Aeronautical Information Manual (AIM), page 480

Index   479 -- Page 480 -- 481


priority is desired on the frequency and for ATC

2. The pilot still retains the option of initiating

the communications using the urgency call "PAN-

PAN" 3 times to alert all listening parties of a special

handling condition which will receive ATC priority

for issuance of a clearance or assistance.
3. ATC will:

(a) Approve the deviation.

(b) Provide vertical separation and then
approve the deviation; or

(c) If ATC is unable to establish vertical

separation, ATC must advise the pilot that standard
separation cannot be applied; provide essential traffic
information for all affected aircraft, to the extent
practicable; and if possible, suggest a course of
action. ATC may suggest that the pilot climb or
descend to a contingency altitude (1,000 feet above or
below that assigned if operating above FL 290;
500 feet above or below that assigned if operating at
or below FL 290).
descent) TO (appropriate altitude); TRAFFIC (position


4. The pilot will follow the ATC advisory
altitude when approximately 10 NM from track as
well as execute the procedures detailed in para-
graph 7-1-13c5.

5. If contact cannot be established or revised

ATC clearance or advisory is not available and
deviation from track is required, the pilot must take
the following actions:

(a) If possible, deviate away from an
organized track or route system.

(b) Broadcast aircraft position and intentions

on the frequency in use, as well as on frequency
121.5 MHz at suitable intervals stating: flight
identification (operator call sign), flight level, track
code or ATS route designator, and extent of deviation


(c) Watch for conflicting traffic both visually
and by reference to TCAS (if equipped).

(d) Turn on aircraft exterior lights.

(e) Deviations of less than 10 NM or
operations within COMPOSITE (NOPAC and
CEPAC) Airspace, should REMAIN at ASSIGNED

altitude. Otherwise, when the aircraft is approximate-

ly 10 NM from track, initiate an altitude change based

on the following criteria:

TBL 7-1-5

Route Deviations Altitude Change
Centerline/Track >10 NM

East Left Descend 300 Feet
000 - 179M Right Climb 300 Feet
West Left Climb 300 Feet
180-359M Right Descend 300 Feet

Pilot Memory Slogan: "East right up,
West right down."

(f) When returning to track, be at assigned
flight level when the aircraft is within approximately
10 NM of centerline.
(g) If contact was not established prior to
deviating, continue to attempt to contact ATC to
obtain a clearance. If contact was established,
continue to keep ATC advised of intentions and
obtain essential traffic information.

7-1-14. Runway Visual Range (RVR)

There are currently two configurations of RVR in the

NAS commonly identified as Taskers and New
Generation RVR. The Taskers are the existing
configuration which uses transmissometer technolo-
gy. The New Generation RVRs were deployed in
November 1994 and use forward scatter technology.
The New Generation RVRs are currently being

deployed in the NAS to replace the existing Taskers.

a. RVR values are measured by transmissometers
mounted on 14-foot towers along the runway. A full
RVR system consists of:

1. Transmissometer projector and related items.
2. Transmissometer receiver (detector) and

related items.

3. Analog
4. recorder.

5. Signal data converter and related items.

6. Remote digital or remote display program-

b. The transmissometer projector and receiver are
mounted on towers 250 feet apart. A known intensity

7-1-36 Meteorology

Page 480 of the Aeronautical Information Manual (AIM.pdf)
AIM: Official Guide to Basic Flight Information and ATC Procedures

Index   479 -- Page 480 -- 481