19 CFR 122.65 - Failure to depart.
Once an aircraft has been cleared or given permission to depart it must depart within 72 hours. The aircraft commander or agent shall report promptly to the port director if departure is delayed beyond or cancelled within 72 hours after the aircraft received clearance or permission to depart.
Title 19 published on 2013-04-01
no entries appear in the Federal Register after this date.