PHAK Glossary: L

See local area augmentation system.

The delay that occurs before an instrument needle attains a stable indication.

A coastal breeze flowing from land to sea caused by temperature differences when the sea surface is warmer than the adjacent land. The land breeze usually occurs at night and alternates with the sea breeze that blows in the opposite direction by day.

Land without delay at the nearest suitable area, such as an open field, at which a safe approach and landing is assured.

The landing site and duration of flight are at the discretion of the pilot. Extended flight beyond the nearest approved landing area is not recommended.

The urgency of the landing is paramount. The primary consideration is to ensure the survival of the occupants. Landing in trees, water, or other unsafe areas should be considered only as a last resort.

An imaginary line passing through the center of gravity of an airplane and extending across the airplane from wingtip to wingtip.

The stability about the longitudinal axis of an aircraft. Rolling stability or the ability of an airplane to return to level flight due to a disturbance that causes one of the wings to drop.

Measurement north or south of the equator in degrees, minutes, and seconds. Lines of latitude are also referred to as parallels.

See localizer-type directional aid.

The radial at which the turn from the DME arc to the inbound course is started.

The part of an airfoil that meets the airflow first.

High lift devices which are found on the leading edge of the airfoil. The most common types are fixed slots, movable slats, and leading edge flaps.

A portion of the leading edge of an airplane wing that folds downward to increase the camber, lift, and drag of the wing. The leading-edge flaps are extended for takeoffs and landings to increase the amount of aerodynamic lift that is produced at any given airspeed.

A physical sensation caused by an abrupt correction of a banked attitude entered too slowly to stimulate the motion sensing system in the inner ear. The abrupt correction can create the illusion of banking in the opposite direction.

The empty weight that consists of the airframe, engine(s), unusable fuel, and undrainable oil plus standard and optional equipment as specified in the equipment list. Some manufacturers used this term prior to GAMA standardization.

A component of the total aerodynamic force on an airfoil and acts perpendicular to the relative wind.

Amount of stress, or load factor, that an aircraft can withstand before structural damage or failure occurs.

Invisible lines of magnetic force passing between the poles of a magnet.

See low or medium frequency.

See locator middle marker.

The ratio of a specified load to the total weight of the aircraft. The specified load is expressed in terms of any of the following: aerodynamic forces, inertial forces, or ground or water reactions.

A type of ammeter installed between the generator output and the main bus in an aircraft electrical system.

See localizer.

A differential global positioning system (DGPS) that improves the accuracy of the system by determining position error from the GPS satellites, then transmitting the error, or corrective factors, to the airborne GPS receiver.

The portion of an ILS that gives left/right guidance information down the centerline of the instrument runway for final approach.

A NAVAID used for nonprecision instrument approaches with utility and accuracy comparable to a localizer but which is not a part of a complete ILS and is not aligned with the runway. Some LDAs are equipped with a glideslope.

Nondirectional radio beacon (NDB) compass locator, collocated with a middle marker (MM).

NDB compass locator, collocated with an outer marker (OM).

See locator outer marker.

Measurement east or west of the Prime Meridian in degrees, minutes, and seconds. The Prime Meridian is 0° longitude and runs through Greenwich, England. Lines of longitude are also referred to as meridians.

An imaginary line through an aircraft from nose to tail, passing through its center of gravity. The longitudinal axis is also called the roll axis of the aircraft. Movement of the ailerons rotates an airplane about its longitudinal axis.

Stability about the lateral axis. A desirable characteristic of an airplane whereby it tends to return to its trimmed angle of attack after displacement.

A frequency range between 190 and 535 kHz with the medium frequency above 300 kHz. Generally associated with nondirectional beacons transmitting a continuous carrier with either a 400 or 1,020 Hz modulation.

The reference line used in a magnetic compass or heading indicator.