Canadian Runway Friction Index

Closed Thread Subscribe

Thread Tools

Search this Thread

21st Feb 2006, 14:17

#1 (permalink)

backofthedrag

Thread Starter

Join Date: Aug 2003

Location: SE Asia - oops redundant

Posts: 68

Likes: 0

Received 0 Likes on 0 Posts

Canadian Runway Friction Index

My Company has the following table

Code \ Braking Action \ CRFI

5 Good .60
4 Medium-Good .59-.50
3 Medium (fair) .49-.40
2 Medium-Poor .39-.26
1 Poor .25

I worked recently for another airline that had

5 Good .40
4 Medium- Good .39-.36
3 Medium .35-.30
2 Medium- Poor .29-.26
1 Poor .25

Our Company use Braking Actions to determine the advisability of TO/Land , the others used performance charts based on friction co-efficients.
Anyone with Canadian experience guide me here ?

21st Feb 2006, 14:50

#2 (permalink)

albatross

Join Date: Sep 2004

Location: Canada

Posts: 1,762

Likes: 46

Received 156 Likes on 78 Posts

http://www.tc.gc.ca/CivilAviation/pu...IR/1-1.htm#1-6

Try here in the Canadian AIM online

21st Feb 2006, 15:40

#3 (permalink)

alf5071h

Join Date: Jul 2003

Location: An Island Province

Posts: 1,257

Likes: 0

Received 1 Like on 1 Post

See "Pilots’ Use of CRFI and Guidance Material"; Para 3.4, table 3.1. Benefit-Cost Analysis of Procedures for Accounting for Runway Friction on Landing. Landing risks and examples are in section 4; and ‘Analysis of CRFI Tables and their Confidence Intervals’ in Appendix B.

Information from Canadian AIP Canadian Runway Friction Index

Also see History of the ICAO Ice and Snow Table

21st Feb 2006, 16:32

#4 (permalink)

tribo

Join Date: Aug 2005

Location: Europe

Posts: 97

Likes: 0

Received 0 Likes on 0 Posts

ICAO Braking Action Table

backofthedrag
Have a look at this tread with respect to your second table.
http://www.pprune.org/forums/showthread.php?t=202109
Please note that the friction measuring device related to the table i 1959 is the Tapley meter.
The Tapley meter are also related to your first table. (minor differences).
From ICAO Study Group on Snow, Slush, Ice and Water on Aerodromes there exist a letter dated 27th October 1967, from UK related to:

Quote:

Tapley - or spot measurement decelerometer speed 25-30 mph and figures as follows:

Good 0.6 and above
Medium Good 0.59 - 0.51
Medium 0.5 - 0-4
Medium Poor 0.39 - 0.3
Poor 0.30 and below

Both tables can not be right.
Transport Canada
Information Circular 0/6/70 23rd February - Use of James Brake Decelerometer.

The following scale is provided as a [U]guide[U]to aircraft operators:
0 - 9 Nil to Very Poor
10 - 17 Poor
18 - 21 Fair
22 - 24 Good
25 - 32 Excellent

Information Circular 0/2/73 16 th February - Use of James Brake Decelerometer and its application to aircraft performance

Table A - List of airports providing JBI's
Table B - Landing distance required corrected for JBI - Aircraft under 12,500 lbs. No factor
Table C - Landing distance required corrected for JBI - Aircraft over 12,500 lbs. 60% factor
Table D - Cross wind limits for JBI
Table E - Runway surface condition and JBI equivalent
Bare and dry 25 and above
Damp - Less than .01" water 20-22
Very light snow patches 18 - 22
Wet concrete .01" -.03" water 12 - 18
Wet asphalt .01"-.03" water 10 - 20
Sanded packed snow or ice 12
Heavy rain .03"-.1 water 9 - 10
Snow covered 8 - 10
Compacted snow 6 - 8
Cold ice below -10degC or 26degF 4 - 6
Wet ice at or above 0degC or 32degF 2 - 4
Hydroplaning standing water .1" or more 2

Aerodrome Safety Cicular No 98-005, 1998.11.12 - Canadian Runway Friction Index (CRFI) Reporting

Quote:

Purpose
This circular is intended to clarify information with regard to use of the term Canadian Runway Friction Index (CRFI) which replaces the James Brake Index (JBI) term.

21st Feb 2006, 17:18

#5 (permalink)

backofthedrag

Thread Starter

Join Date: Aug 2003

Location: SE Asia - oops redundant

Posts: 68

Likes: 0

Received 0 Likes on 0 Posts

Wow ! What a lot of information . The CRFI replaced the JBI . Tribo seems to indicate that at JBI 25 and above relates to a good surface. The second table I produced seems to be the standard ICAO ( give or take ) .
When landing at YYZ not so long ago we were given friction coefficient .33 braking action fair which I would have expected given the ICAO table which seems to be in use in Scandanavia. I saw .61 in the weather for Goose the other day but I read in the Canadian AIP that reports are only given when the coefficient drops below .40
Is there any way of relating CRFI to ICAO friction index ?

23rd Feb 2006, 09:44

#6 (permalink)

alf5071h

Join Date: Jul 2003

Location: An Island Province

Posts: 1,257

Likes: 0

Received 1 Like on 1 Post

Quote:

Originally Posted by backofthedrag

Is there any way of relating CRFI to ICAO friction index ?

I doubt that there is a scientifically reliable method due to the many variables – notable that “there is not, at present, a common friction index for all ground friction measuring devices. Hence it is not practicable at the present time to determine aeroplane performance on the basis of an internationally accepted friction index measured by ground friction devices.” (JAA EASA NPA 14/2004).
There is a plot of ‘braking mu’ vs CRFI for the Falcon aircraft in Fig B-2 in Benefit-Cost Analysis of Procedures for Accounting for Runway Friction on Landing (3.6mb) Appendix B. However, without knowing what the relationship between braking mu and measured mu is, then there would only be tenuous links with the ICAO index. Table B-2 appears to indicate a 2:1 relationship, which I believe is used by some operators, but the extent of the variability and possible error, is shown in Fig 3-1 where on a wet runway there can be a range of 1-3 CRFI units depending on how wet the runway is and the construction materials used – beware wet concrete.
Also see Managing Threats and Errors During Approach and Landing PPT 2.7M where slide 27 attempts to pull some of the variables together in a practical way.