Electric boost pump legality?

P

planebones

New member
Greetings: I have a copy of the BAC drawings and form 337's used to install a Facet electric pump in the Franklin powered Cruisair in place of the wobble pump. The 337's mentioned there are actually part of a conversion to install a Lyc. 0-435. Does anyone have a Franklin powered 14-13-2 with the boost pump installed that he has gotten FAA approval on in the last 15 years.?????? thanks Ken
 
Because it has to have been done to be done again. I think Bones meant "over the past 15 years" because, if it happened longer ago than that, it has been done but it was done too long ago :roll:
 
Why does it need to be within 15 years? I need one also because mine does not have the proper paper work. The best thing is to find one that was done prior to 1956 because at that time all the GADO fellows that signed them were engineers so it can be used as approved data.

Kevin
 
I was just guessing, Kevin. I have a Facit electric aux pump, in addition to the Wobble, but I'm going to go with an IA logbook entry...now that it's finally mounted properly.
 
I have a 337 dated July 13, 1985 for a revised fuel system which includes a "Bendix piston type aircraft fuel pump (art no. 476-459)..." If anyone needs it, let me know and I will scan it and send to them. Larry
 
Oh btw, I have a Franklin 150 in my Cruisair. Also, CAA 337's approved prior to 10-1-1955 are APPROVED data in the eyes of the FAA...though am not sure how much that will help in this case.
 
I could use a good 337 for the Crusair for the fuel pump and the Cleveland brakes.

Thanks,
Kevin
kgassert@fuse.net
 
15 years old has nothing to do with anything really.....just mechanics used to use entries like "removed rotted Bellanca wings and installed Beech Bonanza wings IAW 43-13-1 flt test OK." Now you must have "instructions for further Airworthiness" ( how to maintain it, where to find parts, how ofte nto inspect it etc) so the more info a 337 has, the better the FAA likes it....thanks for the good input Ken
 
The club ownes the STC to install an electric boost pump I have a copy and talked the last owner into letting the club have it for anyone that wants it. Contact Robert.....Greg
 
I have a 14-13-3 (Franklin 150HP) that has an electric fuel pump and cleveland brakes. Contact me if you would like copies of my 337 forms to help with your installation. a.harstine@comcast.net.

Allen N1413B
 
When I bought my 14-13-2 it had a Facet electric fuel pump installed in place of the hand wobble pump. There were no log entries that referenced the installation. It was plumbed in line with the engine driven fuel pump. For a few years all was well and I used the electric fuel pump on take off & landing. Then one day I notice moisture on my windshield during climb out. I landed and found oil had spread all over the plane. I thought that I might have blown out the crank seal. I checked the oil & found it to be 2 quarts higher than when I had checked it that morning at Carson City. It was also quite thin. (I had flown from Carson City, NV to Marysville, CA. About a 1 hour flight.) I removed the engine driven fuel pump & found that there was a leak in the diaphram. This condition allows fuel to be pumped into the crankcase. (a double diaphram pump would eliminate the issue). Installing an electric fuel pump in line with the engine driven fuel pump is not a good idea! I rebuilt the fuel pump & changed the oil. I went in search of a better idea. I found that there is an STC for replacing the wobble pump With a Facet electric fuel pump which involves separate fuel lines & 2 check valves. The electric pump does not pump fuel through the engine driven pump thus eliminating the possibility of it pushing fuel into the crankcase via the engine driven pump. I re-plumbed the fuel system according to the STC. It works great & I feel safer. The STC is SA1-431.
 
Check valves aren't a no-brainer better solution. What's the most likely failure going to be and how bad are the consequences?

Plumb in series: The engine driven fuel pump can suffer a diaphragm failure. Happens but very rarely. Failure of the diaphragm = need to make a landing soon but you have time. You could also get the electric pump failing and somehow blocking the flow when failed. Never heard of that happening.

Plumb in parallel: More hoses and you have two check valves to contend with. Failure of either check valve = engine may stop. I've seen check valves fail too.

Personally I'll stick with series plumbing, have no external check valves, have fewer hoses/tubes, and accept the risk of a forced landing with power like you suffered.
 
In response to RW Flyer

Indeed the parallel pump installation in my Crusair has more hoses & parts than a series type of pump installation. I spent considerable time thinking through the "what ifs" before I decided to modify the fuel system. Failure of one of the additional check valves would have no negative effect on the fuel supply to the carb. The electric pump has a check valve that would prevent fuel from flowing back through it and the engine driven pump has internal check valves, The output check valve would prevent backflow of fuel. I consider the system very safe in comparison to the series system. I might add that the leaky fuel pump diapham that I refered to in my prior post had only a small leak. It appeared that the increased pressure of the electric pump was able to push a significant quantity of fuel throught the diagphram & into the crank case. If oil had not hit my windshield and brought my attention to the problem, it is possible that more fuel would have entered the crankcase & caused damage to the case or even an explosion/fire. I do a lot of mountain flying where forced landings are next to impossible. The choice is yours, but I feel that the parallel pump system is a great improvement and makes for safer flying..
 
You must log in or register to reply here.
Back
Top