Would someone please explain to me how often a B737-400/800 "A"Check is performed and what in general terms is checked and/or replaced.
I've heard the term "D" Check too. I know that the higher the letter the more serious the check but I have no idea what it actually means and what the time interval between checks are.
As a pilot I think this is general knowledge that I should know.
Can someone please enlighten me! Thank you.
PS I've tried an internet search and a PPRuNe search and had no luck.