Rules of the Air Article 16

Aircraft shall not be flown in formation except by prearrangement among the pilots-in-command of the aircraft taking part in the flight and, for formation flight in controlled airspace, in accordance with the conditions prescribed by the appropriate ATC authority(ies). These conditions shall include the following:1. the formation operates as a single aircraft with regard to navigation and position reporting;2. separation between aircraft in the flight shall be the responsibility of the flight leader and the pilots-in-command of the other aircraft in the flight and shall include periods of transition when aircraft are manoeuvring to attain their own separation within the formation and during join-up and break-away; and3. a distance not exceeding 1 nautical mile laterally and longitudinally and 100 ft vertically from the flight leader shall be maintained by each aircraft.