Purpose of antenna?

[PEHowland]

Hello. I was at Prague yesterday, waiting for a connecting flight, and noticed a Swiss Air Airbus 319 with an unusual antenna housing towards the rear of the aircraft, on the top, and between the two normal VHF antenna. It was fairly long and low and unpainted - I assume it is housing a microwave array of some kind. You can see it in this picture online here (http://www.airliners.net/photo/Swiss-International-Air/Airbus-A319-112/1520458/&sid=def8618fdfd59ee8aced906c47185f52). What is it's purpose? ACARS? Passenger telecoms?

Thanks,

Paul

[Dan Winterland]

Looks like an INMARSAT (INternational MARitime SATellite) aerial. Used for passenger SATCOM and crew communications, both voice and ACARS.

[STBYRUD]

After referring to the Airbus FCOM I can tell you that if they have the standard antenna arrangement this cannot be the SATCOM antenna (its a lot too large for that, too), that should be forward of the middle next to the GPS receivers - I'm not entirely sure, does Swiss have Airphone service on their aircraft? Provisions for satellite TV? Compare it to the antenna that Frontier has installed on their busses: http://www.luftfahrt.net/galerie/photos/2004/16/1103932043_N914FR_Airbus-A319-111_Frontier.jpg

Looks relatively similar, at least in size - Frontier is using it for their DIRECTV service.

[STBYRUD]

Excuse the double post, but Dan is probably right - since Swiss uses these on their A340s (saw a press statement about it a while back), they might have them on their A319s as well (looks very similar): CMA-2102 SATCOM High Gain Antenna System (http://www.cmcelectronics.ca/En/Prodserv/satcom_high_gain.html)