Satellite Available Bandwidth
Originally Posted by
mixture
No, it really doesn't.
Do you buy an A380 and the leave it on the tarmac and just shout to the world that you've got capacity 400 people ?
No.
Well its the same with satellites.
Satellites cost a lot of money to build, get into space and monitor.
A satellite is in use 24 hours a day, 365 days a year as soon as the satellite reaches space, the operators will already be activating contracts ..... the cost of using satellite transmissions reflects the limited spare capacity available.
.....{{SNIP}}}........
So please guys... ENOUGH of these stupid requests for realtime streaming data from all aircraft .... it just isn't workable. Period.
It is dangerous in any technology field to say something is impossible.
Check INMARSAT latest offerings for broadband internet to passengers
Inmarsat S-band services - Inmarsat
Check their new connectivity for ATM services
SwiftBroadband - Inmarsat
Iridium Next is also adding broadband links
https://www.iridium.com//About/Iridi...echnology.aspx including importantly 'short burst data with bandwidth on demand'
Tracking
That brings me to the repeated posts on Tracking. Both INMARSAT and Iridium Next are offering a free tracking service. This is for aircraft carrying ADS-C (that is Automatic Dependent Surveillance - Contract over Satellite links). All widebodies are equipped for this from the factory, even if the operators turn the equipment off it is standard fit. It provides more than ADS-B and is usually transmitted at 4 or 10 minute intervals. After AF447 the French BEA asked for the transmissions to be increased in regularity. This was avoided as beancounters in the operating companies did not want to pay the cost. As the SATCOM companies are providing it FREE there is now no excuse not to regularly pass ADS-C reports (which can contain a lot more data than just position and altitude.
It is mandated in many areas for aircraft to broadcast their position at up to twice a second on Automatic Dependent Surveillance - Broadcast (ADS-B Out). This is line of sight transmission to ground systems and other aircraft. In this case the aircraft WAS broadcasting its position. The air traffic unit will have stopped receiving it if the aircraft was below the horizon (below line of sight) or the power failed in the aircraft.
Emergency Location Beacons
These ELTs are carried by large numbers of aircraft both fixed and portable. In most cases the fixed beacons have a g-switch and the portable beacons an immersion switch that activates them. They broadcast mainly to 406Khz and give aircraft ID and position. Note people they already exist. However, if the aircraft sinks and the crew have not deployed life rafts with ELTs then the ELTs will not be able to send radio transmissions through the water. There are several military aircraft that have deployable external ELTs that would float. Needless to say the beancounters have not gone for these on commercial aircraft. Standard response: How many aircraft have been lost at sea that would have been helped by an ELT in the last 10 years? How many flights have there been in the last 10 years? What is the chance of one of our aircraft being one of those 3 or 4 that might crash in the next 10 years? Have you seen how much these things cost and the life-cycle maintenance cost? Go away.
So to sum up-
There IS sufficient satellite bandwidth to send DFDR/CVR data but probably as a short burst when the aircraft thinks it has a problem rather than a continuous download.
There are already tracking systems on aircraft that can provide accurate positions all the way to the surface - but no compulsion for the airlines to switch them on despite the satellite comms providers providing the tracking as a FREE service.
There are already methods of auto deploying ELTs when an aircraft crashes on land or in water, but only the military have fitted them to aircraft.