Mach the ratio between the speed of an aircraft and the speed of sound. For example, an aircraft flying at Mach 2 would be traveling at two times the speed of sound.
marshaller a taxiway crew member who uses bats or batons to direct aircraft ground traffic.
marshalling ground crew signaling with batons to direct aircraft ground traffic.
Mayday the international distress call.
microwave landing system a radio landing aid guiding aircraft to a runway from several directions by a microwave beam.
payload cargo, baggage, and passengers.
pitching the nose of an airplane forced up or down by wind.
port light the red light situated on the left side of aircraft, an identification and anticollision aid. See starboard light.
pressurize in an aircraft compartment, to create an air pressure higher than the low atmospheric pressure found at high altitudes.
prop wash the powerful air current driven behind an aircraft by its propellers; also known as the slipstream.
red-eye an overnight or late-night flight.
rib one of the fore-and-aft supporting members in a wing.
roll to roll left or right; also an acrobatic maneuver in which the craft is rotated completely around while maintaining course.
roll-out the distance an aircraft requires to come to a safe stop after touchdown.
rudder the hinged surface on the tail that is used to turn the airplane left or right.
slipstream the airstream behind the propeller.
sonic boom the explosion heard when an aircraft breaks the speed of sound.
sortie an aircraft sent out on a single military mission.
spin an out-of-control, rotating descent, evolving from a stall.
spinner the spinning, cone-shaped covering over the propeller hub.
spiral a tight, descending turn or series of turns.
spoiler one of the special flaps raised on the wings to "spoil" lift by disrupting airflow, used to slow an aircraft or greatly increase the rate of descent.
stabilizer a fixed horizontal surface on the tail to which the elevator is attached, providing longitudinal stability.
stack when landings are delayed, two or more aircraft circling one above the other at 1,000-foot intervals awaiting approach clearance.
stall the loss of lift when airspeed is too slow, resulting in the nose pitching down and the plane fluttering like a falling leaf.
standing waves the currents of air created by a strong wind blowing over a mountain, hazardous to aircraft.
starboard light the green light situated on the right side of aircraft, an identification and anticollision aid.
strobes the bright, white flashing lights situated on the wingtips as an anticollision aid.
supersonic faster than the speed of sound.
TACAN tactical air navigation system; an electronic navigational aid used principally by the military.
taxi to maneuver an airplane on the ground.
TCAS traffic alert and collision avoidance system; an onboard, radar-based collision alerting system.
thermal a rising column of warm air, adding lift to light aircraft.
thrust the force of the engines that propel the craft forward.
three-point landing a perfect landing.
torque the left-turning twisting motion of an aircraft caused by the right-turning propeller, compensated by special rigging automatically, but corrected only manually in some aircraft above cruise speed.
turboprop a turbojet engine connected with a propeller.
turbulence disturbed air.
VTOL vertical takeoff and landing aircraft; any aircraft, such as a helicopter, with the capability of lifting straight up into the air.
wind shear a rapid change of wind direction or speed affecting airflow over the wings, extremely hazardous to aircraft low to the ground.
Aircraft
Balloons
aeronaut balloon pilot or passenger.
aerostation the art of operating a lighter-than-air craft.
altimeter device that measures the altitude of an aircraft by sensing differences in air pressure.
anemometer device that measures wind speed.
apex the top of a balloon.
apex rope rope attached to the top of the balloon used during inflation to control the balloons movement; also known as a crown line.
appendix sleeve at the bottom of a balloon where the balloon is filled and through which expanding gas escapes.
attitude the balloon's position relative to the horizon.
ballast disposable weight, usually in the form of sandbags, used to maintain altitude or to slow a descent.
balloonmeister authority responsible for the safe operation of ground-based balloon activities.
basket the basket that carries the aeronauts, controls, and fuel; also known as a gondola.
blast-off high-speed liftoff used in windy conditions.
blast valve high-pressure fuel valve.
blimp an airship.
burner unit that burns propane gas to heat the envelope of the balloon.
ceiling distance between the ground and cloud cover.
chase crew crew members who assist in the launch and chase the balloon in flight to aid in its landing.
deflation port panel of the upper envelope that detaches to allow hot air to escape to aid in deflation.
dirigible a powered balloon with directional controls.
envelope interior balloon fabric that contains the hot air.
equator area of the balloon's greatest girth. gondola see basket.
gore length of balloon fabric tapering at the end to form sections when sewn to other gores.
helium nonflammable lighter-than-air gas.
hydrogen flammable lighter-than-air gas.
mouth the opening at the base of a balloon.
pyrometer instrument that displays the temperature of the hot air near the top of the balloon.
redline temperature the hottest temperature a balloon fabric can withstand without damage.
rip line a line that is pulled to open the deflation port.
sink rate of descent.
sparker device for igniting the burner's pilot light.
telltale heat-sensitive material near the top of a balloon providing a warning of dangerously high temperatures.
tether anchor line.
thermal rising column of warm air.
variometer device that measures vertical airspeed or the rate of climb or descent.
Blimps
ballast bags 50-pound bags hung from a ring encircling the car to help maintain proper weight when loads are light.
ballonets fitted within the large gas bag, two smaller bags that are filled with air to add weight or emptied of air to subtract weight.
bite the volume of air propeller moves, according to the propeller's pitch and speed.