WG-98 Call for Participation

EUROCAE is launching this Call for Participation to inform interested parties about a new activity and to provide a possibility to nominate project participants.

If your company is interested in a contribution to this activity, please complete the registration form the latest by Friday,  2 March 2018.

The Kick-off meeting of this new activity within WG-98 is scheduled for 18-19 April 2018 in EUROCAE premises.


EUROCAE WG-98 will begin work on the following deliverable:

  • ED-xxx, Minimum Aviation System Performance Specification for Aircraft Emergency Locator Transmitter Return Link Service

The Kick-Off meeting for this activity is scheduled for 18 and 19 April 2018 at the EUROCAE premises in Paris. The agenda and meeting details will be sent to nominated participants following the deadline of this call for participation.



Several aircraft disappearances occurred over water, including Malaysian MH370, for which the potential survivors, the wreckage and the flight recorders have not been recovered. As the long-lasting or non-recovery of recorders greatly reduces the likelihood of discovering the actual cause of accidents, and in order to improve the recovery of wreckage and flight recorders following an accident or incident, it is necessary to improve performance standards for new-generation Emergency Locator Transmitters (ELTs) and their means of activation.

In addition, remote activation from the ground of ELT offers the possibility to localize in-flight a non-cooperative aircraft and therefor participates to the ICAO Global Aeronautical Distress & Safety System (GADSS) concept of operations.

Additionally, a general effort has been made to make General Aviation (GA) safer, to make the complete ELT system more reliable (from the ELT unit to the antenna, including the cables) and reduce the GA distress cases where the ELT unit is operational but not the complete ELT system (unplugged antenna, damaged cables). In particular, this effort led to the development of ELT with internal/integral GNSS receiver and SAR antenna. For those integrated ELT, a remote activation from ground would be relevant for disappearance cases when the ELT is not triggered by G-switch or manually.

The SAR/Galileo Service, with its Forward Link Service (FLS) is an integral part of the future medium orbit satellite system and ensures the detection and localization of the ELT distress signals through the relay of these signals by the SAR repeaters on board the Galileo satellites. Their reception by the ground stations and alerts transmission to the Mission Control Centres (MCC). In addition, the SAR/Galileo Service also introduces a new SAR function, called the Return Link Service (RLS), which currently provides the capability to send acknowledgment messages to distress beacons equipped with a Galileo receiver. Other medium orbit constellations (e.g., GLONASS) should be equipped with similar features.

Two different expected acknowledgement types are: Type 1, automatic acknowledgment with automatic transmission of a Return Link Message (RLM) to the emitting ELT after the alert has been detected; Type 2, manual transmission of a RLM to an ELT only after it has received an appropriate authorization.

The Type 1 RLS should be operational by 2018. However, several other use cases of the RLS for Search And Rescue (SAR) in general, and aeronautical SAR in particular, can be foreseen among which the remote activation/deactivation from ground or the transmission of Return Link command messages. Indeed, the RLS will offer the possibility of a specific communication link between the ground segment and an ELT for Distress Tracking to remotely activate and deactivate the ELT. This link will enable the ELT to be triggered from the ground, by a third party having access to the RLS Provider, for example the relevant aviation authorities facing a non-cooperative aircraft with loss of radar position and/or VHF communications. The remotely triggered ELT will start transmitting an alert message with the encoded position of the aircraft.

EUROCAE WG-98 will develop Minimum Aviation Systems Specifications Aircraft for Emergency Locator Transmitter Return Link Service covering the function to trigger ELT transmission from the ground and define high-level concepts and typical functional interface requirements between the ELT and the ground. These overall concepts will also cover the satellite segment of the system. The use of new generation ELTs triggered from the ground through RLS will solve the issue of localization of non-cooperative aircraft overwater and of General Aviation aircraft that have crashed with no ELT crash sensor  activation if applicable or manual activation. The correct definition of the standard applicable to RLS triggering of new generation ELTs, in particular when associated with accidents and incidents that occur over water, will greatly aid the application to either new-design or new-build aircraft. The WG should review the practicality of installing new generation ELTs either for new-design, new-build aircraft or retrofit, for use by regulators.  It is also anticipated using the output of the working group to update the applicable EASA European Technical Standard Order (ETSO) and Part–OPS within the revised EASA rule structure.

The MASPS will also be useful in the ICAO context (Annex 6, GADSS) and Cospas-Sarsat environment. The MASPS will also address the high-level definition of the acknowledgement and the compatible ELTs within this service.


If you are interested in this activity and would like to contribute to the development of the two standards, please complete the registration form.