Excellent replies to my paranoid fantasy brainstorming! LOL!
Okay- Let's then positively rule out the bomb designed to explode on 103A, for the good reasons you've related. So Iran wants a big bang for their buck (or 10 million bucks) and they want a high profile transatlantic target- either PA101 or PA103.
When Haffez Dalkamoni was arrested with Khreesat;
"In the boot of Dalkamoni’s car was a Toshiba cassette recorder with Semtex moulded inside it, a simple time delay switch and a barometric switch."1
So, if the bomb was an identical copy of Khreesat's, or actually one of Khreesat's, it included a simple time delay switch. This tells me that a timer exclusive of the barometric switch is in play. Does the barometric switch only activate after the timer has been set and expired, or do both have to be set to run concurrently? (Khreesat would know, but he isn't talking.) That would allow the bomb to be armed well in advance (given the timer limitation), and it to sit and await the appropriate drop in air pressure to arm the barometric timer.
I think Caustic Logic already explained this. Someone else gave us the info in a different thread. The "simple" timer attached to the altimeter is usually called an "ice-cube" because of its appearance. These things work on capacitance. Nothing happens until the timer is triggered. This was done by the altimeter, when the pre-set pressure was reached. (Even though the plane is pressurised, cabin pressure isn't maintained at sea level values, they compromise on the equivalent of about 8,000 feet, which is comfortable enough if you're not indulging in a lot of exercise. As Jibril liked to point out later, the bombs would also go off if someone drove up a mountain road. Us, deliberately targeting planes? Why would you think that?)
So, the plane climbs and the pressure inside falls low enough to trigger the altimeter. This takes a few minutes I believe. Once that happens, the battery starts charging the capacitor. While it's charging, nothing goes right on happening. When the capacitor is fully charged, it discharges, and that discharge triggers the detonator. Bang.
The time a particular capacitor takes is sort of fixed, and can't be varied by the operator. It will vary a bit depending on how often it's been tested out beforehand, as Caustic Logic described, and with temperature. Around half an hour (nominal) is about the longest time you can get with this type of device, hence, like it or not, if you're using this method you can't aim for "way out over the Atlantic" even if you want to. But you will
not get a detonation on the tarmac.
A lot of experiments were done with similar devices, and I think the actual window for detonation is rather wider than the 35 to 45 minutes (after takeoff) usually quoted, but that's about it. Either
Maid of the Seas was the victim of a device like this, or else some wild coincidence with a timer either malfunctioning, or set far too early, or accidentally getting routed on to the wrong plane, just happened to mimic the ice-cube timer pretty much exactly. And as I said, I'm ODing on coincidences.
Regardless, the only sure way it seems, to have the bomb placed exactly where one wishes it, would be at Heathrow, and the Bedford bag(s)(one or two?), seem to be the most logical, defensible conclusion.
Yup. Total agreement.
I'd still like to unearth some sort of evidence to lend credence to how the spot nearest the skin was chosen, and how one would know a 20 inch hole (plus the sudden decompression forces) would be effective enough to bring down the aircraft. Was it just pure chance, or was there some PFLP-GC experience driving this exact placement of the bag containing the device? I realize that a piece of the fuselage falling off the plane, for example is not the same as a bomb going off. (See mach stem wave.)2
Well, the PFLP-GC at least had some experience in the field. The calculations are all straightforward for people who understand these things, and they had the people. They also had the motive, and the reward, and the Semtex and the Toshiba radios and a brown Samsonite suitcase and a shed-load of clothes sourced from Maltese factories. (Fhimah and Megrahi had precisely none of these things.)
So, that leaves us with AVE4041. Who knew it was destined for PA103? if you or I walk into a baggage handling area, it is a jumble of containers, seeming random baggage cart placements, and other contraptions. I wouldn't know if AVE4041 was destined for Singapore or Sydney, let alone New York. Who could procure this information for the PFLP-GC? An Iran Air representative, conveniently located right next door to Pan Am at Heathrow?
Bedford in his evidence describes selecting that container and labelling it up for that particular flight. I imagine he did that every day, though not necessarily always the same container of course. I think he would have placed a fairly clear mark on it to show which flight it was for, almost certainly labelling it "PA103" in a reasonably prominent position.
To us, it would all look confused and random, but to someone working there it would all make sense and things would be where they were supposed to be. A container labelled "PA103" would be expected to be about there, every day at that time, with a few bags in it, waiting for PA103A to land. That, I would say, is an opportunity.
You could be right about the Iranair personnel, but I'm not sure. Not every Iranian is a terrorist, and this job needed a terrorist. It also needed someone familiar with the baggage handling system specifically, which is not as far as I know done by individual airlines as a rule, but by handling companies like Servisair. I think, rather than infiltrating the Iranair ground staff, it might have been that a terrorist got a job as a baggage handler and was able to identify exactly where and when an opportunity would present itself.
So, the PFLP-GC has the idea all worked out, but they need to ID the container, and place the bag.(s) So, that means constant surveilance of whatever container is going to be used, as well as an opportunity to place the bags. Was Khamboj lured away from his post by somebody flashing loose cash? Would you want to wait all day long shepherding a bomb bag, and waiting to place it, when you could lure the guy nearest the container to leave the area unattended for a few minutes?
1.
http://www.lrb.co.uk/v31/n18/gareth-peirce/the-framing-of-al-megrahi
2.
http://plane-truth.com/Aoude/geocities/mach.html
I counsel against paying too much attention to Gareth Pierce. She has come very lately to this affair, due to her reputation as a human rights lawyer in
England, and she seems merely to be hypothesising based on the same information we have. She even trots out some aspects that we've discounted on closer examination of the evidence. Also, although the Plane Truth site has some useful factual evidence, aren't they a CT web site? I'm always a bit wary of CTers in this context.
However, Kamboj. I suggested exactly the same thing a few pages back. Bribing anyone to put a case in a very precise location is far too risky, because it doesn't take a genius to figure out the probable reason. Bribing someone to be somewhere else for five minutes is far more likely - they're going to assume it's drug smuggling, and they may not have a problem with that. The only thing is, you'd have to be fairly sure Kamboj was bribable in that way. Again that could suggest a terrorist having worked in the area and having made an assessment of his character. Or it could simply have been the terrorists were fairly confident of that container being unattended for a few minutes.
Rolfe.