I saw a similar report. I'm not sure what force could cause a part of a plane to travel rapidly backwards, other than a massive explosion. Of course, there is an assumption that the tail section (or whatever) was moving away from the rest of the plane. It is quite possible that it was decelerating suddenly after detaching, while the main part of the plane continued on at its cruising velocity. Explosive decompression too, could be responsible. We should know more when they analyze the plane remains for explosive residue and interpret how it came apart.
I found this:
JAL 747 JA8119, 12 August 1985 crashed in to Mt. Osutaka, Japan.
"The aircraft suffered an explosive decompression while climbing through 23,000 feet. The failure of the rear pressure bulkhead caused a portion of the vertical stabilizer to be blown away, rupturing all four main hydraulic fluid lines. Controlling the aircraft solely by engine thrust, the crew was attempting to return to Tokyo when the aircraft clipped one mountain ridge, flew across a valley, and impacted a second mountain approximately 400 feet from the summit. This accident remains the deadliest single-airplane accident in aviation history."
http://www.airdisaster.com/cgi _bin/view_details.cgi?date=081 21985&airline=Japan+Air+Li nes
"There was no sign of an explosion on the recovered debris, and no distress call was received from the flight crew. Weather around the time of the accident was clear."
http://www.airdisaster.com/pho tos/ci611/photo.shtml
VRN