Page 22 - AFMAN 15-111, 12 MAR 2019

22 AFMAN15-111 12 MARCH 2019

4.9. Cooperative Weather Watch. Encompasses the report of tower visibility, local pilot
reports (PIREPs), and any occurrence of previously unreported conditions from ATC that are
critical to the safety or efficiency of local operations and resources. At a minimum, the cooperative
weather watch documents:

4.9.1. Procedures for task certified ATC personnel to report changes in tower visibility when
it is less than 4 SM (6000 m) and differs from the prevailing visibility by at least one reportable
value.

4.9.2. Procedures for ATC personnel to relay PIREPs as soon as practical, within ATC
established duty priorities.

4.9.3. As part of the cooperative weather watch, if continuous RVR reporting is needed outside
controlled airfield hours, WFs/Dets notify airfield leadership that the RVR system requires the
runway lights to be left on to work properly. This practice supports the possibility that an
aircraft may divert into the location in an emergency.

4.10. Control Tower Observations
4.10.1. ATC Personnel. ATC directives (e.g., AFI 13-204, Volume 3, Airfield Operations
Procedures and Programs; FAAO JO 7110.65, Air Traffic Control; Army Training Circular
3-04.81, Air Traffic Control Facility Operations, Training, Maintenance, and
Standardization), require task certified ATC personnel to take tower visibility observations
when the prevailing visibility at the point of observation or at the tower level, is less than 4 SM
(6000 m). Control tower personnel task certified to take visibility observations also notify the
weather technician when the observed tower prevailing visibility decreases to less than 4 SM
(6000 m) or increases to or exceeds 4 SM (6000 m).

4.10.2. Weather personnel:
4.10.2.1. Evaluate prevailing visibility as soon as practicable upon receipt of tower
visibility report that differs from the latest reported surface visibility.
4.10.2.2. Use tower visibility values as a guide in determining the surface visibility when
portions of the horizon are obstructed by buildings, aircraft, etc. Note: The presence of a
surface-based obscuration, uniformly distributed to heights above the level of the tower, is
sufficient reason to consider the prevailing visibility the same as at the control tower level.
4.10.2.3. Include a tower visibility remark in the next METAR or SPECI when either the
surface prevailing visibility or the control tower visibility is less than 4 SM (6000 m) and
the control tower visibility differs from the surface prevailing visibility by a reportable
value.

4.11. Observing Aids for Visibility. Visibility reference tools that are photographs should be
high quality color photos taken on a predominantly cloud and obscuration free day. It is also
recommended observing locations develop map-type visibility charts to augment the photographic
visibility markers.
4.11.1. Objects in the visibility reference tool must be clearly identified with distance and
direction from the observation point as well as whether the markers are day or nighttime aids
(See Figure 4.1). (T-2). It is highly recommended that the visibility reference tool be in hard-
copy format.