Damp Runway
 

Hi,

About the effect of damp runway on Take Off Performance, there are different views:

Airbus New E-FCOM (pfd) (Same as 2.04.10 P 2)

1. On a damp runway no performance degradation should be considered.


Airbus Getting The Grips with Aircraft Performance:

The FAA does not make any reference to damp runways, which are
considered as wet, whereas JAR-OPS 1.475 states that a damp runway is
equivalent to a dry one in terms of takeoff performance. Recently, JAR 25 and JAROPS
Study Groups came to the conclusion that a damp runway should be considered
closer to a wet one than to a dry one in terms of friction coefficient (μ)1. As of today,
a JAA Notice for Proposed Amendment (NPA) is under discussion, so that in the
future, a damp runway may have to be considered as wet.



EU OPS 1.475

“Dry runway”. A dry runway is one which is neither wet nor contaminated, and includes those paved runways
which have been specially prepared with grooves or porous pavement and maintained to retain “effectively dry”
braking action even when moisture is present


And An EU OPS Operator LPC Manual:

The definition of airspeeds, runway condition (dry, wet, contaminants and equivalent depths) are contained in FCOM 3.4.10 and 2.4.10 and respectively. For takeoff calculation purposes, a damp runway shall be considered wet, as it does not meet the definition of dry.

Which one of these is more accurate, what your Airline is advising about this?

Thanks in advance

Thanks for info.
Always use dry perf when rwy damp.
I will check for recent amendments.

Thank yoo De Facto

Waiting for reply

Don't know about the accuracy of the statements as that is what is under discussion in JAA land. My airline uses damp = dry.

Remember that using wet figures on a dry-ish runway does not necessarily lead to a statistically safer operation as margins may be reduced.

The LGW ATIS was broadcasting "Moist, moist, moist" when I landed there some years ago... :)

My mob recently changed to damp=wet....

Theoretically a damp rwy is a dry rwy.

In practice , when the runway is damp , I consider it wet for perf purposes unless I`m payload limited.

My 2 cents

A320