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PSA CRJ 200 Skids off Runway at CRW

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PSA CRJ 200 Skids off Runway at CRW

Old 01-25-2010, 06:05 AM
  #101  
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Originally Posted by joethepilot View Post
I have to admit I didn't read the whole thread... so this may have been brought up earlier... but The FAR's say that you can use a stop way to balance your runway length for an abort (25.109). I.E. the EMAS ACTUAL length of 100 feet adds 1000 feet of "runway" length that can be used in the accelerate stop distance calculation. So if this abort was indeed initiated right at V1, the expected outcome would have been to end up in the EMAS.
EMAS is specifically exluded from ASDA calculations. It is not stopway.
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Old 01-25-2010, 09:19 AM
  #102  
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Yeager Airport save 6th in U.S. for emergency-stop ... - News - The Charleston Gazette - West Virginia News and Sports

January 20, 2010
Yeager Airport save 6th in U.S. for emergency-stop system
33 people were aboard when US Airways Express jet skidded off end of runway

Chris Dorst
Skid marks that extend nearly 1,000 feet down the main runway at Yeager Airport end in the crushed concrete blocks of an Engineered Materials Arresting System overlooking downtown Charleston.


Sorry for the dumb question, but why are there 1000 ft of skid marks? A/SKID isn't MELable, or is it? But if it was MEL'd then V1 would have been reduced. And if it was functional, it would have prevented skidding for 1000 feet, right?

Not going anywhere with this other than thinking there shouldn't have been skid marks.
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Old 01-25-2010, 09:31 AM
  #103  
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Maybe the CA though the brakes weren't working as they should and used emergency pneumatic brakes for which antiskid doesn't work?

/don't mean to speculate, have forgotten most of my CRJ systems and might be confusing Citation stuff
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Old 01-25-2010, 10:22 AM
  #104  
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Anti-skid is disable below a certain speed too right?

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Old 01-25-2010, 10:24 AM
  #105  
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Originally Posted by AirportEngineer View Post
EMAS is specifically exluded from ASDA calculations. It is not stopway.
I stand corrected

Originally Posted by robthree View Post
Yeager Airport save 6th in U.S. for emergency-stop ... - News - The Charleston Gazette - West Virginia News and Sports

January 20, 2010
Yeager Airport save 6th in U.S. for emergency-stop system
33 people were aboard when US Airways Express jet skidded off end of runway

Chris Dorst
Skid marks that extend nearly 1,000 feet down the main runway at Yeager Airport end in the crushed concrete blocks of an Engineered Materials Arresting System overlooking downtown Charleston.


Sorry for the dumb question, but why are there 1000 ft of skid marks? A/SKID isn't MELable, or is it? But if it was MEL'd then V1 would have been reduced. And if it was functional, it would have prevented skidding for 1000 feet, right?

Not going anywhere with this other than thinking there shouldn't have been skid marks.
Anti-Skid is some what of a confusing name. In order to acheive maximum braking the tires actually have to partially be skidding.... I think its like 66 % of the speed they would be moving if they were rolling. Actually makes you stop faster
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Old 01-25-2010, 03:00 PM
  #106  
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Originally Posted by USMCFLYR View Post
Anti-skid is disable below a certain speed too right?

USMCFLYR
10kts.

Just b/c antisid is working doesn't mean their won't be skid marks. It just pulses the brakes. At some point the wheel is not rotating but still moving resulting in a skid mark.

Once again, they could not have aborted due to an a/skid message as all Caution messages are disabled above 70%ish N1 on the ground.
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Old 01-25-2010, 03:22 PM
  #107  
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Originally Posted by FlyingNasaForm View Post
10kts.

Once again, they could not have aborted due to an a/skid message as all Caution messages are disabled above 70%ish N1 on the ground.
That's not true. Not all caution messages are inhibited. Anti skid is not inhibited.
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Old 01-25-2010, 07:05 PM
  #108  
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Default Anti-Skid

Here is some information on the CRJ antiskid system:

Hydro Aire Mark III Brake Control System

14 CFR 25.735 Brakes and Braking Systems (See pg. 422).

AC-25.735-1 Brakes and Braking Sytems Certification Tests and Analysis (See pg. 9).

The "accelerate-stop/accelerate-go vs. balanced field length" confusion arises because most transport category operators use balanced field length calculations located on runway analysis reports. The operator's authorization to use this method is located in their individual operations specifications.

The best definition of "balanced field length" is located in the Pilot Guide to Takeoff Safety.

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Last edited by winglet; 01-25-2010 at 07:20 PM.
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Old 01-26-2010, 03:39 AM
  #109  
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Originally Posted by B00sted View Post
That's not true. Not all caution messages are inhibited. Anti skid is not inhibited.
Yup, you are right. Thanks for the correction.
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Old 01-26-2010, 11:00 PM
  #110  
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Originally Posted by BoilerUP View Post
Just curious...how long was the runway? Max braking and TRs used during the abort?

One thing I NEVER worried about in the CRJ-200 was stopping...those brakes are MASSIVE.
It was a EMB 145. The runway was in the 6500-7000 ft hood. Lucky for us we had one of the planes that had T/R's that day...or we probably would've gone off the end.
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