MAA- 

(See MAXIMUM AUTHORIZED ALTITUDE.) 

MACH NUMBER- The ratio of true airspeed to the speed of sound; e.g., MACH .82, MACH 1.6. 

(See AIRSPEED.) 

MACH TECHNIQUE [ICAO]- Describes a control technique used by air traffic control whereby turbojet aircraft operating successively along suitable routes are cleared to maintain appropriate MACH numbers for a relevant portion of the en route phase of flight. The principle objective is to achieve improved utilization of the airspace and to ensure that separation between successive aircraft does not decrease below the established minima. 

MAHWP- Missed Approach Holding Waypoint 

## MAINTAIN- 

a. Concerning altitude/flight level, the term means to remain at the altitude/flight level specified. The phrase “climb and” or “descend and” normally precedes “maintain” and the altitude assignment; e.g., “descend and maintain 5,000.” 

b. Concerning other ATC instructions, the term is used in its literal sense; e.g., maintain VFR. 

MAINTENANCE PLANNING FRICTION LEVEL- The friction level specified in AC 150/5320-12, Measurement, Construction, and Maintenance of Skid Resistant Airport Pavement Surfaces, which represents the friction value below which the runway pavement surface remains acceptable for any category or class of aircraft operations but which is beginning to show signs of deterioration. This value will vary depending on the particular friction measurement equipment used. 

MAKE SHORT APPROACH- Used by ATC to inform a pilot to alter his/her traffic pattern so as to make a short final approach. 

(See TRAFFIC PATTERN.) 

MAN PORTABLE AIR DEFENSE SYSTEMS (MANPADS)- MANPADS are lightweight, shoulder-launched, missile systems used to bring down aircraft and create mass casualties. The potential for MANPADS use against airborne aircraft 

## M 

is real and requires familiarity with the subject. Terrorists choose MANPADS because the weapons are low cost, highly mobile, require minimal set-up time, and are easy to use and maintain. Although the weapons have limited range, and their accuracy is affected by poor visibility and adverse weather, they can be fired from anywhere on land or from boats where there is unrestricted visibility to the target. 

MANDATORY ALTITUDE- An altitude depicted on an instrument Approach Procedure Chart requiring the aircraft to maintain altitude at the depicted value. 

MANPADS- 

MAP- 

MARKER BEACON- An electronic navigation facility transmitting a 75 MHz vertical fan or boneshaped radiation pattern. Marker beacons are identified by their modulation frequency and keying code, and when received by compatible airborne equipment, indicate to the pilot, both aurally and visually, that he/she is passing over the facility. 

MARSA- 

MAWP- Missed Approach Waypoint 

MAXIMUM AUTHORIZED ALTITUDE- A pub- lished altitude representing the maximum usable altitude or flight level for an airspace structure or route segment. It is the highest altitude on a Federal airway, jet route, area navigation low or high route, or other direct route for which an MEA is designated in 14 CFR Part 95 at which adequate reception of navigation aid signals is assured. 

MAYDAY- The international radiotelephony distress signal. When repeated three times, it indicates 

(See MAN PORTABLE AIR DEFENSE SYSTEMS.) 

(See MISSED APPROACH POINT.) 

(See INNER MARKER.) (See MIDDLE MARKER.) (See OUTER MARKER.) (Refer to AIM.) 

(See MILITARY AUTHORITY ASSUMES RESPONSIBILITY FOR SEPARATION OF AIRCRAFT.) 

