M20F-1968 Posted June 9, 2021 Report Posted June 9, 2021 1 hour ago, hoot777 said: One problem with using fuel flow instruments is it will not show you a fuel leak. It happened to my dad in a V35 BO. The fuel drain came off in flight and he made a precautionary landing in Chattanooga . The gauge did show empty and it was. I have a M20 G and only one gauge is trustworthy to a point. Time your fuel burns and always be conservative. Fly safely. Then there should be a serious mismatch between the fuel totalizer and the tank gauges, which should be taken as a red flag. This scenario argues to keep ALL available equipment working properly. Multiple instruments which corroborate other instruments are helpful to identify problems you can not otherwise directly see. John Breda Quote
carusoam Posted June 9, 2021 Report Posted June 9, 2021 1 hour ago, hoot777 said: One problem with using fuel flow instruments is it will not show you a fuel leak. It happened to my dad in a V35 BO. The fuel drain came off in flight and he made a precautionary landing in Chattanooga . The gauge did show empty and it was. I have a M20 G and only one gauge is trustworthy to a point. Time your fuel burns and always be conservative. Fly safely. Depends on where your leak is... before or after the FF sensor... For determining an inflight fuel leak... One can consider using a fuel level sensor like Ceis.... calculate FF (automatically), compare to your FF instrument... note if they are within reason... alarm when they are not... Our planes are notable for not handling a variety of almost common problems... How often do we get a fuel leak that drains a tank in flight? I’m pretty good at checking fuel used and comparing to fuel level on my old analog gauges... it would be nice to have an oil level gauge inside the engine... a few MSers have run out of oil in a flight... a hint that you have only two quarts left would be really helpful... Best regards, -a- Quote
Will.iam Posted June 9, 2021 Report Posted June 9, 2021 14 minutes ago, carusoam said: Depends on where your leak is... before or after the FF sensor... For determining an inflight fuel leak... One can consider using a fuel level sensor like Ceis.... calculate FF (automatically), compare to your FF instrument... note if they are within reason... alarm when they are not... Our planes are notable for not handling a variety of almost common problems... How often do we get a fuel leak that drains a tank in flight? I’m pretty good at checking fuel used and comparing to fuel level on my old analog gauges... it would be nice to have an oil level gauge inside the engine... a few MSers have run out of oil in a flight... a hint that you have only two quarts left would be really helpful... Best regards, -a- you would think a sensor drilled into the side of the oil pan would work for at least knowing you had lost some oil. Wonder if any experimental guys have done that, or how is the dummy oil indicator like in the automotive world setup? 1 Quote
craigsteffen Posted June 11, 2021 Report Posted June 11, 2021 I'd just like to add a bit of information I've discovered about my 1967 M20F. My information is specifically for the planes with the 2x3 engine gauge cluster in the lower left co-pilot panel, but may apply to other configurations as well with resistive fuel gauges. This is particularly true for people with gauges that read sometimes right but sometimes wrong, or particularly when the gauges bounce from indicating empty to a reasonable value and back again. In mine, the oil pressure is direct-read mechanical. CHT and oil temp take supply voltage and ground through the sensor. The ammeter of course isn't grounded at all. And because of their electrical design, the fuel gauges ground through the senders...AND also through the ground point in the gauge cluster itself. The ground point in the gauge cluster takes its ground from a fairly short pigtail that comes out of the canon plug on the back...and screws into the frame member at the bottom of the instrument panel with a single screw. It is a TERRIBLE, not to mention INTERMITTENT ground point. When we were investigating this, I finally realized that with the electrical master on, if I wiggled the little piece of sheet metal that the gauge grounding screw goes through, the fuel gauge needles would flop up and down in rhythm with my wiggling it. So now that ground point has another wire that runs up into the power wiring behind the right side of the panel and attaches to a known good ground point that actually has good contact with the frame. So if your fuel gauges act like this (and reading back through this thread, I'd guess at least half of these folks are exhibiting suspiciously similar symptoms to what I used to have) then I'd electrically check the place where the gauge itself grounds to the plane, and make sure that's solid, and if it's not, connect to a good electrical ground. 1 Quote
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