Join Date: Oct 2006
Location: London, UK
Programs: BA Gold, VS Silver, SQ Silver, IHG Plat Amb, Hilton Gold, Marriott Plat, Accor Silver, Radisson Prem
Posts: 16,872
It is all up to the flight crew and/or how willing the cabin crew are to ask the flight crew.
I have only ever asked to see the cockpit twice - both before departure.
Once was on QF (a B744), they were reluctant and one of the cabin crew offered to take the photo for me. The flash wasn't working, so I was later led to the cockpit for a look and a photograph after confirmation with the flight crew.
The other time was just a couple of weeks ago on the special AF A380 LHR-CDG, where I was only allowed to take a photo from the bottom of the stairs to the cockpit.