Back in the beginning of March 2018, I was tracking down an annoying oil leak that I determined was from a crack in the oil pan. I removed the oil pan, had it welded and reinstalled. I was going to do a quick flight around the pattern and then see if the leak was fixed.
On landing after the flight, I picked up a shimmy in the nose wheel. This had happened once back in November or 2017. I did NOT like it. I had checked the breakaway tension on the fork and it was slightly low, but within specs. I inspected the fork and nose strut for any indication of cracks and found none.
I called Scott Swing and discussed the situation. I was already planning on going down to Sebastian to get main gear booties installed so I decided to go ahead and get a shimmy damper while I was there.
During the first week of December, I spent two days in Sebastian installing main gear booties while Scott installed the shimmy damper. I can’t tell you how much easier it is to taxi with the shimmy damper!
So I figured my shimmy days were behind me.
Which is why that shimmy on the landing caught me off guard. I immediately pulled the nose off. Then decided to go around. So I added power, and went around. I thought that maybe I came in too fast.
I considered raising the gear, but I had no idea where the nose gear was pointing. I knew if it was within about 45 degrees of straight ahead that the nose gear guides would straighten it out. But if it was farther out that 45 degrees, the nose fork could do some damage when retracting. And even worse, might not be able to extend. So I left it down.
Came around for the second attempt. As soon as the nose gear touched down, the shimmy returned. And once again, I pulled the nose off. I briefly considered going around again, but decided that wouldn’t accomplish anything. So I planned on holding it off as long as possible.
I thought that I had the nose back on the ground although I didn’t feel it. But a glance at the airspeed showed about 50kts. So I must have greased the nose down. But as soon as I touched the brakes, the nose hit the runway.
Training is an amazing thing.
Without even realizing it, while I was sliding down the runway, I pulled the mixture. I have absolutely no memory of doing that but once I viewed the video, I saw it. The engine, however, continued to run (but just barely). I eventually realized that the boost pump was still on.
My theory at the time was that the shimmy somehow caused the nose gear to retract.
Because I’m at a very small airport and it was about 7am, the place was deserted. I ran over to the airport office (My plane was blocking the runway) and got the airport maintenance guy. We grabbed the engine hoist that I used when pulling the oil pan, hooked up to the back of his truck and went out to retrieve my plane.
Now at this point, I was thinking that all I needed to do was raise up the nose, and pull the gear down, slide in the overcenter pin and we could tow it back to the hangar. But I’ve got a hidden latch that has to be accessed from the nose gear opening. Which I couldn’t do because it was sitting on its nose.
So we put a sling around the nose and hoisted it up enough to unlatch the nose hatch. When I opened the hatch, I was dumbfounded. THE NOSE GEAR WASN’T THERE!
The nose compartment was empty! I also noticed a spot on the leading edge of the left wing where the paint and filler were missing. I guessed that during the shimmy, the nose gear departed, flew off to the left, impacted the leading edge and then continued on.
But we had to get the airplane off the runway. So we took 2×4 and wedged it in the nose compartment, wrapped a strap around it and lifted up the nose. Then I sat on the tailgate to keep the plane somewhat stable while he drove to my hangar. About 15 minutes after the nose began scraping along runway 36, the plane was back in the hangar.
Then we drove out to find the nose gear. I found it on in the grass on the left side of the runway about 500’ from the end of the runway.
Let’s go to the tape: Video.
I couldn’t identify anything out of the ordinary in the landing (other than the shimmy). But on the second landing attempt, I believe that I can hear the “BANG” when the nose strut broke off. Definitely not something I enjoy watching.
I called Scott and discussed the “event”. The strut sheared off right at the bottom of the gusset. My plane has an older style “Taco” gusset. It’s a piece of steel that is folded over on either side of the strut. The current struts use a much longer, solid gusset. The best guess is that when the first shimmy occurred, an unseen stress fracture was created. It’s possible that the fracture caused the shimmy. Or the shimmy could have been caused by an out of balance nose wheel which then weakened the strut enough that it broke. Unfortunately, there’s no way to know for sure. What I do know is Velocity changed from the old Taco Gusset struts to the new style for a reason.
The nose strut was broke just below the gusset. I checked the strut thoroughly and could not see anything which provided any clues as to what causes the shimmy or what caused the break.
The bracket which holds the pin for the shimmy damper was broken. But that either happened from the shimmy or impact after the strut broke away. It was not like that before the flight.
The bottom of the nose was depressing. I had gotten the plane painted less than a year ago! The bottom was flat as a pancake. The outlet for the oil cooler was ground down flush. The rear arm of the left gear door broken, but the canard bulkhead was undamaged and there was no structural damage.
The left door had a broken hinge arm that would have to be replaced.
There was also some damage to the top of the cowl at the prop opening and to the spinner. When the nose dropped after the gear departed, the back of the plane (and engine) were moving up. When the nose hit and stopped its downward motion, the engine continued up a bit. The inertia of the prop moving up and forward caused the spinner to make contact with the cowling.
The leading edge of the left wing took some damage from where the nose gear hit. All things considered, this is much better than had it gone straight back and hit the prop.
Time to get busy:
I pulled the canard, nose gear doors and nose strut that day. Scott had a new strut gear door hinge arm and shimmy damper pin bracket on the way up that afternoon. I held off repairing any fiberglass until I had the new nose gear hardware in. I also left the gear pivot brackets alone hoping that the new nose strut would drop right.
Once the new nose strut arrived I compared it to the one I have.
The new style has a single layer gusset and it’s a LOT longer. It will require opening up the slot in the canard bulkhead to accommodate it.
The first challenges… 1) The top of the new strut would not align with the captivator plate. And 2) when retracted, the fork was offset enough that it was rubbing on one of the guides. I talked to Scott about options. He said that I could grind one side of the captivator plate to get it to fit. Then I could send the strut back down and he could put it in a fixture and bend it so the fork would fit between the two guides. In the end we decided that the correct fix was to remove the pivot brackets and re-mount them.
I pulled the plates, used a soldering iron to heat up the bushings and got those out. Then it was like I was back in Sebastian a couple days after I bought the kit when I was installing the nose gear for the first time. After a while (a long while), I got the nose gear exactly where I wanted it. Got everything reassembled and did numerous gear cycles to make sure.
I took the nose fork to a local welding shop and they used dye penetrant to check for any cracks that may have resulted from its trip after leaving the airplane.
No apparent cracks.
Now it was time to get started on the cosmetic work. I thought about adding a bunch of micro to the bottom of the nose to recreate the curve but in the end I decided that since it’s on the bottom, nobody would ever see it anyway. And even if they did, it could be hard to tell. So I got the grinder out and removed the finish around the area to give the fiberglass something to bond to.
The oil cooler outlet needed to be recreated. Malcolm did a real good job of creating that. So good that the nose oil cooler alone can keep the oil temps down to 140F without a vernatherm. I tried my best to recreate that outlet.
Once that was done, I smeared micro over the exposed foam and covered the area with multiple layers of fiberglass.
The leading edge on the left wing only suffered superficial damage. Basically, the filler get knocked off. So that would wait until it was time for the filling task. The gear doors required a lot of work as well. The edge where the doors meet was completely gone. So I had to recreate that part of the door. And the rear hinge arm was gone on the left door so that had to be reinstalled. I probably spent more time rebuilding the doors than any other part of the repair.
When doing the filler before, the plane was upside down. So I would be doing this laying on my back. This was a PAIN! And it was HOT! Fortunately, I still had my Hutchins Hustler. So the sanding phase was quick. The absolute worst part was the airport is an hour from the house. So I would drive out, sand the filler, figure out where more was needed, spread the filler, then I was done. Total time are the airport was about 90 minutes with two hours driving time.
The leading edge of the wing and the cowling was a walk in the park by comparison. The spinner was a whole different story. It’s made of kevlar. So you really can’t sand it because it just fuzzes up. Fortunately, I know Malcolm. And he knows just about everything about composites. Turns out, the fix is super glue. Sorry, isocyanate adhesive. 😉 Once you get the area sanded about where you want it, you cover the area with the glue. After it cures, you do a final sanding and then apply the epoxy and fiberglass. I used a very lightweight veil since I didn’t want to impact the balance too much.
After a few days of this, I was ready to prime.
At this point, since the canard was out, I made some modifications. First was to put in bellows around the rudder pedal push rods. Then I made some baffles around the nose gear pivot. These mods were to block air from entering the cabin to help keep it warm in the winter. You can read about those here.
The last improvement/modification I made was to install at anti-slop block where the control stick attaches to the aileron torque tube.
As I was getting ready to reinstall the canard, I noticed the copilot elevator had some slop between the elevator and the torque tube. Turns out that while the insert that the torque tube plate attaches to was countersunk, it wasn’t countersunk enough. That was allowing a little play between the two. The fix was to countersink the insert just a bit more.
Fortunately, I still have some Akzo-Nobel gray and white primer left. So once I had the areas primed in white, it wasn’t too noticeable.
Now it’s time for paint. I asked Scott about bringing it down there, but scheduling was a challenge and it was going to be kind of pricey. The shop on the field put me in touch with the guy who used to paint for Gulf Coast Helicopters. The only downside is that there was a bunch of overspray. So I have a bunch of cleanup and buffing work to do.
In 2006 I had the nose gear on my 182RG collapse after landing in Greensboro, NC. That incident cost about $60,000 to repair. Around $35,000 of that was engine teardown and a new prop. The rest was replacing/repairing everything else that got damaged. When all was said and done, this “incident” ended up costing me about $1,000 ($550 for a new nose gear parts and about $450 for painting). I spent quite a few hours making repairs, but that doesn’t count… because it’s working on the plane.
Post repair test flights indicate that I must have gotten the nose oil cooler outlet shape right because it’s keeping the oil cool all by itself.
What’s the takeaway?
If you have the old style taco gusset, maybe consider proactively replacing it. I know there are still many out there, so I can’t say that this is a necessity. Inspecting the nose gear leg doesn’t seem very useful. After the shimmy in November, I looked at the gear leg carefully. As did Scott. But nothing was found to indicate a problem. So I’m not sure there’s a good lesson to be learned other than when the nose hits the runway, GET ON THE BRAKES… HARD! Had I done that, I think the damage to the nose would have be much less.