Aeronautical Information Manual (AIM), page 277

Index   276 -- Page 277 -- 278


1. Background. S-LRNS operations in the Gulf
of Mexico, the Caribbean Sea and the other
designated areas have been conducted for at least 25
years. Provisions allowing aircraft equipage with a
S-LRNS for operations in specified oceanic and
off-shore areas are contained in the following
sections of 14 Code of Federal Regulations (CFR):
91.511, 121.351, 125.203 and 135.165.
2. ICAO PBN Manual Reference. In reference
to RNP 10 authorization, the ICAO PBN Manual,
Volume II, Part B, Chapter 1, paragraph states
that: "A State authority may approve the use of a
single LRNS in specific circumstances (e.g., North
Atlantic MNPS and 14 CFR 121.351 (c) refer). An
RNP 10 approval is still required."
3. Policy Development. The FAA worked with
the ICAO NACC Office (North American, Central
American and Caribbean), State regulators and ATS
providers in the GoMex and Caribbean areas to
implement a policy for S-LRNS equipped aircraft to

qualify for RNP 10 for GoMex operations. Allowing

S-LRNS equipped aircraft to qualify for RNP 10
enables more operator aircraft to be authorized RNP
10, thereby creating a more uniform operating
environment for the application of 50 NM lateral
separation. The factors considered were: the
shortness of the legs outside the range of ground
navigation aids, the availability of radar and VHF
coverage in a large portion of GoMex airspace and the
absence of events attributed to S-LRNS in GoMex

4. Single LRNS/RNP 10 Authorization Limited
to Gulf of Mexico. At this time, qualification for RNP
10 based on use of a single long-range navigation
system (LRNS) only applies to Gulf of Mexico
operations. Any expansion of this provision will
require assessment and agreement by the appropriate
State authorities.

f. RNP 10 Time Limit for INS or IRU Only
Equipped Aircraft. Operators should review their
Airplane Flight Manual (AFM), AFM Supplement or
other appropriate documents and/or contact the
airplane or avionics manufacturer to determine the
RNP 10 time limit applicable to their aircraft. They
will then need to determine its effect, if any, on their
operation. Unless otherwise approved, the basic RNP
10 time limit is 6.2 hours between position updates
for aircraft on which Inertial Navigation Systems
(INS) or Inertial Reference Units (IRU) provide the

only source of long range navigation. Extended RNP
10 time limits of 10 hours and greater are already
approved for many IRU systems. FAA Advisory
Circular 90-105 contains provisions for extending
RNP 10 time limits.

4-7-7. Flight Planning Requirements
Operators must make ICAO flight plan annotations
in accordance with this paragraph and, if applicable,
Paragraph 4-7-4, Provisions for Non-RNP 10
Aircraft (Not Authorized RNP 10 or RNP 4).
a. ICAO Flight Plan Requirement. ICAO flight
plans must be filed for operation on oceanic routes
and areas in the Houston Oceanic CTA/FIR, the Gulf
of Mexico portion of the Miami CTA/FIR, the
Monterrey CTA and Merida High CTA.
b. To inform ATC that they have obtained RNP 10
or RNP 4 authorization and are eligible for 50 NM
lateral separation, operators must:

1. Annotate ICAO Flight Plan Item 10

(Equipment) with the letter "R" and

2. Annotate Item 18 (Other Information) with,
as appropriate, "PBN/A1" (for RNP10) or "PBN/L1"
(for RNP4).
On the ICAO Flight Plan, the letter "R" in Item 10
indicates that the flight is authorized for PBN operations.
Item 18 PBN/ indicates the types of PBN capabilities that
are authorized.
c. 50 NM lateral separation will only be applied to
operators/aircraft that annotate the ICAO flight plan
in accordance with this policy. (See 4-7-7 b.)

d. Operators that have not obtained RNP 10 or
RNP 4 authorization must not annotate ICAO flight
plan Item 18 (Other information) with "PBN/A1" or
"PBN/L1", but must follow the practices detailed in
paragraph 4-7-4.

4-7-8. Pilot and Dispatcher Procedures:
Basic and In-flight Contingency

a. Basic Pilot Procedures. The RNP 10 and
RNP 4 Job Aids contain references to pilot and, if
applicable, dispatcher procedures contained in
Advisory Circular 90-105 and ICAO PBN Manual,
Volume II, Parts B and C, Chapter 1.
b. ICAO Doc 4444, In-Flight Contingency
Procedures. Chapter 15 of ICAO Doc 4444

Operational Policy/Procedures for the Gulf of Mexico 50 NM Lateral Separation Initiative 4-7-3

Page 277 of the Aeronautical Information Manual (AIM.pdf)
AIM: Official Guide to Basic Flight Information and ATC Procedures

Index   276 -- Page 277 -- 278