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Check this if you have an injected engine...

vic syracuse

Well Known Member
Advertiser
Mentor
In the interest of safety I figure I should post this. I discovered it yesterday during a Prebuy inspection on an RV-10 that had been flying for 8 years and 300 hours. The rubber shipping cap had been left installed on the fitting at the injection spider on top of the engine. This fitting is typically connected to a round dial fuel flow gauge, such as in older Bonanzas and Cessnas. Pressure at this point varies in relation to fuel flow, and can be anywhere from 1.5 PSI to over 35 psi! If not plugged or capped properly, a high pressure fuel stream will be the result, possibly causing a fire in the engine compartment. The builder mentioned that the plans never said to remove it. Perhaps others should check their installations? I told the builder I wanted his Guardian Angel!

(For those of you who are used to the newer electronic fuel flow sensors and wondering how this would work, basically the round dial gauge is nothing but a pressure gauge that has a faceplate on it calibrated to read fuel flow.)


https://photos.smugmug.com/My-New-Gallery/i-Kk5Gmxp/0/9fffd49e/X3/CyKNn9nvR+edp4TKhZUQug-X3.jpg

https://photos.smugmug.com/My-New-Gallery/i-gHRBvKF/0/602c2c28/X3/htLC0pPnTdyCCABcfQ%L7Q-X3.jpg

On another note, I am still finding way too many RV's WITHOUT the Operating Limitations, especially on RV's owned by non-builders. So, for those of you who may have purchased your airplane, please understand that the Operating Limitations, which should be on FAA letterhead, need to be in the aircraft AT ALL TIMES. The Airworthiness Certificate is invalid without them.

For those of you who are selling your airplanes to non-builders, please remember to have this discussion with them.

Many of them show me a POH when I ask about the Operating Limitations. :(
 
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Good catch Vic. Wow!

Also, for those that don?t know, the Operating Limitations alone are considered the POH in experimental aircraft. You don?t need a ?POH? although it is a very good idea as the OPs limits are useful only to a point like for V speeds, etc....
 
Something Odd

In the interest of safety I figure I should post this. I discovered it yesterday during a Prebuy inspection on an RV-10 that had been flying for 8 years and 300 hours. The rubber shipping cap had been left installed on the fitting at the injection spider on top of the engine. This fitting is typically connected to a round dial fuel flow gauge, such as in older Bonanzas and Cessnas. Pressure at this point varies in relation to fuel flow, and can be anywhere from 1.5 PSI to over 35 psi! If not plugged or capped properly, a high pressure fuel stream will be the result, possibly causing a fire in the engine compartment. The builder mentioned that the plans never said to remove it. Perhaps others should check their installations? I told the builder I wanted his Guardian Angel!

(For those of you who are used to the newer electronic fuel flow sensors and wondering how this would work, basically the round dial gauge is nothing but a pressure gauge that has a faceplate on it calibrated to read fuel flow.)


https://photos.smugmug.com/My-New-Gallery/i-Kk5Gmxp/0/9fffd49e/X3/CyKNn9nvR+edp4TKhZUQug-X3.jpg

https://photos.smugmug.com/My-New-Gallery/i-gHRBvKF/0/602c2c28/X3/htLC0pPnTdyCCABcfQ%L7Q-X3.jpg

On another note, I am still finding way too many RV's WITHOUT the Operating Limitations, especially on RV's owned by non-builders. So, for those of you who may have purchased your airplane, please understand that the Operating Limitations, which should be on FAA letterhead, need to be in the aircraft AT ALL TIMES. The Airworthiness Certificate is invalid without them.

For those of you who are selling your airplanes to non-builders, please remember to have this discussion with them.

Many of them show me a POH when I ask about the Operating Limitations. :(

Vic,

Something strikes me as odd here. Was this originally installed as a new engine or an aftermarket/rebuilt one? The cap that you show looks like a schrader valve cap. The factory Lycoming engines come with a red cap installed on that fitting (or at least they used to). Furthermore, your second picture shows something stuck to the AN fitting like someone tried to use adhesive or sealant on that cap. Here's how mine came from the Lycoming factory:

DSCN3668cropped.jpg


That safety wire job doesnt look legit to me.....at least not as I was taught.

The safety wiring is legit and is how the factory delivers them, as you can see from the picture above. Also, here's an image from AC43-13 showing this technique:

E2yac.jpghttp:


Skylor
RV-8
 
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I couldn't tell you how it originally came and whether that valve cap was purposefully installed. The builder made the comment that the instructions did not say to remove it. it was a Van's engine, so most likely delivered from Lycoming.
What I don't know is did someone install that cap during the last 8 years? It did look like it either had some black RTV or the cap had melted some.

Vic
 
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My engine is nearly the same vintage (2010) and yes, they ship with red plastic covers where real hardware needs to go. IMHO the builder knew the red plastic piece had to be replaced, but inexplicably chose hardware (Schrader cap) that was not at all suitable for the application. The correct part is $5 IIRC.
 
I couldn't find any reference to this temporary plug in the Van's FWF instructions for my RV-10, which surprised me. So before I removed it and plugged it with a proper plug, I contacted Van's to confirm that it wasn't used and did need to be plugged. With all the other details in the Van's plans, I'm surprised they missed this one.
 
Woah, that's disturbing! Good catch Vic!
Just checked some old pictures of my 2009 engine that came from Van's and it also had the red cap.
 
What do we use to plug it?

I am working on FWF and have a red cap as depicted in Skylor?s photo. What is the correct part to plug this little doober?
 
I am working on FWF and have a red cap as depicted in Skylor?s photo. What is the correct part to plug this little doober?

If you are not running a Cessna-style "pressure-to-flow" meter, then just a standard NPT plug will do the trick. Teflon PASTE - never TAPE.
 
AN Cap

I am working on FWF and have a red cap as depicted in Skylor?s photo. What is the correct part to plug this little doober?

That?s either a -2 or -3 AN cap (I don?t recall the exact size) that should go over the fitting. Aluminum ones can be found here:


http://www.aircraftspruce.com/menus/ha/an.html

Some prefer steel or stainless on FWF fuel lines and fittings but they are a little harder to find. Genuine Aircraft Hardware Co. should have them.

Skylor
 
I am working on FWF and have a red cap as depicted in Skylor?s photo. What is the correct part to plug this little doober?

When I removed the plug from my #4 cylinder to install the fitting for measuring manifold pressure, I used that plug for the fuel spider.
 
When I removed the plug from my #4 cylinder to install the fitting for measuring manifold pressure, I used that plug for the fuel spider.

I do the exact same thing every time. The FWF kit includes several of these caps too, but they usually are needed for the soil and fuel pressure manifold that bolts to the firewall. If there is a piece of red plastic on the engine, it is supposed to be removed and replaced with something. That?s why it is red.

Good catch, Vic.
 
The safety wiring is legit and is how the factory delivers them, as you can see from the picture above. Also, here's an image from AC43-13 showing this technique:

E2yac.jpghttp:


Skylor
RV-8

Well, the factory didnt do that on my rebuilt motor....and I know the AC43-13 reference....just does it really qualify as "screws in a closely spaced...."...? I guess its a judgement call, where the ability to get the pliers into the location is what the AC is driving at, but for me in this case its not legit. I'd agree if the screws were like a 1/2" apart, but there not.

I know this could be a never ending debate and I'm not trying to make one, just saying I'd replace that single wire with a twist because I should and I can.
 
Nice work, Vic!

I hope everyone appreciates the seriousness of this error. I would think an in-air, fuel-fed fire, would be a _very likely_ result if that cap were to come off in flight. Or melt off. The high volume of cool air flowing across the top of that cooling plenum is probably the only reason this didn't happen. There would also be a significant drop in fuel pressure which would likely cause the operator to turn on the boost pump. Arghhh!...

Guardian Angels...absolutely!

Again, nice job.
 
Where do I find the Operating Limitations that are pertinent to my build, airframe, engine, other systems?

They should have been, or will be, issued to you by the person who does your airworthiness inspection. They need to be kept in the airplane.
 
Where do I find the Operating Limitations that are pertinent to my build, airframe, engine, other systems?

Operating limitations are part of the 8130-7 form (airworthiness certificate)

Many times they are actually attached/stapled to the certificate when it is issued (that is how document issued by my local FSDO are provided).

BTW, the FAA is in the process of revising how C of A's are issued for experimentals. New documents issues by a FSDO right now are no longer separated. The C of A is printed on the top of the first page of the operating limitations. I imagine this was to resolve the issue of people not having them in the airplane. Unfortunately that still wont resolve the issue of people not having ever read them (at first issuance, it is a required part of the certification process that the issuer review them with the applicant and confirm they understand they are operational requirements for the airplane. Unfortunately, it is common that when an airplane is sold, the new owner is clueless about them).
DAR's are still using the old documents, but it is my understanding that once the FAA works out the document security issues, that all new or amended documents will be issued this way.
One plus to the new process for us users is that since it is generated and signed digitally, a replacement can be sent via e-mail and printed locally.

The down side -
There is now four 8 1/2 X 11 sheets (they specifically say modifying them in any way is prohibited) that have to be folded up in a bundle small enough to fit into the traditional document pouch that has always been sized for the pink 8130-7 form.
 
True confessions

I read this with interest because the same thing happened to me. I helped a friend finish his RV-7, including getting it painted (by someone else), final assembly, panel design and procurement, installation of panel and associated wiring, flight test prep and most of the Phase I flight testing. I did the requisite fuel flow testing to ensure that the boost pump was making 150% of takeoff fuel flow but I did NOT pressure test the fuel system with the throttle and mixture open and closed.

First flights were noneventful except for some funky CHTs and EGTs. As I recall, EGTs on one side of the engine were higher, indicating that side was running leaner than the other. Long story short, in looking at possible causes we noticed some blue dye residue around the spider on top of the engine. It was a very small amount. I didn't even notice that fitting on the spider, which did not have a red cap on it, although in looking at photos from before the flights it had a red plastic cap on it before the first flight. Figuring there might be a fuel leak I pressurized the fuel system with the boost pump and...PSSSSt, a constant stream of fuel shot out of that fitting, which is one of those pressure dampening fittings. Yikes.

In retrospect, I had noticed a VERY slight fuel odor during first flights but so slight as to be intermittent and not all that unusual around an airplane. I realize this could have ended badly and could have been prevented by simply looking for ANY fuel leak like I should have by pressurizing the system. After removing the fitting and plugging it with a solid plug, the EGTs and CHTs evened out.

I speculate that the only reason I didn't get a fire was that the pressure reducing fitting limited the amount of fuel and the fuel/air ratio was too lean to burn. Pretty narrow margin of safety and unlikely to have continued under all phases of flight. I found the leak while still during engine break in, running max power and full rich during all phases except landing and taxi. It may not have produced any fuel during taxi but I can't say for sure.

I wondered why this fitting was even left on this engine, which came from Van's. In my opinion they should be noted or better yet, removed. Still, the fault was mine and everyone should be aware of it.

Side note: this fitting was NOT present on my RV-10 engine that I bought from Aerosport Power.
 
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