Self Loading freight your scenario is bang on.
I was itching to post this scenario immediately when the aircraft crashed, but the website was down and I've been away from home for a week.
So if it did happen, how could we tell? As far as I know, the passengers weren't asked about their mobile usage after the event - and it's doubtful that much useful would be learned had they been.
From 2000-2002 I was baggage handling for Air New Zealand which expressly forbids cellphone use in the air, in accordance with NZ CAA policy.
In my personal experience however in the baggage hall cell phones were constantly ringing inside luggage sitting on baggage trolleys awaiting loading on planes. As a pilot I was aware of the EMC issues and made attempts to locate ringing cell phones (without success), but more importantly my efforts drew derision from workmates and foremen who couldn't care less.
Air New Zealand itself didn't want to know and couldn't care less either. Incidentally Air NZ now operates the Boeing 777 too.
You may prevent passengers in the cabin using cell phones, but you can't prevent cell phones in baggage responding to incoming calls. I am almost certain this scenario is the only one which will fit the facts.
When a cell phone receives a call from a cell tower the cell phone calls the tower back whilst the phone is ringing and thus it is not necessary for someone to actively make a call. Cell phones operate passively too.
The BA 777 as I understood the news a week ago had sufficient fuel and both engines quit simultaneously which is an impossibility from fuel contamination from two different fuel tanks at the identical same moment.
Couple of points to ponder: Let us not forget the Martinair 757 several years ago which lost all it's electronics and went through an excursion before computers came back online.
Let us not forget the Egyptair 767 flight 990 out of JFK which off Maine disconnected autopilot and went on a wild roller coaster ride to a watery grave.
Let me throw another less well known CFIT crash into the mix. One which NZ Civil Aviation Authority and the NZ Police concealed from the wider aviation community:
In about June or July 1995 on IFR appraoch to PMR a Dash 8-100 of Ansett NZ was flown into terrain on approach with remarkably few casualties.
Notwithstanding that the radio altimeter aerials and their warning stencils were painted over some months earlier. Notwithstanding that the RHMG uplock latch was worn beyong tolerances and was not repaired according to service bulletins. Notwithstanding that NZCAA permitted in the airline's Ops manual an instrument approach to be conducted with the distraction of gear failure...
Notwithstanding all of the above...
Captain Gary Sotheran testified that the radio altimeter display flipped 1,000ft quite suddenly as he watched it. Nobody believed him.
NZ Police used cockpit voice recordings to prosecute him for manslaughter, but what they concealed was that Police investigations uncovered evidence of a cell phone call being made by a passenger inside the cabin during the instrument approach.
The case was abandoned for other unrelated reasons.
It was a television news programme which leaked information which ought to have been relevant to the international aviation community. An Ansett NZ call centre operator at Christchurch by the name Cauldwell reported to Police that she had a call from an irate passenger before the time of impact complaining about being delayed by problems with the undercarriage.
Captain Sotheran was in all likelihood telling the truth that his radio altimeter flipped 1,000 ft. He was made a scapegoat for an issue the authorities and airplane manufacturers would probably rather the public not discover.
This I believe was proof positive that cell phone use interferes with flight instruments and does cause disasters.
We do need a debate on this issue, but I assure you Boeing and Airbus don't want that debate. Nor do the airlines.
What really stands out from this is the potential for terrorists to plant cell phones on flights and use this as an EMP weapon to down aircraft on finals.