Pilot/Controller Glossary 

4/20/23 

route applies to the entire width of the airway, segment, or route between the radio fixes defining the airway, 

segment, or route. 

(Refer to 14 CFR Part 91.) 
(Refer to 14 CFR Part 95.) 
(Refer to AIM.) 

MINIMUM FRICTION LEVEL

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 The friction level specified in AC 150/5320-12, Measurement, Construction, 

and Maintenance of Skid Resistant Airport Pavement Surfaces, that represents the minimum recommended wet 

pavement surface friction value for any turbojet aircraft engaged in LAHSO. This value will vary with the 

particular friction measurement equipment used. 
MINIMUM FUEL

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Indicates that an aircraft’s fuel supply has reached a state where, upon reaching the 

destination, it can accept little or no delay. This is not an emergency situation but merely indicates an emergency 

situation is possible should any undue delay occur. 

(Refer to AIM.) 

MINIMUM HOLDING ALTITUDE

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 The lowest altitude prescribed for a holding pattern which assures 

navigational signal coverage, communications, and meets obstacle clearance requirements. 
MINIMUM IFR ALTITUDES (MIA)

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 Minimum altitudes for IFR operations as prescribed in 14 CFR Part 91. 

These altitudes are published on aeronautical charts and prescribed in 14 CFR Part 95 for airways and routes, 

and in 14 CFR Part 97 for standard instrument approach procedures. If no applicable minimum altitude is 

prescribed in 14 CFR Part 95 or 14 CFR Part 97, the following minimum IFR altitude applies: 

a. 

In designated mountainous areas, 2,000 feet above the highest obstacle within a horizontal distance of 4 

nautical miles from the course to be flown; or 

b. 

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 

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 OBSTRUCTION CLEARANCE ALTITUDE (MOCA)

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 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 (MRA)

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 The lowest altitude at which an intersection can be determined. 

(Refer to 14 CFR Part 95.) 

MINIMUM SAFE ALTITUDE (MSA)

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a. 

The Minimum Safe Altitude (MSA) specified in 14 CFR Part 91 for various aircraft operations. 

b. 

Altitudes depicted on approach charts or departure procedure (DP) graphic 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 or on a DP graphic chart which 

provide at least 1,000 feet of obstacle clearance within a 25

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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.) 

PCG M

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