[ERJCaptain]

It was in international airspace, but in Dakar Oceanic’s ATC sector.

As for the lack of radio transmissions, when you’re over the open ocean, transmissions are done over HF frequencies. HF is somewhat unreliable, so even if they wanted to broadcast a mayday, there is a chance that Dakar wouldn’t hear it.

[livius]

Oh, OK, that’s interesting. Thanks!

I don’t think Dakar was responsible for this, btw, I was just surprised that this was their airspace.

[zipper]

I’m sure they had satcom voice — the messages over ACRS were via satcom.

But they had multiple failures by the time they plummeted so they were probably too busy to try it, or by then it wasn’t available.

Truly a nightmare scenario.

[bill1952]

Mmmm. The distress call is 1st done by setting the transponder to 7700.

Radar picks up that without radio.

[Vendome]

If they did transmit someone, somewhere heard it. There radio hobbyists all over the world with sophisticated equipment that listen in on just about anything.

[dragnet2]

As for the lack of radio transmissions, when you’re over the open ocean, transmissions are done over HF frequencies. HF is somewhat unreliable, so even if they wanted to broadcast a mayday, there is a chance that Dakar wouldn’t hear it.

You could be correct, but please know, I personally spoke with someone in the Azores, (middle of the Atlantic) from the west coast U.S., on HF during recent thunderstorm activity, and this was using 100 watts of power, with an antenna only 40 feet off the ground.

[cynwoody]

As for the lack of radio transmissions, when you’re over the open ocean, transmissions are done over HF frequencies.

VHF would have a range of three or four hundred miles between planes at cruising altitude. My understanding was that pilots crossing oceans routinely exchange information about conditions encountered using air to air VHF. How many other airplanes would have been within that radius?

[zipper]

Few, if any, commercial aircraft are equipped for voice satellite communications as its prohibitively expensive. Instead, we have ACARS which uses satellites, but only transmits data — that’s how their maintenance base in Paris got the error messages from the aircraft.

This statement was true a few years ago: "few, if any, commercial aircraft equipped for voice satellite communications" but not any more. Now it is fairly common for overwater operators and ATC facilities to have datalink comm with ATC, as well as surveillance via SATCOM from ATC, and SATCOM voice, all at the same time.

In your first post you said:

As for the lack of radio transmissions, when you’re over the open ocean, transmissions are done over HF frequencies.

So apparently you meant only voice transmissions, because, as you mentioned in your reply to mine in which I pointed out ACARS messages were delivered in the final minutes via SATCOM:

ACARS which uses satellites, but only transmits data — that’s how their maintenance base in Paris got the error messages from the aircraft.

I'm not saying this crew was in contact with ATC via SATCOM voice, but I am willing to wager that if the airplane was equipped with the ability to send ACARS messages via SATCOM, then it follows they likely had more ATC communications functions available (if the ATC facilty in question even had that capability).

By the way I don't think they were in the Dakar Oceanic airspace. They were about 70-some-odd miles NE of ORARO, which would have them at least around 30 miles from Dakar Oceanic airspace. They were in the Atlantico FIR, SBAO.