The Sterile Cockpit Rule is an informal name for the Federal Aviation Administration (FAA) regulation stating that all operators certificate holders shall not require, nor may any flight crewmember perform, any duties during a critical phase of flight except those duties required for the safe operation of the aircraft.
That means all non-essential activities in the cockpit during critical phases of flight, normally below 10,000 feet (3,050 m) are not allowed. The FAA imposed the rule in 1981, after reviewing a series of accidents that were caused by flight crews who were distracted from their flying duties by engaging in non-essential conversations and activities during critical parts of the flight.
One such accident was Eastern Air Lines Flight 212, which crashed just short of the runway at Charlotte/Douglas International Airport in 1974 while conducting an instrument approach in dense fog. The National Transportation Safety Board (NTSB) concluded that a probable cause of the accident was lack of altitude awareness due to distraction from idle chatter among the flight crew during the approach phase of the flight Similar is the case of Colgan Air Flight 3407 in 2009..