| AGL |
Above ground level. A height, not an altitude. |
| AIRAC |
The 28-day cycle on which aeronautical data is updated. |
| AMSL / MSL |
Above (mean) sea level. |
| ATZ, CTR, TMA, CTA, RMZ, TMZ |
Types of airspace: aerodrome traffic zone, control zone, terminal and control areas, radio mandatory zone, transponder mandatory zone. |
| Class A to G |
Airspace classes. OpenVFR shows C, D, E/F, G as the display class, with the type separately (for example CTR). |
| Contingency |
Extra fuel as a percentage of en-route fuel. |
| ETA / ETE |
Estimated time of arrival / en route. |
| FIR |
Flight information region. |
| FL |
Flight level: pressure altitude in hundreds of feet on 1013.25 hPa. FL095 is 9,500 ft. |
| GS |
Ground speed. |
| IAS / TAS |
Indicated / true airspeed. |
| MEF |
Maximum elevation figure: the highest terrain or obstacle in an area. Used for the MSA. |
| METAR / TAF |
Aerodrome weather report / forecast. |
| MH / MT / TT |
Magnetic heading / magnetic track / true track. |
| MSA |
Minimum safe altitude: terrain or obstacles in a corridor plus a clearance. |
| MVFR / IFR / LIFR |
Flight categories by ceiling and visibility. |
| NOTAM |
Notice to airmen. |
| POH |
Pilot’s operating handbook. |
| PPR |
Prior permission required. |
| QNH |
Pressure setting that makes the altimeter read altitude above sea level. |
| TOC / TOD |
Top of climb / top of descent. |
| UTC |
Coordinated universal time. Times are shown in UTC unless a setting says local. |
| VFR |
Visual flight rules. |
| VOR / NDB |
Radio navaids. |
| WCA |
Wind correction angle: the angle between track and heading needed to hold the track in the wind. |
| MRP |
Reporting point (shown as its own layer). |
| Virtual Radar |
The vertical profile chart. See Virtual Radar. |
