ENR 1.3 INSTRUMENT FLIGHT RULES

1 Rules Applicable to all IFR Flights

1.1 Aircraft Equipment
Aircraft shall be equipped with suitable instruments and with navigation equipment appropriate to the route to be flown.
1.2 Minimum Levels
Except when necessary for take-off or landing or when specifically authorized by Civil Aviation Authority of Viet Nam, IFR flight shall be flown at a level that is not below the minimum flight altitude established. Where no such minimum flight altitude has been established; IFR flight shall be flown:
  1. Over high terrain or in mountainous areas, at a level which is at least 600 m above the highest obstacle located within 8 km of the estimated position of the aircraft;
  2. Elsewhere than as specified in (a.) at a level which is at least 300 m above the highest obstacle located within 8 km of the estimated position of the aircraft.
Note: The estimated position of the aircraft will take account of the navigational facilities accuracy which can be achieved on the relevant route segment, having regard to the navigational facilities available on the ground and in the aircraft.
1.3 Change from IFR Flight to VFR Flight
1.3.1 
An aircraft electing to change the conduct of its flight from compliance with the IFR to compliance with the VFR shall, if a flight plan was submitted, notify the appropriate air traffic services unit specifically that the IFR flight is cancelled and communicate thereto the changes to be made to its current flight plan.
1.3.2 
When an aircraft operating under the IFR is flown in or encounters visual meteorological conditions, it shall not cancel its IFR flight unless it is anticipated, and intended that the flight will be continued for a reasonable period of time in uninterrupted visual meteorological conditions.

2 Rules Applicable to IFR Flight within Controlled Airspace

2.1 
IFR flights shall comply with the provision of 3.6 of Annex 2 - ICAO to the Convention on International Civil Aviation and Articles 30, 31, 32, 33 and 34 of Regulation on Rules of the Air and Air Traffic Services of Viet Nam when operated in controlled airspace.
2.2 
An IFR flight operating in cruising flight in controlled airspace shall be flown at a cruising level, or if authorized to employ cruise climb techniques, between two levels or above a level selected from the Table of cruising levels in AIP item ENR 1.7, except that the correlation of levels to track prescribed therein shall not apply whenere otherwise indicated in air traffic control clearance or specified by Civil Aviation Authority of Viet Nam.

3 Rules Applicable to IFR Flights outside Controlled Airspace

3.1 Cruising Levels
An IFR flight operating in cruising level outside of controlled airspace shall be flown at a cruising level appropriate to its track as specified in the Tables of cruising levels in AIP item ENR1.7, except when otherwise specified by Civil Aviation Authority of Viet Nam for flight at or below 900 m AMSL.
3.2 Communication
An IFR flight operating outside controlled airspace but within or into areas, or along routes, designated in Article 23, item 2, point c or d of Regulation on Rules of the Air and Air Traffic Services of Viet Nam or as required by the provision of 3.3.1.2 c) or d) of Annex 2 ICAO shall maintain a listening watch on the appropriate radio frequency and establish two-way communication, as necessary, with the air traffic services unit providing flight information service.
3.3 Position Reports
An IFR flight operating outside controlled airspace and required by Civil Aviation Authority of Viet Nam to:
  • Submit a flight plan, and
  • Establish two-way communication with the air traffic services unit shall report position as specified in Article 32 of Regulation on Rules of the Air and Air Traffic Services of Viet Nam for controlled flights.
Note: Aircraft electing to use the air traffic advisory service whilst operating IFR within specified advisory airspace are expected to comply with the above provisions, except that the flight plan and changes there to are not subjected to clearances and that two-way communication will be maintained with the unit providing the air traffic advisory service.