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Pilot/Controller Glossary

3/29/18

PCG O−1

O

OBSTACLE− An existing object, object of natural

growth, or terrain at a fixed geographical location or

which may be expected at a fixed location within a

prescribed area with reference to which vertical

clearance is or must be provided during flight

operation.

OBSTACLE DEPARTURE PROCEDURE (ODP)−

A preplanned instrument flight rule (IFR) departure

procedure printed for pilot use in textual or graphic

form to provide obstruction clearance via the least

onerous route from the terminal area to the

appropriate en route structure. ODPs are recom-

mended for obstruction clearance and may be flown

without ATC clearance unless an alternate departure

procedure (SID or radar vector) has been specifically

assigned by ATC.

(See IFR TAKEOFF MINIMUMS AND

DEPARTURE PROCEDURES.)

(See STANDARD INSTRUMENT

DEPARTURES.)

(Refer to AIM.)

OBSTACLE FREE ZONE− The  OFZ  is a

three−dimensional volume of airspace which protects

for the transition of aircraft to and from the runway.

The OFZ clearing standard precludes taxiing and

parked airplanes and object penetrations, except for

frangible NAVAID locations that are fixed by

function. Additionally, vehicles, equipment, and

personnel may be authorized by air traffic control to

enter the area using the provisions of FAA Order

JO 7110.65, Paragraph 3−1−5Vehicles/Equipment/

Personnal Near/On Runways. The runway OFZ and

when applicable, the inner-approach OFZ, and the

inner-transitional OFZ, comprise the OFZ.

a. Runway OFZ. The runway OFZ is a defined

volume of airspace centered above the runway. The

runway OFZ is the airspace above a surface whose

elevation at any point is the same as the elevation of

the nearest point on the runway centerline. The

runway OFZ extends 200 feet beyond each end of the

runway. The width is as follows:

1. For runways serving large airplanes, the

greater of:

(a) 400 feet, or

(b) 180 feet, plus the wingspan of the most

demanding airplane, plus 20 feet per 1,000 feet of

airport elevation.

2. For runways serving only small airplanes:

(a) 300 feet for precision instrument run-

ways.

(b) 250 feet for other runways serving small

airplanes with approach speeds of 50 knots, or more.

(c) 120 feet for other runways serving small

airplanes with approach speeds of less than 50 knots.

b. Inner-approach OFZ. The inner-approach OFZ

is a defined volume of airspace centered on the

approach area. The inner-approach OFZ applies only

to runways with an approach lighting system. The

inner-approach OFZ begins 200 feet from the runway

threshold at the same elevation as the runway

threshold and extends 200 feet beyond the last light

unit in the approach lighting system. The width of the

inner-approach OFZ is the same as the runway OFZ

and rises at a slope of 50 (horizontal) to 1 (vertical)

from the beginning.

c. Inner-transitional OFZ. The inner transitional

surface OFZ is a defined volume of airspace along the

sides of the runway and inner-approach OFZ and

applies only to precision instrument runways. The

inner-transitional surface OFZ slopes 3 (horizontal)

to 1 (vertical) out from the edges of the runway OFZ

and inner-approach OFZ to a height of 150 feet above

the established airport elevation.

(Refer to AC 150/5300-13, Chapter 3.)
(Refer to FAA Order JO 7110.65, Para 3−1−5,

Vehicles/Equipment/Personnel Near/On

Runways.)

OBSTRUCTION− Any object/obstacle exceeding

the obstruction standards specified by 14 CFR

Part 77, Subpart C.
OBSTRUCTION LIGHT− A light or one of a group

of lights, usually red or white, frequently mounted on

a surface structure or natural terrain to warn pilots of

the presence of an obstruction.
OCEANIC AIRSPACE− Airspace over the oceans of

the world, considered international airspace, where

oceanic separation and procedures per the Interna-

tional Civil Aviation Organization are applied.

Responsibility for the provisions of air traffic control