Pilots, Ratings, and other basic stuff

ATP     Airline Transport Pilot (the "highest" grade of pilot certificate)
AME	Aviation Medical Examiner (U.S.)
FAR     Federal Aviation Regulations (U.S.)
CFI     Certificated Flight Instructor (see suffixes, below)
COM     Commercial (pilot certificate) (see suffixes, below)
IFR     Instrument Flight Rules (see below)
PP      Private Pilot
PVT     Private (pilot certificate) (see suffixes, below)
VFR     Visual Flight Rules (see below)

        Pilot and instructor certificates may be suffixed with certain
        combinations of the following:
        A  Airplane     ME  Multi-Engine        L  Land         I Instrument
        G  Glider       SE  Single-Engine       S  Sea
        H  Helicopter
        For example, the typical private pilot is "PP-ASEL" or "PVT-ASEL".
        Ratings are more complex than this limited explanation -- for
        example, Rotorcraft come in two flavors, Helicopter and Gyroplane;
        Lighter-than-Air aircraft come in two flavors, Free Balloon and
        Airship; and there are specific type ratings for aircraft over 12,500
        pounds.  One can spend several lifetimes accumulating ratings.

        A pilot who does not hold an instrument rating must fly under VFR,
        which specify minimum cloud clearance and visibility requirements.
        In some countries other than the U.S., VFR flight at night is not
        permitted.  Pilots who fly under VFR do so by looking out the
        window.  Flight through clouds is permitted only under IFR, which
        requires an instrument rating and an appropriately-equipped
        aircraft.  Instrument-rated pilots may control the aircraft solely by
        reference to instruments, but if they are flying in VMC, they are
        expected to look out the window to avoid other aircraft.

Navigation, Instruments, and Avionics

ADF     Automatic Direction Finder - an instrument in an airplane which
        displays the relative bearing to an NDB (see below) -- it
        essentially "points at the NDB"
AI      Attitude Indicator (also known as AH - Artificial Horizon) - an
        instrument which provides the pilot with pitch and roll information
ASR     Airport Surveillance Radar (usually, a type of instrument approach
        which provides only horizontal guidance to the pilot)
CDI     Course Deviation Indicator - part of a VOR navigation system, which
        shows how far off a desired course the aircraft is
DG      Directional Gyro - a compass-like device which uses a gyroscope to
        provide stable directional information for a pilot
DME     Distance Measuring Equipment
EFIS    Electronic Flight Instrumentation System
ELT     Emergency Locator Transmitter
GCA     Ground-Controlled (instrument) Approach (uses radar, see ASR and PAR)
GPS     Global Positioning System - a satellite-based navigation system,
        just coming up now
GS      Glideslope - the vertical guidance component of an ILS
HSI     Horizontal Situation Indicator - combines the functions of a VOR
        and a DG
IAC	International Aerobatic Club, see
	http://acro.harvard.edu/IAC/iac_homepg.html
IFF     Identify Friend or Foe -- see transponder
ILS     Instrument Landing System - a system which allows appropriately
        equipped aircraft to find a runway and land, when the clouds may
        be as low as 200 feet (or lower for special circumstances)
INS     Inertial Navigation System
IRS     Inertial Reference System
LOC     Localizer - the horizontal guidance component of an ILS
LORAN   Long RANge Navigation -- a navigation system, originally for marine
        use, which utilizes timing differences between multiple
        low-frequency transmissions to provide accurate latitude/longitude
        position information, at best to within 50 feet
MLS     Microwave Landing System - not in use yet, but it's getting warmer...
Mode-A  A transponder which does not give the controllers altitude information
Mode-C  A transponder and encoding altimeter which together give air
        traffic controllers altitude information
Mode-S  A new "flavor" of transponder which features unique identification
        per unit, the potential for low-speed up and down datalinks, and
        "selective interrogation" triggered by ground facilities
NDB     Non-Directional Beacon - an older type of electronic navigation
        aid, basically a low-power AM radio station
OBS     Omnibearing Selector - part of a VOR receiver system, which allows
        the pilot to select a course to or from a VOR station
PAR     Precision Approach Radar - a ground-radar based instrument approach
        which provides both horizontal and vertical guidance
RMI     Radio Magnetic Indicator - an ADF-like display with a pair of
        pointers which might be attached to either VOR or ADF receivers
RNAV    aRea Navigation - a VOR/DME based system which allows one to fly to
        an arbitrary point, rather than to a point under which a VOR exists
Squawk  A 4-digit (actually 4-octal-digit -> 12-bit) number which is
        set into a transponder by the pilot to identify the aircraft
        to air traffic controllers
Transponder  an airborne transmitter which responds to a ground-based
        interrogation signal to provide air traffic controllers with more
        accurate and reliable position information than would be possible
        with "passive" radar; a transponder may also provide air traffic
        control with an aircraft's altitude
VOR     VHF Omnidirectional Range - a common type of electronic navigation aid;
        the acronym refers both to the ground station and the airborne
        receiver.

Organizations, etc.

99's    The Ninety-Nines, Inc., Will Rogers World Airport, P.O. Box 59965,
        Oklahoma City, OK 73159; 405/685-7969, fax 405/685-7985
        [the 99's is the International Organization of Women Pilots]
AOPA    Aircraft Owners and Pilots Association, 421 Aviation Way, Frederick,
        MD 21701; 1-800-USA-AOPA or 1-301-695-2000; FAX 1-301-695-2375
 	or http://www.aopa.org/
ARTCC   Air Route Traffic Control Center - a "long-distance" ATC facility,
        known more briefly as "Center"
ASRS    Aviation Safety Reporting System (voluntary NASA safety program)
        [write to:  Aviation Safety Reporting System, NASA Ames Research
        Center, Moffett Field, CA  94035-0189, or call 1-415-969-3969; Sue
        McCarthy should be able to send you copies of form 277 and/or
        a free subscription to the monthly _Callback_ newsletter]
ATC     Air Traffic Control
CAA     Civil Aviation Authority (U.K.)
CAP     Civil Air Patrol
DOT     Department of Transportation (U.S); Department of Transport (Canada)
EAA     Experimental Aircraft Association, PO Box 3086, Oshkosh, WI 54903
        Phone 1-414-426-4800; FAX 1-414-426-4828; Membership 1-800-843-3612
 	or http://www.eaa.org
FAA     Federal Aviation Administration (U.S.)
FAI     Federation Aeronautique International
FBO     Fixed-Base Operator - a firm on an airport which maintains, rents,
        sells, and/or fuels aircraft, and may also provide flight training
FSDO    Flight Standards District Office - an FAA field office
FSS     Flight Service Station - an FAA facility which provides weather
        information to pilots and allows them to file flight plans
GADO    General Aviation District Office - an FAA field office for G.A. only
LTAS    The Lighter-Than-Air Society, 1800 Triplett Blvd., Akron, OH 44306
NASA    National Aeronautics and Space Administration (U.S.)
NOAA    National Oceanic and Atmospheric Administration (U.S.)
NOS     National Ocean Service, part of NOAA [they print aviation charts]
NTSB    National Transportation Safety Board (U.S.)
NWS     National Weather Service (U.S.)
OSH     Oshkosh, WI (see next entry)
Oshkosh Wisconsin is the site of the annual EAA convention, the largest
        gathering of aircraft in the world -- typically, over 15,000
        aircraft are on site.  Oshkosh '96 is August 1 through August 7.
 	Details: http://199.201.68.240/
SSA     Soaring Society of America, PO Box E, Hobbs, NM 88241
 	http://acro.harvard.edu/SSA/ssa_homepg.html
TAP     Trade-A-Plane, PO Box 509, 410 West 4th St., Crossville, TN 38557
        1-615-484-5137
USHGA   United States Hang Gliding Association [POB 8300 Colo Springs CO 80933]

Airspace

Changes to the U.S. Airspace system were instituted on 9/16/93; the changes
are primarily nomenclature, as shown below.  Note that there are a few
rules changes in addition to name changes -- consult the latest AIM.

        Old name:                                       After 9/16/93:
        ---------                                       --------------
ARSA    Airport Radar Service Area                      Class C
ATA     Airport Traffic Area                            Class D
CZ      Control Zone                                    Class E
MOA     Military Operations Area
PCA     Positive Controlled Airspace (above 18,000')    Class A
TCA     Terminal Control Area                           Class B
TRSA    Terminal Radar Service Area                     -> Class C or D
        Uncontrolled Airspace                           Class G

Miscellaneous

A&P     Airframe and Powerplant - the basic FAA aircraft maintenance rating
AGL     Above Ground Level - distance above the ground you're over right now
AIM     Airman's Information Manual
Avgas   Aviation gasoline (two primary grades, 80 and 100 octane)
ATIS    Automatic Terminal Information Service - pre-recorded airport weather
BFR     Biennial Flight Review - an instructional review session required of
        all U.S. pilots once every two years
CAVU    Ceiling and visibility unrestricted (clear or scattered, vis > 10 miles)
DUATS   Direct User Access Terminal System (on-line weather briefings)
FAQ     Frequently Asked Questions (this posting)
FS      Flight Simulator, usually Microsoft's
IA      Inspection Authorization - added to an A&P, allows sign-off of annuals
IMC     Instrument Meteorological Conditions - flying in conditions below
        those required for VFR flight; colloquially, "in the clouds"
IMHO    in my humble opinion
LTA     Lighter Than Air
MEA     Minimum Enroute Altitude (IFR)
MOCA    Minimum Obstacle Clearance Altitude (IFR)
MP      Manifold Pressure (usually refers to the gauge which is the primary
        indication of power output in aircraft with controllable-pitch props)
MSL     Mean Sea Level - altitude above the ocean
Mogas   Motor (automotive) gasoline
NORDO   No-radio
NPRM    Notice of Proposed Rulemaking
O2      Oxygen (Aviator's Breathing Oxygen, of course!)
OAT     Outside Air Temperature
PIC     Pilot In Command
POH     Pilot's Operating Handbook (the manufacturer's guide to the airplane)
SIC     Second In Command
SMOH    Since Major Overhaul
STOH    Since Top Overhaul (cylinders, etc., but not crankshaft, etc.)
STC     Supplemental Type Certificate
SVFR    Special VFR - allows VFR flight in the vicinity of an airport in
        less than VFR conditions under restricted circumstances
TANSTAAFL  There Ain't No Such Thing As A Free Lunch [R. Heinlein]
TBO     Time Between (or Before) Overhaul
TSO     Technical Standard Order
VASI    Visual Approach Slope Indicator
VMC     Visual Meteorological Conditions - flying in conditions at least
        as good as the minimums required for VFR flight

Frequently-Noted Places
AGC     Pittsburgh (Allegheny Co.) PA
BED     Hanscom Field, Bedford MA
BMG     Bloomington, IN
BOS     Boston MA
BVY     Beverly MA
CGX     Chicago (Meigs) IL
CMH     Port Columbus OH
CMI     Champaign-Urbana IL
DCA     Washington (National) DC
DAY     Dayton OH
EFD     Ellington Field, Houston TX
HPN     White Plains NY
HWD     Hayward CA
IAD     Dulles International, Washington DC
IAH     Houston (Intercontinental) TX
IPT     Williamsport PA
LAX     Los Angeles CA
LGB     Long Beach CA
MVY     Martha's Vineyard MA
MYF     Montgomery Field, San Diego CA
OAK     Oakland CA
ORD     Orchard Field, a.k.a O'Hare, Chicago IL
PAO     Palo Alto CA
RHV     Reid-Hillview Intergalactic, San Jose CA
SFO     San Francisco CA
SJC     San Jose CA
SMO     Santa Monica CA
SNA     Santa Ana (Orange County) CA
STL     St. Louis (Lambert) MO
TEB     Teterboro NJ
VNY     Van Nuys CA