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  #1  
Old 01-13-2022, 04:31 PM
kearney kearney is offline
 
Join Date: Dec 2006
Location: Canmore, Alberta, Canada
Posts: 62
Default REDUX - MD-RA and Gascolators

Hi

Below is an email I received from Nicholas Robinson who is the Transport Canada Civil Aviation (TCCA) Director General.

The backstory leading up to this email is involved but the Coles Notes version is this. A few months ago, I became aware that MD-RA was insisting on Gascolator installs without exception. This was at odds with what TCCA told me in 2019 and more recently in Sept of 2021. As recently as December, MD-RA withheld the SCofA for an RV14 builder for this reason. It took a number of emails to TCCA to get this resolved. Concurrently, I reached out to Mr. Robinson’s office for clarification.

This email stands on it owns – it clearly states that provided that a fuel systems functionality is equivalent to a Gascolator, a Gascolator is not required.

Understanding that some MD-RA inspectors are still insisting on Gascolator installs, I suggest builders present this letter to their inspector if necessary. Any builders who still have a problem, feel free to PM me and I’ll let you know who in TCCA to contact.

Cheers

Les


From: Robinson, Nicholas
Sent: January 11, 2022 7:46 AM
To: Les Kearney

Subject: Authority Granted Under the Civil Aviation Regulations by TCCA / MD-RA

UNCLASSIFIED / NON CLASSIFIÉ

Mr. Kearney,

Thank you for your email dated 12 Dec 2021.

Transport Canada Civil Aviation (TCCA) has supported builders of amateur-built aircraft who have decided not to install a gascolator, as required by 2009 TCCA Exemption to AWM Chapter 549.01, as long as the fuel system functionality is considered equivalent to those systems that have used a gascolator. Considering that you were able to obtain a Special CofA flight authority in the Amateur-Built classification for your previous RV-10 project, which did not use a gascolator as part of the fuel system design, confirms our support and position on this subject.

We have recognized that the on-going interpretation issues associated with amateur-built fuel system designs has been primary due to misinterpretations associated with the TCCA guidance that had been provided in the MDRA Inspection Services C52 document and compounded by the fact that we have not been able to provide the required in-person MD-RA Delegate training since 2017.

During the past several months TCCA has been able to provide MDRA Inspection Services with an updated version of the C52 guidance, which you were provided an opportunity to comment on, as well as complete our in-person MD-RA Delegate training at the MDRA Inspections Services facility located in London, ON. We now know that MDRA Inspection Services, and our MD-RA Delegates, are aligned with the guidance provided in the C52 document and the TCCA position on what would be considered an acceptable alternative fuel system design when a gascolator has not been installed.

We are currently not aware of any circumstance where a flight authority has not been issued to an amateur-built aircraft when a gascolator was not installed. We are also not sure why a formal appeal process, or a less formal resolution process, would be required on this subject since TCCA has not refused to issue a Canadian Aviation Document, such as a Special CofA flight authority in the Amateur-Built classification.

Considering that each amateur-built aircraft project is unique, by definition, it is up to the applicant (Builder) to demonstrate compliance with the conditions of issue of its flight authority. Therefore, it is not unusual that there will be differences of opinion, Builder vs the MD-RA Delegate, when determining compliance with acceptable standards of airworthiness. However, we are confident that future discussions regarding alternative fuel system designs that take place between the Builder and their MD-RA Delegate will be resolved based on the work we have completed over the past several months.

Thank you for bringing your concerns to our attention.


Nicholas Robinson
Director General, Civil Aviation
Transport Canada, Place de Ville (AAR), Ottawa Ontario K1A 0N8

Directeur général, Aviation civile
Transports Canada, Place de Ville (AAR), Ottawa Ontario K1A 0N8
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  #2  
Old 01-14-2022, 09:33 AM
riseric's Avatar
riseric riseric is offline
 
Join Date: Oct 2011
Location: Québec, CNV9
Posts: 537
Default Equivalent to a Gascolator

Guys, sorry for the long post...

Les, thanks for sharing and what you're doing is appreciated.
Can you describe what you did to circumvent the Gascolator requirement?

Quote from the new C52 document:
However, in a very few, very specific installations, it may be impractical to install a fuel filter bowl. If that is the case, the builder must be prepared to demonstrate and assure that the fuel system design meets the object of the fuel filter bowl, or “gascolator” requirement.
If the aircraft fuel system does not utilize a “gascolator”, the functions performed by the “gascolator” must still be achieved.


So that our Canadian builder colleagues can add my experience to this ongoing Gascolator issue, I just went through an inspection in last september without a Gascolator.
Having a EFII System32, I believe such a device is not appropriate or useful in my fuel system.
Please remember that I'm not against having a Gascolator as such, and depending on the particulars of one's fuel system, where one is warranted, one shall be installed.

Anticipating that I was to face some resistance, and when the inspector asked "where is the Gascolator", I gave him a prepared document in which I described the particulars of my fuel system in a tailwheel RV, what a Gascolator does in general and especially what a Gascolator does not do and an excerp from an email issued by Jeffrey Phipps, (Chief, Operational Airworthiness (AARTM) Standards Branch Transport Canada Civil Aviation), from a previous thread of your's, here

In short, why in my view a Gascolator was not useful in my system.
As expected, the inspector snagged the final inspection sheet, noting "No Gascolator installed"
A few days later, the Regional MD-RA director called and requested additional details of my fuel system with photos. At this point, he mentionned that the C52 document was under revision and a newer version was expected soon.

After a few emails of questions and explanations, he relayed to me TCCA's conclusions, quote:"As specified in the C52 approved document, you will require a separate fuel drain be connected to each Fuel Filter Assembly that ensures when activated, the contents sampled at pre-flight, originate from that fuel filter.

I have two fuel filters, one coarse pre-pump and one fine post-pump/pre-injectors. They are horizontaly mounted near the fuel pump assembly just left of the left rudder pedal. I questionned how was I to acheive this requirement.

After one month, TCCA finally replied through the MD-RA Regional Director with 2 requirements:
First, that my 2 filters be mounted vertically.
Second, that each filter be fed fuel from below and that each filter be drainable to the outside of the fuselage.
I was asked to provide drawings of my possible modifications to comply with the request for discussion.

Needless to say, this was a major blow inducing a significant modification in a hard to reach area. I replied with drawings, (see below, it's in French but you can get the idea) providing different arguments to demonstrate that a "Gascolator's function" could not be met under those circumstances, stating among other things that water can't defy gravity...
Finnaly, a simpler requirement was suggested where one of my filters could be installed Firewall Forward, vertically, with a drain to the outside...

So my conclusion of all this, considering C52's requirements, quote: If the aircraft fuel system does not utilize a “gascolator”, the functions performed by the “gascolator” must still be achieved.
Functions being filtering and drainage.
If you choose to not install a Gascolator bought from a manufacturer, you will need to install a home-made drainable fuel filter... a home-made gascolator...
Don't think that you don't have to install a Gascolator or a home-made drainable fuel filter... Again, here's another quote from C52:
Fuel Filtration
On all amateur built aircraft there must be a fuel strainer or filter between the fuel tank outlet and the engine. The particular location will vary depending on the specifics of the engine installation.
The fuel strainer or filter should:
(1) be accessible for draining and cleaning;
(2) must incorporate a screen which is easily removable;
(3) have a sediment trap and drain;
(4) be mounted so that its weight is not supported by the connecting lines or by the inlet or outlet connections of the strainer or filter itself, unless adequate strength margins under all loading conditions are provided in the lines and connections; and
(5) be capable of removing contaminants that would affect engine operation.

YMMV.
I tried my best to avoid having to install a Gascolator... did not succed...
Attached Thumbnails
Click image for larger version

Name:	Croquis # 1.pdf
Views:	70
Size:	315.4 KB
ID:	20974  
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  #3  
Old 01-14-2022, 11:49 AM
kearney kearney is offline
 
Join Date: Dec 2006
Location: Canmore, Alberta, Canada
Posts: 62
Default Gascolator Equivalent

Eric

Much has been happening on this issue since your inspection.

My RV10 (inspected in 2019) has three filters - two HORIZONTALLY mounted in the wing roots and one vertically mounted on the firewall. There are only TWO drains - the ones in the fuel tank.

This setup, which meets manufacturer (SDS) recommendations, was passed by TCCA over MD-RA objections.

Recently, an RV14 builder had the same system passed, again over MD-RA objections.

To be clear, MD-RA does not make the rules. What you were required to do is something that is not found in any certified aircraft. Effectively, you have turned your fuel filters into a homebrew gascolator which is clearly not required.

If any other builder is presented with this option, please let me know and I will reach out to TCCA for clarification.

For the record, in 2019 TCCA stated "an easily serviceably filter, in addition to a drain in the lowest point of the fuel system, is acceptable for aircraft built to either the exemption or to Standard 549".

This does not require any change to filter orientation or addition of drains below the filter.
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  #4  
Old 01-14-2022, 03:02 PM
riseric's Avatar
riseric riseric is offline
 
Join Date: Oct 2011
Location: Québec, CNV9
Posts: 537
Default

Thanks Les,

I may have wrongly led to believe that MD-RA or TCCA were telling me how to do modifications.

TCCA initially wrote concerning my specific setup that something was required, quote: As specified in the C52 approved document, you will require a separate fuel drain be connected to each Fuel Filter Assembly that ensures when activated, the contents sampled at pre-flight, originate from that fuel filter

My inspection was September 2021. The TCCA requirements were based on the new 2021 C52.
Maybe it's a regional MD-RA and/or a regional TCCA thing... I can't say but their final suggestion/requirement was to have a vertical, drainable filter on the firewall.

After six weeks of arguing and providing scientific evidence that, in my specific fuel system, what was required did not better filter the fuel nor remove any water, I gave up trying to prove my point.
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Last edited by riseric : 01-14-2022 at 03:14 PM. Reason: Added info
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  #5  
Old 01-14-2022, 07:21 PM
kearney kearney is offline
 
Join Date: Dec 2006
Location: Canmore, Alberta, Canada
Posts: 62
Default

Eric

The quote you provided does not exist in C52E.

There is no requirement for the filter to have a drain. MD-RA and perhaps some in TCCA may have wanted this but there is no statutory basis for this requirement.

What a filter with a drain is is nothing more than an ersatz gascolator. It has all the deficiencies of a gascolator when installed in a low wing aircraft.
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  #6  
Old 01-15-2022, 07:32 AM
riseric's Avatar
riseric riseric is offline
 
Join Date: Oct 2011
Location: Québec, CNV9
Posts: 537
Default

Hi Les,
What was quoted in post # 4 was from TCCA to MD-RA concerning my setup, not from C52.

However, in the current C52 document concerning fuel filtration, they do mention draining, maybe you missed it...:
Fuel Filtration
On all amateur built aircraft there must be a fuel strainer or filter between the fuel tank outlet and the engine. The particular location will vary depending on the specifics of the engine installation.
The fuel strainer or filter should:
(1) be accessible for draining and cleaning;
(2) must incorporate a screen which is easily removable;
(3) have a sediment trap and drain;
(4) be mounted so that its weight is not supported by the connecting lines or by the inlet or outlet connections of the strainer or filter itself, unless adequate strength margins under all loading conditions are provided in the lines and connections; and
(5) be capable of removing contaminants that would affect engine operation.


So maybe it could be argued with TCCA about the should (as in "desirable") instead of shall (as in "mandatory")...???
P.S. the attachement looks weird but you clic on it it will open in Acrobat Reader and it's the current C52E document from MD-RA
Attached Thumbnails
Click image for larger version

Name:	C52E.pdf
Views:	39
Size:	254.4 KB
ID:	21006  
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2022 =VAF= paid
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Grove Airfoiled Gear, Wheels & Brakes
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Aerosport IO-375, MTV-9-B/183
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Last edited by riseric : 01-15-2022 at 07:34 AM. Reason: Added info
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  #7  
Old 01-15-2022, 10:22 AM
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Snowflake Snowflake is offline
 
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Location: Sidney, BC, Canada
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Default

Quote:
Originally Posted by riseric View Post
I have two fuel filters, one coarse pre-pump and one fine post-pump/pre-injectors. They are horizontaly mounted near the fuel pump assembly just left of the left rudder pedal.
Quote:
Needless to say, this was a major blow inducing a significant modification in a hard to reach area.
Eric, isn't this a poor location for the filters in any case, given the requirement for accessibility for maintenance?
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  #8  
Old 01-15-2022, 10:36 AM
kearney kearney is offline
 
Join Date: Dec 2006
Location: Canmore, Alberta, Canada
Posts: 62
Default

Eric

C52 is poorly written, technically incoherent and internally inconsistent. I have said as much to TCCA. In response I was told that they will be issuing an advisory circular in the coming months.

C52 is not a legal document and has no force in law. Mr Robinson’s email requires the FUNCTION of a gascolator be duplicated. That means 1) fuel filtration and 2) a drain to detect contaminants. That drain is in the fuel tank, which we all agree is the only place that work work. The filter is located where ever makes sense.

I will never, ever put a drain between my tanks and my engine. In low wing aircraft it serves no purpose, as you have stated, and introduces an unnecessary point of failure.

As builders we need push back on ad hoc requirements that are not grounded in science.

Bias and opinion do not trump the basic laws of physics.
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  #9  
Old 01-15-2022, 12:36 PM
riseric's Avatar
riseric riseric is offline
 
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Location: Québec, CNV9
Posts: 537
Default Meant hard to reach for mods.

Quote:
Originally Posted by Snowflake View Post
Eric, isn't this a poor location for the filters in any case, given the requirement for accessibility for maintenance?
Rob, I meant that for maintenance, to remove, check or replace the filters, it's not the easiest place to go, but doable.
What I meant was to go there, dismantle the filters and all plumbing, re-install them properly, safely and securely vertically and re-plumbing them would be a big, big pain...
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2022 =VAF= paid
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VPX-Pro, EFII System 32, EarthX batteries
Aerosport IO-375, MTV-9-B/183
Skyview HDX
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Last edited by riseric : 01-15-2022 at 12:36 PM. Reason: Added info
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  #10  
Old 01-15-2022, 01:54 PM
riseric's Avatar
riseric riseric is offline
 
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Location: Québec, CNV9
Posts: 537
Default

Les, I agree with you that C52 could be better.
Good to know that your intervention will have TCCA review it and maybe make it more coherent.

C52 and all the other MD-RA documents are reference that builders and inspectors turn to. It seems that they wish to have a wide reaching policy, trying to include anything and everything that flies. With so many options and variety of systems, especially with newer technology, there needs to be common sense, reference to best practices and respect for the laws of physics and science.
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VPX-Pro, EFII System 32, EarthX batteries
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