Aviatrix, the blogger behind the Cockpit Conversation blog, recently had a reader express concern about taking avgas from a relatively small facility that sells a fairly limited amount of avgas in a month. After all, the risk of contaminated or bad fuel is (at least in theory) probably greater with such facilities. Hence, Aviatrix pointed out some of the precautions they take when using it:
Whenever possible we fuel the night before and then check the fuel sumps in the morning, giving time for water and particulate matter to settle to the bottom of the tank where we can see it. During this operation I have never found appreciable water in the fuel system, and never found any that didn’t correlate with precipitation during fuelling.
Ironically though, Aviatrix also mentioned that the one time her company drew contaminated fuel, it was from a large operator in the USA and she further recounted a story about how much of Australia’s general aviation was grounded a few years ago due to contaminated fuel from another large operator.
Hence and perhaps the risk of contamination is actually equal or greater with large operators rather than with small ones who know their customers and have their personal reputations on the line.