NPC 172/03 - Proposed Amendments to Manual of Standards (MOS) Part 172 - Air Traffic Service Providers and Flight crew requirements for use of Global Positioning System
This Notice of Proposed Change (NPC) covers a proposal to:
- Revise one of the ATC separation standards based on Global Positioning System (GPS) report, and
- change the pilot procedures for reporting Receiver Autonomous Integrity Monitoring (RAIM) loss or outage loss.
The ATC separation change involves reducing the Circular Error of Position (CEP) tolerance applied to aircraft GPS position reports from 12 nautical miles to 7 nautical miles. Extensive research has been conducted to validate the new tolerance, and analysis has demonstrated the intrinsic aircraft safety will be maintained.
The revised tolerance is expected to have both immediate and long term positive effects on enroute airspace. It will enable the existing airspace to be more efficiently utilised, and will provide greater capacity for aircraft to achieve their preferred levels and tracking.
However, to ensure the integrity of the revised tolerances, it will be necessary to change the time interval after which a pilot must tell ATC about a RAIM loss or outage from the current 10 minutes to 5 minutes. Initial consultation with industry had indicated that the change to RAIM loss reporting is not expected to significantly increase operational workload.
How to respond
Comment period now closed.
- NPC 172/03 - Proposed Amendments to Manual of Standards (MOS) Part 172 - Air Traffic Service Providers and Flight crew requirements for use of Global Positioning System (GPS)
- Annex A - Proposed Amendments to Manual of Standards (MOS) Part 172
- Comments closed: 20 October 2008