to edit out of the archive, plus a Flight Aware map of their flightpath.

http://flightaware.com/live/flight/ACA429/history/20080710/0139Z/CYUL/CYYZ



Offline cessna157

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Re: ACA429 IFE - Flaps Failure
« Reply #1 on: July 21, 2008, 05:13:09 PM »
Thats a nice little catch you've got there.

Flap failures, while obviously an emergency, aren't necessarily a super bad emergency.  As pilots, we don't get too worked up if/when it happens.  It might get your heart going a little and definitely has a bit of a pucker factor, just due to the speeds that you must fly for the approach/landing.

Luckily (knock on wood) I haven't had this happen to me yet.  We do train for it in the simulator constantly though.  Fortunately for me, Flap Fails do not happen nearly as much in the CRJ700 and 900 as opposed to the horrid flap system on the 100 and 200.

Offline bcradio

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Re: ACA429 IFE - Flaps Failure
« Reply #2 on: July 21, 2008, 05:21:48 PM »
Thanks!

Seems like Air Canada isn't having much luck with their 190s, eh? :-)


Offline KSYR-pjr

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Re: ACA429 IFE - Flaps Failure
« Reply #3 on: July 21, 2008, 05:44:16 PM »
Flap failures, while obviously an emergency, aren't necessarily a super bad emergency.  As pilots, we don't get too worked up if/when it happens. 

What about asymmetric flap failures(*) ?    Are those events even possible in your type of aircraft?

(*) - for those who don't know:   where one flap deploys and/or retracts while the other one remains in its current state, causing drag on one side that pulls the aircraft to that side.

edit:  changed wording slightly -
« Last Edit: July 21, 2008, 05:48:47 PM by KSYR-pjr »

Offline cessna157

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Re: ACA429 IFE - Flaps Failure
« Reply #4 on: July 21, 2008, 09:00:08 PM »
Well, I'd never say anything was impossible but its more likely that you'd have a double engine shutdown, or something just as bad.

There is a shaft that runs from the middle of the left wing, through the belly where the 2 flap motors are, and all the way out to the middle of the right wing.  So that basically covers the basis that all 4 of the flap panels will come out together.  In fact, the CRJ100/200 is known for having a flap system prone to failing due to this fact.  It is a flexible shaft on those airplanes (that allows it to make the turns in the wing) that can get kinked.  There are numerous sensors on the flap actuators that make sure they all turn at the same rate, and if it detects that just one is off just the slightest bit, it will shut down the flap system and you'll get the "FLAP FAIL" caution message.

So, I guess the answer to your question is yes and no.  Yes, asymmetric flap deployment is possible, but there are so many protection factors that prevent the flaps from coming out wrong that it disables the system to prevent such a thing happening.

Make sense?

Offline cessna157

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Re: ACA429 IFE - Flaps Failure
« Reply #5 on: July 21, 2008, 09:07:41 PM »
Attached is a diagram of the CRJ700 flap drive system.  It is a little different than the 100/200 that I was talking about, but it has the same sort of thing.  It is just less prone to failure due to the fact that is has solid rods that connect it from side to side.

In the center of the aircraft is where the flap drive motors are (PDU=Power Drive Unit)
« Last Edit: July 21, 2008, 09:14:53 PM by cessna157 »

Offline SweedChef

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Re: ACA429 IFE - Flaps Failure
« Reply #6 on: July 22, 2008, 07:19:40 PM »
I've heard a few emergencies like this now...thanks to liveatc.net. It appears to me that this sort of situatuion's checklist calls to "delclare an emergency" as your airspeed it variable and your aircraft can't handle any speed restrictions normal in a busy airport.

It seems declaring an "emergency" isn't life or death.....just that you need priority over any other aircraft as yours' is not preforming to it's aircraft specs.

Nice find!

Offline KSYR-pjr

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Re: ACA429 IFE - Flaps Failure
« Reply #7 on: July 22, 2008, 08:57:32 PM »
So, I guess the answer to your question is yes and no.  Yes, asymmetric flap deployment is possible, but there are so many protection factors that prevent the flaps from coming out wrong that it disables the system to prevent such a thing happening.

Make sense?

Yes, it does.  I didn't realize that there were so many layers of protection in place to detect that particular type of condition.  Thanks for the information.