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Old 04-04-2020, 07:26 PM
RhinoDrvr RhinoDrvr is offline
Join Date: Jun 2014
Location: Lemoore (Fresno), CA
Posts: 174
Default FI Fuel Metering Line Disconnected: Engine Failure on Short Final to a Military Base


U.S. Air Force Plant 42 (KPMD) in Palmdale, California. A small DoD facility in the Mojave Desert that was the home to such famed projects as the Space Shuttle Orbiter, the F-117A, and right now, my Vans RV-8. I was in no mood to appreciate the rich aviation history of the location as I pondered how I found myself on the wide expanse of Plant 42?s ramp in my little homebuilt.
The flight had originated at Inyokern Airport (IYK) in California, just North of Edwards Air Force Base, and West of Naval Air Weapons Station China Lake where I was stationed as an Operational Evaluation (OpEval) F/A-18 pilot. I grew up in General Aviation, having taken my first flying lesson at age 11, but had stepped away when I joined the military, and the RV-8 was my return to the joys of GA flying. I purchased the airplane from the builder a few years previous and had flown it to Oshkosh twice, accumulating about 300 hours in the aircraft. I was beginning to feel fairly confident in the machine, as well as the owner-assisted maintenance program that I was learning under the tutelage of a local A&P mechanic.

Leading up to the flight there had been some fairly extensive maintenance. I recently had the aircraft re-wired with a full Garmin glass cockpit setup and engine monitor, and had all the hoses firewall forward replaced with Teflon-steel braid hoses for longer service life. I?d flown the airplane for 50 hours since the work had been completed, so I changed the oil, and took advantage of the downtime to rework the engine baffle seals for better cooling. The higher fidelity of the Garmin engine monitor had revealed some inadequacies in my cooling setup in the high desert heat with CHT?s reaching 400F+ during takeoff, so I took on the project of improving the airflow under the cowl. I also rebuilt the tailwheel assembly. After a quick leak check, a successful post-maintenance check flight put the airplane back in service.
The next day I came out to fly, and found that the battery was dead. The battery was new, only 6 months old, but I checked and cleaned all the connections, ordered a new battery and installed it on the afternoon of the incident flight.

Once I had the fresh battery installed and ready to go I pulled the airplane out, and started it up. The engine start was noticeably rough. The Lycoming O-360 coughed to life one cylinder at a time more like a radial than the quick snarling starts typical of the horizontal motors. I chalked it up to over-priming and taxied to the runway. The idle was a little rough with something of a lope, as it had been recently (if not slightly worse today), but I justified this as the common issue seen with fuel injection systems of fuel boiling in the low pressure injector lines. I found it annoying, but minimized the problem to the max extent I could by leaning aggressively while taxing out.
After an uneventful runup, I lined up on Runway 33, smoothly pushed the throttle forward and felt that glorious acceleration as the Hartzell prop dragged the 1100lb airplane and me into the late afternoon sky. On climbout I noted with satisfaction that the baffle work seemed to have worked; cylinder head temperatures were now about 370 vice the 405 I had been seeing previously during climb, and I patted myself on the back as I climbed overhead the airfield. The airplane was running well, and I wanted to fly for at least an hour to get a good charge on the battery, so I turned South and started leaning the mixture for Lean of Peak (LOP) cruise.

I had installed custom tuned injector nozzles to allow all the cylinders to peak simultaneously as fuel flow settled down, and I found myself 50 degrees LOP flowing 8.5 GPH. This seemed moderately higher than the 7.5-8.0 GPH that other RV-8 owners were claiming, but they probably weren?t running the same power settings that I was. Plus, pilots are known for exaggerating their performance numbers. Other than an occasional light stumble LOP, I took comfort in the fact that I was running cooler cylinder head temps and saving a little bit of gas as I cruised around the Mojave area.

Looking for something to do instead of just burning gas, I figured some practice approaches would help me get more familiar with the new autopilot and glass displays during ILS and RNAV LPV approaches. I initially set a course for Victorville Airport (VCV) and contacted Joshua Approach for Flight Following services. Joshua advised me that Victorville was not currently accepting practice approaches, and asked what my intentions were. Still desiring to try an ILS Approach, I asked if Palmdale was accepting VFR practice approaches. After a short pause, ATC issued vectors for the ILS and I shot the first approach with the autopilot coupled to the approach all the way to minimums for a published missed approach. Being a USAF base, civilian aircraft are not permitted to touchdown, so I planned on low approaches to Runway 25. The GPS flawlessly sequenced the missed approach, and I accepted further vectors while I programmed the RNAV LPV Runway 25 approach into the panel.

Joshua Approach handed me off to Tower and the RNAV went smoothly until 100? above Decision Height. As I watched the minimums bug march down the EFIS tape, I reduced power to idle and a flashing yellow box in the bottom right corner of the display caught my eye. The EGT?s on all cylinders were climbing above 1500 degrees. Now, I know that the exact numbers are less important than the Delta when it comes to EGT, but this engine has never had an absolute EGT above 1500?even when descending well LOP. I reached over, and pushed the mixture up. The lever didn?t move; it was already fully forward. I snapped on the electric boost pump, and the EGT?s continued to rise to 1575. During my early Private Pilot training, I had an instructor tell me; if the airplane does something you don?t like; undo what you last did. In this case, pulling the throttle to idle. I advanced the throttle and was met with sounds of backfiring and no reassuring press of the seat against my backside. The radio exchange with Palmdale Tower at 200? AGL took maybe 10 seconds.

?Tower, RV has an engine issue and needs to full stop.?

?RV, are you declaring an emergency??


?Cleared to land, Runway 25.?

The landing and touchdown were uneventful, but the engine condition deteriorated noticeably as the RV decelerated on the runway. The prop began to stop, and I advanced the throttle in an attempt to keep it running to clear the duty runway. The engine wouldn?t run with the throttle anywhere below 1400 RPM, and it ran awful at that power setting. I managed to snap, crackle and pop my way onto a taxiway where I notified tower I was going to shut down and egress. Fire crews were on station immediately, and security personnel shortly thereafter. Now that I was safely on deck, the administrative nightmare of landing a civilian airplane on a military installation began.

Upon landing at a military facility expect to be asked for a Photo ID, Pilot Certificate, Medical, and Proof of Insurance. A Department of Defense ID would help the process along if you happen to have one. Second, security personnel are going to want to inspect the aircraft to ensure there are no explosives or other contraband onboard. These tasks complete, the first challenge was a total lack of chocks or tiedowns available. All the ground support equipment at military installations is centered around large fighter or transport category aircraft. Chocks and tiedowns for General Aviation aircraft typically aren?t available unless the field you find yourself at has a Flying Club. At Palmdale, our solution was to use bungee cords provided by Airfield Management to tie the airplane down to grounding points in the concrete, and I had chocks that I carry with me in the airplane. Don?t bank on hangar space; the potential liability is too great. I called the Airfield Manager, and exchanged information, as well as inquiring as to any shelter from the wind. Unfortunately, none was available, but as it turned out, the wind forecast proved inaccurate and the air was calm for the duration of the stay at the base.

All said and done, the paperwork took about 3 hours. This included a Hold Harmless Agreement for the departure the next day, a Proof of Insurance document, and an official statement of the events that had transpired. All in all, relatively simple. In addition, the base required a mechanic to authorize the departure, and that mechanic had to be someone other than the Pilot in Command. The only other administrative requirement was a phone call the next day from the local Flight Standards District Office (FSDO) confirming the events that had occurred, and they called the case closed. Very painless by all accounts.

So, what actually happened to cause my predicament? The cause became immediately clear as soon as the mechanic and I uncowled the engine. The first thing that caught my eye was a large blue stain on the #1 cylinder intake tube that hadn?t been there previously. There was also blue staining on the alternator, as well as the #1 cylinder itself (both top and bottom) and the inside of the cowling. There was obviously a world-class fuel leak under the cowl. I powered up the battery and engaged the boost pump. At once the culprit exposed itself. The B-nut on the main fuel line that runs between Cylinder #1 and #3 from the servo to the fuel spider was not torqued. In fact, it wasn?t even finger tight. The sudden leak had caused all 4 cylinders to immediately run lean, which I noted in the cockpit as very high EGT?s. The line and B-nut were inspected, deemed airworthy, tightened, and the airplane flew home without issue.
Evan Levesque
RV-8 N88MJ (Built by Michael Robbins)
Lemoore, CA
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Old 04-04-2020, 07:30 PM
RhinoDrvr RhinoDrvr is offline
Join Date: Jun 2014
Location: Lemoore (Fresno), CA
Posts: 174


Having been fortunate enough to spend my entire adult life in professional aviation, I think the most important thing following any incident such as this is to breakdown the goods, and others of the situation and what one should strive to do differently were the situation repeated. I?ve attempted to do this below as open and honestly as possible;

The Goods:

? The Garmin G3X system was set up with notifications to immediately draw my attention to a parameter that was, while not technically outside of limits, definitely outside the norm. While Lycoming doesn?t put a limit on absolute EGT in non-turbocharged engines, 1500 is definitely higher than I ever see in normal operation, so this threshold accurately drew my attention to a change in the normal operating parameters of the engine.

? Initial reaction to the symptoms was good. Verify mixture to full rich, boost pump on, and attempt to smoothly add power. Due to the failure, there was no positive result, but I was happy with the immediate action steps that were taken.

? The decision to land at Palmdale (PMD) despite it being a military airfield. In the hours following my landing, while doing paperwork and unsuccessfully attempting to find shelter / tie downs for the airplane I debated whether it would have been a better decision to try and limp the airplane the 9 miles to Lancaster, CA where there was a civilian field with maintenance support. Some fellow pilots expressed the same opinion. In the heat of the moment I debated both options, and almost instantly my Navy training kicked in. Don?t worry about anything but getting the airplane on deck. Do what needs to be done to get the airplane down safe, and deal with any inconveniences after the wheels are on the ground. I didn?t know it at the time, but I suspect now if I had been able to get enough power out of the engine to attempt a divert to Lancaster a severe in-flight fire would have resulted.

? Palmdale Tower was extremely professional with their timely issuance of landing clearance and getting the Fire Truck rolled in extremely short notice. (The emergency was declared at 200? AGL on final)

? Some pilots, especially Airframe and Powerplant (A&P) Mechanic rated pilots, have expressed to me the opinion that I should have done more troubleshooting of the problem. An in-flight mag check perhaps to verify that the symptoms would clear. I disagree. With a suitable airfield made, the correct steps (in my mind) are to prioritize landing the aircraft, evaluate its mechanical status once on the ground, and then begin troubleshooting. But without any knowledge of what?s gone wrong, troubleshooting airborne could lead to undue delay and possible compounding of the emergency.

The Others:

? Normalization of deviance. The airplane had been giving me signs for the past couple months that I had an issue with the motor, I just didn?t realize them compounding. I suspect the B-nut had been working loose for months before finally presenting itself as a major fuel leak. The hollow bullets below were the issues that could have led to finding the issue before it became catastrophic.

o Engine starts had become significantly more difficult recently requiring multiple attempts, and rough running for thirty seconds or a minute until it seemed like the engine settled out at idle. My PMAGS had typically resulted in starts on the second blade previously.

o Idle was noticeably rougher than when I had first bought the airplane. I explained this as the hotter climate in Inyokern causing fuel boiling issues that I hadn?t noticed in my previous, cooler, duty station.

o CHT?s were high on takeoff because the cylinders were running leaner than they should have been.

o EGT?s were higher on takeoff (1400+) as well, but I incorrectly justified this as a byproduct of installing tuned injectors to get a 0.1 GAMI spread. The truth of the matter, as explained to me by Don Rivera of Airflow Performance, is that ?tuning the nozzles does not increase EGT on takeoff. Unless the restrictor size was reduced to the point that the total pressure drops in the metering system (fuel control, flow divider and injector nozzles) exceed the fuel pressure available, fuel flow and EGT would remain the same.?

o Fuel flow would hunt around in cruise more than I had noticed before.

o The engine had an unexplained stumble (a single occasional missed ignition event) every 5 or 10 minutes or so at Lean-of-Peak (LOP) cruise at altitude that it hadn?t had when I?d bought it.

o In running LOP cruise, my fuel flow was 8.5 gph. This seemed too high for an O-360-A1A (180HP Parallel Valve) at 65% power LOP, but again, I ignored this.

? All of the signs above were prompting me to take a serious look at the condition of the engine and associated induction, fuel and ignition systems, but the onset had been slow enough that I had justified them all in my head. I found myself flying with the engine monitor as the primary display for all flights. I had slowly lost confidence in the engine, but hadn?t taken the time to step back, acknowledge the fact, and find the reason why. Once the problem presented itself, and was fixed, the performance on the ferry flight home was immediately back to the way the airplane had been when I?d bought it. The difference was stark when it all happened at once.

? I did not exercise the due diligence required on what was effectively a post-maintenance check flight. With numerous significant maintenance events occurring in the very recent past (Oil Change, New Baffling, Tailwheel Rebuild, Battery Replacement) I should have stayed local within gliding distance of my home airfield, with known maintenance support and familiar airspace.

? Systems knowledge. In today?s day and age, we do not emphasize systems knowledge as we used to. The era of the Flight Engineer is gone, but I think with a better understanding of the fuel system in my airplane, how it was plumbed and how different anomalies would present in the engine indications, I would have been able to more easily diagnose and search for the problem in a proactive manner.

? As an owner / maintainer, the responsibility lies upon ME to actively ensure the safe condition of the airplane for further operation. I?d had the airplane uncowled for weeks prior to this incident and hadn?t done any detailed inspection for fuel staining or loose fittings. I?d never put a wrench on the fuel line in question in the time I?d owned the airplane. Most people ask ?Were there any fuel stains visible around that fitting before the incident flight?? The honest answer is; I don?t know. It is imperative to take the opportunity during routine maintenance evolutions to verify the condition of all systems in the airplane that are open to inspection, not just the subsystem that is being worked on.


I feel that it is very important to learn from this event, and pass those lessons along to the community so that we can all be better for it. It?s often said ?I?d rather be lucky than good?, and I agree with that. However, the quote below from one of my favorite authors I feel is a strong one;

This thing we call luck is merely professionalism and attention to detail, it?s your awareness of everything that is going on around you, it?s how well you know and understand your airplane and your own limitations. We make our own luck. Each of us. None of us is Superman. Luck is the sum total of your abilities as an aviator. If you think your luck is running low, you?d better get busy and make some more. Work harder. Pay more attention. Study your [POH] more. Do better preflights.
- Stephen Coonts "The Intruders"

I think I?d better get to making some more luck.
Evan Levesque
RV-8 N88MJ (Built by Michael Robbins)
Lemoore, CA
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Old 04-04-2020, 07:39 PM
Mike S's Avatar
Mike S Mike S is online now
Senior Curmudgeon
Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 16,096
Default Good read

Evan, first off, good that you and the plane are OK.

Second, thanks for sharing and for the honest report.
Mike Starkey
VAF 909

Rv-10, N210LM.

Flying as of 12/4/2010

Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.

"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
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Old 04-04-2020, 08:32 PM
JDeanda JDeanda is offline
Join Date: Apr 2013
Location: Ventura, CA
Posts: 273
Default Nice!

Great, bald-faced honest write-up! I?m an A&P and I think you did the right thing minimizing troubleshooting to use the runway right in front of you when things went to worms. I?m smarter now, thanks for sharing. Safe flying!
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Old 04-04-2020, 08:49 PM
Jskyking Jskyking is offline
Join Date: Apr 2018
Location: Huntsville,AL
Posts: 170

Very good after-action report. Pretty work in all respects. I think everyone who reads it will learn something....especially normalization of deviance....I’ll take a bruised ego every time over a bruised airframe or worse.
Fly Navy.
RV14 Empenage complete
Wings in work
Dues bypass eligible- paid anyhow
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Old 04-04-2020, 10:36 PM
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wjb wjb is offline
Join Date: Nov 2012
Location: Half Moon Bay, CA
Posts: 1,120

Thanks for the brutally honest report and analysis .. I learned much and agree with your decision/training to get the bird on the ground safely, and then deal with the aftermath without a bent airframe or damaged pilot. Thanks much for the detailed writeup.

Fly Navy!
Bill Bencze
N430WB RV-7 @KHAF, Flying 100+ hrs
VAF 2021 donation happily made
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Old 04-05-2020, 12:54 AM
seward747 seward747 is offline
Join Date: Jan 2005
Posts: 201

Rhino: To quote from a rather well known movie, "You had a **** of a ?..PMCF".

About as professional and thorough a debrief as I've read on these pages. I'm confident your baring your soul here will be appreciated by many. I bet the Maintenance Control chiefs would have loved reading through the MAFs on this one.

Thanks for the nitty gritty on landing a light civil on a DOD aerodrome (did it once myself but was pre approved for an open house event - a little different situation). With ATC approval, I frequently find myself overflying a particular NAS up here in the northwest and occasionally wonder; what if???

Also, appreciate the words of wisdom from Naval Aviator/attorney/author Steven Coonts. A fellow squadron mate, though from a different era. He speaks the truth here.

Bravo Zulu on the save; fly safe, stay healthy!

Seattle area (pretty close to NUW)
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Old 04-05-2020, 02:49 AM
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rv8ch rv8ch is offline
Join Date: Feb 2005
Location: LSGY
Posts: 4,306
Default Thanks - great writeup

Thanks for sharing this - really is food for thought for all of us. "Normalization of deviance" is really insidious, and humans are wired for this - we also call it "adaptation" when it's constructive. Two sides of the same coin.
Mickey Coggins
"Hello, world!"
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Old 04-05-2020, 03:33 AM
PCHunt PCHunt is offline
Join Date: Feb 2007
Location: San Diego, CA
Posts: 1,816
Default Great PMCF debrief

Thanks for all the detail, it really helps.

If I could summarize your two posts in one sentence:

Our airplanes talk to us............. and as you have pointed out: We must listen!


Pete Hunt, [San Diego] VAF #1069
RV-6, RV-6A, T-6G

2021 Donation+, Gladly Sent
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Old 04-05-2020, 08:48 AM
rmarshall234 rmarshall234 is offline
Join Date: Jun 2008
Location: San Diego, CA
Posts: 292

Excellent. Nice work. A great after action report for all of us to learn from and a very honest self-evaluation.

As for the suggestion from friends regarding airborne troubleshooting...we have a saying in the skydiving world which is related and goes like this: "In-air rigging is ALWAYS a bad idea". What it means, is if you have a problem with your main parachute _don't_ try to fix it. Cut away and open your reserve instead. It comes form decades and hundreds of fatalities from jumpers loosing precious altitude trying to deal with a problem and running out of options. It seems to me you were potentially seconds away from a fuel fed engine fire with raw fuel spraying on the alternator like that. Which would have changed the nature of the emergency dramatically.

Again, Kudos. You made the right decision - in the end when it really mattered.

Robert Marshall
A&P / IA
Parachute Rigger
Skydiving Instructor
"What Matters is the Outcome"
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