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Pilot/Controller Glossary

3/29/18

PCG O

−1

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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