AIM

4/3/14

1−1−25

Navigation Aids

directional facility (SDF) procedures. These proced-

ures are identified by the name of the procedure and

“or GPS” (for example, VOR/DME or GPS RWY15).

Other previous types of overlays have either been

converted to this format or replaced with stand-alone

procedures. Only approaches contained in the current

onboard navigation database are authorized. The

navigation database may contain information about

non-overlay approach procedures that is intended to

be used to enhance position orientation, generally by

providing a map, while flying these approaches using

conventional NAVAIDs. This approach information

should not be confused with a GPS overlay approach.

(See the receiver operating manual, AFM, or AFM

Supplement for details on how to identify these

approaches in the navigation database.)

f. General Database Requirements

1.

The onboard navigation data must be current

and appropriate for the region of intended operation

and should include the navigation aids, waypoints,

and relevant coded terminal airspace procedures for

the departure, arrival, and alternate airfields.

(a)

Further database guidance for terminal

and en route requirements may be found in AC

90-100, U.S. Terminal and En Route Area Navigation

(RNAV) Operations.

(b)

Further database guidance on Required

Navigation Performance (RNP) instrument approach

operations, RNP terminal, and RNP en route

requirements may be found in AC 90-105, Approval

Guidance for RNP Operations and Barometric

Vertical Navigation in the U.S. National Airspace

System.

(c)

All approach procedures to be flown must

be retrievable from the current airborne navigation

database supplied by the equipment manufacturer or

other FAA approved source. The system must be able

to retrieve the procedure by name from the aircraft

navigation database, not just as a manually entered

series of waypoints. Manual entry of waypoints using

latitude/longitude or place/bearing is not permitted

for approach procedures.

(d)

Prior to using a procedure or waypoint

retrieved from the airborne navigation database, the

pilot should verify the validity of the database. This

verification should include the following preflight

and inflight steps:

(1) Preflight:

[a]

Determine the date of database

issuance, and verify that the date/time of proposed

use is before the expiration date/time.

[b]

Verify that the database provider has

not published a notice limiting the use of the specific

waypoint or procedure.

(2) Inflight:

[a]

Determine that the waypoints and

transition names coincide with names found on the

procedure chart. Do not use waypoints which do not

exactly match the spelling shown on published

procedure charts.

[b]

Determine that the waypoints are

generally logical in location, in the correct order, and

that their orientation to each other is as found on the

procedure chart, both laterally and vertically.

NOTE

−

There is no specific requirement to check each waypoint
latitude and longitude, type of waypoint and/or altitude
constraint, only the general relationship of waypoints in
the procedure, or the logic of an individual waypoint’s
location.

[c]

If the cursory check of procedure

logic or individual waypoint location, specified in [b]

above, indicates a potential error, do not use the

retrieved procedure or waypoint until a verification of

latitude and longitude, waypoint type, and altitude

constraints indicate full conformity with the

published data.

g. GPS Approach Procedures

As the production of stand−alone GPS approaches

has progressed, many of the original overlay

approaches have been replaced with stand−alone

procedures specifically designed for use by GPS

systems. The title of the remaining GPS overlay

procedures has been revised on the approach chart to

“or GPS” (e.g., VOR or GPS RWY 24). Therefore, all

the approaches that can be used by GPS now contain

“GPS” in the title (e.g., “VOR or GPS RWY 24,”

“GPS RWY 24,” or “RNAV (GPS) RWY 24”).

During these GPS approaches, underlying ground−

based NAVAIDs are not required to be operational

and associated aircraft avionics need not be installed,

operational, turned on or monitored (monitoring of

the underlying approach is suggested when equip-

ment is available and functional). Existing overlay

approaches may be requested using the GPS title,