What it boils down to is that if it is my aircraft and I am flying in it, I am very likely going to be treated as PIC. Even if someone else is at the controls. That does affect how you need to behave when flying with other pilots including instructors.
What it boils down to is that if it is my aircraft and I am flying in it, I am very likely going to be treated as PIC
Do you have a reference for that i.e. the owner is presumed to be PIC?
There are all kinds of scenarios where that interpretation would be daft. For example a lot of bizjet or TBM/PC12 owners do have a PPL, and could technically be PIC, but they choose to be flown by somebody (a CPL/IR or ATP) who gets paid for it. The owner will probably not be sitting in the back...
I have long lost count of the number of times I have seen a TBM owner (with a PPL or even a PPL/IR) I know climbing out of his TBM, closely followed by the pilot.
Often the owner sits LHS with a "perpetual" instructor in the RHS (must be a horrid instructing job, flying to nice warm places and staying in cheap €300/night hotels all the time) which makes it even more "interesting".
I am speaking about me. Of course you can come up with scenarios where it may be treated differently. An owner sitting in the back with a pro pilot etc.
I can't believe that if the PIC for a given flight turns out not to have the correct papers, then a passenger sat in the RHS, who happens to have the correct papers, can be declared PIC against his will.
As Peter says, if that were the case then every time I stepped onto a commercial flight I'd need to check both the Captain and First Officer's papers in order to guard against accidentally being declared PIC in the event of something going wrong.
On other points:
I don't think that in the event of a fatal accident any of the lawyers involved would let the insurers walk away just because there was uncertainty over who was PIC. In a common likely scenario (two PPLs renting a club a/c) the club's insurance would cover either to be PIC and so it makes no difference to them.
It seems to be a fairly common belief amongst the general pubic that insurers are empowered to 'decide' things in cases like this. They absolutely are not. You are not bound by their 'decisions' and you can both negotiate and challenge them legally based on the contract you hold with them. The most common one seems to be valuations for written-off cars: people seem to think the insurers can 'decide' the value. They can make an offer, but you can challenge it and if you offer evidence they generally back down and make a more sensible offer because they know a court wouldn't find in their favour.
I'm not a fan of uncertainty regarding who is PIC. If I fly with someone else who holds a licence, then I generally work on the basis that left seat is PIC unless agreed otherwise. In my world, PIC is generally paying and will therefore want to sit in the left seat.
If I fly with someone who happens to hold an instructor rating, then I prefer (awkward conversations permitting) to establish who is PIC before departure.
I've had the following situations which have been slightly awkward:
Making a short flight back to home base as part of a multi-aircraft flyout, with an instructor in the RHS following a people/planes reshuffle for this leg. Upon arriving at home base the instructor suggested a couple of circuits with engine failure drills and I agreed (perhaps without thinking much about it). For those ten minutes or so the instructor seemed to switch from being a passenger into full-on instructional mode, which in my mind created uncertainty about who was making decisions when it came to giving way to other aircraft, making radio calls regarding our intentions etc. I found it slightly uncomfortable, given I'd established in my mind that I was PIC for the flight and someone else now appeared to be taking over.
Flying RHS as a passenger with another PPL. Said PPL (with no IMCr or IR) inadvertently entered cloud and in attempting to descend out of it unwittingly got quite a lot of bank on. Once it was threatening to become a spiral dive I declared "I have control" and levelled the wings before continuing the descent out of cloud and then passing control back. Also felt uncomfortable, as I'd usurped someone's position of command but only because I'd had to in order to remain safe. Lord knows what I'd have done if I'd have been in the back with a non-pilot sat in the RHS.
Command shouldn't be a grey area, but too often it appears it is. Always good to keep discussing it to share experiences and try to prevent tricky situations.
Graham, that is my view.
The position with less experienced/rated pilots is simpler (in my plane). If there is any doubt in my mind - in particular if I wanted to make it clear I was NOT PIC, I make it explicit.
That said, survival instincts trump legalities and I would equally step in as you did to prevent arriving at the scene of the accident.
Are aircraft insurance companies really that horrible to coop with?
Some time ago one of our Diamond syndicate members went flying, and during the preflight checks he let the passenger do the oil level checking.
Now the passenger forgot to put the oil cap back on, and they got engine damage because of this.
It got all covered by the insurance as it was considered "pilot error".
Jason - My original point is that if you are dead, you are not in a great position to dispute the assertion of a survivor that he/she was a "passenger" - irrespective of the provable fact that you were always the PIC in your plane on every flight previously logged in your plane. Do you always fly only in your plane, and never in anybody else's? The point of my post is not that you are liable if you are PIC; the point is that you can be liable if you are a passenger and somebody alleges you were actually PIC. If you fly say 300hrs/year in a turboprop, the chances are that you have 10x more hours (and 10x more paper) than the person in the LHS, so an allegation that you were acting as PIC would not be exactly hard to make stick. All the LHS would need to do is allege that there was some mentoring going on and that he/she got confused and you offered to fly the plane. If you are an instructor (even the bare CRI would do fine) then all bets are off... What you do in your own turboprop is irrelevant.
It got all covered by the insurance as it was considered "pilot error".
It would be because the PIC is PIC, all the time he/she is living 
But my scenario is nothing to do with the insurance company. It is to do with a survivor having a huge incentive to change some "details" to collect a few million instead of collecting nothing.
Another angle is this: under the UK Civil Aviation Act, there is no liability to passengers unless the pilot is negligent. So if your engine was maintained to schedule, and it blows up, and passengers are injured/killed, the passengers can't collect anything (not sure if EU law modifies this now, into a strict liability?). But if you fly into a hill, they can claim. So post any accident where there is passenger injury, the Job #1 for the passengers' lawyers is to have the pilot declared as "negligent" because it opens the doors to collecting any money. Now, insurance does cover negligence, but if the scenario is such that the insurance may be void (say an expired license or medical) then the family of the pilot is going to try damn hard to not have him declared as negligent because their family estate is going to get wiped out otherwise. I did wonder why, in certain high profile crashes (non GA; I am thinking about the RAF) the word "negligent" was so emotional...
Do you always fly only in your plane, and never in anybody else's? The point of my post is not that you are liable if you are PIC; the point is that you can be liable if you are a passenger and somebody alleges you were actually PIC.
Yes, and that is why I said:
If there is any doubt in my mind - in particular if I wanted to make it clear I was NOT PIC, I make it explicit.
I would get it in writing if I felt it was important.
Agreed. Being dead does seem to adversely affect one's negotiating position in the event that the details become disputed.
This is probably why those who approach aviation in a more practical manner, when debating with the rigid rule-followers who believe that the powers-that-be know best in every circumstance, often cite a preference for being alive over being legal.
