Английский словарь американских идиом - fall asleep at the switch

{v. phr.} To fail to perform an expected task; be remiss in one's duty. * /The two airplanes wouldn't have collided, if the control tower operator hadn't fallen asleep at the switch./ * /The dean promised our department $250,000 but the foundation never sent the money because someone in the dean's office fell asleep at the switch./