This is just a theory, nothing official—although the official story changes from day to day, so it's not like officialness means anything in the disappearing 777 saga. Last week, I put up the theory from a Stanford student about the skin of the fuselage rupturing, causing a decompression event that incapacitated the passengers and crew. But now we know authorities don't think the plane was flying on autopilot with a dead crew. This new theory from hobby pilot and aviation enthusiast Keith Ledgerwood fits snugly into the latest line of official thinking that the plane was deliberately diverted by someone who knew what they were doing.
Did the plane go off course and land in, say, Turkmenistan or Iran or China or Kyrgyzstan? And if so, how would it have been able to fly undetected through India's airspace or Pakistan's airspace?
Ledgerwood says he has found evidence of another airplane in the sky, a Singapore Airlines flight, in the "immediate vicinity as the missing MH370 flight at precisely the same time." He goes on to write:
Singapore Airlines Flight 68 proceeded across the Andaman Sea into the Bay of Bengal and finally into India’s airspace. From there it appears to have proceeded across India, Pakistan, Afghanistan, and finally Turkmenistan before proceeding onward across Europe to its final destination of Barcelona, Spain.
I'm not airplane-ologist so I'm going to let him explain what this could mean:
It is my belief that MH370 likely flew in the shadow of SIA68 through India and Afghanistan airspace. As MH370 was flying “dark” without transponder / ADS-B output, SIA68 would have had no knowledge that MH370 was anywhere around and as it entered Indian airspace, it would have shown up as one single blip on the radar…
Once MH370 had cleared the volatile airspaces and was safe from being detected by military radar sites in India, Pakistan, and Afghanistan it would have been free to break off from the shadow of SIA68 and could have then flown a path to it’s final landing site. There are several locations along the flight path of SIA68 where it could have easily broken contact and flown and landed in Xingjian province, Kyrgyzstan, or Turkmenistan. Each of these final locations would match up almost perfectly with the 7.5 hours of total flight time and trailing SIA68.
Ledgerwood shows more of his work—there's a bunch of technical stuff I couldn't begin to understand—over on his Tumblr page.