Plans to shift aviation from magnetic navigation to true navigation
While professional mariners stopped using the earth's magnetic field as their primary directional reference some 50 years ago, civil aviation did not, because at that time accurate inertial navigation systems were too heavy and bulky for aircraft use. Today navigation by global navigation satellite systems - backed up by ring laser gyro-stabilised INS/attitude and heading reference system platforms, radio beacons and air traffic control surveillance using multiple technologies - means that aviation has no real need to use a magnetic reference. The debate about changing from Magnetic to True navigation is now moving towards how to change, and when, with March 2030 as the proposed date. Modern civil and military aircraft have the capability to fly to a True North reference at the push of a button: the flight management system is designed to identify True North at start up, and when a magnetic reference is required it is computed from True by applying local magnetic variation via embedded look-up tables. Moving from Magnetic to True reference is no more challenging than, for example, the periodic task of re-orientating VHF omnidirectional radio range and TACAN radio navigation beacons for local magnetic variation changes. Aviators in the northern Canadian airspace have employed tried and tested procedures for both traditional radio navigation beacons and all types of performance-based navigation systems. To sceptics reluctant to abandon any heading reference system - especially one as familiar as the magnetic compass - despite the existence of proven alternatives, AHRTAG member Dai Whittingham points out that modern aviation rulemaking is risk-based.