What is this "dial/knob" on BA 747's adjacent to the lights?
 

Never saw this before....and didn't feel like messing w/it. What does it do?
https://cimg4.ibsrv.net/gimg/www.fly...2c9c35067b.jpg

Theraputic outlet for oxygen. In a medical situation crew can plug a mask into this outlet and supply oxygen at eiher 4 or 8 litres a minute.

Thank you for the information, I NEVER would have guessed that. That said, I've been on virtually every aircraft type, including many 747's (but never BA)....and have never seen this device. Is it unique to BA? If so, why is it not on other aircraft? (or if it is, maybe placed in another location?) Still, only on BA in my experience....odd.

Always wondered this and never knew; thanks for asking the question!

Well it kind of is.. :D

It is not unique to BA, or even jets. I had been on a LM SAAB 2000 where an infant can only be placed in certain seats as only at those position, such an oxygen supply exists (otherwise 2 per seat pair with no extra). The crew also placed an infant oxygen mask (along with the infant life raft) in the overhead locker.

You will also see the same "knob" above the outboard seats on our 777s, so I suspect it's a Boeing item rather than specifically BA...

One possible reason you may not have seen it on other aircraft types is that I think it would depend on the type of emergency passenger oxygen system fitted to the aircraft; a bottled-oxygen system or a chemical-generator oxygen system.

Aircraft, such as the DC-10 which BA used to operate, had an emergency passenger oxygen supplied by a chemical-generators, which, once activated, could not be turned off, and would run until depletion. On those aircraft types cabin crew would supply therapeutic oxygen to an ailing passenger using small portable oxygen bottles.

To supply therapeutic oxygen, via a plug -in mask, to an individual passenger who needs it, requires the aircraft to have a ring-main passenger oxygen system, supplied and pressurised by oxygen bottles in the holds, with the associated ability to turn the oxygen supply off once therapeutic oxygen is no longer needed. In both cases, as mentioned by sammyh25 different flow rates can be selected by a switch on the mask.

As an aside, the procedure for turning on, and particularly off, the therapeutic oxygen on earlier series of B747, if not followed exactly, or if the passenger disconnected the mask themself, would result in all the passenger emergency oxygen masks dropping down, something I suspect some of the older more senior and experienced cabin crew on this forum may have experienced!

It is an air vent... well sort of :-)