Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

How much crosswind will you accept with poor braking action on a very long runway?

Tech Log The very best in practical technical discussion on the web

How much crosswind will you accept with poor braking action on a very long runway?

Old 12th Dec 2000, 09:19
  #1 (permalink)  
Ignition Override
Guest
 
Posts: n/a
Red face How much crosswind will you accept with poor braking action on a very long runway?

We only had a quartering headwind of seven knots for a snowy runway with good visibility. Any ideas for this winter? How about with long runway and fair braking from a B-727?

Incidentally, some general aviation pilots report good after only using the prop to slow and turnoff the runway.

I'm not landing on any more poor reports if anything better is within fuel range.

[This message has been edited by Ignition Override (edited 12 December 2000).]
 
Old 12th Dec 2000, 09:51
  #2 (permalink)  
BJBATMAN
Guest
 
Posts: n/a
Post

I woudn't ever get to fly anywhere if we cancelled every flight with a 7 knot quartering head wind in the winter, and usually no runway reports till you give one. Of course this is Alaska.

[This message has been edited by BJBATMAN (edited 12 December 2000).]

[This message has been edited by BJBATMAN (edited 12 December 2000).]
 
Old 12th Dec 2000, 10:46
  #3 (permalink)  
ijp
Guest
 
Posts: n/a
Post

Use A/C limitations, then your own,if they are less than the AFM
 
Old 12th Dec 2000, 11:58
  #4 (permalink)  
m&v
Guest
 
Posts: n/a
Wink

Depends on the coeficient of friction,hard to check while enroute. Query ATC as to aircraft landing ,how long ago-where did they stop on the runway??,or did they use it all??.At one time Carriers were 'shy'to stipulate any x/wind limit,apart from the "limitation's" section of the AFM!!Now adays the general limit for a poor braking report is 5knots on the beam,keeping in mind that any report less than fair(about .3 JBI/MU)means that your going to use more runway than Certification(have you enough??)allows.Operations shouldn't be planned on any fair to poor runway.If they happen to 'end up'so-divert.
 
Old 12th Dec 2000, 13:08
  #5 (permalink)  
Noctivaga
Guest
 
Posts: n/a
Post

IO, it depends on the runway braking action, but at my company we have a sliding (pun intended) scale which ends with a 10 kt crosswind after starting at 35. Runway length also has to be calculated based on the braking action report which is supposed to be included in the ATIS any time it goes below o.40.
In a previous existence, as a Safety Board investigator, I was called out to investigate a DC-10 which slid off the end of the runway. He had decided to land based on the report "Previous aircraft reports braking action Fair" from the tower. Trouble was that the previous aircraft was a Piper Aztec. So personally I don't put much faith in pilot reports unless I know the aircraft type.
If you care to search in the McDonnell Douglas archives, which are probably now with Boeing, there is an excellent article in the Tri-Jet newsletter from about 5 years ago which addresses landing on slippery runways. The explanation of the pitfalls of using reverse thrust in slippery conditions is absolutely spot on.
As advice, use the best info you can get to make the calculations, and if you have ANY doubts then fudge it to the good side and go elsewhere. Life is too short to waste time in a snowbank.
 
Old 12th Dec 2000, 13:31
  #6 (permalink)  
slizer
Guest
 
Posts: n/a
Post

To endorse Noctivarga's comments, I once landed in an airfield in northern Germany having ben told by the tower that the braking action was good.
After an interesting braking section of the landing, I went to the tower to find out the source of their 'braking action good' in their airfield weather readout prior to landing. They said that the last pilot to land reported 'braking action good'.
I looked on the ramp at the only other aircraft there (apart from the one I was operating), it was a F27 with all its covers fitted. I said 'is that the last aircraft to land?' ATC said 'yes'. I said when did it land and was all this snow about then?' ATC said 'It landed about half an hour ago and we've had a heavy snow storm since then!'
I LEARNT ABOUT FLYING FROM THAT!
Have a shot at an approach by all means but: IF IN DOUBT. DIVERT.
Do not trust reports unless you are absolutely sure they are accurate.
 
Old 12th Dec 2000, 17:07
  #7 (permalink)  
sparrow
Guest
 
Posts: n/a
Unhappy

My company SOP's prohibit landing on a 'poor' condition runway.

Noctivaga, any link to that report would be most interesting!

Can one ask the tower to go out and measure average coefficient, the same way they can do contaminant depth?

Chirp!
 
Old 12th Dec 2000, 19:51
  #8 (permalink)  
Jet Captain
Guest
 
Posts: n/a
Post

Ignition Override,

Here in Canada the airport operator will issue a "Canadian Runway Friction Index" or "CFRI", this is similar to the old "James Brake Index" or "JBI".

Transport Canada publishes a chart that shows recommended maximum crosswind components for reported CFRI values.

In my experience as a B727 pilot these recommended crosswind maximums are realistic and for the most part what I use as a limiting factor.

For example, from the chart, with a reported CFRI of O.30 the recommended maximum crosswind component is 10 knots.

It should be pointed out that these are recommended values and the type and extent of the runway contamination will also factor into the decision. A reported CFRI on a partially covered gravel runway at a very cold temperature is not quite the same as a reported CFRI on an paved icy runway with the temperature just below freezing.

My primary experience dealing with contaminated runways has been in Canada, where for the most part reported conditions are up to date and accurate, although there is certainly room for improvement.

I'm curious how this situation is handled in other parts of the world ? Are "friction indexes" reported at the airports you regularly operate into ? I'd be particularly interested in comments from pilots operating in the US and Northern Europe.

JC

 
Old 12th Dec 2000, 19:57
  #9 (permalink)  
mcrit
Guest
 
Posts: n/a
Question

On a related but slightly different topic…..If for example your x-wind limit was 30 kts and wind reported was all across at 25 gusting 35 could you land??
 
Old 12th Dec 2000, 20:08
  #10 (permalink)  
con-pilot
Guest
 
Posts: n/a
Unhappy

I have landed the 72 in some pretty bad conditions on 7,000ft ruways that have been snow covered. I never did have any problems, but that was in the 72 which is a great short field A/C. But we had NO fixed rules, it was up to the PIC. The only time I turned down a landing was on a snow covered runway, 6,000ft. 90 degree crosswind of 20kts gusting to 30. The 72 could have probably handled it if it had to, but we didn't have to land and I went somwehere else. So in my opinion with a 7kt quartering headwind, I don't see any problem.

[This message has been edited by con-pilot (edited 12 December 2000).]
 
Old 12th Dec 2000, 22:50
  #11 (permalink)  
Mattvitale
Guest
 
Posts: n/a
Post

My company prohibits dispatching to a "poor" braking action runway. However, once airborne, it is Capt's decision. General manufacturer guidline is x-wind to not exceed 1/2 of max (so 15kts) if the BA is poor. Also, the company SP's say that any BA reports we use as controlling must be from an aircarrier or large biz jet, or the airport authority having done friction tests.
Also, I make it a point that my ac type (EMB-120) is included with any braking action reports given. Almost always the ac type is included in any BA report given out.
 
Old 13th Dec 2000, 02:27
  #12 (permalink)  
FL390
Guest
 
Posts: n/a
Red face

Funny you should start this topic....a BA747-200 has just over-shot the runway at LHR (see post on main moard) with high winds and rain.........
 
Old 13th Dec 2000, 10:40
  #13 (permalink)  
Ignition Override
Guest
 
Posts: n/a
Thumbs up

I appreciate everyone's comments. A few nights ago at Detroit, MI (DTW), conditions other than the poor braking report on 3R (wind, vis and ceiling) were not bad at all. I talked later to another DC-9 guy who turned off of runway 3R, and he called the braking "poor to nil" so that the tower would finally close the runway, which they did.

After we taxied in that night, I told the First Officer (a former C-141 IP and Air Force Lear pilot) that we were remaining at the gate on the next plane until we heard at least a fair report from a jet, before deciding to takeoff. No debate there. Luckily for our passengers, the airport folks cleared the snow from 3C and 3L with much better reports from transport category jets. Other than refusing future landings with poor reports, I will also keep the reversers just above idle instead of stowing, until clear of the runway and on the taxiway-one Captain receiving operating experience (OE) two years ago only stopped on the runway turnoff because the check airman grabbed the reversers-their turnoff had not been treated, or refroze!

I have seen numerous jets takeoff from 21C following deicing last winter, and there were no landing reports available, because the runway was ONLY USED FOR TAKEOFF, and there might have been lousy conditions for a high-speed abort.

We now have recommended crosswind limits for good, fair, poor braking action, less than the normal dry limits, but I would not land anywhere near the max recommended crosswinds unless in good braking conditions. This was a result of a union safety rep having to use reversers to stop, after the actual braking was found to be much worse than reported. The company Flt Ops people and the FAA (I have no doubt about the FAA's indifference) probably would never have initiated/created these reduced limits without some incidents last winter.

By the way, our union Safety Officers claim that the FAA Flight Standards people etc don't even care how often airports plow/spray chemicals on runways (some negligence happens even at Michigan's, Wisconson's... smaller airports)! I wish I were kidding about any of this.

[This message has been edited by Ignition Override (edited 13 December 2000).]
 

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.