What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Gascolator "requirement" in Canada

riseric

Well Known Member
Patron
Folks,

Many posts and threads here on VAF mention the Canadian, or MD-RA "requirement" of needing a gascolator either with a carburated or fuel injected engine.

I don't want to start a debate about the need or no-need of the gascolator versus the different engine choices.

As it goes, from reading posts and acknowledging first hand witnesses, the MD-RA requires a gascolator. Some might question if it's still relevant in some cases.

Being in the planning/building stage of my fuel system (see this post), and after Kevin Horton's post in my thread, I propose to find out if in fact a Canadian certified aircraft with a fuel injection system is flying without the gascolator.

If anyone out there aware of this, can it be shared here?
If there is, it might conclude to having the record set straight about this between the MD-RA, Transport Canada and home-builders about this "requirement".

If in fact, there is no such certified aircraft, so be it... At least we will know where we stand.

Thanks,
 
If in fact, there is no such certified aircraft, so be it... At least we will know where we stand.
Hi Eric,
Having gone thru the very same gascolator discussion with my MDRA inspector last year and again last month, I can tell you that there is little relevance between their assigned mandate and what's installed in a certified aircraft. They are charged with task of making sure all aircraft inspected are as safe as possible and the gascolator is right up there in the list of things that must be present (along with drain holes drilled everywhere, whiskey compass and huge bi-lingual warning signs). I can appreciate where you are coming from but you can churn up a lot of energy and make little to no progress dealing with a delgated organization with bureaucratic roots.
Good luck
Cam Andres
RV9A with Aerosport IO360
C-FTLL "Flying now"
 
Just to make sure we lay blame where it belongs ... MD-RA requires nothing, they're not regulators. Transport Canada requires the gascolator in their 549.01 exemption letter.

According to the CAR 523.997 : http://www.tc.gc.ca/eng/civilaviation/regserv/cars/part5-standards-523-sub-e-274.htm#523_997

"There must be a fuel strainer or filter between the fuel tank outlet and the inlet of either the fuel metering device or an engine driven positive displacement pump, whichever is nearer the fuel tank outlet."

Unless the 549.01 standards for amateur-built aircraft overrides this, which it doesn't, then this requirement also applies to amateur-built.

So, as I interpret this anyways, for any aircraft to obtain a certificate of airworthiness these days, they'd need to have one.

This doesn't make it impossible for a certified aircraft to be without one however, if there was a point in time in the past when gascolators were NOT required at the time of certification. If an aircraft was fully certified without a gascolator, because the rule didn't exist at that time, it may still be around today, still flying without one! I'd expect those would be rather rare, if they exist at all.

Cherokees (like the one I fly) were certified based on regulations dated 1956, and they have gascolators.

This copy of CAR 3 (what came before the current FAA FARs): http://www.navioneer.org/riprelay/Yet More Navion Files/car_part3.pdf

Says this:

"§ 3.552 Fuel strainer. A fuel strainer shall
be provided between the fuel tank outlet and the
carburetor inlet. If an engine-driven fuel pump is
provided, the strainer shall be located between
the tank outlet and the engine-driven pump inlet.
The strainer shall be accessible for drainage and
cleaning, and the strainer screen shall be
removable."

And that revision is for Nov 1 1949.

So yeah ... not sure you're going to have much luck finding a type-certified aircraft without one, unless it's a really really really old one ...
 
My memory might be completely failing, but I don't recall there being a gascolator on my Grumman Yankee, a U.S. Certified aircraft that I know was owned by many Canadians.That might possibly be an avenue to explore.
 
Hi Eric,
They are charged with task of making sure all aircraft inspected are as safe as possible now"

Just a slight correction, they are charged with making sure the airplane is compliant with the regulations, not as safe as possible. There is a significant difference. If they were charged with making it as safe as possible they would remove the propellors from all the airplanes so that we couldn't fly! :) They have a set of requirements, they have to enforce them and they have no latittude in applying common sense or giving credit for new technology. That has to come in the form of a regulatory change.

I too am a Transport Canada delegate in the certified aircraft world and appreciate their position, although it can be exasperating at times.
 
Just to make sure we lay blame where it belongs ... MD-RA requires nothing, they're not regulators. Transport Canada requires the gascolator in their 549.01 exemption letter.

According to the CAR 523.997 : http://www.tc.gc.ca/eng/civilaviation/regserv/cars/part5-standards-523-sub-e-274.htm#523_997

"There must be a fuel strainer or filter between the fuel tank outlet and the inlet of either the fuel metering device or an engine driven positive displacement pump, whichever is nearer the fuel tank outlet."

Unless the 549.01 standards for amateur-built aircraft overrides this, which it doesn't, then this requirement also applies to amateur-built.

So, as I interpret this anyways, for any aircraft to obtain a certificate of airworthiness these days, they'd need to have one.

This doesn't make it impossible for a certified aircraft to be without one however, if there was a point in time in the past when gascolators were NOT required at the time of certification. If an aircraft was fully certified without a gascolator, because the rule didn't exist at that time, it may still be around today, still flying without one! I'd expect those would be rather rare, if they exist at all.

Cherokees (like the one I fly) were certified based on regulations dated 1956, and they have gascolators.

This copy of CAR 3 (what came before the current FAA FARs): http://www.navioneer.org/riprelay/Yet More Navion Files/car_part3.pdf

Says this:

"? 3.552 Fuel strainer. A fuel strainer shall
be provided between the fuel tank outlet and the
carburetor inlet. If an engine-driven fuel pump is
provided, the strainer shall be located between
the tank outlet and the engine-driven pump inlet.
The strainer shall be accessible for drainage and
cleaning, and the strainer screen shall be
removable."

And that revision is for Nov 1 1949.

So yeah ... not sure you're going to have much luck finding a type-certified aircraft without one, unless it's a really really really old one ...

I wasn't aware that TC had snuck that gascolator item into the exemption from 549.01. Thanks for finding it. I work in the same building as the TC folks who are in charge of amateur-built design requirements. I'll try to track down the responsible party to discuss the issue. But, even if they agree that perhaps gascolators should not be required for some aircraft, I know there is already a huge regulatory backlog, and this would be too low a priority to see the light of day in the next five years. :(

As far as the text from 523.997 - that is for type-certificated aircraft, and a fuel filter would be all that is required to comply with the requirement - i.e. you wouldn't need a gascolator.
 
This issue just keeps popping up and I wonder why the gascolator has been seen as such a bad item. As it is already required on homebuilts in Canada and is installed in almost all the small certified aircraft in the world I have to ask the question, "are there airplanes falling out of the sky due to the use of gascolators"?
The "modern" gascolator as sold by Van's (the blue one) and the Andair gascolator are nothing like the old units found on tractors and lawn mowers, they are a quality item.
I have concerns about using filters in systems that can not be sumped, prior to flight. How do you know if there is foreign material in your filter device. If when I am testing the gascolator, before flight, I start to see material it is most surely time to see what is going on with my fuel system.
Are there filters on the market that have the ability to be sumped? I would consider units like that in my next build.
 
Last edited:
Fair enough on the certification thing, though I'm not sure a fuel filter can be drained and cleaned and have an easily removable screen. Would you not need a gascolator for that?

A regular old filter will always be full of fuel, unless you place it at just he right spot beyond the fuel selector valve.

In fact, if you place a gascolator in your RV wing root, how do you shut off the fuel so you can drain it and inspect it? Same scenario with a fuel filter mind you.

As for the exemption letter ... it's about the only spot on the entire TC web site that explicitly uses the word "gascolator"! I don't know why they didn't use the "Fuel strain or filter" verbiage instead ...
 
This issue just keeps popping up and I wonder why the gascolator has been seen as such a bad item. As it is already required on homebuilts in Canada and is installed in almost all the small certified aircraft in the world I have to ask the question, "are there airplanes falling out of the sky due to the use of gascolators"?
The "modern" gascolator as sold by Van's (the blue one) and the Andair gascolator are nothing like the old units found on tractors and lawn mowers, they are a quality item.
I have concerns about using filters in systems that can not be sumped, prior to flight. How do you know if there is foreign material in your filter device. If when I am testing the gascolator, before flight, I start to see material it is most surely time to see what is going on with my fuel system.
Are there filters on the market that have the ability to be sumped? I would consider units like that in my next build.

Well maybe it's my "certified aircraft owner" brain talking, but I'm also not understanding all this anti-gascolator talk.

Seems to me filtering your fuel is a pretty good idea, wouldn't take much to plug up an injector or even just the nozzle in your carburetor ...

When I inspect my gascolator in my cherokee, I find stuff in there, every year ... not much, but there is something, and it takes is one grain of sand, or very small stone, to ruin your day ...
 
In fact, if you place a gascolator in your RV wing root, how do you shut off the fuel so you can drain it and inspect it?

It can be done......

I ran my fuel lines from both tanks into the Selector then back out to the right wing root, through a gascolator then back into the centre, through the electric fuel pump, etc.

This lets you shut off the fuel when you want to inspect the gascolator and keeps it in a cool location (not FW forward, which is the alternative) so helps avoid potential vapour lock. Plus you only need one gascolator, not two ( one in each wing root, as some have done). Just makes the pipe work a little trickier!

Steve
 
A gascolator serves no useful purpose on FI equipped aircraft with return fuel layouts past the fuel filtering part which is more easily and less expensively taken care of with a simple filter than can easily be inspected/ cleaned. Unfortunately TC paints all installations with the same brush.

One fellow out here with an EFI equipped RV10 applied for an exemption under some different inspection text and was granted it after a short fly off time. I'll try to track down the details of it if I can.
 
I did a gascolator on each side, one for each tank, mainly for ease of plumbing but also provides a seperate filter for each tank, right at the tank. Immediately prior to the gascolator, I have installed a mini ball valve for fuel shutoff during maintenance so I can remove the gascolator's bowl with minimal fuel loss due to siphoning. The ball valve is safetied open. I believe it was this one..

http://www.summitracing.com/int/parts/ear-230502erl/overview/

Not flying yet so I cannot comment on how well it actually works but I am not anticipating any problems. It is all easily removable to revert back to the traditional way if needed. Not advocating anyone else do this without independant analysis. Be careful.

Bevan
 
My memory might be completely failing, but I don't recall there being a gascolator on my Grumman Yankee, a U.S. Certified aircraft that I know was owned by many Canadians.That might possibly be an avenue to explore.

There is no gascolator per se in the Grumman 4-seater AA5-series aircraft either. They do have low point drains (sumps) in each wing root, and the electric fuel pump, located between the tank and the engine-driven fuel pump, has a filter screen which is cleaned annually or every 100 hours, whichever comes first. These engines have carbs rather than injection.
 
A gascolator serves no useful purpose on FI equipped aircraft with return fuel layouts past the fuel filtering part which is more easily and less expensively taken care of with a simple filter than can easily be inspected/ cleaned.

I don't follow, perhaps I just don't understand fuel-injected systems.

As best I understand it, the fuel comes from the tank, goes through a filter (or gascolator), into the FI system, and there's a return line from the FI system back to the tank. The return line never supplies fuel *to* the FI system, it's just a return line. Your primary line *out* of the tank is filtered. So why can't that filter be a gascolator instead of an inline filter?
 
I don't follow, perhaps I just don't understand fuel-injected systems.

So why can't that filter be a gascolator instead of an inline filter?

Exactly- good question for TC. With an EFI/ return type system, as soon as you turn the pump on without the engine running, 100% of the fuel is returned back to the tank at very high flow so fuel is immediately all mixed up with any water that might be in there. It all passes through the engine with no harm done. Any water present is always kept mixed and evenly distributed within the fuel due to the high return rates, even at full power due to excess pump capacity.

Of course, we should still have drains in the low points as RVs already have by design.
 
There have been many references to "carb" and "fuel injection" systems especially in connection with the Canadian requirement for a "gascolator" in the fuel system.

I think it is important to distinguish the different types of fuel injection systems before saying a "gascolator" serves no purpose.

1. Bendix (Precision Airmotive) type fuel injection systems. Common on RVs. Demand sensed by venturi in servo. No fuel return to the tank.
2. Continental type fuel injection systems. Not common on RVs. Demand not sensed. Excess fuel returned to tank.
3. Automotive style. As Ross says, excess fuel returned to tank.

So in my view, whether we call it a "gascolator" or a fuel strainer/filter/drain is less important than its function. For a Bendix fuel injection system I think a fuel strainer/filter/drain is an important part of the fuel system since it removes particulate contamination and provides a preflight inspectable capability (drain or sumping).

For an automotive style fuel injection system, given the inherent mixing of fuel/water perhaps a filter only is sufficient. Of course the fuel tank quick drains should always be checked preflight.

Unfortunately the Canadian regulations do not distinguish between the different types of fuel injection, thus the requirement for a "gascolator".

For my system with Bendix fuel injection, I will have an Andair 70 micron gascolator in each wingroot to protect the pump, and a Falls Filtration 17 micron gascolator on the firewall to protect the injection servo.
 
Gascolator

A point that has not been discussed is the inherent danger of many typical gascolator installations on older GA aircraft. I am talking about the glass and metal bowl style used on many Pipers thru at least the 60's. The typical firewall mounted gascolator was at the very bottom of the firewall, so as to be at the lowest part of the fuel system. In even a minor fender bender these gascolators could be damaged and now you had fuel running all over. Also the Piper style gascolators were inherently fragile and could come apart in flight. A lot of these gascolators found their way into early EAB aircraft.
Many years later the Pipers with fuselage tanks were found lacking in their ability to remove water from the tank. This was addressed by an AD which installs a quick drain in the bottom of the tank with a line running overboard.
I much prefer a tank drain and a race car type all metal filter that can be cleaned at regular intervals.
 
The liability of a gascolator has been experienced by a number of people with EFI systems on their aircraft where ethanol attacked the O-rings or gaskets on the gascolator and they were mounted on the inlet side of the pumps (maybe not a great idea). Air was introduced into the system, engines leaned out or full blown vapor lock caused the engines to stop. Certain pump designs like Bosch don't fancy air in them at all and may fail to reprime which is bad news either way. Air in an EFI system on the high pressure side is unacceptable and a lot more dangerous than some water mixed up in there.

Obviously, if we are using ethanol laced mogas, we want to make sure all seals are ethanol compatible. If gascolators must be used, we recommend that are the high pressure type mounted downstream of the pumps. We recommend filters placed upstream of the pumps to keep junk out of the pumps.

The main causes of water in the fuel are leaking caps with the aircraft parked outside and aircraft parked outside for long periods with partially filled tanks and large daily temperature variations causing condensation. For aircraft parked indoors, the chances of getting any substantial amounts of water in the tanks or system are practically nil. Mogas and avgas from the pumps is well screened for water prior to pumping.

I have something close to 20,000 hours in cars and aircraft with EFI, never a water issue in all that time and I live in a climate which can have massive daily temperature variations. Have never found water sumping my aircraft either.
 
My gascolator is much more than a water separator.

I actually don't mind having the gascolator in place. It serves multiple purposes but the 70 micron cleanable and easily inspectable filter of the Andair unit is a nice form factor for a filter, which I need upstream of the aux fuel pump anyway. The water separating and sumping abilities are additional features that may or may not be useful one day.

As long as the gascolator does not intruduce new risks such as letting air in (deteriorating O-ring) and absorbing heat, I guess I can live with it.

Putting the gascolator in the wing roots solves the heat problem, minimizes the risk of O-ring failures, and allows me to check the filter without making any fuel drips in the cockpit.

Bevan
 
Last edited:
Thanks for all the great inputs!!!

Sorry for the long post...
Don't be mistaken, I'm not on an anti-gascolator campaign...

Just trying to reason the why and how instead of blindly doing something.
For what I understand, a gascolator is a very good element to have as a water separator and filter.

My issue is that with the 10 micron uncloggable filter after the boost pump (to protect the injectors) , I don't see the use of a gascolator (with a 70 micron mesh) FWF. Not to mention that with the 8's engine mount, there is not that much space on the lower firewall...

So I understand putting 1 before the boost pump to catch the debris that went through the fuel pick-up mesh in the tank.
That means just after the selector, in the cabin. Not my preferred solution, more on this further down.
Hence my planning on putting 1 in each wing root as Bevan and others did.
But that implies increasing the complexity of the system, and I'd like to avoid that.

As for water, I can see 4 possible ways (there may be more) that it can pollute the fuel.
- Condensation in tanks (removed by draining pre-flight)
- Leaky fuel caps when parked outside in rain (removed by draining, cured by changing caps)
- Contamination while refueling (this is always a risk, of course mitigated by draining afterwards)
- Condensation in the remainder of system (IMO, this is unlikely to happen as all the system should remain primed with fuel, especially if check valves are installed)

Gascolator in the cabin:
The main (new) issue here is this heads-up I got from Robert Paisley of Protek (flyefii):
It would be best to use a positive locking drain valve on the gascolator. You don't want a push-to-open valve in the suction side of the fuel system. These can get sucked open by the pump and cause air to enter the system.

The Protek boost pump continuously delivers approx 30 GPH.

If I remember correctly, (memory tends to fade after some years... :roll eyes:)
on some Piper aircraft there was this drain valve that had to be ¼ turned before it was possible to push in. I assume this is what Robert is talking about.

In the cabin, with the gascolator near the floor, I believe it would be awkward to operate while catching the fuel for inspection.
Maybe I'm wrong here and over-thinking it...

On the regulatory side, I may understand where the gascolator requirement comes by reading from the Normal, Utility, Aerobatic And Commuter Category Aeroplanes:
(only (a) & (b) are relevant here...)

523.997 Fuel Strainer or Filter

There must be a fuel strainer or filter between the fuel tank outlet and the inlet of either the fuel metering device or an engine driven positive displacement pump, whichever is nearer the fuel tank outlet. This fuel strainer or filter must:

(a) Be accessible for draining and cleaning and must incorporate a screen or element which is easily removable;

(b) Have a sediment trap and drain except that it need not have a drain if the strainer or filter is easily removable for drain purposes;


The magic words here are : draining, easily removable, sediment trap, drain, drain purposes.

There doesn't seem to be a waiver for this in the Amateur-Built Aircraft chapter (549).
I didn't see any...
 
With an EFI/ return type system, as soon as you turn the pump on without the engine running, 100% of the fuel is returned back to the tank at very high flow so fuel is immediately all mixed up with any water that might be in there.
If the gascolator is between the fuel tank and the point in your fuel system where the return line connects, then even if the fuel is running in bypass mode and looping back to the tank, it's getting circulated through the gascolator every time it goes through. Doesn't that remove water as it goes?

Bear with me, i'm just trying to understand...
 
For my system with Bendix fuel injection, I will have an Andair 70 micron gascolator in each wingroot to protect the pump, and a Falls Filtration 17 micron gascolator on the firewall to protect the injection servo.

Terry, might want to skip that 17 micron filter. A Bendix servo has a built-in 74 micron tubular screen accessible by removing the inlet fitting. That would suggest a 17 micron filter is unnecessarily restrictive, in particular if installed inline prior to the engine driven fuel pump.

With an EFI/ return type system, as soon as you turn the pump on without the engine running, 100% of the fuel is returned back to the tank at very high flow

In even a minor fender bender these gascolators could be damaged and now you had fuel running all over.

Fuel release after damage is an additional risk factor for a system with a full-time electric pump (no engine driven pump). Fuel is pumped in high volume, and pumping does not cease when the prop stops. With a recirculating FI system, the high volume flow extends all the back through the return system plumbing, increasing the number of components exposed to damage. In cars, the problem of fuel flow after impact is sometimes addressed with a G-switch. In a forced landing, a good pilot will probably remember to kill the electrical supply prior to impact. I'm not sure how an auto-cutoff might be incorporated for an aircraft. People do forget things under pressure, and few accidents are planned.

...even if the fuel is running in bypass mode and looping back to the tank, it's getting circulated through the gascolator every time it goes through. Doesn't that remove water as it goes?

The very high flow rate of a recirculating system would not allow water to settle in the cup.
 
Last edited:
Terry, might want to skip that 17 micron filter. A Bendix servo has a built-in 74 micron tubular screen accessible by removing the inlet fitting. That would suggest a 17 micron filter is unnecessarily restrictive, in particular if installed inline prior to the engine driven fuel pump.





Fuel release after damage is an additional risk factor for a system with a full-time electric pump (no engine driven pump). Fuel is pumped in high volume, and pumping does not cease when the prop stops. With a recirculating FI system, the high volume flow extends all the back through the return system plumbing, increasing the number of components exposed to damage. In cars, the problem of fuel flow after impact is sometimes addressed with a G-switch. In a forced landing, a good pilot will probably remember to kill the electrical supply prior to impact. I'm not sure how an auto-cutoff might be incorporated for an aircraft. People do forget things under pressure, and few accidents are planned.



The very high flow rate of a recirculating system would not allow water to settle in the cup.

I agree, 17 microns is smaller than you need here. We use a 35 micron sintered bronze filter on our dual pump module and these are well proven in tens of thousands of flight hours in aircraft.

For fuel pump cutoff in the event of a forced landing, our ECU will shut off the pump after 2.8 seconds of not detecting crank rotation.

Ditto the comment that on these systems, the high mixing and flow rates basically make collection of water in the gascolator cup improbable- therefore useless in that capacity.
 
I have my sumpable filter (Andair gascolator) installed in the stick bay in the cabin. In this location it is just after the selector and before the boost pump. I have done this same mounting in numerous aircraft, including an RV10. It keeps this unit cool and isolated from vibration. It is easy to reach down under the cabin and get a sample before flight.
As I understand this thread, the only installation that perhaps should not use one of these units is a full automotive fuel type system. I will certainly take a look at the different options if I ever go that route, until then I will stay with what has safely worked for me.
 
I agree, 17 microns is smaller than you need here. We use a 35 micron sintered bronze filter on our dual pump module....

I was suggesting the additional filter was unnecessary with an RSA-5.

For fuel pump cutoff in the event of a forced landing, our ECU will shut off the pump after 2.8 seconds of not detecting crank rotation.

Yes, with the fuel pump relay control option installed in an SDS EM-5. Probably have that on your own RV-6.

However, the OP is thinking about installing a Protec EFii system. It drives the pump relay from the optional Bus Manager (not the ECU), in order to incorporate automatic pump switching. Pump #1 is always powered from the essential bus or emergency bus; the pump is wired to the NC relay terminal. And anyway, the Protek ECU harness doesn't seem to include a pump relay control wire. Have the systems been revised?

 
Terry, might want to skip that 17 micron filter. A Bendix servo has a built-in 74 micron tubular screen accessible by removing the inlet fitting. That would suggest a 17 micron filter is unnecessarily restrictive, in particular if installed inline prior to the engine driven fuel pump.QUOTE]

Agreed 17 micron may be overly restrictive. Not sure about the Bendix but my Precision FI system (which I understand is the experimental version of the Bendix) requires a filter (stated as 32 micron in the literature) either immediately before or after the mechanical fuel pump. This is to protect from larger volume of debris (conceivably fuel pump rubber diaphram debris) obstructing the smaller fine filter within the servo itself.

I was not able to find a 32 micron filter other than paper element type which I did not want. I was able to find a 40 micron cleanable mesh filter that fit inside the AP filter housing I had on hand now relocated downstream of the mechanical fuel pump. This was acceptable to the tech at Precision I was working with.

Bevan
 
In cars, the problem of fuel flow after impact is sometimes addressed with a G-switch. In a forced landing, a good pilot will probably remember to kill the electrical supply prior to impact. I'm not sure how an auto-cutoff might be incorporated for an aircraft. People do forget things under pressure, and few accidents are planned.

This was a subject that got a lot of attention after Kyle Franklin's crash, that killed his wife------although it was smoke oil, not gasoline. But either one will fuel a fire.............

As I recall, Kahuna developed a G switch to cut off smoke oil-------perhaps it could be used in this situation also???
 
35 microns is about .0015 inches- much smaller than any orifice in an EFI injector. 17 micron is just overkill IMO with any FI system and unless it has a larger filtering area, perhaps restrictive in some cases.

Cars usually have both G switches, roll over switches and the ECU which can cut off the fuel pump in the event of an accident- food for thought in aircraft with electric pumps of any kind.

I couldn't comment on the recommended EFII fuel pump control layout. Robert will probably pipe up here.

I'd say about 1/3rd of our SDS aviation customers use the standard ECU controlled fuel pump relay, the rest, like me, use separate switches directly controlling the pumps. Preference really.
 
Gascolator

My fuel filter selection was driven by the ?Installation and Detail Specifications for the Silver Hawk EX-5VA1 Servo Kit? manufactured by Precision Airmotive.

Section 4.0 Fuel Filtration
The fuel supplied to the servo shall be filtered to 32 micron nominal. This filtration may occur prior to the engine driven pump, but all other pumps and valves shall be upstream of the filter.

I corresponded with Precision Airmotive when I was having trouble finding such a filter and was advised as follows:

We recommend a nominal 32 micron filter because the finger screen in the inlet of the servo is 70 micron and is not meant to be a primary filter. We agree that most certified aircraft should have a similar filter installed but we have no way of knowing what they use as they are separated from us by the engine manufacturer, which gives engine installation specs. Also, from our experience, many do not use a sufficiently fine filter.

I selected an Air Maze brand fuel filter from Falls Filtration with a filtration rating of 20 micron nominal (17 microns in my earlier post was in error) as this was as close to the 32 micron requirement that they could provide. Nominal describes the ability of the filter media to retain the majority of particulate (at 60%-98%) the rated pore size.
 
EFII pump control

EFII fuel pump management is handled automatically by the Bus Manager (if so equipped). Otherwise it is controlled by a builder supplied switch.
It is not part of the EFII wiring.

Robert
 
I agree, 17 microns is smaller than you need here. We use a 35 micron sintered bronze filter on our dual pump module and these are well proven in tens of thousands of flight hours in aircraft.

For fuel pump cutoff in the event of a forced landing, our ECU will shut off the pump after 2.8 seconds of not detecting crank rotation.

Ditto the comment that on these systems, the high mixing and flow rates basically make collection of water in the gascolator cup improbable- therefore useless in that capacity.

Ross, what is the relative advantage of sintered bronze vs ss pleated mesh as a fuel filter?

Thanks
 
Ross, what is the relative advantage of sintered bronze vs ss pleated mesh as a fuel filter?

Thanks

Pleated metallic mesh has more surface area so that could be an advantage. The sintered elements were widely produced by the tens of millions for OEM applications and they are compact, inexpensive, readily available and well proven plus easy to inspect for debris. Either would work fine IMO.
 
Pleated metallic mesh has more surface area so that could be an advantage. The sintered elements were widely produced by the tens of millions for OEM applications and they are compact, inexpensive, readily available and well proven plus easy to inspect for debris. Either would work fine IMO.

I purchased a Fuelab ss 40 micron filter for my FI system. Dig deep into the bowels of the instructions and they say it is not suitable for aircraft of any type. Lucky I have a Rocket and not an airplane....
 
One fellow out here with an EFI equipped RV10 applied for an exemption under some different inspection text and was granted it after a short fly off time. I'll try to track down the details of it if I can.

Do we even know how to start the process to apply for an exemption ?
 
Check the difference in gascolator requirements between "The Exemption from Section 549.01" and "Chapter 549".
You could request MD-RA to inspect your project to Chapter 549 standards instead. In this 549.13 does not list a gascolator as required equipment.
 
Last edited:
Check the difference in gascolator requirements between "The Exemption from Section 549.01" and "Chapter 549".
You could request MD-RA to inspect your project to Chapter 549 standards instead. In this 549.13 does not list a gascolator as required equipment.

Also CAR 523.997 doesn't mention the word gascolator, just fuel strainers and filters.
http://www.tc.gc.ca/eng/civilaviation/regserv/cars/part5-standards-523-sub-e-274.htm#523_997


So this argument would be with MD-RA and not Transport Canada?
 
Just the facts ma?am, Just the facts

Hi

I am the guy Ross mentioned in an earlier post. I built an RV10 that had a gascolator when first inspected by MDRA. The inspection basis was the exemption to CARS 549 which, at the time in 2012, was the only inspection type performed by MDRA.

After an engine change a new inspection was performed by Transport Canada. The inspection basis was CARS 549 and NOT the exemption. This was at my request as I did not want to install a gascolator. As Ralph noted CARS 549 does not require a gascolator.

Fast forward to 2017 when I started my second build. I asked Transport Canada and MDRA if I could get MDRA to inspect the new airframe using CARS 549 and not the exemption. In rather short order word came back that this is in fact was possible.

My project RV10 will be inspected under CARS 549 hopefully in Feb or Mar.

In short just let MDRA know that you want to be inspected under CARS 549 and they will be more than happy to accommodate.

When making this request be mindful that there are differences between the exemption and CARS 549. Be sure to read each and comply with all requirements. For example placards and the data plates are not the same.

Just because CARS 549 does not require a gascolator that doesn’t mean you can’t install one if it makes sense. For example a gascolator on a high wing would seem to be essential to drain fuel lines of water.

Cheers

Les
 
Last edited:
wow, great info.

It was a hot topic when I was building my -9A back in 2008. Just started a -12iS and was wondering how I would cope with that requirement on Rotax 912iS equipped plane.
 
wow, great info.

It was a hot topic when I was building my -9A back in 2008. Just started a -12iS and was wondering how I would cope with that requirement on Rotax 912iS equipped plane.

This is exactly why we wished Transport would revisit the requirement on EFI equipped engines. Gascolators do nothing to increase safety and are actually a liability in our view or at minimum, useless. At least through this process, they can legally be eliminated.
 
When making this request be mindful that there are differences between the exemption and CARS 549. Be sure to read each and comply with all requirements. For example placards and the data plates are not the same.

I'm about to submit my letter of intent to MD-RA for my new -12iS kit and there's now a check box in the form to select if you're going to use the exemption or not for the project.

-->http://www.md-ra.com/docs/C01E.pdf

Aparts for the placards / data plates... anything else major that should be noted as a caveats of going that way?
 
RV12IS and gascolator 'requirement' in Canada, Australia, and some European countries. I followed this thread with interest because in some case it affects what we do. The RV14 project caught may attention, but the question of the RV12IS really got me thinking again.

The reg says:
Fuel Strainer or Filter, (gascolator)
On all amateur built aircraft there must be a fuel strainer or filter between the fuel tank outlet and the inlet of
either the carburetor or an engine driven fuel pump.
The fuel strainer or filter must:
(a) be accessible for draining and cleaning and must incorporate a screen which is easily removable;
(b) have a sediment trap and drain.
(d) have the capacity to ensure that engine fuel system functioning is not impaired, with the fuel
contaminated to a degree that is greater than that established for the engine during its type certificate.

Well, with a low point drain via the FLF-00013 drain block, the 12IS meets that criteria. The filter is accessible for 'cleaning' in a broad sense of the word. I guess if you remove it and replace it with a new 'clean' filter, it satisfies the reg.
I'm quite certain that Scott and the engineering staff at Vans that worked on the 12IS project took all of that into consideration. Certainly the 12IS is approved to build and fly in Canada and other countries with its current design system without having to redo the system to incorporate a gascolator. Further, if it was an absolute requirement for conformance, then they would have made a provision for one, AND included it in the kit.

Tom
 
I just got the reply from MD-RA.

The letter of intent now allows you to select if you want to inspect your plane using the exemption OR the CARs themselves.

They wrote :

1-CAR's and the Exemption 549.01 does give you a choice whether to construct your aircraft under the CAR's or the Exemption.

2- CAR's does not directly state a Gascolator is required, however it does reference or allows for references to sections within the CAR's to identify what constitutes a Fuel system and lays out applicable standards. CAR 523.951, 523.971, 523.997, 523.999

3- If you choose CAR's 549 you will be required to provide pertinent data to support your fuel system and to show you have met the standards as provided in the CAR's. Drains, filters, sumps are required in CAR's 549 no matter what engine or fuel system you choose.

4-If your chosen fuel system comes with manufacturer recommendations to omit certain requirements found in our CAR's and / or 549.01 Exemption, a letter from the manufacturer will be required to support this matter.

for reference, the Exemption states :

Minimum equipment :
[...]
f)a tachometer for each engine;
g)an oil pressure indicator for each engine that uses a pressure lubricating system;
h)a temperature indicator for each engine (displaying the temperature of the cylinder heads, lubricating oil, coolant or exhaust gas, as applicable to the type of engine);
i)a fuel quantity indicating system for each main fuel tank;
j)a gascolator located at the lowest point in the fuel system; and
k)a manifold pressure indicator for each supercharged engine, and for each engine equipped with a variable pitch propeller.

Since the -12iS fuel system doesn't have a proper gascolator, we'll need to comply to the CARs.



RV12IS and gascolator 'requirement' in Canada, Australia, and some European countries. I followed this thread with interest because in some case it affects what we do. The RV14 project caught may attention, but the question of the RV12IS really got me thinking again.

The reg says:
Fuel Strainer or Filter, (gascolator)
On all amateur built aircraft there must be a fuel strainer or filter between the fuel tank outlet and the inlet of
either the carburetor or an engine driven fuel pump.
The fuel strainer or filter must:
(a) be accessible for draining and cleaning and must incorporate a screen which is easily removable;
(b) have a sediment trap and drain.
(d) have the capacity to ensure that engine fuel system functioning is not impaired, with the fuel
contaminated to a degree that is greater than that established for the engine during its type certificate.
[...]

After reviewing "CARs 523.951, 523.971, 523.997, 523.999", I believe you are correct for the filter part but there's one about having a sump with a 0.25% tank capacity.

523.971 :

(a) Each fuel tank must have a drainable sump with an effective capacity, in the normal ground and flight attitudes, of 0.25 percent of the tank capacity, or 1/16 gallon, whichever is greater.

(b) Each fuel tank must allow drainage of any hazardous quantity of water from any part of the tank to its sump with the aeroplane in the normal ground attitude.

(c) Each reciprocating engine fuel system must have a sediment bowl or chamber that is accessible for drainage; has a capacity of 1 ounce for every 20 gallons of fuel tank capacity; and each fuel tank outlet is located so that, in the normal flight attitude, water will drain from all parts of the tank except the sump to the sediment bowl or chamber.

(d) Each sump, sediment bowl, and sediment chamber drain required by paragraphs (a), (b), and (c) of this section must comply with the drain provisions of 523.999(b)(1) and (b)(2).

So : we can consider the lines from the tank all the way up to the pre-filter as the sump.. so we comply to "A", "B" and "D". But what about "C" ? That part doesn't work : "each fuel tank outlet is located so that, in the normal flight attitude, water will drain from all parts of the tank except the sump to the sediment bowl or chamber"

That's basically saying "we want a device that traps water from the tank"... which we clearly don't
 
The thing with EFI using a return system is it doesn't care about water in the system much as it returns a gallon/ minute back to the tank and mixes all the water up with the fuel in short order.

You want to be able to sump the tanks pre-flight but some small amount of water won't affect anything. Even a quart of water in 20 gallons would have little discernable effect on how the engine runs because it's mixed homogeneously.
 
Yeah, I know that a gascolator is 100% useless in a -12iS. The POH clearly states you must let the plane sit with the pump off then drain the water if you have the iS engine.

Post-Flight Rotax 912ULS:
• Fuel Pump - ON
• Fuel Sample - CHECK until no more water or fuel/water mixture is present. • Fuel Pump – OFF

Post-Flight Rotax 912iS:
• Let fuel settle to allow water to come out of solution.
• Fuel Sample - CHECK until no more water or fuel/water mixture is present.

The drain is perfect for the job... but looking at the plans, I could probably install a gascolator instead of the drain... wouldn't be much work. Asking Vans about it. Asking them if they can also supply a letter that states that a gascolator isn't needed because of the recirculation.

edit :

So basically, it seems I have 3 options :

1) Install a gascolator and inspect it using the exemption <-- hopefully that won't mess up the fuel system (flow rate, etc)
2) Get a letter from Rotax (was just told a letter from Van's wouldn't be accepted by TC) to waive the requirement of the gascolator and inspect it using the exemption
3) Go the CARs 549 way but then it's on me to prove that my fuel system complies with all requirements
 
Last edited:
Just contacted the Rotax distributor in Canada for more info. Since they've been selling the 912iS in Canada... I'm guessing they know more :)
 
Philippe, BEFORE I'd make any changes in this system, I'd contact Gus or Rian at Vans Aircraft. Their team designed the system. I still feel that certainly they built the system to comply with the various regs of the countries where the plane would be sold.

I'M SURE WE ALL WOULD LIKE TO KNOW THE OUTCOME.

Hey Scott----if you're listening, can you email me @[email protected]?

Tom
 
Back
Top