About time for an international standard??

[ironbutt57]

http://www.centredaily.com/mld/centr...s/14782386.htm

[vapilot2004]

I agree completely !

I still find fault with the runway traction coefficient reporting system in use during snow/ice conditions at all civilian US facilities and think that the FAA should address this entirely obvious issue in depth. The current data models and reporting systems go back to limited almost one-off tests made decades ago.


After this ruling announcment, Southwest must be breathing a bit easier now.

[Zeffy]

Full text of FAA policy change announcement here:
http://tinyurl.com/jyxax

[westhawk]

Full text of FAA policy change announcement here:

Interesting read. We have always stayed with the original pre-dispatch 1.67 X the raw book distance requirement (dry, wet or icy as applicable per anticipated conditions) for landing on wet or contaminated surfaces even though it was not required upon arrival. This new scheme seems like a good move since obviously, not all operators currently follow guidelines more conservative than required. (must be calculated to stop within the ALD considering actual arrival conditions at the ATA) The bottom line appears to be that 15% margin beyond the unfactored landing distance for the conditions will be required under the new rule, if adopted. Interestingly, in view of the fact that credit was allowed to be taken for the effect of reverse thrust in the SWA overrun and that the reversers did not in fact deploy until they could do little to affect the landing distance, the aircraft might still apparently have required more than 115% of the ALD under those conditions with no reverse. This NPRM does not appear to address the reversers issue directly here.

Until a global standard assuring accurate runway friction coefficient is developed and implemented, it would seem that using the current runway condition reporting plus a safety margin is the best we can do. I will continue to apply the 167% used during pre-flight planning as the standard for actual arrival unless it can be shown that less is necessary and can safely be accomplished without slamming the airplane onto the ground and standing on the brakes! (as was done in flight test to establish the certified landing distance) As fun as this might be, our 30 year old aircraft will not stand up to much of that. Neither would our paying pax. Really a shame that in addition to the certified minimum landing distances published, we don't have "normal" landing distances as well.

On dry surfaces, I have always felt "normal" is at least 150% of book values while it may be somewhat closer to book values for wet, icy or contaminated surfaces. The difference lies in flare distance and brake energy applied. For critical runways, I do what I must, but making anything close to the book numbers still requires a "firm" touchdown and heavy anti-skid braking on other than dry surfaces. Reverse may be less a stopping factor on slippery runways in some aircraft due to directional control issues. I know it is in mine.

So at least in some cases, this new rule would add a safety margin that does not exist under the current rules. Many operators allready employ larger margins than the new rule would require. I hope they continue to do so.

Best regards,

Westhawk