Various.....
The Switches...Are we entirely sure that the switch shown in the photo is actually the power switch for the Tans alone.??????????......it is an appendage piggy-backed to the Tans and extends across the top and down over the rear of the Tans 'proper' ...........it could be anything from a master avionics switch to a control for the DTD from which the Tans waypoints can be loaded . It is not an attachment used in all installations...?????????.....
..plus the lower rotary switch does not seem to be in the EXT position as described.....?????........or is there a reflection caused by the camera flash which looks like an index mark on the knob...????...
The Turn...........
..Again I challenge the suggestion that there was any defined 'turn' on approach to the Mull , the average course for the whole journey and the GPS locations show :---
...................BEL VOR to true point of impact = 21.23 degrees true....
Waypoint change GPS to Last steering update = 22.22 degrees true...
.....Last Steering update to Tans power down = 20.51 degrees true........
Tans power down to last GPS(not processed) = 20.69 degrees true....
which show the track only varies by about 1.72 degrees max. between recorded locations............this is more likely due to wind variations or hunting in the servo systems than any deliberate turn...
When you have a series of co-ordinates as I describe from the GPS source...........and you know that there are some errors on the GPS signal..but all the lat/longs. appear to be in a straight line on the map there are really only two possibilities.................
The wandering GPS signal error has magically followed and matched the turns of the aircraft in timing and rate and direction.............or
The GPS values are reliable and the aircraft was travelling in a straight line.................
..the other values from the Racal report such as heading are suspect......as the a/c may have already hit the ground when these were logged .......any gyro source would be suspect after a severe shock.........and the pitch and roll values( roll changes over 10 degrees in four seconds)suggest that the a/c was gyrating in pitch roll and yaw...........again probably after first impact......
.as the GPS antenna and the Doppler head are mounted forward of the cofg...any severe yaw would give inaccurate track indications as the signal 'source' is not moving on the same track as the fuselage as a whole , but on a slight diagonal....
The Times......
......any reference to 36 seconds should read 26......or more accurately 25.6 seconds.......as the difference between the 16:59:10.4 ..and 16:59:36.0 timestamps.....the GPS clock is as recorded inside the Tans........so when the Tans is powered off it saves the last value it had for the GPS clock.......but the two(Tans , GPS) may not have powered off at the same actual time , as the gps recorded a last location further on across the hillside.....The Tans had gone to a frozen state at this time and was not accepting any more data until the power came back.......depends where the power feed to the GPS was connected ..
The Waypoint Change
..I see nothing strange about changing to Waypoint B........they would have had a warning from the Tans one minute to run before passing (abeam) Waypoint A......depending apon what airspeed you like to believe that gives between 20 and 30 seconds to run when they made the change..........it would have required an extremely violent turn in order to avoid Waypoint A....as they were so close.
rgds all....