international UA90
From United:
2. For international flights covered by this Plan that depart from or arrive at a U.S. airport, United will not permit an aircraft to remain on the tarmac at a U.S. airport for more than four hours before allowing passengers to deplane unless: either the pilot-in-command determines there is a safety-related or security-related reason (e.g., weather, a directive from an appropriate government agency) that the aircraft cannot leave its position on the tarmac to deplane passengers; or air traffic control advises the pilot-in-command that returning to the gate or another disembarkation point in order to deplane passengers would significantly disrupt airport operations.
3. For all flights covered by this Plan, United will provide adequate food and drinking water no later than two hours after the aircraft leaves the gate (in the case of departure) or touches down (in the case of arrival) if the aircraft remains on the tarmac, unless the pilot-in-command determines that safety or security considerations preclude such service.