IRS mode panels
Something I've been wondering for a long time:
why do short to mid range (Boeing/Airbus) aircraft have IRS position entry panels on the overhead while their long range counterparts don't?
As an example:
B737 (NG and Classic with EFIS) are so equipped while the 744 only has the three IRS mode selectors.
A319/320/321 family has the equipment while the A340 doesn't.
What about the 767? I've seen both options there. Maybe something that has to do with age? (old ones not equipped while the new ones are equipped with it?)
Regards,
Mark