I think the answer is in the specs you provided in your next post:
And here's the answer to your next questionHere are the main features :
- 3 hands analog altimeter (Hundreds, thousands & tens of thousands).
- Sensor "Autostart" feature (see preferences).
- Automatic sensor stop on exit.
- Preferences save on exit (including calibration data).
- 2 altitudes providers : Barometric sensor(*) or GPS chip (no network).
- Robust Barometric Algorithm.
- Units are feet or meters for altitude and hPa or inHg for pressure (*).
- Displays QFE / Altitude / QNH (*).
- Altitude speech.
- Calibration function(*) with altitude or pressure (QNH) including a reset function.
- User interface in English, French, German (Thanks Peter), Italian (Thanks Cosimo !).
- Free application... no ad !
What is QNH and QFE?
QNH is sea-level pressure. It’s used to cause the altimeter to register height above sea level. When sitting on the ground at an airport, dialing QNH into the altimeter will cause it to display the airport’s altitude above sea level.
QFE is air pressure at the current ground level. It’s used to cause the altimeter to register height above the ground (for a certain area). When sitting on the ground at an airport, dialing QFE into the altimeter will cause it to display zero feet.
Western countries largely standard on using QNH during takeoff and landing. It allows you to accurately know your height above sea level, but you must know the height of the local terrain to know if you are at risk of impacting terrain. Eastern countries have sometimes standardized on using QFE, which allows you to know your height above the airport by just reading the altimeter.
This should hopefully make the risk obvious. Imagine you’re landing at an airport that is 300 feet above sea level. You've dialed in QNH thinking that you dialed in QFE. Your altimeter reads 400 feet. Because you think you dialed in QFE, you believe you’re 400 feet above the ground, but since you actually dialed in QNH, you’re only 100 feet above the ground, and at risk of impacting obstacles.
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