Glossary

Load factor. The ratio of a specified load to the total weight Low or medium frequency. A frequency range between of the aircraft. The specified load is expressed in terms of 190 and 535 kHz with the medium frequency above 300 any of the following: aerodynamic forces, inertial forces, or kHz. Generally associated with nondirectional beacons ground or water reactions. transmitting a continuous carrier with either a 400 or 1,020 Hz modulation. Loadmeter. A type of ammeter installed between the generator output and the main bus in an aircraft electrical system. Lubber line. The reference line used in a magnetic compass or heading indicator. LOC. See localizer. M Local area augmentation system (LAAS). A differential MAA. See maximum authorized altitude. global positioning system (DGPS) that improves the accuracy of the system by determining position error from the GPS MAC. See mean aerodynamic chord. satellites, then transmitting the error, or corrective factors, to the airborne GPS receiver. Mach number. The ratio of the true airspeed of the aircraft to the speed of sound in the same atmospheric conditions, Localizer (LOC). The portion of an ILS that gives left/right named in honor of Ernst Mach, late 19th century physicist. guidance information down the centerline of the instrument runway for final approach. Mach meter. The instrument that displays the ratio of the speed of sound to the true airspeed an aircraft is flying. Localizer-type directional aid (LDA). A NAVAID used for nonprecision instrument approaches with utility and Magnetic bearing (MB). The direction to or from a radio accuracy comparable to a localizer but which is not a part transmitting station measured relative to magnetic north. of a complete ILS and is not aligned with the runway. Some LDAs are equipped with a glideslope. Magnetic compass. A device for determining direction measured from magnetic north. Locator middle marker (LMM). Nondirectional radio beacon (NDB) compass locator, collocated with a middle Magnetic dip. A vertical attraction between a compass marker (MM). needle and the magnetic poles. The closer the aircraft is to a pole, the more severe the effect. Locator outer marker (LOM). NDB compass locator, collocated with an outer marker (OM). Magnetic heading (MH). The direction an aircraft is pointed with respect to magnetic north. LOM. See locator outer marker. Magneto. A self-contained, engine-driven unit that supplies Longitude. Measurement east or west of the Prime Meridian electrical current to the spark plugs; completely independent in degrees, minutes, and seconds. The Prime Meridian is 0° of the airplane’s electrical system. Normally there are two longitude and runs through Greenwich, England. Lines of magnetos per engine. longitude are also referred to as meridians. Magnus effect. Lifting force produced when a rotating Longitudinal axis. An imaginary line through an aircraft cylinder produces a pressure differential. This is the same from nose to tail, passing through its center of gravity. The effect that makes a baseball curve or a golf ball slice. longitudinal axis is also called the roll axis of the aircraft. Movement of the ailerons rotates an airplane about its Mandatory altitude. An altitude depicted on an instrument longitudinal axis. approach chart with the altitude value both underscored and overscored. Aircraft are required to maintain altitude at the Longitudinal stability (pitching). Stability about the lateral depicted value. axis. A desirable characteristic of an airplane whereby it tends to return to its trimmed angle of attack after displacement. Mandatory block altitude. An altitude depicted on an instrument approach chart with two underscored and overscored altitude values between which aircraft are required to maintain altitude. G-18