Pilot/Controller Glossary 

9/5/24 

identify for VFR traffic where these activities are conducted. Permanent MOAs are depicted on Sectional 

Aeronautical, VFR Terminal Area, and applicable En Route Low Altitude Charts. 

Note: Temporary MOAs are not charted. 
(Refer to AIM.) 

d. 

National Security Area (NSA)– Airspace of defined vertical and lateral dimensions established at locations 

where there is a requirement for increased security of ground facilities. Pilots are requested to voluntarily avoid 

flying through the depicted NSA. When a greater level of security is required, flight through an NSA may be 

temporarily prohibited by establishing a TFR under the provisions of 14 CFR Section 99.7. Such prohibitions 

will be issued by FAA Headquarters and disseminated via the U.S. NOTAM System. 

(Refer to AIM) 

e. 

Prohibited Area

−

 Airspace designated under 14 CFR Part 73 within which no person may operate an 

aircraft without the permission of the using agency. 

(Refer to AIM.) 
(Refer to En Route Charts.) 

f. 

Restricted Area

−

 Permanent and temporary restricted areas are airspace designated under 14 CFR Part 73, 

within which the flight of aircraft, while not wholly prohibited, is subject to restriction. Most restricted areas 

are designated joint use and IFR/VFR operations in the area may be authorized by the controlling ATC facility 

when it is not being utilized by the using agency. Permanent restricted areas are depicted on Sectional 

Aeronautical, VFR Terminal Area, and applicable En Route charts. Where joint use is authorized, the name of 

the ATC controlling facility is also shown. 

Note: Temporary restricted areas are not charted. 
(Refer to 14 CFR Part 73.) 
(Refer to AIM.) 

g. 

Warning Area

−

 A warning area is airspace of defined dimensions extending from 3 nautical miles outward 

from the coast of the United States, that contains activity that may be hazardous to nonparticipating aircraft. The 

purpose of such warning area is to warn nonparticipating pilots of the potential danger. A warning area may be 

located over domestic or international waters or both. 
SPECIAL VFR CONDITIONS

−

 Meteorological conditions that are less than those required for basic VFR flight 

in Class B, C, D, or E surface areas and in which some aircraft are permitted flight under visual flight rules. 

(See SPECIAL VFR OPERATIONS.) 
(Refer to 14 CFR Part 91.) 

SPECIAL VFR FLIGHT [ICAO]

−

 A VFR flight cleared by air traffic control to operate within Class B, C, D, 

and E surface areas in meteorological conditions below VMC. 
SPECIAL VFR OPERATIONS

−

 Aircraft operating in accordance with clearances within Class B, C, D, and E 

surface areas in weather conditions less than the basic VFR weather minima. Such operations must be requested 

by the pilot and approved by ATC. 

(See SPECIAL VFR CONDITIONS.) 
(See ICAO term SPECIAL VFR FLIGHT.) 

SPECIALIST

−

PROVIDED SERVICES– 

Services delivered directly by a flight service specialist via ground/ground communication, air/ground 

communication, in

−

person, or technology (for example, speech

−

to

−

text, email, or short message service). 

SPEED

−

 

(See AIRSPEED.) 
(See GROUND SPEED.) 

SPEED ADJUSTMENT

−

 An ATC procedure used to request pilots to adjust aircraft speed to a specific value 

for the purpose of providing desired spacing. Pilots are expected to maintain a speed of plus or minus 10 knots 

or 0.02 Mach number of the specified speed. Examples of speed adjustments are: 

PCG S

−

8