Malaysian Airlines MH370 contact lost
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Please tell me this isn't true. The nightmare scenario of some misguided or malicious person dropping a pinger overboard in the search area doesn't bear thinking about.
There must be as much effort being put into not giving anything away as there is in finding the aircraft.
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The conspiracy theories you lot come up with 
Yes, they might not use the latest and greatest but remember the two navies have worked together before with ship under way and other live fire exercises so it is not totally new to each other.
Yes, they might not use the latest and greatest but remember the two navies have worked together before with ship under way and other live fire exercises so it is not totally new to each other.
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Doppler
For all the intelligent discourse earlier in this thread regarding Doppler effects of electromagnetic waves, the mention of Doppler with respect to sound waves is curiously missing even though the effect is far more pronounced. The odds of getting precisely a 37.5 kHz return in an extremely noisy ocean are pretty low, at any considerable distance from the source.
These underwater sounds that have been heard may be the haystack we are looking for, or they may not. The odds are not in our favor without some kind of verified physical debris in hand. We shouldn't get our hopes up until then.
These underwater sounds that have been heard may be the haystack we are looking for, or they may not. The odds are not in our favor without some kind of verified physical debris in hand. We shouldn't get our hopes up until then.
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Doppler
The effect is more pronounced with acoustics.
It will be useful if the the frequency is exact, it isn't. There will be a frequency difference when you travel towards or away.
The frequency of a soft ping will be difficult to detect accurately.
It will be useful if the the frequency is exact, it isn't. There will be a frequency difference when you travel towards or away.
The frequency of a soft ping will be difficult to detect accurately.
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@iamhere 9586
What else is going to be transmitting on 37.5kHz in the Indian ocean ?
Lets try this again.
The media say the authorities say that they believe the signals are comming from a flight data recorder.
Only believe
What else is going to be transmitting on 37.5kHz in the Indian ocean ?
Suggest you listen to this . BBC Radio 4 - Broadcasting House, 06/04/2014 ..about 09:53 minutes in... which gives a pretty authoritative explanation as to WHY they are being cautious.
What else is going to be transmitting on 37.5kHz in the Indian ocean ?
Lets try this again.
The media say the authorities say that they believe the signals are comming from a flight data recorder.
Only believe
What else is going to be transmitting on 37.5kHz in the Indian ocean ?
Suggest you listen to this . BBC Radio 4 - Broadcasting House, 06/04/2014 ..about 09:53 minutes in... which gives a pretty authoritative explanation as to WHY they are being cautious.
Suggest you listen to this
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I think a Trent engine windmilling will keep a genny on line, providing the TAS remains reasonably high, so the partial ping will not necessarily coincide with fuel exhaustion time.
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For all the intelligent discourse earlier in this thread regarding Doppler effects of electromagnetic waves, the mention of Doppler with respect to sound waves is curiously missing even though the effect is far more pronounced. The odds of getting precisely a 37.5 kHz return in an extremely noisy ocean are pretty low, at any considerable distance from the source.
re the Chinese RIB, I believe that was a handheld detector. (the kind the Chinese have is designed for shallow water/handheld use e.g. by a diver)
I think a Trent engine windmilling will keep a genny on line, providing the TAS remains reasonably high, so the partial ping will not necessarily coincide with fuel exhaustion time.
On the B777 does the RAT automatically deploy with a loss of both generators?
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Lonewolf/RHAG, the answer to the problem, resolving differences, is a twin system. A ULB that remains with the airframe and a FLB (ELT) that is released on impact.
There appear to be two problems with the existing ELT - is it buoyant and does it have sufficient battery life?
As the ELT would help locate a crashed aircraft in the first vital 48 hours its short battery life was understandable. Even the existing short battery life should enable detection and localisation.
So, make the ELT ejectable and buoyant and give it the same black box capability of the ULB.
There appear to be two problems with the existing ELT - is it buoyant and does it have sufficient battery life?
As the ELT would help locate a crashed aircraft in the first vital 48 hours its short battery life was understandable. Even the existing short battery life should enable detection and localisation.
So, make the ELT ejectable and buoyant and give it the same black box capability of the ULB.
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Looking at AIS (marine traffic), there seems to be frequent if not a great amount of traffic in or near the search areas at any one time, not including the vessels involved in the current search. I assume this means that the area is fairly close to some designated shipping lanes. Would be interesting to have historical data as you can with FR24, just to see what was in the general area around the early morning of 8/3.
I'm sure that someone will remind me of the vast expanse of the area involved and the chances of a vessel being remotely close are slim, but you never know.
BTW I'm only talking about seeing or hearing something, not being involved in any way....
I'm sure that someone will remind me of the vast expanse of the area involved and the chances of a vessel being remotely close are slim, but you never know.
BTW I'm only talking about seeing or hearing something, not being involved in any way....
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Floating beacon and memory module
I thought I posted this earlier, but it appears to have evaporated in the ether. This HR Smith Group : (Technical Developments), Techtest Limited, Specmat Limited, Specmat outfit make just such a thing. I guess that the cost will be immoderate, but less so than the cost of the AF447 and current SAR efforts.
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ULB
How much difference would it make to locating an ULB if the pulse rate was lower, or perhaps 1 pulse every 10 seconds for, say, five pulses then one every second for a further five pulses. The aim being to extend the battery life. Or even making pulses less and less frequent after 5 days, then after 10 days and so on. Anything to make the battery last longer. The electronics to do this would be simple enough and would consume only very minimal power.
The people that wrote the specs probably never considered a situation like this - which is hardly surprising!
And why not a second ULB with a far longer interval at a low frequency to facilitate long range detection and rough position finding, then rely on the ultrasonic unit for precise location. It would need to have a long interval to make the battery last - low frequencies will require greater energy per pulse, but travel far greater distances. I suspect having one ULB operating at both low and ultrasonic frequencies would be rather too challenging, so on the KISS principle have two.
But that would of course not be necessary had the plane not been "lost" in the first place!
The people that wrote the specs probably never considered a situation like this - which is hardly surprising!
And why not a second ULB with a far longer interval at a low frequency to facilitate long range detection and rough position finding, then rely on the ultrasonic unit for precise location. It would need to have a long interval to make the battery last - low frequencies will require greater energy per pulse, but travel far greater distances. I suspect having one ULB operating at both low and ultrasonic frequencies would be rather too challenging, so on the KISS principle have two.
But that would of course not be necessary had the plane not been "lost" in the first place!
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Adding to things to improve detectability:
A floatable transponder, activated by g and/or seawater, that can be interrogated by search aircraft equipped with I band interrogators. Most military aircraft will have such interrogators for IFF (Mode2)
The transponder could be set inside part of the fuselage (wing root? tail area?) and be accompanied by a fluorescent dye marker. The panel could be released by g and/or seawater battery. Might de-icing be a problem here?
Having been winched out of survival dinghies many times in my aircrew career, I know how effective dye markers are. One idiot on my crew asked what does THIS do? while pointing the day end of a day/night flare INSIDE the dinghy. Needless to say he got wet. Had this been the Med, as opposed to the Moray Firth, we would have got wet to get the orange dye off. Instead the local pub was full of men who looked like we'd just been Tango'd!!!
A floatable transponder, activated by g and/or seawater, that can be interrogated by search aircraft equipped with I band interrogators. Most military aircraft will have such interrogators for IFF (Mode2)
The transponder could be set inside part of the fuselage (wing root? tail area?) and be accompanied by a fluorescent dye marker. The panel could be released by g and/or seawater battery. Might de-icing be a problem here?
Having been winched out of survival dinghies many times in my aircrew career, I know how effective dye markers are. One idiot on my crew asked what does THIS do? while pointing the day end of a day/night flare INSIDE the dinghy. Needless to say he got wet. Had this been the Med, as opposed to the Moray Firth, we would have got wet to get the orange dye off. Instead the local pub was full of men who looked like we'd just been Tango'd!!!
Best wishes.
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I doubt that both engines would have shut down simultaneously from fuel exhaustion. My experience (12,000 hours) has been that engines always burn fuel a little different, even when set in cruise to the same numbers. I can see a situation where one engine sucked air first, then the autopilot tried to maintain heading or track and altitude or speed, which resulted in a large yaw with roll angle followed by a spiral into the water. Not a long smooth glide as some have talked about here.
Yes, on the B-777 the APU will auto start with loss of both AC generators. Yes, the RAT will auto deploy with loss of both AC generators. Auto electrical load shedding occurs with loss of even one engine AC generator.
Yes, on the B-777 the APU will auto start with loss of both AC generators. Yes, the RAT will auto deploy with loss of both AC generators. Auto electrical load shedding occurs with loss of even one engine AC generator.
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Search Strategy
Australian Air Chief Marshal Angus Houston announced on April 6 that the Australian vessel Ocean Shield detected two pingers in the water and showed a map displaying the location of the sighting as S21°E104°. The map also showed the location of the sighting by the Chinese vessel HaiXun01 as S25°E101°, and showed that the two sightings were about 600 km apart. A map supplied later by the Australian government showed the same two sightings as lying on an arc going from northeast to southwest that corresponded to “satellite handshake calculation number 7”, which was made from the Inmarsat satellite data corresponding to the last partial ping of flight MH370. The aircraft is believed to have gone down somewhere along this arc, with slower air speeds corresponding to locations further northeast, and faster air speeds corresponding to locations further southwest.
It is interesting that there is an air route that passes between these two points on its way to Perth, route L894, as determined by waypoints POLUM at S19°59.95' E98°32.91' and NINOB at S26°0.15' E106°28.84. This air route happens to be the most southern of all air routes in the south Indian ocean and passes from northwest to southeast on its way to Perth. Is it possible that flight MH370 was on this air route just before ditching when its fuel ran out? If it had been flying by waypoints from POLUM to NINOB, this would have been consistent with using waypoints to fly from VAMPI to IGREX over the Andaman sea, and possibly also from IGARI to VAMPI to pass over the Malaysian peninsula. It would also have been consistent with using waypoints to fly around the Indonesian peninsula on its way south from IGREX to avoid Indonesian radar. If one assumes that MH370 used a waypoint like NISOK to avoid Indonesian radar on its way south from IGREX, then one can construct a flight plan consisting of the waypoints WMKK PIBOS GUNBO IKUKO IGARI VAMPI GIVAL MAPSO IGREX NISOK POLUM NINOB and determine how long it might take to get from Kuala Lumpur to the area between POLUM and NINOB. When you do this, you find that the flight time from Kuala Lumpur to NINOB is 7 hours and 52 minutes at 430 knots, which compares quite closely to the actual 7 hours and 54 minutes flight time determined by the 0:25 a.m. departure time and the 8:19 a.m. time of the last partial ping. Allowing for the possibility of additional waypoints between IGREX and NINOB would mean a longer flight distance, which would mean that the aircraft did not quite reach NINOB, but instead went down somewhere on the flight path between POLUM and NINOB. This, of course, assumes an airspeed of 430 knots. A faster air speed would have caused the plane to come down further southeast along the air route, and a slower air speed would have caused the plane to come down further northwest along the air route.
If one combines the Inmarsat data with the assumed flight path data, one gets two lines which intersect at nearly a 90° angle. The intersection point is almost exactly half way between the two ping sightings by the Chinese vessel HaiXun01 at S25°E101° and the Ocean Shield at S21°E104°. This means that the most likely place where MH370 went down is approximately S23°4.24’ E102°27.58’, which is the only point to lie on both the 40° arc and the L894 flight path. Given the short time remaining in the pinger lifetime, it would be well worth searching around this location.
It is interesting that there is an air route that passes between these two points on its way to Perth, route L894, as determined by waypoints POLUM at S19°59.95' E98°32.91' and NINOB at S26°0.15' E106°28.84. This air route happens to be the most southern of all air routes in the south Indian ocean and passes from northwest to southeast on its way to Perth. Is it possible that flight MH370 was on this air route just before ditching when its fuel ran out? If it had been flying by waypoints from POLUM to NINOB, this would have been consistent with using waypoints to fly from VAMPI to IGREX over the Andaman sea, and possibly also from IGARI to VAMPI to pass over the Malaysian peninsula. It would also have been consistent with using waypoints to fly around the Indonesian peninsula on its way south from IGREX to avoid Indonesian radar. If one assumes that MH370 used a waypoint like NISOK to avoid Indonesian radar on its way south from IGREX, then one can construct a flight plan consisting of the waypoints WMKK PIBOS GUNBO IKUKO IGARI VAMPI GIVAL MAPSO IGREX NISOK POLUM NINOB and determine how long it might take to get from Kuala Lumpur to the area between POLUM and NINOB. When you do this, you find that the flight time from Kuala Lumpur to NINOB is 7 hours and 52 minutes at 430 knots, which compares quite closely to the actual 7 hours and 54 minutes flight time determined by the 0:25 a.m. departure time and the 8:19 a.m. time of the last partial ping. Allowing for the possibility of additional waypoints between IGREX and NINOB would mean a longer flight distance, which would mean that the aircraft did not quite reach NINOB, but instead went down somewhere on the flight path between POLUM and NINOB. This, of course, assumes an airspeed of 430 knots. A faster air speed would have caused the plane to come down further southeast along the air route, and a slower air speed would have caused the plane to come down further northwest along the air route.
If one combines the Inmarsat data with the assumed flight path data, one gets two lines which intersect at nearly a 90° angle. The intersection point is almost exactly half way between the two ping sightings by the Chinese vessel HaiXun01 at S25°E101° and the Ocean Shield at S21°E104°. This means that the most likely place where MH370 went down is approximately S23°4.24’ E102°27.58’, which is the only point to lie on both the 40° arc and the L894 flight path. Given the short time remaining in the pinger lifetime, it would be well worth searching around this location.
Last edited by Double07; 8th Apr 2014 at 17:56. Reason: Better coordinates for intersection of 40° arc and L894 flight path