SoS;
Quote:
Anyway, the point I am making is that in the absence of any other limiting factors, if the controller could see the landing lights from the tower, the flight crew should have been able to see the PAPIs at half that distance.
The line of sight along the PAPIs ends at the touch down zone, right?
If then, we know they impacted a hillside, that means they vere below the top of the hill. The runway on the other side of the hill is well below the top of the hill, don't remember by how many foot. That means they could NOT see the PAPIs in the moment before they impacted the hillside. Have anyone done some triangulation calculations to see if the top of the hill also was blocking the line of sight to the PAPIs so they couldnt see the PAPIs when they cut the first threes? Maybe they vere too low so early that they never saw the PAPIs?
I was looking at this as well. Perhaps they were below the hill and could see the PAPI and the controller could see them -IF- there was some kind of refraction of the lights (both ways) due to humid air lying over the crest of the hill and they were effectively looking through a mirage. That would explain how a controller could see an aircraft that was below topographic line of sight and the otherwise inexplicable descent of the aircraft.
I am not sure how much refraction of the lights would be made by very humid cold
er air. But with the terrain being that close perhaps not much is needed.
There is also an interesting presentation from Airbus on Visual Illusions Awareness that could apply...
http://www.airbus.com/fileadmin/medi..._PER-SEQ11.pdf
see in particular pages 8 and 9