Pilot/Controller Glossary

OFF-ROUTE OBSTRUCTION CLEARANCE ALTITUDE (OROCA)- An off-route altitude which
provides obstruction clearance with a 1,000 foot
buffer in non-mountainous terrain areas and a 2,000
foot buffer in designated mountainous areas within
the United States. This altitude may not provide
signal coverage from ground-based navigational
aids, air traffic control radar, or communications
coverage.
OTR-
(See OCEANIC TRANSITION ROUTE.)

OTS-
(See ORGANIZED TRACK SYSTEM.)

OUT- The conversation is ended and no response is
expected.
OUT OF SERVICE- When a piece of equipment, a
system, 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)-
Non-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-IFR separation; IFR/
VFR-traffic advisories and conflict resolution; and
VFR/VFR-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 arend other airspace
as appropriate.
(See CONFLICT RESOLUTION.)
(See CONTROLLED AIRSPACE.)

OUTER COMPASS LOCATOR-
(See COMPASS LOCATOR.)

OUTER FIX- 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
OUTER FIX- An adapted fix along the converted
route of flight, prior to the meter fix, for which
crossing times are calculated and displayed in the
metering position list.
OUTER FIX ARC- A semicircle, usually about a
50-70 mile radius from a meter fix, usually in high
altitude, which is used by CTAS/ERAM to calculate
outer fix times and determine appropriate sector
meter list assignments for aircraft on an established
arrival route that will traverse the arc.
OUTER FIX TIME- A calculated time to depart the
outer fix in order to cross the vertex at the ACLT. The
time reflects descent speed adjustments and any
applicable delay time that must be absorbed prior to
crossing the meter fix.
OUTER MARKER- A marker beacon at or near the
glideslope intercept altitude of an ILS approach. It is
keyed to transmit two dashes per second on a 400 Hz
tone, which is received aurally and visually by
compatible airborne equipment. The OM is normally
located four to seven miles from the runway threshold
on the extended centerline of the runway.
(See INSTRUMENT LANDING SYSTEM.)
(See MARKER BEACON.)
(Refer to AIM.)

OVER- My transmission is ended; I expect a
response.
OVERHEAD MANEUVER- A series of predetermined maneuvers prescribed for aircraft (often in
formation) for entry into the visual flight rules (VFR)
traffic pattern and to proceed to a landing. An
overhead maneuver is not an instrument flight rules
(IFR) approach procedure. An aircraft executing an
overhead maneuver is considered VFR and the IFR
flight plan is canceled when the aircraft reaches the
"initial point" on the initial approach portion of the
maneuver. The pattern usually specifies the
following:
a. The radio contact required of the pilot.
b. The speed to be maintained.
c. An initial approach 3 to 5 miles in length.
d. An elliptical pattern consisting of two 180
degree turns.
e. A break point at which the first 180 degree turn
is started.
f. The direction of turns.