Nigelh,
Although it obviously seems very clear to you right now, there are quite a few "traps" in doing what you propose.
Firstly, your goggles may be seriously degraded by operating them in a non-nvg compatible cockpit. "White" panel lights cause a "bloom" effect, similar to switching on a landing lamp in hazy conditions, causing them to close down badly. You may well miss external details that they might otherwise "see" e.g. wires and whip aerials, tree branches etc.
Secondly, if you try to talk your handling pilot into doing something he cannot actually see, such as landing somewhere he might not otherwise do, you might well cause a handling accident. Firstly, he will be straining his eyes to see what you are talking to him about and the likelihood is that neither of you will be paying attention to the instruments (IAS, ROD, Tq..... get my drift)?
If he then switches on the searchlight, your goggles will instantly become useless. Your night vision will be poor as your eyes and his take a while to adjust and you remove the goggles from your eyeline..... etc.
NVG operators have (or should have) a well tried set of SOPs, outlining minimum light levels and minimum wx limits (NEVER use NVGs to try to extend night wx minima - this is potentially fatal). These SOPs outline crew responsibilities and procedures for goggle up, hover, transition and climb, cruise, descent and landing, manouevring close to obstructions and so forth. Also emergency procedures including goggle failure and inadvertent IMC.
You need to be extremely careful. Without serious thought, training and care, you are possibly about to embark on something very dangerous.
Do bear in mind that the sad side of aviation history is littered with the remains of pilots who thought: "Actually, I have a better idea" or "It can't happen to me".
On the other hand, if you operate merely as a passenger and play no part in the actual operation of the aircraft, then I see no harm in it. Go ahead and play - but don't accidentally drop the goggles down amongst the yaw pedals.
