My final TANS entry (for now anyway)
After PM's to a couple of other contributors, I am more than ever convinced that none of us fully understands the implications of the final entries into the TANS followed by the (apparent), deliberate switch off by the crew. Further research by a real expert is needed.
A couple of items are worth highlighting before I withdraw from this subject.
1. Read again para 1.1.5 from The RACAL report in Brian's last entry. RACAL concede that no reconstruction based on the TANS can be considered anywhere near factual.
2. If the TANS were operating to anywhere near the accuracies of the report the crew would never deliberately switch it off. It would be too useful in primary and secondary modes.
Can I offer any explanations?
1. Read the many excellent entries by Tucumseh. Is it possible that EMC problems made the TANS more of a problem than a solution?
2. Was the RACAL report so flawed that it had no validity at all?
I Know of at least six incidents on the C130 HINS Navigation computer where the equipment was in error by up to 60nms without displaying error codes. The groundcrew could not replicate the fault on the ground. All these six computers were undamaged.
3. The TANS was spot on but the crew, for whatever reason, chose not to accept the information. Spatial Disorientation? It has happened.
All theories based on past experience. But still only theories.