Meteorology Applied to Flight Planning
Meteorology applied to flight planning test your ability to convert forecasts and observations into fuel, alternate and performance decisions. The exam includes NZ-specific weather, MET products, winds and temperatures aloft, icing, turbulence, volcanic ash and altimetry corrections.
MET products
- METAR/TAF, graphical area forecasts, SIGMET, AIRMET, winds/temperature charts and MetService briefings.
- Check validity, issue time and whether TEMPO or BECMG affects the ETA.
- NZ hazards: Southern Alps mountain waves and foehn, Cook Strait turbulence, low cloud, icing in stratiform and cumuliform cloud, and volcanic ash.
Altimetry
QNH is used for terrain clearance; QFE for aerodrome height. In cold air the altimeter overreads, so the aircraft is lower than indicated. Apply the operator's cold-temperature correction to MDA/DA and minimum grid heights.
Worked example
Aerodrome OAT −5°C, MDA 600 ft. ISA temperature at the aerodrome is about 15°C, so the temperature is 20°C below ISA. Using the operator's correction table, add approximately 60 ft: corrected MDA = 660 ft. The reason is that the altimeter overreads in cold air; without correction, obstacle clearance is reduced.
Traps
- Using QFE as the en-route altimeter setting.
- Ignoring a SIGMET for volcanic ash or severe turbulence because the TAF looks fine.
- Assuming a TAF is valid at ETA without checking its period.
- Not applying cold-temperature correction at high-elevation NZ aerodromes.