Kikapu wrote:Paphitis wrote:Sorry but you're both wrong because with each ping they are able to calculate the distance from the Satellite placing the aircraft on a particular arc. The previous pings then mean very little other than providing a reference point and determining whether the previous calculations were accurate enough.
The error would be a lot less than 300 kms and I only say that if the Satellites were not using an Atomic Clock in which case the calculations would be completed to the the tenth decimal place I which case it would be + or - 10 kms.
If MH370 was handshakes by 2 other Satellites then they would be able to triangulate the exact position similar to how GPS triangulated position.
With each handshake, the previous becomes irrelevant other than as a cross check because Aircraft Performance Analysts would be able to derive the distance travelled, calculate the Ground Speed and since the GPWT is known they could work backwards and calculate a Mach Number and flex (power settings) which gives them a True Air Speed and with the temperature recalculate the fuel consumption and fuel burn.
In other words they can calculate the aircraft's likely performance.
In that case, where is the aircraft (debris) if ONLY the last ping is relevant, because then the "crash site" would be much smaller area than what Pyro is saying?
But if what Pyro is saying is anything like each ping being a "Dead Reckoning" (DR), which I used often while sailing in the ocean because I was not able to get a "Fix" through Celestial Navigation with a sextant due to bad weather conditions but used only distance traveled over the water log and Compass Heading, I could plot our DR position from the last know Fix position minus the "Leeway" distance travelled by the boat depending on wind direction and strength (10% leeway with my Catamaran when on a "Close Reach" and decreasing as the wind shifts all the way around to "Beam Reach" to "Broad Reach" and almost zero % on a "Run"), sea currents in one direction or the other, accuracy of the log meter and so on. If I did 7 DRs over a period of time, then each one would be based on the previous one, and if the first DR was wrong and they always were some because I didn't have accurate information on ALL the factors, then so would be ALL the following DRs. By the time I got to my 7th DR, I could be off my "True" position by a long shot.
One of the scenarios that the IIT is considering is that there was no one alive on board the aircraft when it ditched from fuel starvation. Of course, with every single scenario, there are a number of assumptions which can't be verified without a Black Box. The other scenario is that someone deliberately ditched the aircraft somewhere in the Indian Ocean. With the former scenario it is easier for Performance Engineers to reconstruct the entire flight since they are presuming
fuel starvation. They can calculate the aircraft's performance with reasonable accuracy + or - 5%.
You must understand that Flight Planning and Navigation is never an exact science when you take away all the Navigation Systems on board, such as GPS/RNAV, VOR, DME, Inertial Nav, and the FMC (Flight Management Computer). I remember one of my senior instructors (a RAF PILOT that served in Egypt and Cyprus) say to us in the class room, that Flight Planning is a science but it is also an art. He is not at all wrong. It's not as if you can plug all the numbers into a formula and calculate the answer. We are dealing with Atmospheric Physics and Meteorology here.
The Air Transport Pilot Licence Exams involve planning a flight (using a B777) from A to B and your answer must be + or - 1% for it to be correct as long as the methodology is accepted as per the curriculum. In flight simulators and during operational training, accuracies must be + or - 2%. There are many reasons why it is mandatory to carry reserve fuel and one is deviations in forecast winds and temperatures which have a dramatic effect in the way engines perform and also the fuel consumption, range, and flight times. Of course the FMC will calculate everything for you down to the last kg and minute. Performance Analysts/Engineers know very little about MH370, therefore all they can do is look at likely scenarios and calculate from there. If they get their assumptions right, I believe they can get to within + or - 5%. The individuals on the IIT from Boeing would know the B777 inside out and better than the Pilots that fly them. These Performance Analysts, who will be reconstructing the flight, are very lucky that they have the Inmarsat data because that gives them somewhere to start from. It gives them a set of 7 points on a map which they will use to plot the flight as they go along and without this data then you might as well draw a circle around the last primary contact with a radius of the aircraft's best case scenario range and call that your search area.
Now presuming that no one was alive when the aircraft crashed, then there would be scattered debris somewhere. Unfortunately, there was a massive delay when the search teams were looking in the wrong places in the South China Sea. By the time they got to the Indian Ocean nearly 2 weeks later, the debris had already drifted and scattered and most of it would have eventually sunk in rough seas. Then the search party began looking too far south, and meanwhile the debris would be drifting up to 200 kms per day. By now, any surviving debris could be half way across the globe. It could be anywhere. It's not that hard to understand. They have not denied the presence of debris but only stated that looking for it now, is very futile. This does not mean that finding some debris is NOT inevitable. It might just take some years before someone finds something washed up on a remote beach somewhere.
Dead Reckoning is what the authorities were using when looking for the debris. At one stage the search for debris was 1000 kms west of the probable impact zone. However, once again, there are many assumptions and the JACC and AMSA have been analysing the ocean currents and seas in order to make their determinations (intelligent guesses) for the Air Search Zones but the models they used are by no means consistent. It's a bit like getting your Route Sector Winds and Temperatures before going flying. The forecast tells you that the wind and temperature will be such and such but when you get there it is something entirely different as shown on the FMC which automatically recalculates everything for you.
But don't make any mistake about it because the Handshake calculations would be independent from the previous pings. It does not mean that the other pings are discounted because that is untrue, but any errors will not compound to the next handshake ping. It would merely be another dot on a map (albeit with some defined error margin) as a reference point.
This stuff is extremely complicated and it is very difficult to explain in simple terms to the layman.
Where do you get all this bullshit from?
