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 270N 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 600W and south of 38030'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 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:

1. 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.)
2. 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.”