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Realtime Runway Braking Action measurement

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Realtime Runway Braking Action measurement

Old 24th Feb 2012, 13:49
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Question Realtime Runway Braking Action measurement

Quite a few Runway excursions recently have been attributed to quickly changing surface friction conditions on the runway. e.g. Trans States E145 at Rochester on Feb 22nd 2012

I was wondering, are there any products (or could there be feasible) that would more dynamically give a runway surface friction measurement? The spatial non-uniformity of surface must also be a factor, so not an easy task I guess. But wondering what's out there and would it help?
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Old 24th Feb 2012, 14:10
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Would it be possible to have onboard systems measure it, and then relay it to ATC?
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Old 24th Feb 2012, 15:10
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ft
 
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Ah, some kind of semi-intelligent device which monitors the braking action vs what experience says the aircraft should be able to achieve, and which then by radio informs the tower of the result?

I think I've seen that somewhere. In fact, I recall there being two of said device, for reduncancy... and in order to let one system communicate with the tower while the other was busy getting the approach charts back in the binder.
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Old 24th Feb 2012, 15:32
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Hehe, semi-intelligent?? You think too much of these devices
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Old 24th Feb 2012, 15:50
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I'd rather not have a machine that uses coffee as fuel......
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Old 24th Feb 2012, 16:24
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A lot of people trying, … but …
EASA - Research projects - Airports Runway friction characteristics measurement and aircraft braking

http://www.saferroads.org.uk/Papers_...on%20...FP.pdf

Determination of runway landing conditions - The Boeing Company

AeroSafety World August 2007 | Flight Safety Foundation ‘Improving braking action reports’


Some of the problems:
AeroSafety World November 2011 | Flight Safety Foundation ‘Can you stop’, ‘Valuable Intelligence’

AeroSafety World September 2011 | Flight Safety Foundation ‘Point of no return’

AeroSafety World November 2010 | Flight Safety Foundation ‘Unveiling the matrix’

http://ntrs.nasa.gov/archive/nasa/ca...1975012279.pdf Wet Runways
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Old 24th Feb 2012, 17:51
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Sir George Cayley
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Try this for size.

SafeLand - Aviation Safety Technologies (AST)

Not sure if it works but an interesting use of onboard data.

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Old 24th Feb 2012, 18:04
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There is always the question of whether the measured friction is applicable only to the specific combination of aircraft, tires and brakes used, and the possible combinations thereof, or whether it is useful to other aircraft.
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Old 24th Feb 2012, 19:24
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ICAO Circular

The ICAO Circular 329 - Runway Surface Conditions Assessment, Measurement and Reporting - might be of interest.
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Old 25th Feb 2012, 00:01
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Would it be possible to have onboard systems measure it, and then relay it to ATC?
ABSOLUTELY! Use the human side of the human-machine interface!

Most experienced pilots can tell when the antiskid cycles the brakes, and can detect the minor swerving when one side of the runway is slipperier than the other. Tell Tower or Ground where you experienced the most active antiskid cycling, so they can take care of it AND advise others.
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Old 25th Feb 2012, 05:48
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Most experienced pilots can tell when the antiskid cycles the brakes
Isn't there an indicator light on the panel when the antiskid kicks in?
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Old 25th Feb 2012, 14:15
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ross, I cannot recall any aircraft/system having a light indicating operation (anti-skid activity). Anti-skid can cycle the brake pressure very rapidly on wet and dry runways; see http://www.faa.gov/aircraft/draft_do...airAC25_7C.pdf page 55 onwards. Thus an activity indication may be meaningless or not even feasible.
I suspect you are thinking of an indication of the anti-skid system being available or not.

The problem with aircraft-based detection / analysis systems is that their output is historical – someone has to experience the conditions before a computation can be made; and even then the conditions can change quickly.
The ICAO guidance (thanks tribo), seeks to gather the highest quality of information to pass to a pilot before landing. Even at best, this information is only an estimate of ‘braking action’ (estimated surface friction).

It is interesting to note from the accident report (post #1) that the preceding aircraft (CRJ) reported having no braking problems. This could have been due to rapidly changing conditions or perhaps the CRJ’s use of reverse thrust. Reverse and auto-brake, can mask the actual braking condition (dependent on the source of decelerating force) because full brake effectiveness may not be demanded.
Any automatic assessment system would have to take account of this, but even so the result may only be an estimate for a particular aircraft type.
An automated system may reduce many of the risks arising from the use of PIREPS for guidance (highly subjective and type / operation specific), but in all instances where advanced information is not available, good judgement must be used – knowledge, awareness, risk assessment; how are these to be computed.
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Old 25th Feb 2012, 18:59
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Isn't there an indicator light on the panel when the antiskid kicks in?
No. The only lights are failure messages.
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