There are three different ways of expressing the SPEED of an aircraft such as the P-3 Orion: Indicated Airspeed (IAS or KIAS). This is the indication given on the aircraft “Airspeed Indicator.” It becomes less accurate the higher you go and the warmer the air temperature. Speed is usually expressed in knots (K).
True Airspeed (TAS). This is the indicated airspeed corrected for altitude, barometric pressure and temperature. TAS is usually higher than IAS.
Ground Speed (GS). The speed the aircraft is making over the ground. If, for example, an airplane is flying at 200 knots TAS into a 50 knot headwind, the GS would be150 knots.
Yes, for the technical nitpickers, there is a fourth way of expressing speed: Mach Number. A typical cruise speed for a Boeing 747 would be Mach 0.84 - or 84% the speed of sound.
There are several ways of expressing ALTITUDE: MSL (Mean Sea Level) As the name implies, this is altitude above sea level and is adjusted for local barometric pressure by a little knob on the Altimeter.
AGL (Above Ground Level) How high the airplane is actually above the ground below. This can be measured only by a radar altimeter.
FL (Flight Level) This is just a handy way to knock off the last two zeros. FL220 would mean 22,000 feet MSL. When FL is used, the altimeter is set to a standard barometric pressure of 29.92” or 1013 Millibars (Hectopascals).
There is one more instrument associated with the above group: VSI (Vertical Speed Indicator). This tells the pilot how fast he is going up or down in thousands-of-feet per minute.
FLIGHT CONTROLS
Airplanes have three active flight control systems: AILERONS (roll), ELEVATORS (pitch) and RUDDER (yaw).
Turning is accomplished (mostly) by the ailerons “rolling” the aircraft left (port) or right (starboard). The rudder is just for “coordinating” (cleaning up) the turn. Note: Left and Right in an aircraft is ALWAYS the pilot’s left and right.
The elevators raise or lower the attitude of the aircraft nose up or nose down. This affects both climb/descent and speed.
The controls of an airplane are completely and utterly UNLIKE a car. The three flight controls and the throttles (engine power) work together (hopefully in concert) to control the aircraft attitude and “flight envelope.”
TRIM (or Trim Tabs) are small devices found on the flight control surfaces used to set a “bias.” Up or down, left or right, whatever is needed to zero the pilot’s pressure on the controls. They just make flying physically easier.
Most large aircraft have RADAR. It is mostly used for weather mapping, although military aircraft may use it in “search” mode. The radar antenna is usually located in the aircraft nose and must be protected (and streamlined) by a cover called a “Radome.” The radome is made of fiberglass and must be protected by a coat of radar transparent paint. This paint used to always be black (neoprene), but now you can get it an any color.
RADIOS: There are basically three types of aircraft radios: HF (High Frequency), VHF (Very High Frequency) and UHF (Ultra High Frequency). HF is needed for very long range communications.
ENGINES: On multi-engine aircraft, engines are numbered from left to right. Number One Engine would be the leftmost.
FOD (Foreign Object Damage) Jet engines do not like to ingest nuts, bolts and birds. Turboprops are jet engines connected through a gearbox to a propeller.
PITOT/STATIC System: The Airspeed, Altitude and VSI indicators need a sample of the dynamic and static wind pressures on the aircraft in order to provide proper readings. This is accomplished by a “Pitot Tube” and “Static Port” mounted on the outside of the aircraft. The pilot’s and co-pilots instruments are independently given these air pressure samples by separate systems. Unfortunately, on the P-3, the pitot tubes are mounted fairly close together - therefore were subject to simultaneous damage by the Chinese fighter.
SNAP ROLL: the immediate application of FULL aileron (either left or right) that results in a very rapid roll.
WINDMILLING: If an engine must be shut down (on a multi-engine prop aircraft), the propeller blades are turned into the wind (feathered) so the prop will not rotate and cause drag. If the engine is shut down and the prop can not be feathered, the prop will spin and act like a dragging brake. If a propeller is badly damaged (as was the case with the P-3), not only does the offending prop cause drag, but serious vibration as well.
More US P3 Orion Meets PRC F-8
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© Copyright 2001 by David W. Tschanz.
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