Altimeter setting question below?
A pilot departs an airport with a given setting of 29.92Hg. If his destination give him the setting 28.92Hg but he doesn t change it, will the aircraft fly 1000 feet above or below the indicated altitude?
In my mind 28.92 is a lower pressure so he would be flying 1000ft above his indicated altitude but I know that s wrong. can someone explain why please
- USAFisnumber1Lv 76 months ago
When you take off you KNOW the altitude of that airport. You also KNOW the air pressure at that airport. So you set the altimeter to match the two facts you KNOW. The difference between the two is just 1 mm of mercury. (The readings are 29.92 mmHg and 28.92 mmHg. They are not altitudes) That is just 50 feet of altitude difference. Not enough to really worry about.
- Tracy LLv 78 months ago
An area of high pressure to an area of low pressure the aircraft will be lower than what it indicates if there is no change to the sub-scale setting on the altimeter.
Simple phrase to remember... --- "HIGH TO LOW, LOOK OUT BELOW" meaning if you fly from a high pressure to a low pressure you will be LOWER than indicated altitude. Thus the ground will be closer to the aircraft! Here is a good article with pictures and good explanations. https://sabushpilot.com/high-to-low-look-out-below...
- Anonymous8 months ago
The setting is the pressure that would normally exist at sea level. Flying into an area where the pressure is lower would erroneously indicate a HIGHER altitude than real, since pressure drops when flying higher.
Wanting to keep the same indicated altitude would mean flying lower.