Sunfish tells us of the latest rumors at LLoyds.
First, a word of caution. Insurance people do not necessarily know any more than anyone else does, and they are not necessarily technically trained (indeed, most of them whom I have met aren't technical people at all).
Second, some sort of EMI effect has by no means been ruled out by any info available to us. Neither has the manifestation of a digital logic error of some sort (the EEC has of the order of hundreds of thousands of lines of code (LOC; a kLOC is a thousand LOC). The crude average error rate for safety-critical systems is of the order of 1 error per kLOC. The very very best measured rate of which I know in a largish system with hundreds of thousands of lines of code is 1 error per 25 kLOC. That doesn't mean the errors show up in any safety-critical way, but that cannot be ruled out either).
Concerning EMI with a source outside the aircraft, let's do a sanity check on this.
If somebody on the ground is EM-radiating in such a way as to cause well-shielded systems some 700 ft in the air to go haywire, the question is how that could happen without any other effects being noted. If that signal is broadcast, and it happens to be on a road, then lots of less well-shielded auto electronics are going to go crazy also, let alone stuff in buildings. Which means that if it is somebody travelling down the road, lots of people within 700 ft (oh, let's say 1000 ft) are going to experience problems with their cars and their company electronics. And our intrepid journalists would have had that all over the front pages within a day or two. Didn't happen. So not a broadcast.
Suppose it was directed. Then somebody would have been pointing a strong EM source at or near a landing aircraft for some reason. I think there is no chance at all that anybody working for the PM would have done such a thing.
External source does not cover the EMI hypothesis fully, of course. There is also the possibility of EMI from within AC systems themselves, which is the case which Green-dot has been pursuing, since he knows of instances.
PBL
Last edited by PBL; 9th Apr 2008 at 06:34.
Reason: To reinstate a comment about directed radiation that had apparently disappeared