fuel pressure issues...

T

trombair

New member
greetings, bellanca types!

ok, here's a weird one.

first, 14-19 Cruisemaster, N522A, O-435-A ~550SMOH, bendix electric boost pump.

whenever i turn off the boost pump after getting level in cruise or switching tanks, the fuel pressure indicator drops to 0 ( :shock: ) or close to it. then, after about 2 seconds climbs back up to 2 or 3 psi (normal). engine never skips a beat, the needle doesn't quiver or vibrate and i don't see any evidence of fuel leaks anywhere. could this have something to do with the check valves in the system?

this fuel system came to me plumbed in "parallel" (ala piper) as opposed to the stock "series" configuration. at the first annual, my I/A said to leave it as is believing that the parallel system is safer.

comments? similar experiences? shared baffelment? :roll: i'm all ears!

blue skies,
vic & N522A
 
My electric fuel pump is in the same line as the engine pump,no check valves. I have no drop after turning off the elect pump.
 
Sometimes that is the problem with the IA. #1 it doesn't matter if it is safer ( that is an opionion anyway ) It either needs to be the way it came from the factory or a 337. If a fuel line brakes what difference does it make were the pump is in line. My IA wanted me to spit up my fuel shut off and fuel selector. It is the way it came from the factory. :lol: :lol:
 
guys,

well, thanks for the feedback; tho' i was hoping more for actual experience with the specific problem than opinions of my IA's competence.

that said however, i will agree that (strictly speaking) the aircraft should conform to the type certificate and all amendments to be in complete compliance and in an "airworthy" state as far as the regs are concerned.

but...would YOU really want to kick that "sleeping dog" if it was your airplane?...and you had to deal with the VNY FSDO? (a training FSDO where they go "by the book" and NEVER do anything creative-even if it makes sense.)

my IA is well respected in our area and has run a fine repair station for decades. he has been helpful to me beyond compare and has enough common sense to know that SAFE (we did a careful analysis of the whole fuel system) is better than ORIGINAL (as best we could determine) in this instance. this was all done in view of the fact that there is NO CLEAR documentation for the O-435-A installation in the 14-19 Cruisemaster and believe me, i've looked! the factory has none, NASM has none, the type certificate has no detailed description...so what makes the most sense here? do it per a VERY small, fuzzy diagram (in the owner's manual) or mimic a proven, safe example (piper cherokee 180)? in many ways, these rare old airplanes are more like homebuilts than factory builts.

i'm not trying to pick a fight here, only to show that since our cherished airplanes are relatively rare and (in my case) have little in the way of clear systems documentation, it seems more sensible to go with good technical practice rather than trying to hold out for the last "dotted 'i' and crossed 't'".

still...if anyone has any ideas about the "goofy" fuel pressure situation, i'd really like to hear about it!

blue skies,
vic & N522A
 
You must log in or register to reply here.
Back
Top