Current air traffic management in Reduced Vertical Separation Minimum (RVSM) airspace, which spans flight levels FL 290 to FL 410, relies on a 1000 ft minimum vertical separation between aircraft. As altitude increases, the accuracy of barometric altimetry decreases, necessitating a 2000 ft separation above FL 410. These vertical separation minima limit airspace capacity and contribute to increased emissions through longer routings or flight at unfavourable altitudes.
About the solution
The “Separation minima” solution proposes transitioning to a 500 ft minimum vertical separation within RVSM airspace, enabled by geometric altimetry. Unlike barometric altimetry, geometric altimetry maintains high accuracy far above the altitudes relevant for conventional aviation, allowing the extension of RVSM airspace up to FL 600.
The project focuses on the safety aspects, including collision and wake turbulence risks, using the European RVSM region as a test case.
Standardisation and regulatory aspects
Implementing reduced minimum vertical separation would require changes to the Rules of the Air at ICAO level, specifically an amendment to PANS-ATM (Doc 4444).
Further maturation of the concept would necessitate reworking the entire RVSM implementation process and requirements.
Advancements to MOPS and MASPS for GNSS receivers would likely be required; however, this is beyond the scope of this solution.
BENEFITS
- Increased airspace capacity: More aircraft can fly at optimal flight levels, reducing detours and emissions.
- Environmental benefits: Minimises detours to avoid climate-sensitive areas and supports more efficient routing.
- Support for diverse aviation types: Facilitates integration of civil and military aircraft, unmanned aerial systems (UAS), and high-altitude operations (HAO).
- Enhanced ATM efficiency: Improves overall air traffic management and contributes to environmental sustainability.