The lighting inside the Memorial Chamber was different on my more recent trip some weeks ago.
I paused by one of the cabinets containing books of remembrance, this particular one for those who have died in active service on various assignments since the Korean War. The pages in these cabinets are turned on a regular schedule. The repeated deaths on this page, on the same date and involving the same squadron, led me to look up that date and its significance. The details of what happened are here.