38TH ANNUAL CONFERENCE, Santiago, Chile, 15-19 March 1999WP No. 98Removal of Ground Based Aids |
Introduction
ICAO is proceeding with the definition of global navigation satellite systems (GNSS). The implementation of GNSS may allow the removal of certain ground based navigation aids. The planning for the removal of ground based aids is now commencing and IFATCA should consider developing policy on this subject.
Discussion
The implementation of GNSS will replace some functions currently provided by ground based navigation aids. The ICAO plan for the global use of GNSS allows states to remove ground based aids where GNSS can provide a replacement service. The removal will be the subject of regional planning. The GNSSP has agreed that the ICAO regions should commence this planning process.
At the All Weather Operations Group (AWOG) meeting in May 1998, a paper was presented on the removal of ground based aids in the European region. This paper specifically proposed that a plan should be developed for the removal of VOR’s in Europe.
The European EGNOS system is planned to be operational by 2002 and provide en-route, non- precision approach (NPA) and Cat I precision approach operations. At present, some of these functions are provided by VOR and the implementation of EGNOS provides the opportunity to commence the removal of the VOR service. This would also provide some of the cost/benefits anticipated for GNSS operations.
It should be noted that the BRNAV en-route requirement in Europe is currently met by many aircraft using DME/DME operations. The backup for BRNAV is to revert to VOR operations. The removal of VOR (but not DME) would provide BRNAV based on GNSS with DME/DME BRNAV as a backup should GNSS fail, or fall below the required RNP value. It is proposed that VOR and NDB would be retained for airfield location and NPA.
The paper initially proposed that a plan to remove VOR’s should be developed. In the light of discussions, noting that the operational dates and capabilities of GNSS are not yet guaranteed, it was agreed to recommend to the EANPG that they should consider the need for a plan to remove ground based aids when GNSS should become available.
As well as being discussed in AWOG , it has also been discussed in the EANPG in consultation with Eurocontrol ( based on the Navigation Strategy developed by the Air navigation Team (ANT) will develop a Regional Navigation Strategy for the EUR Region until the year 2015.
IFATCA in its Vision Document states :
“The move towards the use of satellites as sole means for navigation implies a system which ensures a high level of reliability, accuracy and integrity. The current system GPS/GLONASS has known deficiencies which are being addressed. For instance, geostationary satellites become ineffective in the polar regions which means alternative procedures are required since ADS can not be used. These systems are subject to natural temporary degradation and unserviceabilities.”
The process to withdraw ground based aids is becoming commercially driven that the airlines will save user charges. There is a danger that there will be an “underclass” who cannot afford navigation, e.g. for general aviation and private pilots who cannot afford to have GPS, EGNOS and BRNAV in their airplane, then there will be nothing else left.
Conclusion
It is possible that this subject will again come up at the next AWOG meeting in November 1998 when it would be helpful for me to have further guidance on this subject from SC1. This subject will shortly be raised in other ICAO regions and it is appropriate for IFATCA to develop policy on this subject.
IFATCA in its Vision Document clearly states its concerns with regard to the withdrawal of aids and reliance on GPS/GLONASS as sole means for navigation systems.
Adequate navaids should be guaranteed to users regardless of status or ability to pay.
It is recommended that:
Until failsafe procedures have been proven and installed, the removal of terrestrial navigation aids is neither feasible nor safe and would therefore be highly premature, and that adequate navaids should be guaranteed.
Last Update: September 28, 2020