AIM

4/3/14

4−3−12

Airport Operations

pavement surface) to the perpendicular force holding

them in contact (distributed aircraft weight to the

aircraft tire area). Simply stated, friction quantifies

slipperiness of pavement surfaces.

b.

The greek letter MU (pronounced “myew”), is

used to designate a friction value representing

runway surface conditions.

c.

MU (friction) values range from 0 to 100 where

zero is the lowest friction value and 100 is the

maximum friction value obtainable. For frozen

contaminants on runway surfaces, a MU value of

40 or less is the level when the aircraft braking

performance starts to deteriorate and directional

control begins to be less responsive. The lower the

MU value, the less effective braking performance

becomes and the more difficult directional control

becomes.

d.

At airports with friction measuring devices,

airport management should conduct friction mea-

surements on runways covered with compacted snow

and/or ice.

1.

Numerical readings may be obtained by using

any FAA approved friction measuring device. As

these devices do not provide equal numerical

readings on contaminated surfaces, it is necessary to

designate the type of friction measuring device used.

2.

When the MU value for any one−third zone of

an active runway is 40 or less, a report should be given

to ATC by airport management for dissemination to

pilots. The report will identify the runway, the time of

measurement, the type of friction measuring device

used, MU values for each zone, and the contaminant

conditions, e.g., wet snow, dry snow, slush, deicing

chemicals, etc. Measurements for each one−third

zone will be given in the direction of takeoff and

landing on the runway. A report should also be given

when MU values rise above 40 in all zones of a

runway previously reporting a MU below 40.

3.

Airport management should initiate a

NOTAM(D) when the friction measuring device is

out of service.

e.

When MU reports are provided by airport

management, the ATC facility providing approach

control or local airport advisory will provide the

report to any pilot upon request.

f.

Pilots should use MU information with other

knowledge including aircraft performance character-

istics, type, and weight, previous experience, wind

conditions, and aircraft tire type (i.e., bias ply vs.

radial constructed) to determine runway suitability.

g.

No correlation has been established between

MU values and the descriptive terms “good,” “fair,”

“poor,” and “nil” used in braking action reports.

4

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3

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10. Intersection Takeoffs

a.

In order to enhance airport capacities, reduce

taxiing distances, minimize departure delays, and

provide for more efficient movement of air traffic,

controllers may initiate intersection takeoffs as well

as approve them when the pilot requests. If for ANY

reason a pilot prefers to use a different intersection or

the full length of the runway or desires to obtain the

distance between the intersection and the runway end,

THE PILOT IS EXPECTED TO INFORM ATC

ACCORDINGLY.

b.

Pilots are expected to assess the suitability of an

intersection for use at takeoff during their preflight

planning. They must consider the resultant length

reduction to the published runway length and to the

published declared distances from the intersection

intended to be used for takeoff. The minimum runway

required for takeoff must fall within the reduced

runway length and the reduced declared distances

before the intersection can be accepted for takeoff.

REFERENCE

−

AIM, Use of Runways/Declared Distances, Paragraph 4

−3−6.

c.

Controllers will issue the measured distance

from the intersection to the runway end rounded

“down” to the nearest 50 feet to any pilot who

requests and to all military aircraft, unless use of the

intersection is covered in appropriate directives.

Controllers, however, will not be able to inform pilots

of the distance from the intersection to the end of any

of the published declared distances.

REFERENCE

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FAAO JO 7110.65, Ground Traffic Movement, Paragraph 3

−7−1.

d.

An aircraft is expected to taxi to (but not onto)

the end of the assigned runway unless prior approval

for an intersection departure is received from ground

control.

e.

Pilots should state their position on the airport

when calling the tower for takeoff from a runway

intersection.

EXAMPLE

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Cleveland Tower, Apache Three Seven Two Two Papa, at
the intersection of taxiway Oscar and runway two three
right, ready for departure.