| Another ISA question I saw this question posted and I'm trying to solve it. An answer was provided. However, I don't see it! Please pass on some information if you can help out. What is the altimeter error when 10,000 PH (never heard of PH either) at ISA -34? At 10,000 ft standard temp is -5 (2c/1000 feet) Difference of 29c 2% for every 5 degrees variation from ISA (approx 6) 6 x 2% = 12% (Over Reads) Answer given is 14% am I out to lunch or is there answer wrong? Also PH? Pressure height? Thank you guys! UD |