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MH 370 Flew Extra 4 Hours
U.S. investigators suspect that Malaysia Airlines Flight 370 stayed in the air for about four hours past the time it reached its last confirmed location, according to two people familiar with the details and data automatically downloaded and sent to the ground from the Boeing Co. 777's engines as part of a routine maintenance and monitoring program. (online.wsj.com) Más...Sort type: [Top] [Newest]
Please excuse me if my area of inquiry has been covered earlier in this chain, but I have been wondering why transponders in commercial aircraft are not designed so they cannot be "turned off" from inside the aircraft. I have watched news reports and endless talking heads on the topic of this missing aircraft but none I have seen or read has touched on this issue. It would seem axiomatic that shielding the transponder operation from "in flight" tampering would make it easier for the authorities to distinguish incidents involving human intervention from those involving catastrophic system failure.
Pilots will always be able to pull the circuit breaker to disable a transponder (or any piece of avionics equipment) out of safety, since an electrical fire could necessitate removing power to that instrument. Additionally, commercial aircraft usually have two transponders so one needs to be able to powered off/standby when it is not the active one.
FAA rules and regulations require that a transponder be able to be turned off for when the plane in not in flight. Also ability to turn off any electrical circuit is imperative as an electrical fire at 30,000 ft is quite different than on the ground - quickly getting out and letting the firemen handle things isn't really possible in the air.
Even if a pilot or hijacker does turn off the transponder it doesn't actually disappear off of radar. It still shows up, the only change is the plane doesn't report who it is and what altitude it's flying at. If killing a transponder actually did make planes immune to detection by radar the military wouldn't have spent billions on stealth technologies.
Even if a pilot or hijacker does turn off the transponder it doesn't actually disappear off of radar. It still shows up, the only change is the plane doesn't report who it is and what altitude it's flying at. If killing a transponder actually did make planes immune to detection by radar the military wouldn't have spent billions on stealth technologies.
John, I agree to some point however if the FAA or other ATC agencies do not use the "old style" radar imaging, i.e. the "blip" or as I was taught, the raw return image, then turning off the transponder would make the plane disappear from the ATC screen. Again, this is only true if our FAA and other ATC agencies do NOT use the raw radar return whic I'm told is the case.
Earlier in this thread I asked if the FAA still uses the "old style" raw radar return in CONJUNCTION with the transponder digital data. I didn't get a reply, or at least one that answered the question.
Stealth technology is attempting to remove, or at least make the raw radar return i.e. the "blip" smaller or completely disappear. This is of course assuming the aircraft has it's transponder turned off.
Earlier in this thread I asked if the FAA still uses the "old style" raw radar return in CONJUNCTION with the transponder digital data. I didn't get a reply, or at least one that answered the question.
Stealth technology is attempting to remove, or at least make the raw radar return i.e. the "blip" smaller or completely disappear. This is of course assuming the aircraft has it's transponder turned off.
Are you forgetting this aircraft was outside US airspace when it disappeared? FAA etal have no meaning in Malaysia. I don't know what their laws and regulations are. Their scheduled destination was Beijing via Cambodia and Vietnam and I don't know their requirments.
Mark,
Yes, I know it was outside US airspace and the FAA rules do not apply. My main question was if ATC agencies around the world still use the raw radar return or just transponder digital data to "see" aircraft. I was asking if anyone knew if here in the US the control centers still use BOTH the raw radar image AND the transponder digital data/information.
The systems I am familiar with could only use raw radar image that was no further then 60 miles from the transmitter yet the transponder information could be used up to 200 miles away.
Yes, I know it was outside US airspace and the FAA rules do not apply. My main question was if ATC agencies around the world still use the raw radar return or just transponder digital data to "see" aircraft. I was asking if anyone knew if here in the US the control centers still use BOTH the raw radar image AND the transponder digital data/information.
The systems I am familiar with could only use raw radar image that was no further then 60 miles from the transmitter yet the transponder information could be used up to 200 miles away.
A good question,certainly. I'm not familiar with ATC on that side of the world any more. It used to be that the transponder signal, "primary radar" was an overlay to the blip on the radar screen, a CRT back then. I haven't kept up wit advances.
Transponders are strange critters. I read an account where the back up to AF1 squawked the identity for a Gulfstream as a "cloaking device". I forget where it landed now, but the airport authority was pretty amazed when a 747 made the approach.
Transponders are strange critters. I read an account where the back up to AF1 squawked the identity for a Gulfstream as a "cloaking device". I forget where it landed now, but the airport authority was pretty amazed when a 747 made the approach.
I am in agreement. I understand what Jeff Lawson is saying about needing the ability to disconnect the electrical power to electrical equipment due to a hazardous condition. But, there should be some way, in an event like this, that tracking is possible. We had a situation in the 9/11 attacks where transponders were turned off, and tracking was not possible. We also have this case now, where it is apparent that vital tracking systems were turned off. One point of reference, we don't find accidents where the NTSB reports: "We found the Flight Data Recorder, but cannot determine what happened during the flight because the pilot turned it off before the flight......" We do find certain things happen that cause some data to be lost because of a power loss right before the crash, but, usually, much data is available. In the same way, there should be some sort of transponder that can signal it position in the same way the transponder does that cannot be turned "off" in the same way that the FDR cannot be turned off.