Relevant Discussion: AIM 5-4-5, 7-1-11, 7-2-1 through 7-2-5, P/C Glossary, FAA-H-8083-16, AC 00-45, AC 91-70, AC 120-28D, Order 7110.65T
Everything Explained: Altimetry Around the World
Key Takeaways:
- Aviation altimeter settings use specific Q-codes: **QNH** (local barometric pressure, altimeter reads field elevation on ground, used below transition altitude), **QNE** (standard pressure of 29.92 inHg/1013.2 hPa, used at or above transition altitude, also known as pressure altitude), and **QFE** (altimeter reads zero feet on the ground, now less common).
- The **transition altitude** (for climbing) and **transition level** (for descending) define the airspace where pilots switch between local (QNH) and standard (QNE) altimeter settings; this is 18,000 feet MSL in the US and Canada but varies significantly worldwide.
- International flight requires pilots to understand altimeter setting conversions between inches of mercury and hectopascals/millibars (1 inHg = 33.863 hPa), and to be aware of varying national procedures regarding transition altitudes/levels and the use of meters versus feet.
Key takeaways sponsored by Aviator Pro | Start Your Training ->
See a mistake? Contact us.
