Euphemist
Despite my post above, still think that it was a TWA800 replay however. Arcing in a fuel tank probe is all that's required to give you a TWA800 - if there's no tank inerting (N2) and the tanks are full of fuel fumes (courtesy of high ambient temperatures and underlying airconditioning packs heat-soaking the Centre Wing Tanks up to the fuel's flash-point).
However the question that's still extant is the role that silver sulfide deposits play in facilitating such arcs. It's one thing to inductively create an unintentional path for a current into a fuel tank, it's quite another for it to create an arc for ignition of those ullage fumes. It has been quietly acknowledged by Smiths Industries (makers of Fuel Tank Quantity Indicating Systems) that silver sulfide is a bad thing to have accumulate on electrical system components within tanks. It is formed from the sulfur that's naturally in the fuel and the silver that's in the silver solder used in wiring and connectors. Trials have indicated that a 9VDC transistor battery will create an arc across any such deposit. Get the idea? The Transient Suppressor units that had to be fitted to Classics under the AD with a completion date of 01 Nov 01 has not been altogether 100% successful (neither the Smiths Industries nor the B.F. Goodrich mod kits). The silver sulfide deposits are a large part of that problem. They have been found in a 757 that was as little as 7 months ex-factory.
So if they don't mandate inerting tanks, then the recurrence of TWA800 and (possibly) CI-611 type accidents is guaranteed. That's freely admitted by the FAA/NTSB in the TWA800 Report - but they didn't expect the next one quite so soon. If they don't want to set up the infrastructure for onboard generation or single-shot (on the ground) Nitrogen inerting, then maybe they should be investigating an immiscible thin layer of distillate that will float overlay the heated fuel in the CWT and either remain in there (via a filtration process) or get pumped out inflight and be assimilated with the engine-supplied fuel. The purpose? It would totally dampen the ullage vapours, much as oil laying on top of water stops evaporation.
That process I've named " EUPHEMIST "
Euphemism: The act of substituting a mild, indirect or vague atmosphere (or proposition or compromise) for one considered harsh, blunt or offensive.
I think the name fits the bill ideally. Maybe we'll hear more about it (under some name or other) - as solutions may well be sought more urgently now. Inerting of fuel tanks is #1 on the NTSB's most wanted Hit Parade. The biggest obstacle to EUPHEMIST is the posturing by the fuel suppliers and the makers of fuel system components regarding testing and purity of aviation fuel. They are 100% against any adulteration of fuel by other than necessary additives (or so I am told). The additives that are presently used are FSII and its variants (for fuel pump lubrication and anti-icing effect on the water held in suspension in the fuel). Some military aircraft have other additives for lubrication of high-speed afterburner pumps etc. But don't let anybody kid you that AVTUR is pure. It is nowhere near pure and an additive such as the one that I have suggested as a solution is technically feasible (and the minimal 50 or 60 gals required in the CWT would contribute its own share of BTU's to the fuel burn). It's just that technical people get as emotive about their fuel quality assurance as you do about the food you give your kids. For that reason it would be as difficult to get it accepted as it will be for the aviation industry to accept the extra infra-structural costs of nitrogen inerting. But bite the bullet time is fast approaching - methinks.