FAA Aviation Mechanic - Airframe (AMA) key terms

The main longitudinal structural beam of a wing or tail surface; it carries bending loads from the skin and ribs and normally runs from root to tip.

A chordwise structural member inside a wing or tail surface that gives the airfoil its shape and transfers loads from the skin to the spar.

Longitudinal structural members of a fuselage that run fore and aft and carry bending loads, usually working together with frames, stringers, and skin.

A slender longitudinal stiffener riveted or bonded to the skin that carries axial loads and helps the skin resist bending and buckling.

A heavy transverse structural member in a fuselage that carries concentrated loads, such as those from a wing spar, landing gear, or engine mount.

A fuselage or wing construction in which the skin shares loads with a framework of stringers, frames, and bulkheads instead of carrying them alone.

A construction method in which the outer skin is thick enough to carry a major share of bending and shear loads, usually stiffened by stringers and frames.

The primary load-carrying structure of a wing, formed by the front and rear spars, the upper and lower skin panels, and the ribs between them.

A heat-resistant bulkhead of stainless steel or similar material that separates the engine compartment from the rest of the aircraft.

The upward angle of a wing measured from the horizontal; it contributes to lateral stability in roll.

A lightweight cellular core, usually aluminum or composite, bonded between facing sheets to form a stiff sandwich panel with a high strength-to-weight ratio.

Separation between bonded layers of a composite laminate, or between a core and its facing, often caused by impact or moisture and found by tap testing or ultrasonic inspection.

Corrosion produced when two dissimilar metals are joined in the presence of an electrolyte, causing the less noble metal to deteriorate.

A threaded barrel-and-terminal fitting used to adjust and hold tension in aircraft control cables, secured after adjustment with safety wire or special clips.

A pivoted lever that changes the direction of motion and force within a flight control or other mechanical linkage.

A small hinged surface on a primary control surface that is adjusted to hold the aircraft in a desired attitude without continuous control pressure.

A shock-absorbing landing gear leg in which a piston compresses nitrogen gas and forces hydraulic fluid through an orifice to cushion landing loads.

Hinged arms connecting the upper and lower sections of a shock strut that keep the wheel aligned and transmit braking and steering torque.

A friction or hydraulic device on a nose or tail wheel assembly that resists rapid side-to-side oscillation of the wheel during ground operation.

A pressure vessel with a trapped nitrogen charge that stores hydraulic energy, dampens pressure surges, and provides a reserve for emergency operation.

A hand- or electrically-operated hydraulic valve that directs pressurized fluid to the extend or retract side of an actuating cylinder.

A tank that holds hydraulic fluid and provides room for expansion, lets air separate from the fluid, and supplies the pump by gravity feed.

A valve on a pressurized aircraft that regulates how fast cabin air escapes overboard, thereby controlling cabin pressure and the rate of pressure change.

The plumbing that supplies impact pressure from the pitot tube and static pressure from flush ports to the airspeed indicator, altimeter, and vertical speed indicator.

A flush opening on the aircraft skin that senses undisturbed outside atmospheric pressure for the altimeter, airspeed indicator, and vertical speed indicator.

An inflatable rubber strip on a wing or tail leading edge that breaks up accumulated ice by alternately inflating and deflating.

A wheel-speed sensing system that momentarily releases brake pressure to keep a tire from skidding during heavy or low-friction braking.

A mandatory FAA regulation issued when an unsafe condition exists in a product; it must be complied with and the action recorded within the stated time.

A manufacturer's notice recommending an inspection, modification, or repair; it is not mandatory by itself unless the FAA adopts it through an airworthiness directive.

A complete inspection of an aircraft and its components required at least every 12 calendar months, performed by an FAA-certificated mechanic holding inspection authorization.

An inspection of the same scope as an annual inspection, required for aircraft operated for hire or in flight instruction, and due every 100 hours of time in service.

An FAA-approved program that divides the inspection workload into smaller segments performed at scheduled intervals, used in place of the annual inspection.

The form used to describe and record a major repair or major alteration, and to obtain FAA approval before the aircraft is returned to service.

The certification by an authorized person, usually through a maintenance record entry, that required work has been completed and the aircraft is airworthy.

The computation and control of an aircraft's empty weight, center of gravity, and loading limits so the CG stays within the approved operating range.

A nondestructive method that induces electrical currents in a conductive part and reads resulting field changes to find cracks, corrosion, and thickness variation.

A nondestructive method for ferromagnetic parts in which magnetized leakage fields at a defect attract iron particles, making surface and near-surface cracks visible.

A nondestructive method that draws a colored or fluorescent liquid out of surface-breaking defects in nonporous materials so they can be seen under visible or ultraviolet light.

A scheduled set of inspections and treatments, often required by the manufacturer or the FAA, that targets known corrosion-prone areas of a specific aircraft model.