|
Originally Posted by Interflug
(Post 8371513)
They say "inaccurate", not "false"…
Accurate would be, if precise data would be named, not only "some time"… just saying… :cool: |
Pberret,
Ads-b is sent over the 1090 mhz mode s link. |
I would add: no emergency beacon so either under water or intact on land. Also, there have been many land accidents in which ELT devices have failed. |
The original WSJ article appeared to have been heavily sourced to U.S. national security officials in Washington. And as Mr. Snowden has revealed, the U.S. captures everything in the ether. You are free to infer whether this capture includes ACARS data. |
ACARS does not equal transponder so what you see on FR24 is not ACARS data. What frequency (or band) does the ADS-B transponder transmit on? Or is it sent to a satelllite? ACARS signals are sent from the a/c and received by a ground station, for onward processing etc. AFAIK, the relevant ground station in that region is Hat Yai in southern Thailand. Here is a copy of SITA's map of their VHF ACARS ground station coverage in Asia: http://bbr.asia/sita.jpg Although the map resolution is not so good, VHF coverage exists throughout the region between KL and the Vietnamese coast. The only area where no coverage is shown is a region to the north of Phuket Island (west coast of Thailand) and out towards the Andaman & Nicobar Islands, (but there does seem to be an ACARS ground station somewhere on the latter islands). HF ACARS is also used, with Hat Yai again the relevant ground station, operating on 5,655MHz and 13,309MHz. ADS-B operates on 1090MHz (UHF). Transmission is generally over a line of sight path. From the above, you can deduce that when a plane is outside the range of reception for VHF ACARS or UHF ADS-B, no data/signal can be received, unless an alternative channel (satellite or HF is used). |
My better half (retired BA 747 skipper) says on the 744 the power for the engine data transmission is shared by the radios..same source ( I think he said main sby bus). So if power is lost to eng data transmission it must also be lost to radios-yet there was a radio call after the last eng data transmission was there not? Or does the 777 have a different system?
|
http://news.sky.com/story/1225034/ma...r-plane-search
US officials said on Wednesday none of the country's satellites detected a mid-air explosion when the plane lost contact with air traffic controllers. Malaysia's air force chief confirmed military radar detected what could have been the airliner in an area in the north of the Strait of Malacca at around 2.15am local time on Saturday - 45 minutes after the plane vanished from air traffic control screens. |
Forget conspiracies, look at reality.
Ops Centers for airlines, ac manufacturers, and of course governments, monitor ac systems real-time or near real time. Currently, due to security issues, public outcry, other issues, it is not generally known the level of surveillience on virtually all ac. From the automated FDR broadcasts, to sats, wifi, and of course, the mobile devices of the passengers, it is out there. In my opinion, the exact reasons and location all already known by these methods. Much like AF 447, the search went on for a very long time and was then abandoned. Yet, a contractor was able to virtually go directly to the site a few years later? I think this is much the same. With methods currently available by National Security Agencies, the location and uotcome is already known. Therefore, it is not in their best interests to reveal the information and associated levels of surviellience. There is no need to rush, the outcome is the same, if the search takes 5 days or 500 days..and therefore, no need to compromise security. |
On a B777 when VHF stations are out of range ACARS uses Satellite coms automatically.
|
LiveryMan;
So, we are essentially back to square one. A 777 is missing. We know how many were supposed to be aboard, the airline and flight number. That's about it. Hypothetical Hello. This is my third attempt to make a post here. Maybe, as I'm new here I'm doing it wrong. I am a licenced engineer, B747. This post attempts to describe, with precedents, a possible single failure that would cause loss of coms, depressurisation and crew disablement due to hypoxia. Precedent: QF30 25 July 2008 Pax oxygen bottle "explodes" tearing a hole in fuselage. Ref: Please google "Qantas oxygen bottle explosion" and view photos of damage. The picture taken inside the fwd cargo compartment shows one bottle missing. there is no evidence of shrapnel damage in the photo. Therefore, no eplosion. The bottle appears to have detached itself from its connections and propelled itself down through the fuselage skin. 777: The crew oxygen bottle is mounted horizontaly on the left aft wall of the nose wheel well structure with the fittings (propelling nozzle) facing forward. This aims the bottle, in the event of a QF30 type failure, directly into the MEC containing all boxes concerned with coms and a lot more. Before all of its energy is spent, an huge amount of damage could be caused to equipment and the bottle could, conceivably, cause a decompression. When the crew respond by doning oxygen mask, there is no oxygen and hypoxia is the next link in this proposed chain of events. This link is entitled "Hypothetical" and is only that. I believe it ticks a few boxes. Hoping this post make it and generates some discussion. Bloxin. |
Pitot Probe #2715
Thanks for the drawing of that oxygen bottle.
http://www.pprune.org/rumours-news/5...ml#post8371268 I understand that the bottle is located within the MEC. So even if a potential failure of the bottle or its connection is not catastrophic, a scenario in which a pure oxygen atmosphere in the MEC bay is created seems possible? Apollo 1 comes to mind. On the other hand it is hard to imagine the A/C continued on autopilot with the MEC destroyed by fire. A report of a previous fire in the MEC of a 772 probably linked here before : http://www.aaib.gov.uk/cms_resources...7%20N786UA.pdf |
Hornbill,
I wonder why RR aren't saying? |
This is strange as it suggests that Subang was tracking it for another hour after the transponder stopped being received. Am I missing something here? |
If it did a u turn they would have known. |
Originally Posted by philipat
(Post 8371638)
Perhaps, yes. The times are all LOCAL not UTC. So remember that Vietnam time is one hour BEHIND Malaysia time (Even though further East).
It later emerged that Subang Air Traffic Control had lost contact with the aircraft at 01:22 and notified Malaysia Airlines at 02:40. Wiki reference 18 points to Crash: Malaysia B772 over Gulf of Thailand on Mar 8th 2014, aircraft missing |
Quote: if RR were to say that they had engine information, it might be of considerable use to the accident investigators, even without any wreckage being found . I wonder why RR aren't saying? Theres probably a protocol in place that dictates that any info found is sent to the situation controlling agency then a controlled/verified/spun release of the info would be made. I think it would be quite improper for RR or Boeing or the Comms vendor to make a statement without either being invited to do so or given the permission of the Malaysians at this time. There are still relatives to consider too. Maybe thats why. |
Passengers on 911 a/c managed to make calls?
My earlier question did not appear. The last message from the a/c was "Ok - roger that" Isn't that rather an unusual response when leaving one ATC for another, surely you always give your callsign? |
Having never tried it, or even thought about it, is it possible to send a text from a cell phone from a aircraft? I think it would be quite improper for RR or Boeing or the Comms vendor to make a statement... |
Can we please put this one o bed for good?
777: The crew oxygen bottle is mounted horizontaly on the left aft wall of the nose wheel well structure with the fittings (propelling nozzle) facing forward. This aims the bottle, in the event of a QF30 type failure, directly into the MEC containing all boxes concerned with coms and a lot more. NO IT ISN'T!! The fittings are on the rear/aft facing end of the bottle. If the fitting was to fail and the restraining straps were also to fail, then potentially, the bottle would go forwards not aft. That would send it either straight through the radome or potentially deflected upwards into the below flightdeck area. This contains the backdrive mechanisms for the control column and rudder pedals. The possibility (of an O2 bottle failing as such) is remote at the extreme but not unprecedented. I don't buy it. |
The last message from the a/c was "Ok - roger that" Isn't that rather an unusual response when leaving one ATC for another, surely you always give your callsign? As for cell phones and aircraft (yet again), hands up all those who have flown between say western europe and the far east and never, ever found the likes of a "welcome to CIS telecom" ( or something similar) text on their phone on arrival in NRT.....:uhoh: :uhoh: |
| All times are GMT. The time now is 20:41. |
Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.