Lima Juliet:-
The most plausible and likely is that it was CFIT
Given that among the many airworthiness problems that afflicted this fleet; "positively dangerous" FADECS that lacked any manual reversion, and flight control malfunctions, 'controlled flight into terrain' might be seen as an 'if only' possibility. Of course an independent (like truly independent!) accident investigation could not produce a 100% certain outcome. Many aviation accident investigations fail that test, but given that its gross unairworthiness was scarcely considered by the BoI, and its findings anyway were overturned by the VSO Reviewing Officers who demonstrated their finding of Gross Negligence of the JO pilots to a Commons Committee with very contentious postulations, it is time that the facts surrounding the Release to Service of the Chinook Mk2 are considered fully with respect to this dreadful tragedy in a fresh accident investigation.
This wasn't a one off, though it is to date the worst airworthiness related military fatal air accident suffered by this country. On that basis alone it deserves further independent investigation in order to avoid future UK Airworthiness Related Military Fatal Air Accidents, the only acceptable reason for any air accident investigation.