Originally Posted by
FlightDetent
Thanks for confirming. Sorry for the simplification, it's understood that 1 hPa is around 27 feet on ISA SL but increasing going up, and thus around 30' below TA/L where pilots need it.
Technically, I cannot come up with any situation where you need to convert hPa into altitude.... the 27 feet is something you learn at the academy, and in most cases never use it again (as a pilot). As a controller there are more situations where it may be relevant, but since most transition levels are now (or should be) at least 1000 feet from the transition altitude, and those calculations are done automatically, that one is not often required anymore at most ATC units.
But yes, if it keeps flipping between 1013 and 1014 (because it's flipping the decimal 3,9 and 4,0), you'd have to pass it. But those situations are relatively rare.... at least where I work.