Facet Electric Fuel Pump

This is a good question!

Many aircraft have the Facet electric fuel pumps installed, and we have seen several airframe manufacturers provide them with either their kits or factory-built aircraft. Since it's a mechanical/electronic component, it can eventually fail (nothing lasts forever).

Since it's not a Rotax part, we can't make any suggestions on when it should be replaced, and if you contact Facet and ask them, they will tell you that it shouldn’t be used on an aircraft. If you go to the manufacturer's website, Motor Components LLC, they state the following: "NOT INTENDED FOR AIRCRAFT USE: WARNING: FACET AND PUROLATOR FUEL PUMPS SHOULD NOT BE USED IN AIRCRAFT AS THEY ARE NOT DESIGNED, TESTED OR MANUFACTURED FOR ANY AIRCRAFT APPLICATIONS." (https://facet-purolator.com/pumps/)

With that said, it's best to use your judgment on when you should replace it. In aviation, they have a saying: "preventative maintenance," meaning that components should be replaced before they fail. These fuel pumps are not expensive; so frequent replacement would be best practice.

It's better to be safe than sorry!

Yes a very good question.

I would expect the Facet pumps to have an expected  total running time, known but undeclared, by the manufacturer. 

Seems to me, much will depend on how you use the pump. 

## Some pilots (systems?) will run, what I call a Boost/Back UP, pump continually.

## Others (like myself) only use the Boost for take-offs/landings. 

Clearly the first example will be seeing a potential pump failure (due to wear) much sooner, in calendar time, than the latter.

Taking the worst case scenario - Complete/unexpected failure of the pump.

## Engine Pre Start Check - Pump ON - No sound ("chatter" of the working pump) No fuel pressure  rise - Pilot takes appropriate action.

## During Flight landing phase - Cant speak for all fuel systems, however in mine - Down Wind - Boost Pump On. I am unlikly to notice the failure of the small rise in pressure, that occurs from activating the healthy pump - continue for Landing. Next Pre Flight Check - refer to above.

Safety is not significantly compromised in either of the above scenarios.

My suggestion:

If your fuel system requires the continual use of a Boost pump(s) replace the pump at the 5 year rubber replacement. No data to support this time/frequency but agree with Rotax Owner "These fuel pumps are not expensive; so frequent replacement would be best practice." It would be simple to make replacement part of your 5 year routine.

If the Boost pump is only used for a few minutes per flight - replace on condition. The risk of this pump failing and causing an engine failure is extremely low.

Just had another thought:

Some of what I said above may depend on:

Rotax recomend, Boost pumps should be installed with a non return, bypass circuit. This would allow the mechanical pump to continue supplying the engine with fuel, in the unlikly event of the Boost pump failing closed (blocking fuel flow).

My Boost pump, has a non return bypass circuit fitted.

Are you using the very common "cube" type?

This website https://www.mcgillmotorsport.com/facet-solid-state-fuel-pump-7-10-psi-34-gph-c-17-p-5878 quotes an MTBF of 6000hrs but I haven't managed to locate an MTBF figure on Facet's own website.

 (That 6000 figure comes up on several motorsport supplier websites so there must be a source for it somewhere.)

This is the Facet Web Page, with all of their pump specifications:

https://facet-purolator.com/specifications/

I can find the pump Part No 4013 on the above web page but no reference to - SS503 from McGill Motor Sport