4/20/23 

Pilot/Controller Glossary 

OPEN LOOP CLEARANCE

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 Provides a lateral vector solution that does not include a return to route point. 

OPERATIONAL

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(See DUE REGARD.) 

OPERATIONS OVER PEOPLE (OOP)

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 Operations of small unmanned aircraft over people. 

(Refer to 14 CFR Part 107) 

OPERATIONS SPECIFICATIONS [ICAO]

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 The authorizations, conditions and limitations associated with the 

air operator certificate and subject to the conditions in the operations manual. 
OPERATOR (UAS)

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 The owner and/or remote pilot of a UAS. 

OPPOSITE DIRECTION AIRCRAFT

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 Aircraft are operating in opposite directions when: 

a. 

They are following the same track in reciprocal directions; or 

b. 

Their tracks are parallel and the aircraft are flying in reciprocal directions; or 

c. 

Their tracks intersect at an angle of more than 135

. 

OPTION APPROACH

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An approach requested and conducted by a pilot which will result in either a 

touch-and-go, missed approach, low approach, stop-and-go, or full stop landing. Pilots should advise ATC if 

they decide to remain on the runway, of any delay in their stop and go, delay clearing the runway, or are unable 

to comply with the instruction(s). 

(See CLEARED FOR THE OPTION.) 
(Refer to AIM.) 

ORGANIZED TRACK SYSTEM

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 A series of ATS routes which are fixed and charted; i.e., CEP, NOPAC, or 

flexible and described by NOTAM; i.e., NAT TRACK MESSAGE. 
OTR

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(See OCEANIC TRANSITION ROUTE.) 

OTS

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(See ORGANIZED TRACK SYSTEM.) 

OUT

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The conversation is ended and no response is expected. 

OUT OF SERVICE/UNSERVICEABLE (U/S)

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 When a piece of equipment, a NAVAID, a facility or a service 

is not operational, certified (if required) and immediately “available” for Air Traffic or public use. 
OUTER AREA (associated with Class C airspace)

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 Non

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regulatory airspace surrounding designated Class C 

airspace airports wherein ATC provides radar vectoring and sequencing on a full-time basis for all IFR and 

participating VFR aircraft. The service provided in the outer area is called Class C service which includes: 

IFR/IFR

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IFR separation; IFR/VFR

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traffic advisories and conflict resolution; and VFR/VFR

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traffic advisories 

and, as appropriate, safety alerts. The normal radius will be 20 nautical miles with some variations based on 

site-specific requirements. The outer area extends outward from the primary Class C airspace airport and extends 

from the lower limits of radar/radio coverage up to the ceiling of the approach control’s delegated airspace 

excluding the Class C charted area and other airspace as appropriate. 

(See CONFLICT RESOLUTION.) 
(See CONTROLLED AIRSPACE.) 

OUTER COMPASS LOCATOR

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(See COMPASS LOCATOR.) 

OUTER FIX

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 A general term used within ATC to describe fixes in the terminal area, other than the final approach 

fix. Aircraft are normally cleared to these fixes by an Air Route Traffic Control Center or an Approach Control 

Facility. Aircraft are normally cleared from these fixes to the final approach fix or final approach course. 

OR 

PCG O

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