MEL (minimum equipment list)
A minimum equipment list is an approved document that specifies which items of equipment may be inoperative for a limited period while the aircraft continues to fly safely, and what conditions or limitations apply. If the second coffee maker or one of two cabin entertainment screens fails, the MEL lets the flight go ahead with the item deferred; if an anti-ice system or a transponder fails, it generally does not. For a passenger, an MEL deferral is a normal, regulated part of operations rather than a sign of neglect, although the crew should tell you if it affects the cabin. A pattern of many open MEL items on one aircraft is a different matter.