NVFR (Fuel pump limitations)

AJ85WA · #1 07-21-2014, 10:06 PM

Hi Guys

After getting my CofA and starting my phase1 testing, my AP called me up and advised me that during phase 2 I would probably not be able to get the aircraft certified for NVFR because of my duel electronic fuel pump setup. (I am saying probably because he did not sound convincing)

Bottom line, I do not have a mechanical fuel pump, I have two independently controlled fuel pumps with multiple redundancies built in.

My question is, does your fuel pump setup have anything to do with NVFR requirements? I'm really confused.
Please see my setup below.

Anybody heard something like this?

RV10inOz · #2 07-21-2014, 11:36 PM

AJ,

First of all I would say that the AP has not applied a suitable risk matrix to come to this conclusion. That being said they have to be comfortable there is no risk.

Having said that you have mitigated the risk of a single point of failure in the pump or power supply so their grounds for refusal are not justified.

I would of course have to ask you why on earth did you decide to do this anyway?

Perhaps your AP needs reminding of a few things

AJ85WA · #3 07-22-2014, 12:24 AM

Hi David

Thanks for the reply and input, I was thinking something along those lines as well. Although I do have allot of respect for my AP, but just because it something different to most doesn't mean its not as safe.

As for my fuel pump setup, The engine I purchased came from a Cessna so the accessory case was not machined for a mech fuel pump. I did not want to waste time and money sending my engine away for machining and fitting. (Hence finishing my RV6 in two years)

I like the solid state elec fuel pumps, less moving parts is always a bonus.

Some might say otherwise, but that's why I like experimental = "freedom"

RV10inOz · #4 07-22-2014, 06:13 AM

Freedom is not FREE?..but that is another story

I think you need to sit down and challenge carefully the risk matrix, refer to other AP's for advice, but if you wish give me a call. I am off to OSH so be quick!

rocketbob · #5 07-22-2014, 07:25 AM

The Comanche 250 has dual electric pumps plumbed similarly without check valves. It is a dumb system really and prone to vapor lock yet it is certified. Yours is not a problem since you have check valves.

N941WR · #6 07-22-2014, 10:42 AM

If you don't have an "H" engine, changing the accessory case is easy and you could do it without removing the engine.

Check out my engine page for details of the swap.

Good luck with whatever direction you go.

AJ85WA · #7 07-22-2014, 04:58 PM

Hi guys

Thanks for the input. I didn't know you can swap the acc case without taking engine off. I will look into that.

David, enjoy OSH, one year I will get there, I should be alright with this one mate, If I do get denied, I will just put the RV back into phase 2 later on once I swapped over the acc case.

AJ

N941WR · #8 07-22-2014, 07:05 PM

Quote:

Originally Posted by AJ85WA

Hi guys

Thanks for the input. I didn't know you can swap the acc case without taking engine off. I will look into that.

...

AJ

One thing to keep in mind, it is MUCH easier to make the swap with the engine off the plane but you can still do it with it one the engine mount. Some of the bolts might be a challenge to get to but it can be done.

Some mechanics don't remove the engine when fixing an oil pump and the pump is bolted to the inside of the accessory case.