RV12 - Final Report - N412JN

[A2022]

RV12 - Preliminary Report - N412JN

well, this is an early report, but if I were an investigator, the first thing I would do is examine the elevator, elevator trim tab, all control linkage and get the flight data. also, look for a tool left behind or loose hardware that could jam the controls. the only thing more important than the engine are the flight controls.

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A Van's RV-12, N412JN, was destroyed when it impacted the roof of a building while on approach to Auburn Municipal Airport (S50), Auburn, Washington. The pilot was fatally injured.

Preliminary information suggests the aircraft was in the base to final phase of the approach when the pilot reported a flight control issue.

https://aviation-safety.net/wikibase/389106

live ATC begins at 27:54
https://archive.liveatc.net/s50/S50-Jun ... -1830Z.mp3

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[rockwoodrv9a]

That is terrible. It looked like such a nice plane. It will be interesting to see what they find.

As for the trim, I am wondering if it is worth the risk having the trim. Especially if you are flying with A/P. I had what I think was a run away trim last week on a flight. I had to really push to overcome it. I went into the VPX power system and was able to control it from the screen after resetting the breaker. It was concerning, but not really scary. I checked all the wires on the stick control and will make sure I verify the trim controls before each flight. I rarely use the elevator trim except a slight bump for landing so maybe I will just turn it off.

What do you think? Do you use your pitch trim often?

[A2022]

well, he may have been using trim on the base leg, so it may be possible that it got away from him.

I use my trim all the time and haven't had any issues with it on the RV9, but I know others that have had runaway trim. I once had runaway trim on a piper arrow, 15 years ago. it was trying to dive me into the ground.

[A2022]

RV12 - Preliminary Report - N412JN

well, the preliminary report reveals that the left side pushrod eyebolt bearing was not connected per the plans and became loose because the bearing could spin in the pushrod threads. it appears the right side was still connected and may have been able to be used if left side pushrod had not possibly jammed. we don't know this and probably never will. how this ever got passed the DAR is a question. a simple 5-minute borescope inspection of the flight control linkage would have found it. are the DAR's doing their job properly? 100 hours until failure. it was not airworthy. the flight controls are the most important feature of the aircraft.

https://data.ntsb.gov/carol-repgen/api/ ... 194412/pdf

The airplane departed Auburn Municipal Airport (S50), Auburn, Washington, for what family members of the pilot reported as a routine pleasure flight. Preliminary Automatic Dependent Surveillance-Broadcast (ADS-B) data indicated that shortly after takeoff the airplane followed a southeast track, and after reaching the eastern foothills of Mt. Rainier performed a 180° right turn, and followed a similar track back to Auburn. As the airplane approached the airport from the east, the pilot reported over the common traffic advisory frequency (CTAF) that he was just over midfield and intended to perform a full stop landing on runway 35. Correlation between recorded CTAF audio and ADS-B data indicated that over the next 60 seconds, 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. A west-facing security camera, located on the exterior wall of a warehouse about ¾ miles southwest of the runway 35 threshold, captured the final 3 seconds of flight. It showed the airplane come into view at the top of the frame while in a 45° descending left turn. The airplanes roll rate rapidly increased, and the airplane struck the warehouse roof inverted in a 45° nose-down attitude. The airplane came to rest inside the reception area of the warehouse. The forward cabin sustained crush damage through to the main wing spar. The complete right, and the inboard left section of the wings remained attached to the fuselage by the main spar, and the outboard fragments of the left wing were located on the building’s roof.

[rockwoodrv9a]

Wow. Seeing that picture is crazy. As for the DAR not finding it, the guy that did mine said he wasnt there to make sure everything was done correctly - that was my job as the builder. If he noticed anything that didnt look right he would point it out but there was no way he could know everything about every plane he inspected and it would take days to give it a complete inspection.

I think the best thing to do is to have a shop or guy that has built and maintained the same type of plane do a complete inspection to make sure everything is good. Sort of like an annual but dont have to change fluids or some of the other minor things but check the controls, cables, nuts, bolts, and anything they know could be an issue.

This accident is causing me to consider taking my plane to Bob in Kokomo for a complete inspection. I think I will give him a call. Im sure the builder thought he had done it correctly and sometimes you need someone else who knows the plane type needs to do a second check.

[rockwoodrv9a]

Looking at the two pictures I am not understanding what is different. Maybe on my phone it is too small. I may pop my floors off to check mine next week when I am back in town.

[rockwoodrv9a]

After looking at it closer I finally figured out what the problem was. Not sure why it was so hard for me to see. That freaks me out even more. Im going to check all my controls from start to finish.

After looking closely at the 9A plans, I dont think this error is possible. The control tubes wouldnt work any other way than the correct way. That makes me feel better. I want to download the 12 plans to see how this could happen.

[A2022]

yep, have someone take a look at it if you feel it is needed. another set of eyes is always beneficial, if they know what they are doing.

on the 9, the flight controls eyebolt bushings are in double shear to all attachments, except for the flap external rod. double shear is a good thing for an eyebolt bushing because it is both stronger and trapped, compared to a cantilevered eyebolt bushing.

Van's Aircraft should make it a standard practice for all flight control eyebolt bushings to be double shear. this would also eliminate the potential for a "backwards install", Muphy proofed.

[A2022]

RV12 - Final Report - N412JN

Well, the final report has been published for this one. The conclusion was that the control linkage was misassembled. Unless Van's Murphy-Proofs this assembly so that it cannot be misassembled, it will happen again. Trust me, when things happen once, they will happen again.

https://data.ntsb.gov/carol-repgen/api/ ... 194412/pdf

Analysis

While returning to the airport from a routine pleasure flight, the pilot of the experimental lightsport airplane reported a total flight control failure while maneuvering to land. Data from the onboard electronic flight instrument system and witness statements indicated that after turning from the crosswind to the downwind leg, the airplane entered an uncontrolled descending left turn consistent with a spin or spiral, culminating in a collision with a warehouse roof about 0.75 mile from the runway threshold.

Postaccident examination revealed that the left side (where the pilot was operating the airplane) control stick pushrod had become disconnected from the flaperon mixer bellcrank due to improper installation during construction. Both left and right pushrod rod-end eyebolt bearings had been installed in reverse orientation. The improper installation allowed the pushrod to gradually unscrew from its eyebolt, ultimately resulting in complete separation of the left pushrod. This condition rendered the primary roll control system on the pilot’s side ineffective.

The aircraft was equipped with an autopilot system featuring a “Level” mode capable of providing roll control independent of the cockpit control sticks. Prompt activation of this feature—or use of the rudder to counteract the developing roll—would likely have allowed the pilot to retain some degree of control. Similarly, the pilot would have been able to fully control the airplane if he had reached to his right and used the other control stick. However, given the sudden onset and rapid progression of the event, it is unlikely the pilot had sufficient time or situational awareness to identify and employ these options before the airplane entered an unusual attitude and became uncontrollable.

The pilot's autopsy identified heart disease, including severe coronary artery disease of a single coronary artery and mild thickening of the left cardiac ventricle. Although the pilot’s heart disease was associated with an increased risk of sudden impairment or incapacitation from a cardiac event, the circumstances of the accident were not consistent with a sudden medical event, and it is unlikely that the pilot’s heart disease contributed to the accident.

The improper assembly error was traced to the original construction of the airplane and was visible in build photographs taken in 2019. The oversight persisted through final inspection and three years of subsequent operation. The airplane kit manufacturer later issued a service bulletin addressing correct installation of the pushrods.