Emergency landing this morning

[rocketbob]

Were there any attempts, before or after, to sump the fuel tanks?

[N184DA]

This happened after reading this interesting post,,

Went flying yesterday, left relatively early in the AM.
Needed fuel, so I taxied over to the self-serve,
Grounded the RV, punched in my numbers & CC,,
Turned on the pump,,

Grabbed the nozzle, extended the hose to one of my tank fillers,,

Thinking about this thread, I looked at the pump nozzle and wondered, “Am I the first fueler for the day?”
Then proceeded to unscrew the hand-tight nozzle from the nozzle body, looked at the screen (it was clean), and peered down the nozzle.

I think I will incorporate this in all of my refuels, if I suspect I am the first after a period of time. No idea what the definition of “period of time” is,
But my top-off checklist just grew by one!

[bobnoffs]

never say never but it is surprising that the dirt found its way so fast to the last filter and in an amount that plugged it. do you think the filter was clean before this?

[AlpineYoda]

Congrats on a great outcome. Sounds like you made some great decisions and did some excellent aviating.

I suggest sending this story to AOPA Pilot and Flying Mag for their regular "I learned something here" columns. This is a story that anyone with a home built fuel system should hear.

[airguy]

Answers to a few of the questions raised here by others...

- Yes, I did make the choice to overfly a perfectly good grass strip runway, but I want to emphasize that I never flew beyond deadstick glide range of that runway, before I was within deadstick glide range of the paved runway I wanted to get to. From my altitude, starting at 9500 and slowly decaying to around 8900 with partial power, I was able to include BOTH airports within my deadstick range and was never outside of gliding range of a suitable airport. This was a judgement call on my part, if my engine had canned itself completely at ANY point I still had a viable runway beneath me at all times. With the engine continuing to produce partial power I elected to try to make a more airplane-friendly paved runway rather than an unknown condition grass runway that was only 2000' long and in poor light - it was just barely after sunrise and I did not have a visual on the runway, just the Dynon airport information about it - for all I knew it might not even exist anymore. Anyone that would choose differently, I promise not to criticize you for your decision. I would ask the same courtesy of mine.

- Sumping the fuel - yes, I regularly sump my tanks, but I'm usually looking for water and could very easily have missed a little muddy color in the poor light when I was fueling. It's also entirely possible the mud had not fully dissolved in the tank and spread yet - gasoline is a fairly poor solvent compared to water for soil agglomerations. At the point where I first noticed the problem, I had been airborne for about 40-45 minutes, I'll have to go check the datalog to be sure but it was roughly there. I started the flight on my right tank, and changed to my left about 25-30 minutes later, and it was maybe 15 minutes after changing tanks that the problem manifested. Of course at that point changing tanks back did not help - because both tanks feed the pumps which combine to a single final fuel filter, which was now plugged.

- The fuel filter is a 10-micron filter as recommended and supplied by Ross Farnham with SDS, fairly substantial but I don't know the cross-sectional area of the pleated design, and the fuel pumps are his fuel pump module as well. The spring bypass is something to think about and perhaps test - but I know that during this event I had both pumps operating and was still only getting 9 psi out at one point, after the filter. I don't know what the pumps are capable of pressurizing to (I shall test and find out) or whether the filter will spring bypass on its own (I shall test and find out) or needs something to act as a bypass around it. I like the idea that was offered for a pressure switch upstream of the final filter to indicate a plugged condition - I'll think more on that. The SDS and EFII32 fuel injection systems (maybe others out there too, I'm not excluding them on purpose, just unaware of them) use an automotive-style electronic injector that has a much smaller orifice than aviation-standard mechanical injection, and requires a finer filter.

- The filter that got plugged was installed new in March of this year when I converted my fuel/ignition system to the SDS product with a Bosch oxygen sensor/AFR input to the SDS programmer. At the time of the problem Saturday morning I had 105 hours on the system. My fuel pressure has remained remarkably stable all this time until Saturday morning - I have no reason to believe this was a slow oncoming chronic event - I believe it to be acute. I am very highly tuned into my engine and aircraft, being a tinkerer and gearhead at heart, and normally keep a very close eye on operating parameters. I first noticed my AFR becoming lean in flight before noticing a low fuel pressure or engine stumble, and from that point to declaring a mayday with essentially no engine power and fuel pressure less than a quarter of normal was just under 2 minutes - this was not a slowly developing situation. The first 15-20 seconds of that time period, by the way, were spent in "denial and reptile-brain mode" - that's a very real phenomenon, you can't avoid it, it will happen to you - YES YOU - and all you can really do about when it happens is take a couple deep breaths and engage your inner Gene Kranz. "Calm down people, let's not make the problem worse by guessing. Think, and work the problem!"

Oh, and one clarification - I was actually on frequency with Abilene Approach at the time, not Center as I stated earlier. I realize now thinking back on it that I called them Center when I was declaring the Mayday, and they had the good common sense to ask how they could help rather than correct my label for them - I had enough on my plate at the moment.

[Brdog42]

Greg,

First, I’m glad it worked out!

Second, Thanks for sharing your experience with detail. And answering other’s questions in detail including your mindset & decision making process.

Sincerely,

[bill.hutchison]

<reads the story, scribbles down notes>

Great story and outcome.

Have added bits of this to my notes for when I teach Primary students about ground ops, re-fueling and things to look for.

[rv6ejguy]

Glad this turned out ok Greg. Good decisions and good job getting down safely.

We specify and supply 40 micron filters on all our systems. We feel that 10 micron ones have the possibility to plug up with very fine debris quicker.

Assuming there are filters before the pumps, the debris can only come from the pumps themselves making metal. Do you note any difference in noise from the pumps when you power them up?

[airguy]

Originally Posted by rv6ejguy

Glad this turned out ok Greg. Good decisions and good job getting down safely.

We specify and supply 40 micron filters on all our systems. We feel that 10 micron ones have the possibility to plug up with very fine debris quicker.

We'll need to discuss that offline, then - I'm with you that they have the possibility to plug, and it only needs to protect the injector orifice, no more than that.

[rv6ejguy]

The injectors also have very fine screens inside them as the last tier in protection.

I would think it would take a lot of metal to plug the downstream filter to this degree and would be surprised if the pump(s) wasn't noisy by now.

Let me know what you find in the downstream filter.