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How much value do you give Braking Action reports?

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How much value do you give Braking Action reports?

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Old 10th Jan 2019, 21:55
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How much value do you give Braking Action reports?

Braking Action PIREPS are subjective. With autobrakes and antiskid systems participating in (and possibly masking) part of the effort to stop, how much value do you give to a previous arrival's braking action report? Are you able to determine the difference between Good and Medium, or Medium and Poor subsequent to your own landings?
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Old 10th Jan 2019, 22:12
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We spend a lot of time on contaminated runways in my operation and I often err on the side of caution. If the margins are tight I'll be probing when was it last checked, by report from pilot or ground test, temperature vs dew point etc.

We also as a company have a look at the performance and compare to the chart (EFB makes this easy) where we should come to a stop if the braking action is accurate and if it is wildly off we will take a look and report that braking action is less than advised.
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Old 11th Jan 2019, 00:46
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Always downgrade a little conservatively, except when reporting GOOD.
So MEDIUM-GOOD becomes MEDIUM for safety reasons, etc...
Too many times I've landed on a reported 1mm covered runway without seeing any lines under the snow layer and traversing over the ridges of snow rolling out, while reported to be MEDIUM-GOOD.
Wonder sometimes why airports give us pilots trying to land readings or measurements which are inaccurate to say the least, based on a runway inspection some time before landing during snowfall without intermediate clearing operations.
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Old 11th Jan 2019, 19:12
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Autobrakes and antiskid are actually valuable indicators in making reports. You should be able to feel the brake releases when antiskid is working. If the antiskid doesn't have to do anything, I call the braking action Good. If I can feel a moderate amount of action, I'll report Medium. If the antiskid is working very hard, and/or there is significant yaw induced because of asymmetrical brake releases, I'll report Poor.
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Old 11th Jan 2019, 21:29
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This is one good reason why it's far nicer to stop first, then land....
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Old 11th Jan 2019, 22:38
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None, #1, ‘none’.

Airbus provides a balanced view in their Safety First magazine - ‘Using Aircraft as a Sensor on Contaminated Runways’.
I heed their view “Making an accurate braking report can be difficult for a pilot because it relies on their subjective experience of the landing”, thus PIREPS are of little or no value in making ‘your’ decision to land.

From a PPRuNe sage “I don’t bet my butt on the feeling in someone else’s butt”, i.e reports are subjective and others have no idea of the reporters experience in the conditions, nor the aircraft or retarding systems selections or characteristics.

It’s very difficult to ignore a report once it has been broadcast. The advice post TALPA is not to give a PIREP unless it downgrades the existing braking action.

https://safetyfirst.airbus.com/using...nated-runways/
download PDF, or via
https://safetyfirst.airbus.com/app/t...df.php?p=13846

Intruder,
your personal subjective scale is exactly the reason why PIREPS should be ignored; there is no standard, measure, yardstick, for pilot sensed braking action.


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Old 12th Jan 2019, 15:37
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Originally Posted by Intruder View Post
Autobrakes and antiskid are actually valuable indicators in making reports. You should be able to feel the brake releases when antiskid is working. If the antiskid doesn't have to do anything, I call the braking action Good. If I can feel a moderate amount of action, I'll report Medium. If the antiskid is working very hard, and/or there is significant yaw induced because of asymmetrical brake releases, I'll report Poor.
Reporting a poor breaking action is no joke . There are plenty of operators that will not allow landing if braking action is reported poor.

I just don't see how pilots would be able to judge breakin action. This is a value that lives depend on. Shouldn't just be left to opinion. Too many factors at play .
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Old 12th Jan 2019, 17:44
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Interesting article from a while ago here. It's basically the same concept as the one safetypee is describing. PIREPS on braking actions can be valuable in a very limited amount of conditions.
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Old 12th Jan 2019, 20:15
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I read somewhere, that airbus or boeing are writing software that monitors deceleration and breaking effort and transmitting it live for real time braking actions. Will be a huge improvement from basically a car doing 50mph on runway, to a 60 ton jet doing 150mph...
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Old 12th Jan 2019, 23:46
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RAAS (runway awareness advisory system) is already available and operational in some airlines...
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Old 13th Jan 2019, 08:52
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RAAS, #10, is a very restricted aid. It is only ‘advisory’ and lacks the ability to alert (or not) in context; see discussion on 777 Dubai accident.

An Airbus alternative is ROPS, which has both predictive alerting - advice in the air, and reactive - ‘commands’ on the ground. Both aspects still depend on the accuracy of the pre-landing data input. The computation has ability to deduce’ the braking action based on reported contaminant type, depth, and extent of coverage, or by crew inputs, i.e. subject to ‘PIREP error’. As with many modern thinking machines, their value depends on input / sensors.

Advantages of ROPS are with combined audio-visual alerts before touchdown, and ability to give a course of action when in the runway. The options for action might be no better than a pilot might have, but the need for change it is sensed (measured) by the aircraft, not the butt, and thus the crew is quickly alerted use all of the remaining safety margin. Some viewpoints support the idea that humans will react to a machine alert quicker that an individual’s decision depending on experience and frailties of ‘biased’ judgement.

ROPS page 21 - http://aerosociety.com/Assets/Docs/E...%20Chapman.pdf
also
page 47- https://www.icao.int/SAM/Documents/2...nting%20RE.pdf
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Old 13th Jan 2019, 15:47
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I would not ignore braking reports by other pilots flying the same model aircraft I am flying. I would use those reports in combination with other sources to attempt to put together a complete picture of braking action on the landing runway. Official reports can be old or, in rapidly changing conditions, invalid. A PIREP from an aircraft which landed immediately in front of me would carrry more weight than a 30 minute old RWYCC. Turbulence reports are also subjective, we don’t ignore those but also put them in the mix in an attempt to create a complete picture.
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Old 13th Jan 2019, 17:57
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Salute Mongo
You have same thots as I, and I cut my teeth on anti-skid lites as a youth flying up in the frozen north across the U.S./Canada border.
Of course, over the years the anti-skid systems got better and we no longer experienced the "complete" release of the brakes at beginning of a skid, but rather a more gentle release of pressure as we experienced carbon-based critters would do. My last jet could allow a hamburger like me to press hard on the brakes and Hal took care of braking pressure.
Getting a PIREP from your wingman/flight lead who landed a minute in front of you is what I would go with 95% of the time, especially if we had discussed braking technique due to the weather forecast and past experience.

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Old 13th Jan 2019, 19:36
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Originally Posted by Airmann View Post
Reporting a poor breaking action is no joke . There are plenty of operators that will not allow landing if braking action is reported poor.

I just don't see how pilots would be able to judge breakin action. This is a value that lives depend on. Shouldn't just be left to opinion. Too many factors at play.
I have just described ONE way to judge breaking action. Along with that is the actual distance needed to stop. Maybe those operators would be thankful that someone warned them ahead of time, and they had enough fuel to go to their alternate...
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Old 13th Jan 2019, 19:43
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Braking action reports are as arbitrary as ‘ride reports’ or turbulence reports.
They are in indication and not the holy word brought down the mountain by Mozes.
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