AA62,
I'll try and answer your question about 'dodgy fuel' and, if any of my facts are wrong, I'm sure that someone will enlighten me
Earlier in the thread, Smuj said that he worked on fuel tank corrosion at Colerne in the late '60s. Fuel and oil are hygroscopic and there has always been a small quantity of water present in fuel tanks. If there is a lot of water present, it forms large 'slugs' which sit at the bottom of the fuel tank.
The corrosion came about because of a micro-organism called Cladosporium Resinae (CR) which lives on the thin layer between water and fuel. The larger the water 'slug' the more CR is present. The secret is to keep the water dispersed throughout the fuel. In more modern fuel systems, this is achieved by having a jet pump installed at the bottom of the tank which, continually, mixes water and fuel.
The 'Water Fuel Check' carried out after re-fuelling is meant to detect any water present - but it is far from fool-proof - particularly in some of the parts of the world where we found ourselves. It was not unknown for the bowser driver to have a 'good' Fuel Check Disc to show to the crews. He may have had it for weeks.
The addition of Fuel System Icing Inhibitor (FSII) came about after one particular incident, which I'm sure a few of you remember.........
In the mid-70s, during the Belize Trouble, we spent a lot of our time operating in and out of Nassau (happy days). Back then, Nassau was a bit of a Sleepy Hollow and we used an awful lot of their fuel - we found out later that one of their underground fuel tanks had a crack and water was getting in.
A crew from, either, 30 or 24 were on their way back to Lyneham from Nassau. Unbeknown to them, they had picked up a LOT of water during the refuel in Nassau. The engine fuel filters started to ice up but it was masked by the Ext/Aux high pressure pumps. When they transferred to the main tanks, the lower pressure couldn't cope with the ice. If I remember correctly, 2 engines ran down and a 3rd had low power.
They turned left towards Newfoundland and, of course, descended. In the descent, as they reached warmer air, the ice started to melt and I think they got 2 of the 'dead' engines back. The Engineer was Mike B---e and, if he is on the forum, he might be able to tell the full story.
After landing, some ice was found in one of the fuel filters. As a result, the 'Powers That Be' decided we needed FSII.
The FSII was to stop the WATER freezing and the fuel filters clogging. It, also, helped stop the formation of water slugs which, in turn, helped inhibit corrosion.
I'm sure you remember the 'high tech' equipment they sent to Nassau to enable the FSII to be added to the fuel; a hand pump and 45 gall drums of the inhibitor!
The usual the 'it was 40 years ago' memory proviso is attached to this post