AIM

8/15/19

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Navigation Aids

(b) Database Requirements. 

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.

(1)

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.

(2)

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.

(3)

All approach procedures to be flown

must be retrievable from the current airborne
navigation database supplied by the equipment
manufacturer or other FAA

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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/bear-
ing is not permitted for approach procedures.

(4)

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:

[a] Preflight:

[1]  

Determine the date of database

issuance, and verify that the date/time of proposed
use is before the expiration date/time.

[2] 

 Verify that the database provider

has not published a notice limiting the use of the
specific waypoint or procedure.

[b] Inflight:

[1] 

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.

[2] 

 Determine that the waypoints are

logical in location, in the correct order, and their

orientation to each other is as found on the procedure
chart, both laterally and vertically.

NOTE

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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.

[3] 

 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.

(5)

Air carrier and commercial operators

must meet the appropriate provisions of their
approved operations specifications.

[a]

During domestic operations for com-

merce or for hire, operators must have a second
navigation system capable of reversion or contin-
gency operations.

[b]

Operators must have two independ-

ent 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

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An aircraft approved for multi-sensor navigation and
equipped with a single navigation system 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-inde-
pendent VOR capability would satisfy this requirement.

[c]

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