Most reliable fuel system?

[xCountry22]

This may seem like a basic question to many of you and I don't want to kindle carb vs. FI wars, but I was interested in a comment made on the RV accident thread. Someone identified fuel system problems as one area of note in some accidents.

I'm in the process of evaluating carb vs. FI and on the 'reliability' issue alone, does anyone have a POV or thoughts for this relative newbie?

I'm well into my wings with QB fuse on the way. I need to start thinking of engine choice soon.

[DaleB]

I started out kind of paranoid about E/AB airplanes, so I read a lot of NTSB reports. I still read up on every accident I can to see what can be learned to try to avoid repeating the event. It's not the fuel delivery mode (carb or FI) that breaks airplanes and kills pilots, it's the builder's (or maintainer's) design and execution of it.

The best carburetor or fuel injection system ever devised by mankind doesn't work if you don't give it a chance. Don't slather RTV on the fittings and choke off the flow, or fail to clean it out so the filter clogs on takeoff, or fail to put gas in the tanks, or put sharp bends in the fuel lines so they kink, or rig things so safety wire or cables saw through fuel lines, or any of the other stuff people have done to explore the glide ratio performance of powered aircraft.

Just my humble opinion.

[Sam Buchanan]

Originally Posted by DaleB

It's not the fuel delivery mode (carb or FI) that breaks airplanes and kills pilots, it's the builder's (or maintainer's) design and execution of it.

Very true. Go with whichever system meets your needs but build and maintain it to certificated (or better) standards. It is possible to have a rock solid fuel system in EAB if established procedures are used for construction. Don't get experimental unless you have the engineering background to anticipate unintended consequences.

[airguy]

Originally Posted by Sam Buchanan

Don't get experimental unless you have the engineering background to anticipate unintended consequences.

I want to really emphasize this part of Sam's comment - it's exactly the correct take-away message.

Things can be changed from the "tried and true" in our experimental aircraft without much (or any) oversight - but new configurations bring out new "gotchas" that have to be considered. It's not that we cannot or should not change things, but we need to sit down and carefully consider what might happen in various scenarios before we pick up the tools.

[Steve Melton]

I like my simple low pressure fuel system and carb for non-acro. use a good carb heat muff. trade-off is carb icing concern, it's real.

[N941WR]

The standard RV fuel system is working fine on thousands of aircraft all around the world. Yet some builders design their own fuel systems with "enhancements" that cause fuel starvation issues down the road.

[Mark Dickens]

It's the basics that seem to cause most of the fuel related events. Things like using non-approved materials, cutting corners by not learning how to properly flare a fuel line, or how to properly torque an AN fitting...or when it's proper to use a thread sealant and when it's not. Read the applicable authoritative texts on the proper techniques (AC 43.13-1B (http://www.faa.gov/regulations_polic...cumentid/99861), and the Aviation Maintenance Technician Handbook (http://www.faa.gov/regulations_polic...t/amt_handbook) to name two of them). Of all things that can go wrong on a homebuilt plane, the fuel system has a high potential to end up killing you. It is not a place to experiment...stay with the well-known materials, and techniques.

[TS Flightlines]

As one of those that plumbs fuel systems, I certainly agree to keep it simple, and as conforming as possible. I agree with all of the statements. Investing in the proper tools AND the time to use them properly, pays huge dividends in our builds, and the reliability of our planes.

Tom

[N941WR]

As a reminder, it isn't always the tools or fittings but how the system is installed.

This thread is a great example of how making changes, such as running the fuel line "in the coolest part of the engine compartment" can cause problems. (Granted, in that installation there were many issues which were addressed by the second owner.)

[pierre smith]

Beware of the "Waddington effect." I had the right engine quit on a 310 as the wheels retracted. It was fresh out of an annual inspection and the fuel line came off the spider. It had been started by hand and never saw a wrench.

Mr. Waddington saw much of this during WWII and told the authorities to stop doing unnecessary maintenance on the bombers and they immediately saw over 30% less post-maintenance issues.

We've had that issue on here...fuel lines not tightened either during assembly or after maintenance.

Best,