AIM

4/3/14

1−1−22

Navigation Aids

flight must rely on other approved equipment, delay

departure, or cancel the flight.

(d)

The GPS operation must be conducted in

accordance with the FAA−approved aircraft flight

manual (AFM) or flight manual supplement. Flight

crew members must be thoroughly familiar with the

particular GPS equipment installed in the aircraft, the

receiver operation manual, and the AFM or flight

manual supplement. Unlike ILS and VOR, the basic

operation, receiver presentation to the pilot and some

capabilities of the equipment can vary greatly. Due to

these differences, operation of different brands, or

even models of the same brand of GPS receiver, under

IFR should not be attempted without thorough study

of the operation of that particular receiver and

installation.  Most receivers have a built−in simulator

mode which will allow the pilot to become familiar

with operation prior to attempting operation in the

aircraft. Using the equipment in flight under VFR

conditions prior to attempting IFR operation will

allow further familiarization.

(e)

Aircraft navigating by IFR approved GPS

are considered to be area navigation (RNAV) aircraft

and have special equipment suffixes. File the

appropriate equipment suffix in accordance with

TBL 5−1−3, on the ATC flight plan. If GPS avionics

become inoperative, the pilot should advise ATC and

amend the equipment suffix.

(f)

Prior to any GPS IFR operation, the pilot

must review appropriate NOTAMs and aeronautical

information. (See GPS NOTAMs/Aeronautical In-

formation.)

(g)

Air carrier and commercial operators

must meet the appropriate provisions of their

approved operations specifications.

(1)

During domestic operations for com-

merce or for hire, operators must have a second

navigation system capable of reversion or contin-

gency operations.

(2)

Operators must have two independent

navigation systems appropriate to the route to be

flown, or one system that is suitable and a second,

independent backup capability that allows the

operator to proceed safely and land at a different

airport, and the aircraft must have sufficient fuel

(reference 14 CFR 121.349, 125.203, 129.17, and

135.165). These rules ensure the safety of the

operation by preventing a single point of failure.

NOTE

−

An aircraft approved for multi-sensor navigation and
equipped with a single FMS must maintain an ability
to navigate or proceed safely in the event that any one
component of the navigation system fails, including
the flight management system (FMS). Retaining a
FMS-independent VOR capability would satisfy this
requirement.

(3)

The requirements for a second system

apply to the entire set of equipment needed to achieve

the navigation capability, not just the individual

components of the system such as the radio

navigation receiver. For example, to use two RNAV

systems (e.g., GPS and DME/DME/IRU) to comply

with the requirements, the aircraft must be equipped

with two independent radio navigation receivers and

two independent navigation computers (e.g., flight

management systems (FMS)). Alternatively, to

comply with the requirements using a single RNAV

system with an installed and operable VOR

capability, the VOR capability must be independent

of the FMS.

(4)

To satisfy the requirement for two

independent navigation systems, if the primary

navigation system is GPS-based, the second system

must be independent of GPS (for example, VOR or

DME/DME/IRU). This allows continued navigation

in case of failure of the GPS or WAAS services.

Recognizing that GPS interference and test events

resulting in the loss of GPS services have become

more common, the FAA requires operators conduct-

ing IFR operations under 14 CFR 121.349, 125.203,

129.17 and 135.65 to retain a non-GPS navigation

capability consisting of either DME/DME, IRU or

VOR for en route and terminal operations, and VOR

and ILS for final approach. Since this system is to be

used as a reversionary capability, single equipage is

sufficient.

e. Use of GPS for IFR Oceanic, Domestic

En Route, Terminal Area, and Approach Opera-
tions

1.

GPS IFR operations in oceanic areas can be

conducted as soon as the proper avionics systems are

installed, provided all general requirements are met.

A GPS installation with TSO−C129 (as revised)

authorization in class A1, A2, B1, B2, C1, or C2 or

TSO-C196 (as revised) may be used to replace one of

the other approved means of long−range navigation,

such as dual INS. (See TBL 1−1−5 and TBL 1−1−6.)

A single TSO-C129 GPS installation meeting the