Rules of the Air

Rules of the Air: Core ATPL Knowledge for Safe, Compliant Flight

The Rules of the Air (ICAO Annex 2 and related guidance) define how aircraft are flown safely and predictably, both in controlled airspace and outside it. For ATPL students, a key principle is that the pilot-in-command (PIC) has the final authority over the aircraft and remains ultimately responsible for safety, including terrain clearance, even when operating under an ATC clearance. ATC provides separation and clearances, but the PIC may deviate if necessary for safety and must request clarification whenever instructions appear conflicting or unsafe.

Separation and obstacle clearance are central. Below FL290, standard IFR vertical separation is 1 000 ft. Over high terrain or mountainous areas where no minimum altitude is published, IFR flights must fly at least 2 000 ft above the highest obstacle within 8 km of the estimated position. On precision approaches, ILS obstacle clearance surfaces assume the pilot remains on track with no more than a half-scale deflection once established—precise tracking is essential to retain the published obstacle clearance margins defined by PANS-OPS.

Communications, transponder use, and interception procedures are frequent exam topics. In a comms failure while in VMC, continue in VMC, land at the nearest suitable aerodrome, and report arrival as soon as possible. Know your SSR codes: 7700 for emergency, 7600 for communications failure, and 7500 for unlawful interference. An intercepted aircraft should immediately attempt contact on 121.5 MHz (then 243.0 MHz if practicable), and—unless otherwise instructed by ATS—select Mode A Code 7700. If radio instructions conflict with the intercepting aircraft’s visual signals, follow the interceptor and request clarification. Light-gun signals also apply: a series of green flashes to an aircraft in flight means return for landing. On the ground, red anti-collision lights may be displayed when engines are running.

Right-of-way and operational rules ensure predictability. An overtaking aircraft approaches from behind within a relative angle of less than 70° to the other aircraft’s plane of symmetry; the overtaken aircraft has right-of-way. ATC applies vertical and horizontal separation methods to manage controlled traffic. Per Annex 7, underwing registration mark height is at least 50 cm, and registration marks are assigned by the State of Registry (or common mark authority). If a transponder is unserviceable before departure and cannot be restored, departure to the nearest suitable aerodrome for repair may be permitted. Changing from IFR to VFR is allowed upon commander request, and the PIC may deliver offenders to competent authorities when necessary under air law.

What this question bank covers

• IFR separation minima below FL290 and ATC separation methods (vertical/horizontal).
• Terrain and obstacle clearance, including mountainous area requirements and ILS tracking tolerances.
• Communication failure procedures and VMC recovery actions.
• SSR transponder use: emergency (7700), comms failure (7600), unlawful interference (7500).
• Intercept procedures: guard frequencies (121.5/243.0 MHz), visual signals, and compliance priorities.
• Visual signals from aerodrome control (e.g., green flashes: return for landing) and anti-collision light use.
• Right-of-way and overtaking rules, definitions, and practical application.
• Aircraft registration and markings per Annex 7 (including minimum underwing mark size).
• Operational provisions: transponder unserviceability, PIC authority, and changing flight rules (IFR to VFR).