Thursday, Mar 27, 2014 at 12:00
"The biggest problem is what the transponder will transmit too and how much power is required to do this.....the plane in question is suspected to have gone down what..2000Km away from the nearest contenent...that is Australia..that is a long way from anywhere."
There has been considerable mention here and elsewhere of the aircraft's transponder. It is not really relevant because it relies on a query from ATC radar (max range about 320km - see Followup 811969 further up the page) before it replies with limited
information (which does NOT include position) to ATC.
The really useful piece of kit is ACARS. This broadcasts, amongst a heap of other things, the aircraft's position, via satellite to whoever wants to receive it. Range from land-based stations is not an issue. For a demonstration, install an app called Flight Radar 24 on your iOS or Android device. (Get it from the Appstore or Google's Playstore. It is free.) It will appear that your phone or tablet has turned into a world-wide radar system. The info required to make this happen comes from ACARS.
The missing aircraft had this equipment and was using it, but along with other communications equipment, it was switched off or deactivated early in the flight for reasons as yet unknown. Had it not been deactivated we would know precisely where the aircraft went down.
I would not be surprised if one of the results of this accident is the compulsory use by commercial aircraft of a tracking device like ACARS that is somehow powered separately from everything else and cannot be switched off while the aircraft is in flight.
This raises issues of the sovereignty of nation states. There is an organisation called the International Civil Aviation Organisation. Member states (the majority of nations) of ICAO bind themselves to its recommendations and directives. Some other states like to go their own way.
Cheers
Frank (retired ATC)
FollowupID:
811972