GadgetFreak

Reuters is reporting that an LH 747-400 was on the same path about 30 minutes in front of the AF flight and an LH cargo plan was about two hours behind it on a slightly more southerly route and neither had particular difficulties with the weather.

pptp

Totally different satellites. What you're thinking of is GPS and it's used to navigate not to track (not yet at least, but it's coming down the pipe). When AC are over large bodies of water, the standard way of tracking them, as archaic as it seems, is for the AC to radio in a position report every so often via a high frequency radio channel. The pilots get their position from GPS and INS (inertial navigation system*); before GPS it was only the latter. ATC may not know a plane is lost until they fail to receive a (roughly) scheduled position report.


*Really quite an amazing system:
An inertial navigation system includes at least a computer and a platform or module containing accelerometers, gyroscopes, or other motion-sensing devices. The INS is initially provided with its position and velocity from another source (a human operator, a GPS satellite receiver, etc.), and thereafter computes its own updated position and velocity by integrating information received from the motion sensors. The advantage of an INS is that it requires no external references in order to determine its position, orientation, or velocity once it has been initialized.

An INS can detect a change in its geographic position (a move east or north, for example), a change in its velocity (speed and direction of movement), and a change in its orientation (rotation about an axis). It does this by measuring the linear and angular accelerations applied to the system. Since it requires no external reference (after initialization), it is immune to jamming and deception.

pilotboy1985YYC

wow, such terrible news. When I heard there was an AF accident today, my first thought was an AF ran off the runway, like what happened in yyz, but everyone survived. When I heard it was a crash into the ocean, I was shocked. What terrible, terrible news.
Where most of us here are frequent travellers, I know this hits pretty close to home. I'm sure most of us have wonder " will I become the next headline" while finding your aisle seat!.

Prayers to the family of everyone involved.

Buster CT1K

I am pretty sure the accident in which the AF 340 overshot the runway at YYZ caused the cancellation of a return YYZ-CDG flight. But perhaps AF has substitute planes at its CDG homebase that can fill the gap caused by the loss of AF447.

My deepest thoughts to the casualties and their families.

YYZ_TVGuy

The on-board GPS could encode its position fix and forward it back to HQ on whatever sidechannel the Iridium or whatever system uses to control calls anyways. Its just bits - in fact, remarkably few - that need shuffling around.

I think several people are just pointing out that such information would be useful on a day like today - and that its certainly not technologically out of our reach, nor would it be prohibitively expensive. Just requires engineers on both sides to expose the correct bits.

(Slightly relevant: I work for a company with a very large RF division.)

colpuck

Black boxes are strong, but not two miles down strong. If they ended up in deep water they could be crushed from the pressure.

pptp

Probably a combination of cost and existing ATC infrastructure.
Yes there are dead spots for the normal radios, that's why the HF radio is used for position reports.

The _Banking_Scot

Hi,

What horible news.

My thoughts are with the familes and friends of all those on board.

alanh

The black box itself may be crushed, but the memory chips are designed to be submerged at 6000m (about 20,000 feet) for up to a month.

Clarkcc1

WAKE UP CALL AIRLINES!!!!

YYZ_TVGuy, that's what I was thinking but wanted to get input first. If it turns out that the lack of simple measures like not piggybacking on Iridium (or whoever the satellite comm provider is for phone service) was a contributing factor in this accident, I will not believe an excuse like "we didn't think it was necessary."

I, being an IT professional and avid traveler, somewhat assumed that the sat phone service also meant communications for the pilots/location of plane. If not that is truly an abomination and inexcusable that simple measures have not been implemented yet.

I could write the requirements document in a day!! Airlines, if you want a Product Manager for this enhancement, PM me.

bwhite

We tend to learn many things and implement changes from unfortunate events like this. Perhaps your suggestion will be one of them.

GadgetFreak

The plane was in contact. Just no people were in contact. Reuters is reporting that there was a 4 minute period of messaging back and forth between the plane and "maintenance computers" (wasnt clear whether they were AF or Airbus Industries computers from the story) about multiple component failures on the plane. This was about 40 minutes after the last verbal contact and about 6 minutes from what I could tell before their next scheduled cockpit communication, which never occurred.

docklander

I always get slightly spooked on those overnight Atlantic crossings once the aircraft has cleared the coast and heading east-and you reach that point of 'no return' in total darkness.Whatever happened in the final moments of AF 447s journey, i truly hope no one suffered too much.tragic

aceflyer2

Is this typical weather for this time of the year on this routing? Also, I thought pilots are now instructed to NOT fly thru thunderstorms?

jfulcher

What doesn't make sense is that the airplane can communicate that information, but not regularly the position!