wolit@mhuxd.UUCP (Jan Wolitzky) (05/05/88)
Last night (Tuesday, 5/3), WNET-TV (PBS, channel 13, Newark) broadcast a 1-hour documentary entitled (I think) "The Crash," a report on the Japan Airlines Boeing 747 crash in 1985, the worst single-plane disaster in history. The film included an amazing computer-generated animation: the producers took the radar track of the plane, provided by air traffic control, and added a terrain elevation map of the route, filled in by color Landsat imagery. They then took Boeing's CAD/CAM data on the 747, overlaid by the JAL paint scheme, and used the information recovered from the plane's digital flight data recorder to generate a God's-eye view (from above and behind) animation of the plane, in its actual flight attitude, flying over the actual Japanese terrain it passed on its way to its demise. They even depicted external damage to the plane visible before the crash, information gleaned from a computer-enhanced snapshot of the plane (taken by someone on the ground along the route of flight, as he noticed the plane flying erratically), which determined that some 60% of the plane's vertical tail had been blown away when the aft pressure bulkhead failed. (The bulkhead failed because Boeing had incorrectly repaired damage to it caused by a hard landing several years earlier.) The animation was accompanied in real time by the actual recording of the radio conversations between the plane and ATC. The Dutch rolls performed by the plane after losing most of its vertical stabilizer and its elevator hydraulic control lines were sickeningly believable. This impressive show will be re-broadcast at 2 a.m. on Monday, 5/9 (the listings will show it as being very late Sunday night, of course). -- Jan Wolitzky, AT&T Bell Labs, Murray Hill, NJ; 201 582-2998; mhuxd!wolit (Affiliation given for identification purposes only)
sxm@philabs.Philips.Com (Sandeep Mehta) (05/06/88)
In article <7237@mhuxd.UUCP> wolit@mhuxd.UUCP (Jan Wolitzky) writes: > ... >depicted external damage to the plane visible before the >crash, information gleaned from a computer-enhanced snapshot >of the plane (taken by someone on the ground along the route >of flight, as he noticed the plane flying erratically), >which determined that some 60% of the plane's vertical tail >had been blown away when the aft pressure bulkhead failed. The animation was certainly impressive, but the image processing techniques were quite normal. The took the image, zoomed into tail section (region of interest); and since the image was very blurred, ran a contrast enhancement algorithm on it. Then the edge was extracted and the contour plotted. The same was repeated for a complete tail section, and the two plots overlaid to determine the percent of the tail section destroyed. I found the terrain and dutch roll simulation very realistic and impressive. sandeep -- Sandeep Mehta (914)-945-6478 Robotics & Flexible Automation uunet!philabs!bebop!sxm Philips Laboratories sxm@philabs.philips.com
nobody@scubed.UUCP (Pseudo news poster) (05/07/88)
In article <7237@mhuxd.UUCP> wolit@mhuxd.UUCP (Jan Wolitzky) writes: >...1-hour documentary...report on the Japan Airlines Boeing 747 crash... >...The film included an amazing computer-generated animation:... >...The Dutch rolls performed by the plane after losing most of its ^^^^^^^^^^^ >vertical stabilizer and its elevator hydraulic control lines were >sickeningly believable. What, pray tell, is a Dutch Roll?...no relation to a Danish, I presume :-). Inquiring minds want to know.
bright@Data-IO.COM (Walter Bright) (05/10/88)
In article <778@scubed.UUCP> rankin@s3mickey.UUCP (Tom Rankin) writes: >In article <7237@mhuxd.UUCP> wolit@mhuxd.UUCP (Jan Wolitzky) writes: >>...The Dutch rolls performed by the plane after losing most of its >What, pray tell, is a Dutch Roll?...no relation to a Danish, I >presume :-). Inquiring minds want to know. Dutch roll occurs when you have yaw instability. (The three axes of rotation are pitch [nose up/down], roll [wing up/down] and yaw [nose left/right].) With yaw instability (common when you lose the rudder!), the tail moves side to side. This causes the left/right wings to have more/less lift, which adds an element of roll and pitch. The net result is the plane traces a corkscrew path. The effect I am told can be quite sickening to the passengers. The last episode of "Test Pilot" on PBS showed a wonderful film of a plane doing a dutch roll. By the way, Dutch people are from Holland! The word dutch is a corruption of 'Deutsch', which means German. Somehow it got misapplied to people from the Netherlands.
sxm@philabs.Philips.Com (Sandeep Mehta) (05/10/88)
In article <1541@dataio.Data-IO.COM> bright@dataio.Data-IO.COM (Walter Bright) writes: > >By the way, Dutch people are from Holland! The word dutch is a >corruption of 'Deutsch', which means German. Somehow it got >misapplied to people from the Netherlands. Wouldn't sound quite right if we said Netherlander Roll !! sandeep -- Sandeep Mehta (914)-945-6478 Robotics & Flexible Automation uunet!philabs!bebop!sxm Philips Laboratories sxm@philabs.philips.com