Instruments checks on ground
Hi all ! These days I had some questions from my instructor concerning the checks of instruments while on ground. I've been looking for the answers but no results...
The questions are :
1) what is the maximum difference between the QFU and your compass when lining up for take off ?
2) the max difference between your compass and your heading on the HSI ?
3) In IFR, 2 altimeters are required, what is the max difference between both altimeters readings ?
Does someone can help me ? And most of all, does someone can give the source of the information found ? For example Jeppesen, ATPL books, ICAO annexes or whatever !
Thanks