background image

6/17/21 

Pilot/Controller Glossary 

centerlines are separated by less than 3,000 feet and 
at least 750 feet. NTZ monitoring is required to 
conduct these approaches. 

(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.) 

LOST LINK (LL)

 An interruption or loss of the 

control link, or when the pilot is unable to effect 
control of the aircraft and, as a result, the UA will 
perform a predictable or planned maneuver.  Loss of 
command and control link between the Control 
Station and the aircraft.  There are two types of links: 

a. 

An uplink which transmits command instruc-

tions to the aircraft, and 

b. 

A downlink which transmits the status of the 

aircraft and provides situational awareness to the 
pilot. 

LOST LINK PROCEDURE

 Preprogrammed or 

predetermined mitigations to ensure the continued 
safe operation of the UA in the event of a lost link 
(LL). In the event positive link cannot be established, 
flight termination must be implemented. 

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 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 (LF)

 The frequency band 

between 30 and 300 kHz. 

(Refer to AIM.) 

LOCALIZER PERFORMANCE WITH VERTI-
CAL GUIDANCE (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.) 

PCG L