MH370 Radar Track Plots
 

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Admin

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MH370 Radar Track Plots
« on: May 06, 2015, 11:36:19 AM »
Source: "Orion"
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Oxy

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Re: MH370 Radar Track Plots
« Reply #1 on: May 07, 2015, 02:29:41 AM »
Nice work on posting the graphic in mh370-radar.study.pdf

Obviously the assumed groundspeeds in GAP-1, 2 and 3 are wrong (Not due to the person posting the graphic). A Boeing 777 is not capable of groundspeeds of 580 to 588 knots with only a 15 knot tailwind. The maximum groundspeed for the given conditions would be 540 knots. Based on Mach 0.87 (87% of the speed of sound), FL300 (30,000 feet), ISA+11 (temperature is 11 degrees Celsius above standard) and tailwind 15 knots.

I am aware that the primary radar accuracy is degraded in height detection due to refraction. Hence, two different primary radars have different height returns in SEG-3 and 4.
But, what would cause this GAP groundspeed error?
Is there a problem with the radar plotter?

If we ignore the GAP segments, and total the primary radar segments, SEG-1, 2, 3 and 4, the total is 128.2 nautical miles in 908 seconds.
Average groundspeed for primary radar segments is then 508 knots.
Average True airspeed is 493 knots. (508 subtract 15)
Or Mach 0.84 for FL360 (36000 feet) in ISA +11.
Mach 0.84 is a standard divert speed for a Boeing 777.
FL360 (36000 feet) is a standard cruise altitude for flying west.

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Re: MH370 Radar Track Plots
« Reply #2 on: May 07, 2015, 09:29:51 AM »
Reconciling the primary radar speed data has been a significant challenge. Based on what my radar friends tell me, the primary radar altitudes are a decent ballpark but nothing more.

The source posted his speed and plotting raw data, which I attached. He also posted a depiction of the descent near VKB which can be found here.

I suspect that we are looking at a radar calibration or interpretation error on the part of the Malaysian Military which cannot be confirmed until they release the raw primary radar data. A very cursory and rough look at the route shows that it could have been accomplished within the time frame published in the factual information document (IGARI turn back at about 1730 and last radar contact ~10 nm W of MEKAR at 1822) at a fairly normal speed, here's a quick plot.
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Oxy

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Re: MH370 Radar Track Plots
« Reply #3 on: May 09, 2015, 07:27:08 AM »
From the Factual Information report, primary radar indicated that the aircraft was 6 nautical miles south of Penang at 1752:35 UTC, and 10 nautical miles past MEKAR at 1822:12 UTC.
The distance between these two points via VAMPI and MEKAR is 248.9 nautical miles. Therefore the average groundspeed is 504 knots (248.9nm in 1777 seconds). If the average tailwind was 11 knots, then the True Airspeed is 493 knots, which is Mach 0.84 at FL360 (36000 feet in ISA +11). That's the same speed it was travelling prior to Penang.

Link to wind:
http://earth.nullschool.net/#2014/03/07/1800Z/wind/isobaric/250hPa/orthographic=-261.34,8.86,3000/grid=on

If the aircraft maintained Mach 0.84, then at 1825:27 UTC, when a Log-On Request was initiated by the aircraft terminal, the aircraft would be passing the NILAM waypoint.



orion

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Re: MH370 Radar Track Plots
« Reply #4 on: May 13, 2015, 09:30:59 PM »