c. As otherwise authorized by the Administrator
or assigned by ATC.
(See MINIMUM CROSSING ALTITUDE.)
(See MINIMUM EN ROUTE IFR ALTITUDE.)

(See MINIMUM OBSTRUCTION CLEARANCE
ALTITUDE.)
(See MINIMUM SAFE ALTITUDE.)
(See MINIMUM VECTORING ALTITUDE.)
(Refer to 14 CFR Part 91.)


MINIMUM NAVIGATION PERFORMANCE

SPECIFICATION- A set of standards which require
aircraft to have a minimum navigation performance
capability in order to operate in MNPS designated
airspace. In addition, aircraft must be certified by
their State of Registry for MNPS operation.

MINIMUM NAVIGATION PERFORMANCE
SPECIFICATION AIRSPACE- Designated airspace
in which MNPS procedures are applied between
MNPS certified and equipped aircraft. Under certain
conditions, non-MNPS aircraft can operate in
MNPSA. However, standard oceanic separation
minima is provided between the non-MNPS aircraft
and other traffic. Currently, the only designated
MNPSA is described as follows:
a. Between FL 285 and FL 420;

b. Between latitudes 27_N and the North Pole;

c. In the east, the eastern boundaries of the CTAs
Santa Maria Oceanic, Shanwick Oceanic, and
Reykjavik;
d. In the west, the western boundaries of CTAs
Reykjavik and Gander Oceanic and New York
Oceanic excluding the area west of 60_W and south
of 38_30'N.

MINIMUM OBSTRUCTION CLEARANCE ALTI-
TUDE (MOCA)- The lowest published altitude in

effect between radio fixes on VOR airways,

off-airway routes, or route segments which meets

obstacle clearance requirements for the entire route

segment and which assures acceptable navigational

signal coverage only within 25 statute (22 nautical)

miles of a VOR.
(Refer to 14 CFR Part 91.)
(Refer to 14 CFR Part 95.)

MINIMUM RECEPTION ALTITUDE- The lowest
altitude at which an intersection can be determined.
(Refer to 14 CFR Part 95.)

MINIMUM SAFE ALTITUDE-

a. The minimum altitude specified in 14 CFR
Part 91 for various aircraft operations.
b. Altitudes depicted on approach charts which
provide at least 1,000 feet of obstacle clearance for
emergency use. These altitudes will be identified as
Minimum Safe Altitudes or Emergency Safe

Altitudes and are established as follows:

1. Minimum Safe Altitude (MSA). Altitudes
depicted on approach charts which provide at least
1,000 feet of obstacle clearance within a 25-mile
radius of the navigation facility, waypoint, or airport
reference point upon which the MSA is predicated.
MSAs are for emergency use only and do not
necessarily assure acceptable navigational signal
coverage.
(See ICAO term Minimum Sector Altitude.)
2. Emergency Safe Altitude (ESA). Altitudes
depicted on approach charts which provide at least
1,000 feet of obstacle clearance in nonmountainous
areas and 2,000 feet of obstacle clearance in
designated mountainous areas within a 100-mile
radius of the navigation facility or waypoint used as
the ESA center. These altitudes are normally used
only in military procedures and are identified on
published procedures as "Emergency Safe
Altitudes."

MINIMUM SAFE ALTITUDE WARNING- A
function of the ARTS III computer that aids the
controller by alerting him/her when a tracked Mode
C equipped aircraft is below or is predicted by the
computer to go below a predetermined minimum safe
altitude.
(Refer to AIM.)

MINIMUM SECTOR ALTITUDE [ICAO]- The

lowest altitude which may be used under emergency

conditions which will provide a minimum clearance

of 300 m (1,000 feet) above all obstacles located in

an area contained within a sector of a circle of 46 km

(25 NM) radius centered on a radio aid to navigation.

MINIMUMS- Weather condition requirements
established for a particular operation or type of