Direct lift from the AAIB Report in relation to the SuperTANS:
The unit was recovered from the cockpit wreckage area slightly fire scorched but with little apparent impact damage (Fig 16.1). The ON/OFF switch was found at OFF, and an absence of substantial damage to the lift-toggle type switch, including its ramp mechanism, together with ground fire sooting patterns suggested that this had been the setting at impact. However, subsequent examination and memory read-out by the manufacturer, Racal Avionics Ltd, reportedly clearly showed that unit had been operating until impact and it appeared that the switch position had in fact been altered by the effects of the crash. The detailed investigation of the unit was covered in a Racal Report.
Direct lift from RACAL's Report:
1.1.4. SuperTANS serial no. 131 was installed in the Chinook, and was in use at the time of the accident. The memory within the SuperTANS is battery backed, and the content of the memory has been extracted for analysis to provide as much information as possible to assist with the investigation.
1.1.5. The data extracted is that pertaining to the time of last powerdown of the system. The equipment is not designed to provide 'historic' data, but attention has been paid to analysis of data items which may indicate the situation at a time earlier in the flight.
1.1.6. The analysis of the data reveals that the SuperTANS, and the navigation sensors to which it interfaces appear to have been performing perfectly at the time of loss of power. The accuracy of the Doppler position also indicates that all had worked equally as well throughout the flight. The pilot had performed the correct installation procedures, and was making use of the navigation facilities.
So, the AAIB state that, from the evidence presented to them, they believe the SuperTANS to have been switched off yet the manufacturer state that not only was it on, but that it was giving the appearance of working perfectly.
No-one can say at what point in the flight the waypoint change was made, and I would suggest that it is just as difficult to say where the powerdown took place. Was it at the point of impact, or somwhere earlier in that leg? There is a 330m difference between the position of the GPS and Doppler at powerdown. Something?, or nothing?
One thing we can all be absolutely certain of though, and I am grateful to AVM Day for this, is that we know, with absolutely no doubt whatsoever, that the box was coloured black.
Regards all.
Brian
"Justice has no expiry date" - John Cook