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Glossary of Terms

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Advancing Blade - The blade on the side of the rotor disc going in the same direction as the helicopter.
Agusta A109 Helicopter G-USTHAgusta 109 - A109 twin turbine engine helicopter manufactured by Agusta. One of the fastest civilian helicopters.

"This particular aircraft ( G-USTH ) was one of a number of helicopters that descended on Southport during the Open Golf tournament held at Royal Birkdale in July 2008."
Airspeed - This is the speed the aircraft is moving through the air. If the aircraft is flying into wind, this would typically be faster than the apparent ground speed.
Airworthiness Check - Every time an aircraft is to be flown, the pilot should make exterior and interior checks to ensure no damage has been sustained on previous flights, and that the aircraft will be able to complete its mission. See also Checklist
Autorotation - Flight without engine power, where the air approaching from below the rotor disc keeps the rotor up to operational speed.
Anti-Torque Pedals - The foot pedals used to control the pitch of the anti-torque or tail rotor of a single rotor helicopter. The anti-torque pedals allow the pilot to control movement of the helicopter about its vertical axis.
ATC - Air Traffic Control
Attitude - Position of aircraft relative to a frame of reference (e.g. the horizon, or direction of motion). Also see Pitch
Balance - When in forward flight, if the aircraft is suffering yaw, then it is said to be out of balance. The anti-torque pedals are used to keep the helicopter in balance.
Carb Heat - Carburettor heat is applied to prevent ice from forming in the carburettor, and starving the engine of fuel.
Circuit - Training circuits exist around many aerodromes. They are a useful exercise combining many aspects of regular flying. Each circuit consists of four stages or legs. After take-off, the aircraft will turn 90° onto the crosswind leg. Then downwind, tracking back parallel to the active runway. A further 90° takes the aircraft onto the base-leg where the descent can begin, and one more turn onto the final approach (or finals). See also Finals.
Checklist - Checklists are used for many aspects of flying - arguably the most useful are the airworthiness and startup/shutdown checklists, which detail the steps to carry out in order.
Collective - The control with simultaneously varies pitch on all the rotor blades by an equal amount.
Cylic - The control which changes pitch of the rotor blades during the cycle of rotation. The cyclic is used to control the tilt of the top path plane.
Dynamic Rollover - A condition where a lateral component of total rotor thrust causes the helicopter to roll about a main landing gear which is normally in light contact with the ground.
Finals - An aircraft approaching, and in proximity to a landing area, is said to be on final approach. Often, a radio call is necessary informing ATC or other ground radio of the position of the aircraft.
Flapback - The act of the rotor disc flapping away from the relative wind.
Flare - Pointing the nose of the aircraft up, often in order to lose speed.
FREDAST Checks - F - Fuel, R - Radio, E - Engine temperatures and pressures, D - Direction, A - Altimeter, S - Security, T - Trim/Transponder
Go Around - After commencing final approach, if for any reason the landing has to be aborted, the landing aircraft will "go around". This would normally mean just rejoining the circuit.
Ground Effect - A beneficial increase in rotor thrust due to slowing down the inflow through the rotor disc, caused by the proximity of the ground.
HASEL Checks - HASEL Checks are carried out prior to practice autorotations. H - Height, A - Area, S - Security, E - Engine temperatures and pressures (apply Carb. Heat), L - Look out
Hover Taxiing - Hovering, but moving the helicopter at a walking pace, in any particular direction.
Induced Flow - The mass of air forced down by rotor action. Most of the induced flow passes through the rotor disc.
Inflow Roll - The tendancy of the helicopter, as it moves forward through the air, to roll towards the advancing blade. The effect is most noticeable at low airspeed.
JetRanger - B206L single turbine engine helicopter manufactured by Bell Helicopter Textron. One of the most popular multi-use helicopters.
Longranger HelicopterLongRanger - B206L an elongated version of the JetRanger. The extra room provides space for two more seats.

"I hitched a ride in this one ( G-PWIT ) back in September 2008 near Gloucestershire."
Manifold Pressure (MAP) - The pressure in the piston engine which is a measure of the power of the engine.
Mast Bumping - Mast bumping is a phenomenon peculiar to two-bladed rotor systems, and occurs when the helicopter's main rotor hub is allowed to contact the main rotor mast. This causes rotor separation from the mast.
MATZ - Military Air Traffic Zone. (Sometimes CMATZ - Combined Military Air Traffic Zone where there are more than one MATZs connected together)
METAR - Aerodrome meteorological report are routine weather observations taken at many aerodromes every thirty minutes. The are text based messages following a standard format.
Pedals - See Anti-torque pedals
PFL - Practice Forced Landing - A training exercise designed to build necessary skills required for landing the aircraft as safely as possible in the event of engine failure. Including entry to autorotation , selection of a suitable landing area, communication of any information necessary in a Mayday radio message, and finally any vital actions that need to be performed, such as turning off fuel supply, electrical switches, etc.
Pitch - Movement about the lateral axis. Forward and backward movement of the cyclic control causes the nose of the helicopter to move down or up respectively, pivoting about the lateral axis.
Power Setting - See Manifold Pressure
Rate of Climb - Rate of climb refers to the speed at which an aircraft is climbing or descending through the air. It is often indicated on an instrument inside the cockpit.
Robinson R22 Helicopter G-CDBFRobinson R-22 - Two seater, single piston engined helicopter manufactured by the Robinson Helicopter Company.

"This helicopter is very popular for training purposes. I flew the R22 pictured ( G-CDBF ) in June 2008, I remember it had particularly decent Bose headsets!"
Roll - Angular movement about the helicopter's longitudinal axis.
Rotor Head - The head in the centre of the rotor system to which the rotor blades are affixed.
RPM - A helicopter has two RPM readings - Rotor RPM (RRPM) and engine RPM (ERPM). Under normal conditions, the R-22 should operate with both RPMs within 97%-104%. (The electronic governer will maintain this at 104% without input from the pilot). In autorotation, the rotor RPM should be maintained within 90%-110%
TAF - Text based weather forecast for aerodrome area covering the next few hours, in a specified international standard.
Temperature and Pressure (T&P) checks - Frequent checks of the engine guages are required to ensure the engine is operating within limits, and there are no unusual occurances.
Torque Effect - The reaction to the turning of the rotor system. If the rotor system turns anti-clockwise, the fuselage reacts by turning clockwise.
Transition - Transition from hover to forward flight and vice-versa.
Translational Lift - Additional lift obtained from increased airspeed, due to increased rotor efficiency.
AS355 Helicopter G-BPRLTwin Squirrel - AS355 twin turbine engine helicopter manufactured by Eurocopter Group.

"This Aerospatiale AS355F1 ( G-BPRL ) was parked on the Beach on the final day of the 2008 Golf open held at Royal Birkdale, Southport."
Vortex Ring - The flow condition existing on the main rotor in a vertical descent when the rate of descent is approximately equal to the induced velocity. Characteristics include: Airframe judder; stick shake; random yawing, pitching and rolling; rotor RPM and MAP variations; increasing rate of descent.
Yaw - Movement about the normal or vertical axis.

Copyright © James T Lowe 2001-02. Photos Copyright © 2018