Q:

1959 Supersonic Transport Aircraft Committee (STAC) report (on Concorde)

I am looking for the 1959 STAC report. This 1977 Atlantic article stated that the report was, at that time, still being withheld by the UK government, probably out of embarrassment.
I think this UK Gov webpage might be it, but unfortunately it says "This record has not been digitised and cannot be downloaded."
Does anyone know what the status of this report is? Is it now publicly available — and if so, where might I find it? Thanks.

A:

The status of the report is shown on the page linked in the question:

Open Document, Open Description

This means that it can be freely accessed, in person, in the Reading Rooms at Kew.
Like the vast majority of the public records at the UK National Archives, the file has not yet been digitised. That is why it isn't available for download.
Although more than 80 million historical documents in the National Archives collection have now been digitised, this is still only a tiny fraction of that collection, which includes over 1,000 years of "iconic national documents".

What this means is that you basically have three options if you want to view the report:

You can visit the National Archives in Kew in person. You will have
to apply for a Reader's Ticket.

If you are unable to visit in person, you can still get a copy of the document:

You can request a "Page Check" which will determine if the
document is suitable for copying and, if so, how much they will
charge to copy it. If it is deemed suitable by the archivists, you can pay 
your fees and they will send you a copy of the file. The current cost of a 
page check is £8.40 (GB).
[Costs are set by the UK government]
You can employ a researcher to visit the National Archives on your
behalf.

If you are able to visit in person, or employ a researcher to visit on your behalf, you should be able to get a copy of the document. Various facilities are available on site. Even if the file is not suitable for photocopying, it is normally possible to take digital photographs of documents (indeed, a number of desks in the public reading rooms are fitted with camera stands to facilitate this). Check the National archives photography policy for more information

