Perry Mick wrote:

Here it is from the word of God (Mr. Rutan) if you don't want to take my word for it, a sump with no selector valve or a BOTH selector valve (pretty much the same thing) NOT recommended:

A Southern California Long-EZ crashed shortly after departing from the Santa Monica airport.  The pilot survived but was badly injured.

A careful post-crash investigation revealed that this airplane's fuel system had been extensively modified by removing the engine driven mechanical fuel pump as well as the electric boost pump.  The fuel tanks had been plumbed together to form a gravity fuel system similar to a Cessna 150.
What does that mean?  No sump AND no selector?
This pilot had also modified the front seat shoulder harness attach point and had installed a "Y" type shoulder harness, installed using a single bolt in the center of the seat bulkhead.  There was no provision to carry the crash loads, no hardpoint and no beef-up of the bulkhead skins.  The result was predictable.  This single bolt pulled through the seat bulkhead and the should harness provided zero restraint.  The seatbelts were installed per the plans and survived undamaged.

This is an absolute No-No!  RAF Thoroughly explored the possibility of a gravity fuel system for the Long-EZ back in 1979 using the prototype, N79RA.  Flight test results forced us to conclude that the margin of safety using a gravity fuel system was too slim and we opted to use a fuel system similar to a Grumman Tiger or Cherokee that includes two separately selectable fuel tanks, an electrically powered in-line fuel boost pump and an engine driven mechanical fuel pump.  All of the above are mandatory in order to provide reliable fuel delivery to the carburetor on a typical Lycoming-powered Long-EZ,.  This information was published in several Canard Pushers as well as in the plans and engine installation instructions.  The following is taken from page 3 of the Section IIL of the Long-EZ plans:  "The most important item to consider is the mechanical fuel pump.  The Long-Ez's fuel system is designed to require the use of an engine driven mechanical fuel pump, backed up by an in-line electric pump.  This is a mandatory requirement and there is no acceptable way around it."

This important safety requirement was not just dreamed up, it was derived from a carefully conducted flight test program - do not try to second-guess the designer's motives behind critical systems such as the fuel system.  The plans built fuel system on the Long-EZ is an excellent, trouble free system that is known to work on hundreds and hundreds of airplanes.

If you know of someone who may be contemplating a change to his or her airplane like this, get involved, help him or her out, don't let another unnecessary accident happen.

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