Operations resources


Cruising level requirements

Navigation position fixing

The following requirements apply to flight under VFR (AIP ENR 1.1):

  • During flight pilots must maintain a time reference accurate to within 30 seconds (ENR 1.1-40,
  • The pilot in command must navigate the aircraft by visual reference to the ground or water, or by using any of the methods specified in AIP ENR 1.1 (IFR navigation requirements) as an alternate means, except that the pilot in command must be able to navigate by visual reference to the ground or water when operating at or below 2000 ft above the ground or water
  • When navigating by visual reference to the ground or water, the pilot in command must positively fix the aircraft’s position by visual reference to features shown on topographical charts at intervals not exceeding 30 minutes. When flying over the sea, visual reference features may include rocks and reefs and fixed man-made objects which are marked on suitable charts and are readily identifiable from the air

  • When navigating by visual reference in controlled airspace the pilot must notify ATC if the aircraft’s track diverges by more than 1 nm from the track approved by ATC, or, if navigating by reference to radio navigation aids, by more than the tolerances given on AIP ENR 1.1
  • VFR flight on top of more than scattered cloud is available provided that
    • VMC can be maintained during the entire flight, (including climb, cruise and descent)
    • the pilot in command can meet the visual position fixing or IFR navigation requirements
    • the pilot in command is sure that current forecasts and observations (including those available in flight) indicate that conditions in the area of, and during the period of, the planned descent below the cloud layer will permit the descent to
      be conducted in VMC, and
    • the position at which descent below cloud is planned to occur must be such as to enable continuation of the flight to the destination and, if required, an alternate aerodrome in VMC (see notes below)
  • when navigating by reference to radio navigation aids or GNSS, the pilot in command must obtain positive fixes at the intervals and by the methods prescribed in AIP ENR 1.1
  • the pilot in command of a VFR flight wishing to navigate by means of radio navigation systems or any other means must indicate in the flight notification only those radio navigation aids with which the aircraft is equipped and the pilot is competent to use under CASR 61.385.
  • VFR flights must not be conducted above FL200 unless:
    • the pilot in command or, if more than one pilot is required, each pilot:
      • is authorised under Part 61 to conduct a flight under the IFR in that airspace, and
      • complies with the recent experience requirements of section set out in CASR Part 61, and
    • the aircraft is equipped for flight under the IFR, and
    • the aircraft is engaged in an ‘IFR pick up’, ‘VFR climb/descent’ or ‘VFR on top’ procedure as published in AIP, and
    • the aircraft remains in Class E airspace.

Track keeping AIP ENR 1.1

Tolerances are applied to tracks to assess containment area for the purposes of ensuring navigational integrity, separation from other aircraft, terrain and obstacle clearance and avoidance of specified airspace. Although allowing for the errors inherent in the navigational systems used, these tolerances are based on the assumption that the pilot will maintain track as closely as possible.

The pilot in command must, at all times, take positive action to regain track as soon as a deviation from the correct track is recognised.

When using radio navigational aids as the primary means of navigation, the aircraft must be navigated by reference to the aid that provides the most precise track guidance, with which the aircraft is equipped and the pilot is qualified to use.

The order of precision is localiser, GNSS, VOR, then NDB.

Position fixing with NAVAIDs

A positive radio fix is one that is determined by the passage of the aircraft:

  • over an NDB
  • over a VOR
  • over a TACAN
  • over a marker beacon
  • over a DME site
  • via the intersection of two or more position lines which intersect with angles of not less than 45° and which are obtained from NDBs, VORs, localisers or DMEs in any combination, or
  • with reference to GNSS meeting the equipment requirements of AIP GEN 1.5.

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