The other iconic accident of modern times – AF447 – didn’t trigger an ELT even though it came more or less straight down vertically.
There is a switch on the panel: ELT: Armed/On/Off. Put it to Off and no one will ever know where you came down.
I now realise the GA ELTs can be thus disabled, but can airliner ones be cockpit-disabled too?
There is news today that some large objects have been spotted off the coast of Australia.
If you make the assumption that something happened to the pilots and they were incapacitated, and a route from Airport A via x,y,z waypoints to Airport B has been programmed in the FMS. What happens from a autopilot point of view if there was no manual intervention (a heading change for example, or a disconnect) – does it carry on through all of the waypoints until it runs out of fuel?
What happens if an aircraft in this situation was not over water and was programmed to head to a large airport suitably in fuel range. Would the AP perform an AutoLand (I thought not as I presume the destination airport is only programmed because a runway and STAR would not be know upon deperature). Would it reach its airport waypoint and then just proceed on that track forever until it did run out of fuel. The reason I ask is because I assume they cant be ‘remote controlled’ from the ground and diverted somewhere else, but you wouldnt want an out of control airliner heading towards a large airport or city like an out of control missile. Maybe the chance of this event happening has thus far been considered 0.01 %?
ELT’s are Armed or ON….I don’t have an Off switch….Airbuses, Triple sevens I assume neither have an Off switch just Armed /On momentaryTest…
I now realise the GA ELTs can be thus disabled, but can airliner ones be cockpit-disabled too?
The GA ELTs that I’ve seen only have an Armed/ON switch, with no OFF setting. To switch it off completely, you’d have to pull the CB – assuming the CB is accessible and can be pulled in the first place.
What happens if an aircraft in this situation was not over water and was programmed to head to a large airport suitably in fuel range.
I think, but am not sure, that FMSs typically fly to the last waypoint of the activated route, and then enter a holding pattern around that waypoint. And it would remain in the hold until running out of fuel. I would assume that that SOP would be to program the FMS before the flight with the plan as it is known before departure, so that would be the route up to the point where the STAR would start.
Once you get vectors from ATC the FMS would just fly those headings until running out of fuel.
The Cypriot 737 which depressurised and crashed in Greece entered a hold at the last waypoint. And the 777 is a Boeing too.
Obviously it depends on whether a route was active then. If they were in HDG, they would just carry on.
The electrical fire theory would fit the known info but it would be a very rare type of fire which would disable the pilots yet allow the plane to fly on for 6-7 hours, on autopilot. Has that ever happened before? I have burnt a number of aircraft tyres myself…
However, how much of the info currently out is reliable, who knows? It’s been a complete mess. No wonder the relatives are going crazy. And if anybody has good data they are not going public with it, because of military considerations. The media reporting has also been atrocious.
And if anybody has good data they are not going public with it, because of military considerations. The media reporting has also been atrocious
Maybe that has just changed…. http://www.bbc.co.uk/news/world-asia-26659583
“15:03: Inmarsat says it learned on 11 March that the plane had continued to fly for seven hours or more and that it was very unlikely to be in the area where the Malaysian authorities were searching. Inmarsat has made the information public because of concerns over the way the search operation has been handled”.
“15:12: The information Inmarsat has revealed to the BBC about the data it gave to the Malaysia authorities matches a report in the Wall Street Journal published earlier on Thursday. Inmarsat claims the Malaysian authorities continued to search in waters close to the plane’s point of departure despite receiving satellite data suggesting that the plane continued to fly for several hours after losing contact with air traffic control.”
I think Immarsat said fairly early on they were getting pings every 30 mins. This had been widely misreported as them having received just one ping after about 7hrs.
The problem is that the plane could have just been flying a holding pattern in the same place. The sat pings reveal only the distance to the satellite.
A serious opinion on the issue from the pilot’s perspective.
http://www.wired.com/autopia/2014/03/mh370-electrical-fire/
EDIT: Disregard, just saw it was earlier posted further up.
The GA ELTs that I’ve seen only have an Armed/ON switch, with no OFF setting. To switch it off completely, you’d have to pull the CB – assuming the CB is accessible and can be pulled in the first place.
Nope. I’ve flown a variety of aircraft that had an on/off switch for the ELT on the panel.
The sat pings reveal only the distance to the satellite.
It reveals the angle between sender (SATCOM in this case) and satellite. However, there is no N or S in there, hence the two possible paths MH370 could have taken, i.e. one North, one South. Given that the northern one would have led over several countries with decent military surveillance capabilities, the southern route was always more likely. Now the Aussies claim to have found what appears to be wreckage. We’ll see…
