Pilot/Controller Glossary

4/3/14

PCG L−3

Approaches (SOIA) to parallel runways whose

centerlines are separated by less than 3,000 feet and

at least 750 feet. NTZ monitoring is required to

conduct these approaches. When the approach course

spacing is less than 3,600 feet at the Missed Approach

Point (MAP), the use of a PRM or other high update

rate surveillance system in order to conduct

simultaneous independent approaches is required.

(See SIMULTANEOUS OFFSET INSTRUMENT

APPROACH (SOIA).)

(Refer to AIM)

LOCALIZER USABLE DISTANCE− The maxi-

mum distance from the localizer transmitter at a

specified altitude, as verified by flight inspection, at

which reliable course information is continuously

received.

(Refer to AIM.)

LOCATOR [ICAO]− An LM/MF NDB used as an aid

to final approach.

Note: A locator usually has an average radius of

rated coverage of between 18.5 and 46.3 km (10
and 25 NM).

LONG RANGE NAVIGATION−

(See LORAN.)

LONGITUDINAL SEPARATION− The longitudi-

nal spacing of aircraft at the same altitude by a

minimum distance expressed in units of time or

miles.

(See SEPARATION.)
(Refer to AIM.)

LORAN− An electronic navigational system by

which hyperbolic lines of position are determined by

measuring the difference in the time of reception of

synchronized pulse signals from two fixed transmit-

ters. Loran A operates in the 1750-1950 kHz

frequency band. Loran C and D operate in the

100-110 kHz frequency band. In 2010, the U.S. Coast

Guard terminated all U.S. LORAN-C transmissions.

(Refer to AIM.)

LOST COMMUNICATIONS− Loss of the ability to

communicate by radio. Aircraft are sometimes

referred to as NORDO (No Radio). Standard pilot

procedures are specified in 14 CFR Part 91. Radar

controllers issue procedures for pilots to follow in the

event of lost communications during a radar approach

when weather reports indicate that an aircraft will

likely encounter IFR weather conditions during the

approach.

(Refer to 14 CFR Part 91.)
(Refer to AIM.)

LOW ALTITUDE AIRWAY STRUCTURE− The

network of airways serving aircraft operations up to

but not including 18,000 feet MSL.

(See AIRWAY.)
(Refer to AIM.)

LOW ALTITUDE ALERT, CHECK YOUR ALTI-
TUDE IMMEDIATELY

−

(See SAFETY ALERT.)

LOW ALTITUDE ALERT SYSTEM− An auto-

mated function of the TPX-42 that alerts the

controller when a Mode C transponder equipped

aircraft on an IFR flight plan is below a

predetermined minimum safe altitude. If requested

by the pilot, Low Altitude Alert System monitoring

is also available to VFR Mode C transponder

equipped aircraft.
LOW APPROACH− An approach over an airport or

runway following an instrument approach or a VFR

approach including the go-around maneuver where

the pilot intentionally does not make contact with the

runway.

(Refer to AIM.)

LOW FREQUENCY− The frequency band between

30 and 300 kHz.

(Refer to AIM.)

LPV− A type of approach with vertical guidance

(APV) based on WAAS, published on RNAV (GPS)

approach charts. This procedure takes advantage of

the precise lateral guidance available from WAAS.

The minima is published as a decision altitude (DA).
LUAW−

(See LINE UP AND WAIT.)