I would NEVER ride in a plane that received its fuel from a storage system I knew was assembled with Teflon tape.
NHRA and other racing sanctioning bodies won't let your car off the trailer if they find any trace of Teflon tape anywhere on the fuel system during inspection. 30 years ago I helped extinguish multiple engine fires and pushed numerous disabled race cars off the tracks due to bits of that stuff stuck in the fuel system orifices and controls.
NEVER NEVER NEVER use that stuff on a fuel system or fuel strorage system.
Dig that pipe back up and go get the recommended sealant on those threads.
Or I'll recommend this article for the Made By Monkeys post.
We use a type of soap to clean our filters of oily residue. A couple years ago the system was updated and the old steel pipes were replaced with Sch 80 PVC as a lower priced alternative to the stainless steel I and another recommended. What the cost cutters didn't look at was the composition of the soap. Basically Formula 409 on steroids. It contained a caustic compound and various methyl-ethyl solvents that were nearly identical to the solvents used in the pipe glue.
Hmmm... Could we have some compatability issues here??
After about 3 months of operation soap was squirting out of most all of the glued joints. A ferensic examination of the failed joints showed that the glue had been completely dissolved.
@WKT, absolutely correct, especially about the severity of problems. There is just no place in the sky to stop and fix an engine. Even worse on some of those jets, which glide like a rock. Problems that would be an irritation in a car can be fatal in a plane.
I suspect that the real problem here is the nature of aviation "jet fuels".... commercial [Jet-A, -B, etc] and military [JP-5, -8]... in that they consist of refined hydrocarbons loosely called "kerosene" AND various additives to control physical properties. Also, all-too-often, various levels of contaminates including moisture, microbes/fungus, particulates, etc become part of the fuel mix.
Ask any fuel formulator to explain "fuel", and You will quickly understand that "pure fuel" consists of dozens of fundamental hydrocarbon molecule chains [chemistries], from very light to very heavy, mixed in various % levels, to make the fuel, IE: gasoline, diesel, kerosene, etc. The whole discussion will make You light-headed/dizzy.
I suspect that jet-fuel additives are most likely the big culprit in this scenario; especially when combined with the lightest fuel hydrocarbons and trace moisture. The additives enhance or control lubricity, static electricity, microbes and fungus, ice formation, free metal ions, coking tendencies, etc/etc. Trace moisture/contaminates can effect changes in the fuel and affect how the additives perform. Throw-in even minor changes in jet fuel "kerosene" [IE Jet B] formulations can force significant alterations in the nature of fuel. Unfortunately, some of these additives and contaminates, even in small quantities... especially in hotter climates... have aggressive effects all-too-similar to paint stripper.
This problem with jet-fuel is one of the reasons that specially formulated rubber seals, and precisely threaded metal-metal pipe connections, are used on aircraft in-lieu-of relying on thread sealants. The other reason thread sealant/tape should be avoided in aviation fuel systems [including in-ground, above-ground and tanker systems] is that the particles released as these materials disintegrate WILL flow into/through-out the aircraft fuel system as particulate contaminates that MUST be captured in the filters to avoid pump and engine fuel control problems.
Combine this with the scenario described where "air" appeared to be in the system and You have aircraft engineer nightmares of particulates, moisture and bio/fungus build-up. Obviously, moisture is a critical element in ice formation in winter operations; and allows fungus/mold build up at the water/fuel interface in warmer climates. Contamination from all sources [many of which I have not mentioned in an effort to KIS this discussion] make for aircraft operator nightmares. When fuel filters become clogged-up, pumps and engines tend to fail, fuel level sensors become erratic, etc. Take my word for it, BAD things happen when an aircraft fuel system is contaminated! It can be a horribly painful, expensive, time-consuming situation to rectify. However, being ignorant of it... or ignoring it [IE: just changing filters more often]... risks possible catastrophe.
The challenge withteflon tape is that the correct application requires both operator skill and good judgement, which is whyISO9000 would forbid it's use. Yes, used correctly it does do a great job, no question. Used incorrectly it can leadto problems. And ISO 9000 does not allow for user judgement,which is required to use it correctly.
Teflon threads in pressure regulators, and "good quality, famous brand" paste drying and disintegrating, clogging small passages too.
And I refer to that famous brand that used to sell its "STT" product (called in spanish: "Sella Tuberias con Teflon" (pipe sealant with Teflon)... no less than "LOCTITE" (!!!).
Now sold as Henkel LOCTITE® 567™ PST®, that stuff appeared to be a great product, until I saw several failures, where the allegedly superior product dried and disintegrated into a powdery residue, which is undesirable too.
In the end, I found that applying the tape myself, carefully applying it, avoiding the first few exposed threads was the less problematic of the two approaches. And using a minimum quantity of lubrication helps (I use what won't cause additional problems, if I can find it, like silicone grease or PAG Synth oil, but only where it definitely won't contaminate the system).
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