Units of measure
Units (imperial on charts and publications, TC AIM GEN 1.4; other units per Table 1.1):
| Quantity | Unit |
|---|---|
| Altitude, elevation, height | feet (ft) |
| Short distances (runway length, obstacle height) | feet (ft) |
| Distance used in navigation | nautical miles (NM) |
| Visibility | statute miles (SM), not NM (TC AIM GEN 1.4.1 Table 1.1; TC AIM MET 1312, 2589) |
| Horizontal speed, wind speed | knots (kt) |
| Vertical speed | feet per minute (ft/min) |
| Runway Visual Range (RVR) | feet (ft) |
| Altimeter setting | inches of mercury (in. Hg) |
| Temperature | degrees Celsius (°C) |
| Weight | pounds, kilograms, or kilonewtons (lb, kg, kN) |
| Tire pressure | pounds per square inch or megapascals (psi, MPa) |
Wind direction:
| Report | Reference |
|---|---|
| Winds aloft, forecast winds | True |
| Observed winds, landing and takeoff | Magnetic; true in Northern Domestic Airspace (TC AIM GEN 1.4.1) |
| FSS winds for a site other than its own | True (TP 1102) |
Geographic coordinates: WGS-84 geodetic reference datum (TC AIM GEN 1.4.2).
Trap: visibility in NM not SM; magnetic landing wind where true applies (or reverse, inside the NDA).
References
- TC AIM GEN 1.4.1 (Table 1.1, units of measurement used in aviation)
- TC AIM GEN 1.4.2 (geographic reference datum)
- TP 1102 (FSS wind reporting)
- TC AIM MET (forecast and prevailing visibility in SM, lines 1312 and 2589)