Dumb question on injectors

[EricJ]

5 minutes ago, RobertGary1 said:

Are you suggesting there is a way to remove the nozzles without the AD applying? Or are you making a theoretical argument without practical purpose?

-Robert

On the internet there is always a risk that a statement can be misread or misunderstood or contextually misinterpreted or whatever, and that it takes an inordinate amount of dialogue to clarify the situation.   I think this is one of those.  The thread is about injectors/nozzles.  You brought up an AD that doesn't apply to the injectors/nozzles and is pretty trivial to comply with, anyway, so I just pointed out that the AD doesn't have to do with the nozzles in case it saved anybody the bother of looking it up.   That was all.  

[RobertGary1]

Just now, EricJ said:

On the internet there is always a risk that a statement can be misread or misunderstood or contextually misinterpreted or whatever, and that it takes an inordinate amount of dialogue to clarify the situation.   I think this is one of those.  The thread is about injectors/nozzles.  You brought up an AD that doesn't apply to the injectors/nozzles and is pretty trivial to comply with, anyway, so I just pointed out that the AD doesn't have to do with the nozzles in case it saved anybody the bother of looking it up.   That was all.  

If you are suggesting there is a way to service the injectors without trigger this AD I'd love to see a video of how you do it.

-Robert

[PT20J]

25 minutes ago, RobertGary1 said:

Are you suggesting there is a way to remove the nozzles without the AD applying? Or are you making a theoretical argument without practical purpose?

-Robert

The nozzles are easily removed without loosening any clamps. The clamps are not near the nozzles, there is a lot off flex in the lines and you don't have to deform or stress them. Just loosen the nut and move the lines slightly to the side. Lycoming SI 1275C "Cleaning Fuel Injector Nozzles" says to "Remove the nozzle assembly from the individual fuel lines using a wrench." It does not mention any need to remove the clamps from the lines.

[RobertGary1]

5 minutes ago, PT20J said:

The nozzles are easily removed without loosening any clamps. The clamps are not near the nozzles, there is a lot off flex in the lines and you don't have to deform or stress them. Just loosen the nut and move the lines slightly to the side. Lycoming SI 1275C "Cleaning Fuel Injector Nozzles" says to "Remove the nozzle assembly from the individual fuel lines using a wrench." It does not mention any need to remove the clamps from the lines.

 

The AD also references removing lines. But even at that I'm not sure I'd want to put that type of strain on the lines. Its hard to work in that area with the lines moving back on top of the injector as you place your socket.

I suppose with a crows foot maybe you could remove the injectors without disconnecting the line but it would be difficult.

-Robert

Edited September 26, 2019 by RobertGary1

[Guest]

The AD doesn’t apply to the OP, unless his Rocket conversion has a Lycoming engine.  Continental engines don’t have this AD.

Clarence

[PT20J]

5 minutes ago, RobertGary1 said:

The AD also references removing lines. But even at that I'm not sure I'd want to put that type of strain on the lines. 

-Robert

The AD is primarily about the clamps. The problems in the field that necessitated the AD are primarily due to missing, mislocated or damaged clamps that do not properly support the fuel injector line and allow vibration to work harden the joints at the fitting attachments eventually causing a fracture. You're really better leaving the clamps alone if they are in good shape and properly located per the Lycoming SB. That's what all the mechanics I've worked with do.

[jetdriven]

7 hours ago, gsxrpilot said:

I disagree on the 100 hour cleaning schedule. Anytime they are out of the plane for cleaning, there is always the chance to contaminate them. Just a single fiber from the cloth they're sitting on after cleaning, can affect fuel flow. Also, there is solvent (100LL) flowing through them constantly. So with "infant mortality" in mind, I only clean mine when I see a problem.

I've gone to only pulling mine for cleaning when I notice a change. For example, on a recent flight, my GAMI spread was way off. One cylinder seemed to be different than usual. So we pulled that injector, cleaned in and put it back. Problem solved, GAMI spread back to normal.

Just my $0.02

THIS

[DonMuncy]

I agree with Paul and Byron. With fuel constantly running through the injectors, there is no need to "clean" them. However, junk can get to them and clog them up sometimes (it has happened to me). When that happens, yes, they have to be removed and unclogged.

[jetdriven]

If you are a LOP operator this is easy, you just can’t get it to run smooth LOP. Your engine monitor will tell you which one is clogged, then just clean that one. 

[gsxrpilot]

Just now, jetdriven said:

If you are a LOP operator this is easy, you just can’t get it to run smooth LOP. Your engine monitor will tell you which one is clogged, then just clean that one. 

Yep! It's amazing how much maintenance and troubleshooting can be saved by having a good engine monitor and knowing how to read it.

[ArtVandelay]

I agree with Paul and Byron. With fuel constantly running through the injectors, there is no need to "clean" them.

Aren’t they exposed to hot exhaust gases, even if not in the cylinder volume?


Tom

[gsxrpilot]

3 minutes ago, ArtVandelay said:

Aren’t they exposed to hot exhaust gases, even if not in the cylinder volume?

I wouldn't think so. They would be behind the closed intake valve when the exhaust valve is open.

[PT20J]

Avgas doesn't contain detergents like mogas to keep the injectors clean, so eventually they will develop deposits. Lycoming SI 1275C recommends cleaning "At overhaul and when engine conditions require." The Precision RSA Operation and Service Manual contains instructions on how to clean the nozzles which is recommended along with other maintenance items "during periodic inspection of the engine." Mooney's 50-Hour/100-Hr/Annual Maintenance Inspection Guide lists cleaning the nozzles.

Personally, I don't mess with anything without good reason.

Skip

[EricJ]

3 hours ago, ArtVandelay said:

Aren’t they exposed to hot exhaust gases, even if not in the cylinder volume?


Tom

Shouldn't be.   They're in the intake path only, behind the valve. 

[N201MKTurbo]

My engine got to where it would not run LOP. I took out the injector nozzles and inspected them under a microscope. They looked fine. I tried to measure them with gauge pins and the orifice size was all over the place. One I could only get a 0.026- gauge into. The biggest would take a 0.028+ gauge. I finally tapped the 0.028+ gauge through the smallest nozzle and a cylinder of transparent varnish was pushed out. I did that with all of them and got similar varnish cylinders with two others. I focused down the bore of the nozzle with the microscope and there was no sign of scraping or any other damage from the gauge pin.

My engine now runs LOP again. 

My takeaway is that you do have to clean your injectors or they may get varnish deposits in them. 

Edited September 27, 2019 by N201MKTurbo

[Austintatious]

Thank you everyone for the replies..

 

I put in the injectors today with the oversight of an A&P who I have known for years.  Learned some things and now I have a rocket with GAMI's.

I have a garbage engine monitor ( working on that) but I can tell you that the engine is running LOP smoothly and efficiently. 

[PT20J]

The latest incarnation of the Lycoming fuel injection line AD 2015-19-07 requires repetitive inspections every 110 hours.

FAR 1 says "Preventive Maintenance means simple or minor preservation operations and the replacement of small standard parts not involving complex assembly operations."

FAR 43 App A lists an example preventive maintenance task as "Replacing prefabricated fuel lines." We know that under a FAA legal interpretation (Coleal 2009) that this list is not considered to be exhaustive, but illustrative.

FAR 43.3 (g) states in pertinent part "The holder of a pilot certificate...may perform preventive maintenance on any aircraft owned or operated by that pilot..."

FAR 43.9 says in pertinent part "Each person who... performs preventive maintenance ... shall make an entry in the maintenance record..."

So, is there is any regulation that prevents me as a pilot owner from performing the simple inspection required by the AD and entering it in the logbook as preventive maintenance?

Skip

Edited September 28, 2019 by PT20J
Correct spelling

[EricJ]

2 hours ago, PT20J said:

The latest incarnation of the Lycoming fuel injection line AD 2015-19-07 requires repetitive inspections every 110 hours.

FAR 1 says "Preventative Maintenance means simple or minor preservation operations and the replacement of small standard parts not involving complex assembly operations."

FAR 43 App A lists an example preventative maintenance task as "Replacing prefabricated fuel lines." We know that under a FAA legal interpretation (Coleal 2009) that this list is not considered to be exhaustive, but illustrative.

FAR 43.3 (g) states in pertinent part "The holder of a pilot certificate...may perform preventative maintenance on any aircraft owned or operated by that pilot..."

FAR 43.9 says in pertinent part "Each person who... performs preventative maintenance ... shall make an entry in the maintenance record..."

So, is there is any regulation that prevents me as a pilot owner from performing the simple inspection required by the AD and entering it in the logbook as preventative maintenance?

Skip

That's an interesting question.   AC39-7D suggests not, sort-of:

13. RESPONSIBILITY FOR AD COMPLIANCE AND RECORDATION. The owner or operator of an aircraft is primarily responsible for maintaining that aircraft in an Airworthy condition, including compliance with ADs.

a. Means of Accomplishment. This responsibility may be met by ensuring that properly certificated and appropriately rated maintenance person(s) accomplish the requirements of the AD and properly record this action in the appropriate maintenance records. ...

____________

"...may be met by..." suggests there might be other methods, but another complication is that the definition of "maintenance" in FAR 1.1 includes "inspection" but the definition of "preventive maintenance" does not.   Another fun fact is that "inspection" is undefined in 1.1, but maybe it doesn't need to be.   The point of that is just that many ADs, like this one, are about "inspection" more than maintenance.   So one might make the argument that the relevant maintenance action could potentially be done by an owner if it falls under "preventive maintenance", but it might be harder to argue that an "inspection" could.   I'm not sure that either argument is a good one, even as much as I lean toward more open interpretation of this stuff.

Note that there is a clear exception when an AD specifically says it can be met by somebody other than a certificated maintenance person, e.g., the Bendix ignition switch AD specifically says:

3. The checks required by this AD may be performed by the pilot.

As usual, YMMV, don't try this at home, etc., etc...

 

Edited September 28, 2019 by EricJ

[N201MKTurbo]

Just clean the damn injectors and don’t tell anybody. It’s your plane. If you screw it up it is your problem. 

There I go posting from the trivia bar again....

[PT20J]

1 hour ago, EricJ said:

That's an interesting question.   AC39-7D suggests not, sort-of:

13. RESPONSIBILITY FOR AD COMPLIANCE AND RECORDATION. The owner or operator of an aircraft is primarily responsible for maintaining that aircraft in an Airworthy condition, including compliance with ADs.

a. Means of Accomplishment. This responsibility may be met by ensuring that properly certificated and appropriately rated maintenance person(s) accomplish the requirements of the AD and properly record this action in the appropriate maintenance records. ...

____________

"...may be met by..." suggests there might be other methods, but another complication is that the definition of "maintenance" in FAR 1.1 includes "inspection" but the definition of "preventive maintenance" does not.   Another fun fact is that "inspection" is undefined in 1.1, but maybe it doesn't need to be.   The point of that is just that many ADs, like this one, are about "inspection" more than maintenance.   So one might make the argument that the relevant maintenance action could potentially be done by an owner if it falls under "preventive maintenance", but it might be harder to argue that an "inspection" could.   I'm not sure that either argument is a good one, even as much as I lean toward more open interpretation of this stuff.

Note that there is a clear exception when an AD specifically says it can be met by somebody other than a certificated maintenance person, e.g., the Bendix ignition switch AD specifically says:

3. The checks required by this AD may be performed by the pilot.

As usual, YMMV, don't try this at home, etc., etc...

 

Well, to add more confusion to it, I just found the attached document which states in the Introduction that "This pamphlet provides information on authorized preventive maintenance." Later it includes a section titled Sample Checklists that are apparently items that fall under preventive maintenance. Many  say "check" in a manner obviously synonymous with "inspect." One item listed is, "Check  condition of fuel lines for leaks (fuel stains) and security."

So, according to this pamphlet, I can check the fuel lines as preventative maintenance, and if I do preventive maintenance I have to log it, and if the preventive maintenance just so happens to satisfy an AD....???

Skip

FAA P-8740-15 Maintenance Aspects of Owning Your Own Aircraft [hi-res] branded.pdf

 

Edited September 28, 2019 by PT20J

[PT20J]

10 minutes ago, N201MKTurbo said:

Just clean the damn injectors and don’t tell anybody. It’s your plane. If you screw it up it is your problem. 

There I go posting from the trivia bar again....

It's not about cleaning the injectors, it's about satisfying the recurrent inspection AD on the injection lines and clamps. It wouldn't be an issue if it recurred annually (because it gets checked every annual) but it recurs every 110 hours. So if I fly 115 hours between annuals, the airplane is unairworthy for the last 5 unless I bother my mechanic to stop what he's doing, look at the lines and sign the logbook.

Skip

[N201MKTurbo]

2 hours ago, PT20J said:

It's not about cleaning the injectors, it's about satisfying the recurrent inspection AD on the injection lines and clamps. It wouldn't be an issue if it recurred annually (because it gets checked every annual) but it recurs every 110 hours. So if I fly 115 hours between annuals, the airplane is unairworthy for the last 5 unless I bother my mechanic to stop what he's doing, look at the lines and sign the logbook.

Skip

Call the FSDO and ask them. They are both sticklers for the rules and know every loophole. It wouldn’t hurt to ask. Sending them a letter may be better because then you would have documentation either approving that you can do the inspection, or not. The worst you will be is where you are now.

[Guest]

Some AD’s state that the pilot may perform the inspection required by the AD, others don’t.  The fuel injection line AD makes no mention of this.  I don’t think the FAA would allow it.

Clarence

[PT20J]

I asked Mike Busch and he pointed out that the Part 1 definition of maintenance includes inspection whereas the definition of preventive maintenance does not. Therefore, an inspection required by regulation cannot be performed as preventive maintenance (unless, in the case of an AD, it is specifically allowed as @EricJ and @M20Doc have noted).

Skip

 

[Guest]

5 hours ago, PT20J said:

I asked Mike Busch and he pointed out that the Part 1 definition of maintenance includes inspection whereas the definition of preventive maintenance does not. Therefore, an inspection required by regulation cannot be performed as preventive maintenance (unless, in the case of an AD, it is specifically allowed as @EricJ and @M20Doc have noted).

Skip

 

Thinking about this further, there is nothing preventing you from inspecting the fuel injection lines and clamps, but without an A&P licence you just can’t sign out the compliance with the AD.

Clarence