Engineers have to carry out a full check of lifejackets on a given frequency but I cannot remember what this is. I think it might even be daily but if not then weekly.

Until recently this involved a physical check, but BA has invested in RFID technology that means a hand-held scanner can be used by someone walking down the aircraft. It’s a no-go issue if any missing items are identified, and this includes outstations.

This was reported in the technical press (supply chain/logistics) when launched so can probably be searched if anyone wants to see the story.