Hi - first post and hope this is in the right place (loads of forums!!)
I was reading a book that says in the ISA, if the atmospheric pressure were to be 300mb/hectopascals, an altimeter would register a height of 30,000 feet.
I've looked into this and I calculate that the altimeter would read 21,397 feet (1013.25hpa - 300hpa = 713.25pa x 30 feet = 21,397)
Can anyone explain - I can't get my head round it.
Thank you,
Jake.