SMoose
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Braking/Spoilers On BAe-146

Tue Oct 17, 2006 8:55 pm

Norwegian media are reporting that investigation into the crash at SRP/ENSO last week found that it may have been caused by the failure to deploy the spoilers/liftdumps upon landing and the speed/lift then resulted in the overrun.

Are the spoilers on the BAe-146 so vital to the stopping of the aircraft that this may be a likely cause?

The runway was 1400 metres long and it had been raining at the time of the accident.
 
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Starlionblue
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RE: Braking/Spoilers On BAe-146

Tue Oct 17, 2006 11:28 pm

They can be important, but would they really make THAT much of a diff over the whole length of the roll-out? I don't know.

Also, the 146 has the split tail brake. What did that do?
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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derekf
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RE: Braking/Spoilers On BAe-146

Wed Oct 18, 2006 12:40 am

The white topped lever next to the P1's right knee is the airbrake/lift spoilers lever.


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Photo © Robert Nicander



You move to the lever backwards to a detent in flight to operate the airbrake. When on the ground you pull the lever through the detent to operate the lift dump. You can make out the two marks on the photo. I believe the lift spoilers can make 40% difference to landing distance. The RJ series has automatically deployed lift spoilers on touch down.

Hope this helps

Derek
Whatever.......
 
vikkyvik
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RE: Braking/Spoilers On BAe-146

Wed Oct 18, 2006 3:19 am

Quoting Starlionblue (Reply 1):
They can be important, but would they really make THAT much of a diff over the whole length of the roll-out? I don't know.

Assuming the -146 has typical upper-wing-surface spoilers (in addition to the split cone airbrake), then they can make a significant difference, especially given slippery conditions. The spoilers dump the lift, putting more weight on the wheels, which gives the wheels increased traction (not to mention, they also add more drag). Hence, no spoilers = reduced traction = increased chance of hydroplaning/skidding.

1400 meters =~ 4600 feet. Assuming touchdown at 1000', you have 3600' in which to stop. I'd imagine it would not be farfetched to have an overrun in the case of some serious hydroplaning.

But I'll leave it to the pilots to confirm/critique (pretty sure we have an ex -146 pilot in here...)
I'm watching Jeopardy. The category is worst Madonna songs. "This one from 1987 is terrible".
 
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Starlionblue
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RE: Braking/Spoilers On BAe-146

Wed Oct 18, 2006 4:13 am

Captain Click seems to be back. He knows the 146/Avro and should be able to tell us. I do remember him often mentioning how it likes to go down more than up.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
MerlinIIIB
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RE: Braking/Spoilers On BAe-146

Fri Oct 20, 2006 6:31 am

Given the short runway, why did the crew perform "several attempts" to deploy the spoilers (according to media here)? Why not initiate TOGA immediatelly when suspecting malfunction of the spolers instead of spending time operating the lever several times?

One of the engines was running several minutes after the crash...
 
MerlinIIIB
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RE: Braking/Spoilers On BAe-146

Sun Oct 22, 2006 5:39 pm

Quoting Starlionblue (Reply 4):
Captain Click seems to be back. He knows the 146/Avro and should be able to tell us. I do remember him often mentioning how it likes to go down more than up.

Yes, I would really like to read Slam's comment on your post and my previous post on this topic. This incident is still hot news here in Norway.

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