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. 

(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.) 

