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Air brakes doesn't stop aircraft (Read 533 times)
Jul 11th, 2004 at 3:30pm

alrot   Offline
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Perhaps is in my mind but I think that in real life the 80%
of stoping of any jet after touchdown it's the airbrake and not  the wheel brakes as it seems to be in FS9 I don't feel in the sim that even retroimpulse of turbine engines doen't do anything,exept by the sound,i think that the stoping of the aircraft should be after landing  be more realistic  at least in the FS9's default jets ,please correct me if i'm wrong
 

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Reply #1 - Jul 11th, 2004 at 3:32pm

Craig.   Offline
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the spoilers dont produce 80% of the braking. They spoil the air to get rid of lift in the wings, and while they may help to brake, the wheel brakes and reversers are in general the primary braking options
Or at least thats what i have always been taught
 
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Reply #2 - Jul 11th, 2004 at 3:37pm

Nexus   Offline
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Craig is dead on. Smiley
the spoilers are designed to kill the lift at touchdown you (hopefully) wont bounce.
Yes it increased the drag on the runway aswell but the wheel brakes are the ones that effectively slows the aircraft down, with assistance of the reverse thrust.
 
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Reply #3 - Jul 11th, 2004 at 4:19pm

alrot   Offline
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I saw in a documental were one aircraft md80 (it was the flight 1450 somewere  U.S.A. i think) crash after the pilot desided to land the plane between an a hurricane you must heard about it,after he touchdown he concentrate to estabilized the plane making mani zig zag thru the runway that he and his cop.forgot to hit the spoilers they pass tru all the runway ending beyond of it .10 people died included the pilot the national Bla BLa security(sorry i forgot the name)made and investigation the wheel marks where in all the runway.conclution the error was not to stop the plane hiting the spoiler.once again correct me if i'm wrong
 

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Reply #4 - Jul 11th, 2004 at 4:26pm

Nexus   Offline
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Yeah those Air disaster docs are aired here in Sweden aswell.  Smiley
I guess you're refering to the AA flight into Little Rock?
They did forget to ARM the spoilers that's why they aquaplaned (spelling?), so they were bascily surfing on the wet runway. Good brakes will do you squat here, what you need is something that pushes the aircraft DOWN and kills the lift, the spoilers do just that Smiley
 
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Reply #5 - Jul 11th, 2004 at 4:31pm

Hagar   Offline
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Apart from flying on them as a passenger in real life I don't know a lot about jet airliners. What Craig & Nexus have told you is correct. Spoilers are used to spoil the lift, hence their name. It's possible that they will help to keep the aircraft on the runway after landing. Thrust reversers + wheel brakes are used to slow it down. If you've ever been on a jet airliner or watched one land you would have noticed the engines increase power after landing. I believe this is quite realistic in FS.
 

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Reply #6 - Jul 11th, 2004 at 4:32pm

Craig.   Offline
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Basically what nexus stated.
However the exact problem here was bad timing. The pilots were told just as they were landing to go around due a to a shift in winds making it an illeagal, at that same time a thunderstorm passed overhead, the crew failed to take note of this and the plane aquaplaned off the side of the runway. In case such as this yes the spoilers would have been a very useful inclusion.
It was american airlines 1420 incase you want to read more into it. I am too busy to read up on the details as i leave for the states tuesday and leave for the airport tomorow
 
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Reply #7 - Jul 11th, 2004 at 4:45pm

alrot   Offline
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Yes,that's why i had the feeling because i've traveled as pasenger many times and it looks like the spoiler makes the principal braking job,thanks you all folks for the informations and the replies
 

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Reply #8 - Jul 11th, 2004 at 5:11pm

Nexus   Offline
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that accident should've never had happened.
The pilot even said something like "I hate flying in the blind like this". Now does that sound like a bloke you'd want as a pilot?
The pilot saw nothing outthere because of the thunderstorms, rain and low visibility conditions

They knew about the storms, they knew about them before they departed
They took a chance in trying to get to Little Rock before the bad weather, but failed...In the attempt of trying to land, finding the runway and keeping the airplane on the glideslope, the crew forgot to arm the spoilers Sad

The aircraft was equipped with a weather radar, more advanced than the radars at little rock. The MD80 was capable of displaying weather in color, while Little rock radar was not. They were told to switch runway and during the downwind leg the radar which is mounted in the nose can't show weather behind you so the crew lost track of it, when they turned to base and final, the thunderstorms (there were 2 different storms that merged into one big) was all over them.

That's how they said on the documentary, and it reflects the NTSB's reasons why the aircraft crashed.
 
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Reply #9 - Jul 11th, 2004 at 9:23pm
EA_KATL   Ex Member

 
If i am thinking about the same crash here didnt it say those pilots were over the 8 hours flying time mark.if so thats the last thing you want is a tired pilot trying to land in bad weather conditions.
 
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Reply #10 - Jul 12th, 2004 at 12:04am

Silver1SWA   Offline
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Well ,while we are talking about what is most responsible for stopping an airliner, I thought this piece of information might be appropriate...

Did you know, that thrust reversers are not factored in to an airliner's minimum landing distance?  They are actually an added bonus and a plane must land on a runway long enough for them to stop if they were not using the reversers.  I recently learned that, and well, I found it surpising.

 

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Reply #11 - Jul 12th, 2004 at 1:23am

logjam   Offline
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Whereas all this info regarding spoilers is correct, one mustn't confuse "Air Brakes" with "spoilers." Air Brakes are fitted to Military and some Civilian A/C besides spoilers. On some, such as the Vulcan or Comet they are placed on the wing upper surface and deploy in an instant. On fighter A/C they may be fitted under the rear fuselage, such as the British Hawk. On others such as the CF18 they are fitted between the Stabilizers. Believe me, they work really well in reducing airspeed down to manoeverability.
 

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Reply #12 - Jul 12th, 2004 at 8:11am

Nexus   Offline
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Quote:
Well ,while we are talking about what is most responsible for stopping an airliner, I thought this piece of information might be appropriate...

Did you know, that thrust reversers are not factored in to an airliner's minimum landing distance?  They are actually an added bonus and a plane must land on a runway long enough for them to stop if they were not using the reversers.  I recently learned that, and well, I found it surpising.



They have not in included the reversers because when performing an engine out landing you can't even deploy the reversers at all, which would leave the crew with incorrect performance tables  Smiley
 
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