FBU 4EVER! From Norway, joined Jan 2001, 998 posts, RR: 7 Reply 1, posted (12 years 4 months 5 days 13 hours ago) and read 7439 times:
You're referring to QNH and it refers to the altimeter setting in inches or HPa.
There used to be many such Q-codes,stemming from the time telegraphy (Morse Code) was used as a means of communication.We're talking of WW2,before and after.
The Q means a question or request for information.QDM meant a request for course to a station,QDR course from a station.A request for QNH gives you the altimeter setting that shows airfield elevation above MSL when on the ground,QFE is the altimeter setting that shows 0 feet when on the ground.The difference between QNH and QFE is called QFF,but this is never used in operations.
FBU 4EVER! From Norway, joined Jan 2001, 998 posts, RR: 7 Reply 4, posted (12 years 4 months 4 days 13 hours ago) and read 7384 times:
Yup,the Q-codes is basically a European (read British) invention,but used worldwide as it has been accepted by ICAO as one of the standards.
There are many minor differences between the U.S. and the rest of the world regarding civil aviation,QNH and Altimeter being one of them.Also,inches instead of HPa is used in North American airspace,there's a fixed transition altitude of 18 000 feet versus a different one for each airport in other countries,etc.,etc.