pack out of service B737 NG
on B 737 NG, when a pack brake down there are two situations:
1 -when it occurs on ground you are limited to FL 250 according to MEL .
2-when it occurs in flight you are not limited according to the QRH.
because when we are on ground ,and after doing the appropriate check list we should consult the MEL.on the other side when we are in flight we do jut the appropriate check list witout consulting the MEL.