RV-12 Fatal Crash - Control Failure 6/6 Auburn, WA
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Ed Haywood
En-Route
He announced his intention to land. He took that time away from himself. Bad decision.
Stay aloft. Declare emergency. Troubleshoot. Make a plan. Don't be in a hurry to crash.
keen9
Pre-takeoff checklist
That is an important point. You do not have control of the aircraft . . . don't waste brain cells making a radio call. Instead, focus on the problem, aka aviate first.
BMan
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BMan
Not heartless at all; you're spot on. This tragedy assessment will stick in my "brain database" of what to do if control failure ever happens to me and seconds count. I tell my daughter my means/methods of doing things the way I do (backing into parking spaces, always locking doors, never reporting a vacation to the USPS, etc.) are due to life lessons learned the hard way or by learning from the unfortunate outcomes of others.
I'm bad at plenty of things. That one I'm good at. It never even came close to the top of the list for me when my engine shut off. I was way too busy doing the important stuff.
wanttaja
En-Route
Factory built?
Lindberg
Final Approach
wanttaja
En-Route
This particular RV-12 was licensed in category 48B; Experimental Light Sport - Kit Built. It is, of course, similar to EAB in that an amateur is constructing the aircraft. The difference is that the kit itself may be developed to a greater extent than one can get with an Experimental Amateur-Built aircraft. "May be" is the key phrase; if the Light Sport kit still qualifies as EAB, the builder can license them either way.
In my studies of EAB accidents, I've found that about 5.6% of them involve mistakes during construction, and 6.1% involve mistakes involving maintenance. It can be a fuzzy line between the two, of course, as something may be classed as a maintenance error but actually be due to a mistake in construction.
Last year, I completed a similar study of Light Sport accidents. There were 475 accidents involving Experimental Light Sport Aircraft in the 2005-2021 time period. Builder error was involved in only 1.1% of them; maintenance error in 5.1%. This includes all variety of aircraft (e.g., powered parachutes and weight-shift aircraft as well as fixed wing) but the percentages hold.
Only 35 of the accidents involved Experimental Light Sport - Kit Built aircraft like the RV-12. Percentages for this small of a sample size can be deceptive, but none of the 35 featured builder error, and three had maintenance error involved.
I show only 12 RV-12 accidents in my 2005-2021 Light Sport accident database. None of them had builder or maintenance error.
Ron Wanttaja
wanttaja
En-Route
The NTSB's "Amateur Built" flag is inaccurate. The NTSB investigators tend to use it to indicate Special airworthiness, rather than just Experimental Amateur Built.
When I analyze a year's accidents, I do an initial sort on the "Amateur-Built" flag (labeled "Homebuilt" in the downloadable database), then weed out planes that are obviously NOT homebuilts. In 2014, for instance, about 25% of the fatal accidents listed as "Homebuilt" were not EABs. There's even a Boeing 737 listed as a "homebuilt" in the NTSB records (DCA13WA007). Unregistered ultralights are also usually listed as "homebuilt."
Primarily, it's the Light Sports getting flagged as "Homebuilt." In 2015, there were 14 accidents flagged as "homebuilt" that weren't. One was a Yak (Experimental Exhibition), one was Standard category (Waco). Ten were Light Sports that received licenses via the ultralight conversion process from the early days of Light Sport (e.g., former ultralights that got N-Numbers).
It does go the other way, as well. Every year, I find 5-10 accidents that are NOT labeled as "Homebuilt" that have obvious homebuilt-like names. I cross-reference to the FAA database to find the actual certifications.
Ron Wanttaja
Lindberg
Final Approach
How does this compare to the rates of builder and maintenance error in factory-built aircraft?
wanttaja
En-Route
Don't have overall figures for production-type aircraft, but I have it for some models. For the 172, it's 0.2% builder error, 2.2% maintenance error.
I use the Cessna 172 and Cessna 210 as a "Control Group" to compare accident causes with homebuilts. It gives a mix of simple and complex aircraft, and the number of aircraft is close to that of homebuilts. Here's a comparison using raw numbers rather than percentages.
Ron Wanttaja
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Baked Potato
Based on recent whistleblower testimony I don't see that as too much of a stretch
Daleandee
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Dale Andee
Thanks Ed. That's an excellent rule to write on the aviation wall.
Couple of years ago I had a flight review where the instructor locked the stick and made me do an approach to landing with just power, trim, & rudder. Learned a lot ...
Ed Haywood
En-Route
Incredible data. Most of it is intuitive. The one real outlier is the Pilot Miscontrol. Wonder why that one skews so far in favor of EAB. More experienced pilots on average?
TipTanks
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My instructor used to make me simulate a control failure. Power, and trim, maybe the rudder still worked sometimes.We would take over control just prior to touchdown. It was tricky, but survivable. This was in training aircraft, inherently stable. Try it sometime next time you are out.
wanttaja
En-Route
Exactly. The pilots of the homebuilts in my analysis have about three times the flight experience as the pilots of the Control Group.
Again, "Pilot Miscontrol", in my analysis, refers to basic stick-and-rudder errors. It includes both loss of control as well as undershoot/overshoots, failure to lower landing gear, etc. It does not include judgment issues such as running out of gas or low flying.
Ron Wanttaja
wanttaja
En-Route
There's reaction time to consider, too. With the airplane on base leg, there's limited time to note and react to a failure like this. Might be that by the time the pilot recognized the problem and formulated potential recoveries, the plane was too far into the event and too low to recover. It's one thing to be typing on the keyboard, it's another thing to watch the ground grow closer in the windshield.
Curiously, I have two other friends that suffered control failures in a homebuilt (in over 30+ years involvement with homebuilts). One had forgotten to connect one aileron pushrod. When he noted the condition, he came back to the airport. However, on the base-to-final turn, the loose pushrod slipped down and jammed into the lower longerons. Couldn't recover from the turn. He came out of it with a broken collarbone and some cuts and bruises. He had turned final at a fairly low altitude, which probably contributed to his survival. Airplane was totally destroyed, which ALSO probably contributed to his survival. BTW, it was his fourth aircraft accident.
Second case happened in the Fly Baby Flying Club in the '80s. Left rudder cable disconnected at the pedal. The rudder cables run along the lower longerons on either side of the pilot, so he just reached down, grabbed a handful of cable, and tugged on it when he needed left rudder. Heel brakes, so he was able to keep it straight after landing. Steve was a former Ag pilot, probably better at solving issues like this.
Control issues are a factor in about 2.7% of homebuilt accidents, vs. just 0.3% of Cessna 172 accidents and 0.8% in Light Sports.
Ron Wanttaja
wanttaja
En-Route
Do a Google search on "wanttaja kitplanes". Most of the articles I've written are online.
Also, I've given talks online for the EAA Homebuilt Week. These were recorded. If you are a member, you can watch the videos.
Ron Wanttaja
Ed Haywood
En-Route
Looking closer at the accident report, I agree, this could have been a factor:
"...the airplane overflew the runway, while descending from 1,500 to 1,250 ft. It then began a left turn, and as it rolled out onto the left downwind leg, the pilot transmitted, “Pan Pan RV412JN, I just had a control failure, I’m inbound for 35, without any controls”.
Over the next 45 seconds, the airplane began a descending left turn, that witnesses described as similar to a spin or spiral dive."
Sounds like the last bit of thread was engaged for the left turn into the downwind. The pushrod would have been pushing the threaded end. When the pilot tried to roll right to level, the stick would have pulled the pushrod, causing it to disengage from the threaded end.
It's unclear from the report what the bank angle was when the control disengaged. If the left bank was large and increasing, then it would have been a tough spot for sure. If the aircraft was close to level, then he should have been able to level the wings with yaw-roll coupling. In that case, the aircraft would have been controllable long enough for the light bulb to go on that he still had a functioning control system two feet to the right.
ChopAndDrop
Pre-takeoff checklist
When he asks if you want to go flying with him, is it rude to say “no” ?
ChopAndDrop
Pre-takeoff checklist
Reading all this was really enlightening especially the information about using the other control stick.
The one thing I’ll add is that controls failures are more of a known thing in the glider community due to the glider being disassembled and reassembled often people can forget to hook up ailerons and other controls.
Another hazard for thought is that in a tandem cockpit you can’t reach the other control, but one hazard is the seatbelt or loose stuff falling and jamming the controls in the other tandem cockpit: for tandem seat Gliders we always make sure to buckle the seatbelt and pull-in the straps on the empty seat, no loose items like water bottles back there, etc.
Best practice in the glider community is to have another pilot help you do a “positive controls check” after assembly, by applying back-force on the controls surface.
This is more than just “moving all the controls” to see movement, like we do on airplane preflight: it involves someone feeling/applying back pressure in both directions to the control surface.
That wouldn’t have made a difference here for the RV (since it was fine at takeoff but unthreaded during flight) but just saying…. whenever my mechanic does anything on Controls surfaces or control cables, I have someone else help me perform the “positive controls check” before I fly.
The one thing I’ll add is that controls failures are more of a known thing in the glider community due to the glider being disassembled and reassembled often people can forget to hook up ailerons and other controls.
Another hazard for thought is that in a tandem cockpit you can’t reach the other control, but one hazard is the seatbelt or loose stuff falling and jamming the controls in the other tandem cockpit: for tandem seat Gliders we always make sure to buckle the seatbelt and pull-in the straps on the empty seat, no loose items like water bottles back there, etc.
Best practice in the glider community is to have another pilot help you do a “positive controls check” after assembly, by applying back-force on the controls surface.
This is more than just “moving all the controls” to see movement, like we do on airplane preflight: it involves someone feeling/applying back pressure in both directions to the control surface.
That wouldn’t have made a difference here for the RV (since it was fine at takeoff but unthreaded during flight) but just saying…. whenever my mechanic does anything on Controls surfaces or control cables, I have someone else help me perform the “positive controls check” before I fly.
ChopAndDrop
Pre-takeoff checklist
Since we are just speculating for safety discussion I’ll add another thing re: the aileron roll/rudder coupling effect for alternative control of the airplane: This effect may not be obvious to most pilots, outside of a few demonstrations of stall recovery / spin avoidance.
Get a CFI to help you do a “falling leaf” stall recovery exercise (if safe to do in your plane) that is really illustrative of the effect.
Get a CFI to help you do a “falling leaf” stall recovery exercise (if safe to do in your plane) that is really illustrative of the effect.
dtuuri
Final Approach
Yeah, but have you tried it with the loose end of the
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wanttaja
En-Route
I flew with Cecil once. When he was coming in on final, we were offset to one side.
I said, "Hey, Cecil, you're lined up on the edge of the runway, not the centerline."
He replied, "I like the contrast between the grass and the asphalt." Seems his cataracts were interfering with his vision. He slid over to the center as we got closer.
Ron Wanttaja
Ed Haywood
En-Route
Push tube would not affect control surfaces, only the stick. Threaded rod end would jam the controls.
Looking closely at the wreckage photo, he might have tried the other stick after all. Note the finish damage to the surface adjacent to the end of the threaded rod end. That would be consistent with repeatedly slamming the right stick sideways.
If that's the case, I take back what I said. This accident may not have been survivable.
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Stuff like this is what always worried me when building my sonex. The assembly process is not mistake proofed and you need to have a bit more knowledge than just what’s in the plans or builders manual at times. It’s not getting the big things wrong like spar pins or tight fit holes that scare me. It’s the little things like putting a bolt on backwards or assembling something on the wrong side of something else where it still works but doesn’t fail until well after flight testing. Many people forget that building an airplane is more than just assembling parts. It’s called experimental aircraft for a reason.
Ed Haywood
En-Route
I had the same concern with rebuilding my Decathlon, even with an A&P supervising me.
Flight controls are critical. I had multiple sets of eyes on my controls before I covered them up. I still inspect them once a month for anything amiss. On my aircraft, all control system fasteners are wired or cottered. Anything not cottered is torque sealed. Torque seal probably would have caught this.
Dan Thomas
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The lack of a jam nut presents more than just the risk of loosening. That jam nut immobilizes the threads on the rod end in the tube end, preventing thread wear and failure.
A couple of years ago the town's grader came to a stop in front of our place. The jam nut on one steering tie rod end had been loose a long time, and the threads just banged back and forth in the rod until they tore right off, and the wheel toed outward all the way and stopped the machine. I walked out and had a look. I suggested putting the blade down to lift the front wheels off, and we horsed the rod into place and turned the wheel to get the rod end back into the rod. A tiedown chain tightened across the whole works held things together so they could crawl back to the shop
A couple of years ago the town's grader came to a stop in front of our place. The jam nut on one steering tie rod end had been loose a long time, and the threads just banged back and forth in the rod until they tore right off, and the wheel toed outward all the way and stopped the machine. I walked out and had a look. I suggested putting the blade down to lift the front wheels off, and we horsed the rod into place and turned the wheel to get the rod end back into the rod. A tiedown chain tightened across the whole works held things together so they could crawl back to the shop
TipTanks
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TipTanks
No Doubt. If you were in a turn and it let go, or any other place other than straight level cruise, it may definitely throw you off. I do think it is something that's good to practice before it happens.
wanttaja
En-Route
Had occasion to review some of my statistics on builder error. About 22% of the cases involve the control system, about the same as cases affecting the fuel system. Engine-related cases are the "top scorer", but not by much.
Interesting to compare the lethality of the cases:
Airframe-related cases are much more likely to result in death, but, fortunately, the percentage of the overall cases is less.
Ron Wanttaja
Interesting to compare the lethality of the cases:
Airframe-related cases are much more likely to result in death, but, fortunately, the percentage of the overall cases is less.
Ron Wanttaja
Multiple eyes are always a good idea but even then they aren't foolproof. I had multiple other builders check my plane over as I was building and I had two other friends who had also completed building a sonex look things over right before I had the DAR out to do the certification inspection. Even with all those eyes the DAR still found a nut holding the tailwheel on was missing a cotter pin. I was lucky in that my DAR was very thorough in his inspection and didn't treat the certification as just a paperwork exercise like some others do. I can very easily see how the RV builder in the accident put the rod end on backward and it went unnoticed until it failed and became safety critical. Its a scary thought but there are so many things that can kill you when flying. The only thing you can do is try your best to avoid what you can and minimize the risk of what you can't. Building and flying your own airplane will never be a zero risk activity.
Interesting statistics and something to think about when building but statistics don't mean anything when you yourself are the outlier like the pilot in this accident was. Even something with a 99.9% success rate it still means that one in a thousand will still experience a failure.
Daleandee
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Dale Andee
A professor said something very similar in one of my lessons, "one in a thousand ain't bad ... unless you're the one."
wanttaja
En-Route
Favorite example came around here a few decades back. Two of our local guys built two Thurston Seafires; think a Lake with a tractor engine.
The shop where these two planes were being built was hounded by local EAAers, and the FAA brought a couple of guys around to sign off on the two airplanes.
Dave was on the runup stand, doing the standard checks. Something didn't ring right. He looked carefully at the wing. The ailerons were working BACKWARDS...left aileron going down when a left turn was wanted etc.
Taxied back and showed it to the stunned crowd. They grabbed a set of plans and traced the aileron connections.
It was made per plans. The airplane had been designed for yokes, but they wanted sticks. They had contacted the designer, and he had generated an addendum to the plans for the joystick conversion. As it turns out, working the ailerons backward.....
Ron Wanttaja
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Dan Thomas
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