...
BA633 ATH-LHR 02 Jan 2020 - ASR
It seems the AAIB are conducting a 'correspondence investigation' rather than a 'field investigation' into the event with G-EUYM, 02 January.
The AAIB list their current (on-going) field investigations here -
https://www.gov.uk/government/publications/aaib-current-field-investigations/air-accidents-investigation-branch-current-field-investigations
They don't seem to have links to on-going correspondence investigations, so you only see them in the full list of final reports - viz
https://www.gov.uk/aaib-reports The one for EI-DEO seems to represent a similar event and nine out of the first ten on the list are correspondence investigations.
Sofar, apparently, the only visible evidence for this
"Full (Annex 13) investigation" (until completed) is via the BEA -
"File Number BEA2020-0004 "Serious incident to an Airbus A320 operated by British Airways on 02/01/2020 near London [Investigation led by AAIB / United Kingdom]"Summary - Preliminary data based on the notification from the United Kingdom authorities:
Ten minutes from landing the flight crew became aware of smell/fumes in the cockpit. First officer became unwell and fainted. Both crew went onto oxygen. Mayday declared. Aircraft landed safely and crew sought medical attention."
Link -
https://www.bea.aero/en/investigation-reports/notified-events/detail/event/serious-incident-to-an-airbus-a320-operated-by-british-airways-on-02012020-near-london-investigat/
According to other posters and reports, the airline has been lobbying the meejah, claiming that the F/O did not faint. It will therefore remain to be seen whether the AAIB and the BEA will give credence to the evidence, or to the BA
PR spinners.
...