Page 24 - AFMAN 15-111, 12 MAR 2019

24 AFMAN15-111 12 MARCH 2019

4.13. Inactive/Parallel Runway Equipment.

4.13.1. Supplemental Data. ATC may occasionally authorize an aircraft to land using an
inactive runway. If weather sensors are installed on the inactive runway, the ATC agency may
initiate a request for observation data to control aircraft using that runway. This is a temporary
measure and the current observation is not affected since the active runway is not changed (i.e.
supplemental data is included in the remarks section of the observation and does not replace
the active/primary sensor data). Use of data from inactive runway sensors must be based on
the following factors:
4.13.1.1. Supplemental RVR data for an inactive runway can be reported in the remarks
section of an observation using the same basic code form as that specified for the active
runway. Example: R03R/1600FT
4.13.1.2. Supplemental wind data for an inactive/parallel runway can be reported in the
remarks section of an observation when there is at least a 6 knot (kt) difference in speed
(sustained or gusts) between the active wind sensor and the inactive sensor(s). Example:
WND RWY 32R 300/10G15KT
4.13.1.3. Cloud heights generally do not differ from one end of a runway to the other.
However, FBWOS discontinuity sensors report cloud ceiling heights as a remark in the
observation. Variations in the sky condition relative to the runways, such as reported in
local PIREPs, can be taken into consideration in the evaluation of sky cover as reported in
the official observation. WFs/Dets may report significant or unusual variations in the sky
condition in the remarks section of the observation. Example: CLD LYR AT 400FT ON
APCH RWY 23 RPRTD BY PIREPS

4.13.2. When the accuracy or validity of data from the active weather sensor is questionable,
WFs/Dets may utilize inactive/parallel runway equipment as their back-up method to obtain
objective elements. However, wind data will be reported as “estimated” if obtained as back-up
from an inactive sensor. Exception: WFs/Dets will not use inactive/parallel runway equipment
to back-up a faulty RVR reading; encode RVRNO as part of the official observation (may still
encode a supplemental RVR reading). (T-1).