2023 Altimetry System Error Workshop

FAA/EUROCONTROL Joint Altimetry System Error (ASE) Workshop 2023

Federal Aviation Administration representatives co-chaired an Altimetry System Error (ASE) Workshop with EUROCONTROL at EUROCONTROL Headquarters in Brussels, Belgium, on September 5 - 7, 2023.

The effort was conducted under the USA/EUROPE via Memorandums of Cooperation on Air Traffic Management (ATM) Action Plan 03 (AP03): Air Traffic Modeling Separation Standards. This was the first workshop held in Europe since 2010 and it provided informational discussions with both the European community of interest as well as United States industry participants.

Attendees of the workshop included aircraft manufacturers, sensor manufacturers, European State Aviation Authorities, State Air Navigation Services, State Regulators, and Weather Services.

Representatives from several Reduced Vertical Separation Minima (RVSM) Regional Monitoring Agencies (North American Approvals Registry and Monitoring Organization NAARMO, Pacific Approvals and Registry Monitoring Organization PARMO, North Atlantic Central Monitoring Agency NATCMA, and European Regional Monitoring Agency EUR RMA) discussed topics such as:

  • Regional Monitoring Agency functions
  • Altimetry System Error monitoring
  • Large height Altimetry System Errors cases
  • RVSM monitoring issues
  • Aircraft and maintenance design by manufacturers
  • Detailed sensor designs
  • Failure mode analysis
  • RVSM above Flight Level 410
  • Alternate approval methods
  • Use of Automatic Dependent Surveillance-Broadcast (ADS-B) data for Mandatory Occurrence Reports (MORs) evaluation

The purpose of this workshop was to build awareness and understanding of the inherent risk associated with Altimetry System Error (ASE) and to provide a forum for aviation-based government and industry peers to exchange experiences, best practices, and ideas related to current and emerging issues associated with ASE.

 Documents from the 2023 ASE Workshop Discussion

Day 1 Presentations
Presentation Document Presented by

Welcome Introduction (PDF)


RVSM & Regional Monitoring Agencies (PDF)


RVSM In 2023: The Issues (PDF)


Separation Standards Analysis Program and Monitoring Agency Overview (PDF) NAARMO / PARMO
RVSM European Restriction List (ERL) (PDF) EUR RMA
State Aircraft and RVSM (PDF) EUR RMA
Height Monitoring for RVSM (PDF) EUR RMA
Meteomatics Background and Height Measurement (PDF) METEOMATICS AG


Day 2 Presentations
Presentation Document Presented by
RVSM - A State's Perspective (PDF) Agencia Estatal de Seguridad Aérea / Spain
Section 9 Approval and ASE Examples (PDF) NAARMO
Can We Simplify the RVSM Approval Process? (PDF) EUR RMA
Break-Out Session: RVSM Above Flight Level 410 (PDF)  
Aircraft Certification Implications of Extending RVSM Flight Levels (PDF) AEROMECH
Dassault Falcon Aircraft RVSM In-Service Experience (PDF) DASSAULT AVIATION


Day 3 Presentations
Presentation Document Presented by
ADS-B Height Monitoring in the USA (PDF) NAARMO
RMA Eurasia Data E135-145 Monitoring Group (PDF) Eurasia RMA
ADS-B Height Monitoring in the North Atlantic (PDF) NATCMA
ASE Workshop 2023 - What Next? (PDF) EUR RMA

For information regarding the 2023 event and presentation documents, please contact NAARMO.

DOT is committed to ensuring that information is available in appropriate alternative formats to meet the requirements of persons who have a disability. If you require an alternative version of files provided on this page, please contact Robert.L-CTR.Miller@faa.gov.


EUROCONTROL event summary:

"Altimetry System Error (ASE) is an often unknown aircraft characteristic which can have a significant and detrimental impact on aircraft separation, but which occurs unnoticed by pilots, controllers and ACAS.

ASE can only be monitored in an operational environment by dedicated height monitoring, utilising specialised systems and techniques. It is important that both State authorities and aircraft operators (civil and military), understand the implications of ASE and know how to respond when receiving reports of aircraft with poor ASE characteristics from the Regional Monitoring Agencies who are tasked with monitoring responsibilities.

EUROCONTROL and the U.S. Federal Aviation Administration (FAA) are jointly organising a workshop focusing on Altimetry System Error (ASE), its causes, how it is detected, how it should be managed and its effect on the operational environment." 

Last updated: Friday, December 1, 2023