M  Pilot/Controller Glossary  8/15/19  MAA- 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  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  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  MAWP- Missed Approach Waypoint  MARSA- (See MILITARY AUTHORITY ASSUMES  RESPONSIBILITY FOR SEPARATION OF  AIRCRAFT.)  (See INNER MARKER.)  (See MIDDLE MARKER.)  (See OUTER MARKER.)  (Refer to AIM.)  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.  MAP- (See MISSED APPROACH POINT.)  MANPADS- (See MAN PORTABLE AIR DEFENSE  SYSTEMS.)  MANDATORY ALTITUDE- An altitude depicted  on an instrument Approach Procedure Chart  requiring the aircraft to maintain altitude at the  depicted value.  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.  (See MAXIMUM AUTHORIZED ALTITUDE.)  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.  MAINTAIN- PCG M-1 