Aeronautical Information Manual (AIM)

Pilot/Controller Glossary

4/3/14

PCG M−4

Other than mountainous areas, 1,000 feet above

the highest obstacle within a horizontal distance of 4

nautical miles from the course to be flown; or

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:

Between FL 285 and FL 420;

Between latitudes 27

_N and the North Pole;

In the east, the eastern boundaries of the CTAs

Santa Maria Oceanic, Shanwick Oceanic, and

Reykjavik;

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−

The minimum altitude specified in 14 CFR

Part 91 for various aircraft operations.

Altitudes depicted on approach charts which

provide at least 1,000 feet of obstacle clearance for

emergency use within a specified distance from the

navigation facility upon which a procedure is

predicated. These altitudes will be identified as

Minimum Sector Altitudes or Emergency Safe

Altitudes and are established as follows:

Minimum Sector Altitudes. Altitudes de-

picted on approach charts which provide at least

1,000 feet of obstacle clearance within a 25-mile

radius of the navigation facility upon which the

procedure is predicated. Sectors depicted on

approach charts must be at least 90 degrees in scope.

These altitudes are for emergency use only and do not

necessarily assure acceptable navigational signal

coverage.

(See ICAO term Minimum Sector Altitude.)

Emergency Safe Altitudes. Altitudes de-

picted 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 upon which the

procedure is predicated and normally used only in

military procedures. These altitudes are identified on

published procedures as “Emergency Safe Alti-

tudes.”
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