THE USE OF FILSER TRANSPONDERS IN THE AMSTERDAM FIR

1 — LIMITATIONS

The Minister of Transport and the Minister of Defence announce in cooperation with the air navigation service providers that the use of the transponders of Funkwerk Avionics types TRT600, TRT800A and TRT800H is not accepted in airspace designated as Transponder Mandatory Zones (TMZs) within the Amsterdam FIR. These areas are published in AIC-A 07/08 and AIP ENR 2.2 paragraph 4. Motorised and non-motorised aircraft equipped with one of the mentioned transponders, have no access to these areas. This measure becomes effective with immediate effect.

This limitation expires after modification of the transponder conform the Airworthiness Directive to be published by EASA.

The Funkwerk Avionics transponder type TRT800 is excluded from this limitation. This transponder is working correctly.

2 — BACKGROUND

The use of mode S transponders of Funkwerk Avionics GmbH (previously Filser Electronics GmbH) types TRT600, TRT800A and TRT800H is not accepted in airspace designated as TMZs within the Amsterdam FIR. The transponders are sometimes intermittent not detectable by the mode S secondary surveillance radar (SSR). For that reason both EASA and the Ministry of Transport have issued an airworthiness directive (AD) to address the problem. The effect of these ADs is that the transponder cannot be used in airspace where transponders are mandatory, unless the navigation service providers accept the use of these transponders before entering their airspace.

Reports from Air Traffic Control the Netherlands and the Ministry of Defence (Dutch Mil) show that the problems with this transponder, as remarked by EASA, do occur in the Amsterdam FIR. But the loss of detection of the mode S function is mostly for a short period, with the result that the transmitted mode S label disappears from the radar for that period. The aircraft is however still visible for the air traffic controller because the mode A/C signal is transmitted without disruption.

In October extensive tests have been performed in Switzerland. The problems with the TRT600, TRT800A and TRT800H have been confirmed during the tests. The test also proved that the transponder type TRT800 works correct. As a result of these tests EASA issued EASA AD 2008-158R1.

During the tests the working of the mentioned transponders was also tested against the working of the airborne collision avoidance system ACAS. On the contrary to earlier indications, the correct working of ACAS cannot be guaranteed. A possible incorrect working of ACAS might have an impact on safety. To guarantee the safety in airspace used by commercial air transport, it is decided that aircraft equipped with one of the mentioned transponders are not accepted within airspace designated as TMZ. Commercial aircraft equipped with ACAS use these TMZs frequently. After modification of the transponder, aircraft are allowed to enter the TMZs.

3 — INFORMATION

With questions about this AIC-A please contact:

4 — DOCUMENT CONTROL

This AIC is a revised version of AIC-A 11/08, dated 09 OCT 2008.