Federal Aviation Administration, DOT

Section 25.109

Where - 
Tire Pressure = maximum airplane operating
tire pressure (psi);
Sectiont/gMAX = maximum tire-to-ground braking
coefficient;
V = airplane true ground speed (knots); and
Linear interpolation may be used for tire
pressures other than those listed.

On-Off ........................................................................
Quasi-Modulating .......................................................
Fully Modulating ........................................................

0.30
0.50
0.80

(d) At the option of the applicant, a
higher wet runway braking coefficient
of friction may be used for runway surfaces that have been grooved or treated
with a porous friction course material.
For grooved and porous friction course
runways, the wet runway braking
coefficent of friction is defined as either:
(1) 70 percent of the dry runway braking coefficient of friction used to determine the dry runway accelerate-stop
distance; or
(2) The wet runway braking coefficient defined in paragraph (c) of this
section, except that a specific anti-skid
system efficiency, if determined, is appropriate for a grooved or porous friction course wet runway, and the maximum tire-to-ground wet runway braking coefficient of friction is defined as:

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(2) The maximum tire-to-ground wet
runway braking coefficient of friction
must be adjusted to take into account
the efficiency of the anti-skid system
on a wet runway. Anti-skid system operation must be demonstrated by flight
testing on a smooth wet runway, and
its efficiency must be determined. Unless a specific anti-skid system efficiency is determined from a quantitative analysis of the flight testing
on a smooth wet runway, the maximum tire-to-ground wet runway braking coefficient of friction determined
in paragraph (c)(1) of this section must
be multiplied by the efficiency value
associated with the type of anti-skid
system installed on the airplane:

Efficiency
value

Type of anti-skid system