Turbulence damage on flight back from OSH to WA

I’m back from OSH, but had a few seconds of severe turbulence that damaged the plane.  I was flying Zenith 650 about 32 miles south of Big Timber airport (approaching Springtime, MT) in moderate winds and very light turbulence.  Certainly very common in any type flying.  Nothing that bounced me out of the seat.  I was hand flying instead of auto-pilot as the winds were not severe, but enough that it would throw AP off a bit.  About 3,000 AGL with I-90 on my left and flat from there to Rockies off in the distance.  To my right was gently rising terrain, no steep slopes.  I was over farmlands.  All was going OK and I-90 was going northwest to the pass that starts through the Rockies.  Suddenly the plane dropped 6 to 10 ft (estimated).  I was held in by the seat belt and don’t remember even hitting the top of the canopy.  Behind my head, as far forward as could be in the baggage area, was a ~10# battery I used to run my pap machine while camping.  On the other side was a 3 ft solar panel that re-charged the battery during day (that system worked perfectly all week).  Also in the baggage area were my back-up aviation portable radio, a bag with telephoto lens for camera along with chargers, spare batteries, and my keys.  In the far back was bulky but lightweight stuff like pillow and summer sleeping bag.  Estimated less than 30#s in baggage area limited to 40#s.  I had shipped two boxes home with estimated 70#’s of stuff via UPS to save weight and bulk, much of it being stuff I bought at OSH, so returning had less weight and bulk than going.  Heavy stuff like tent, bag with clothes etc was in the front seat. (I UPS’d 2 days before leaving, so still needed all my camping stuff.)  I figured put that stuff in where a person would sit for both weight and balance.  Plane was flying great, as well as could be expected with high density altitude.  Anyway, one episode of severe turbulence, worst in my 37 yrs of flying, apparently made the battery jump up 10 ft, and there’s only about 2.5 ft to top of canopy.  It broke the canopy and exited the plane.  The solar panel also hit top of canopy on pax side, broke the glass covering on the panel, but didn’t exit plane - obviously too long (about 3 ft long).  The handheld radio exited plane, along with the small camera bag with lens and other stuff.  My headset came off and exited out the hole in the canopy.  First, I gained control of the plane.  Next was quick damage assessment.  Next I discovered missing headset.  That was out of the plane, but held in by wire.  I pulled on the wire and brought headset back in, looked it over as much as possible in few seconds while flying, and put it on.  No obvious damage and it works fine.  Aviate, navigate, communicate.  First, fly the plane.  I did.  Next, assess damage and determine if off-airport landing is necessary.  I could fly, but not fast or very well.  Still, plane was controllable just not fast and couldn’t climb well.  OK, now navigate.  I searched Dynon map for Nearest and chose the closest airport that was public (not a farmer’s field strip) and had fuel.  I figured fuel availability would also have other things I might need.  That was Big Timber, MT, about 32 miles along original heading.  I was at about 4,000 MSL (having dropped about 1 or 2,000 ft during the event and while gaining control and flying doing damage assessment), 2,000 AGL, slowly rising terrain, and Big Timber is at 4,400 MSL.  I had things under control so didn’t try to contact anyone as there was nothing they could do to help me in the air.  I did announce on Big Timber Unicom I had a damaged aircraft and was making a straight in for runway 24.  At first I was at 4300 MSL and had trouble seeing the airport, even just 3 miles out.  It sits on a plateau about 400 ft above surrounding terrain.  Winds and turbulence were not a factor, just climbing was hard.  Air was coming in the broken canopy and hitting the back bulkhead of baggage area, acting like a brake.  Note that lot of this I figured out after on the ground, including what was missing.  I rose to about 4,500 MSL and made an uneventful landing.  Steve, a local farmer/investor, was waiting for his ride, a business jet, and said Justin the FBO operator, was out flying and would return shortly.  Justin landed, looked over the plane, and said let’s put in hangar.  He had a large hangar available with lots of room for me to park plane and work.  Next was wheels, the airport courtesy car for $5/day.  I spent the next hour or more inspecting and formulating a repair plan.  Then into town to check for supplies and eventually got a room at Super 8 motel.  I wasn’t going to order a new canopy as I didn’t have tools, installation manual, and wasn’t going to take 2 weeks to get everything.  I’d rather patch, as long it was effective and safe, and take my time and install a new canopy properly at home base.  The back 1/3 of the canopy over baggage area was not damaged.  There was a jagged 14 inch strip missing from the back part of the main canopy.  If I could patch it and seal it, I figured (and turned out properly so), I could safely fly home.  I was just on the east edge of Rockies.  Remember, this is Experimental aircraft and I am the manufacturer, so no A&P required.


In town I checked out the Family Dollar store, and the only aircraft parts store, Ace Hardware.  I thought I would cut pieces of plastic from storage containers or trash cans and install with Pop rivets.  I then made a list of tools needed and what I could reasonably expect to borrow from Justin.  Damage was Sunday, about noon or bit after.  I went back and forth to airport 3X or 4X to look at damage, and design a repair plan, into about 9pm.  Tuesday I met Justin at airport and talked things over with him.  Turns out he had a roll of 20 inch wide thin but very strong steel (not aluminum) sheet metal that would work better than plastic.  One issue was metal was flat, but canopy is compound curve, almost part of an egg shape.  Putting a flat plate mated to compound curve would have gaps and buckles.  I would trim canopy Plexiglas and the metal to match closely with only about an inch or two to rivet to eliminate gaps and puckers.  Justin provided tools like a Dremel with cutting tool to clean up the damaged Plexiglas and made a more even hole, relieving stress at the sharp edges.  Also he had Clecos , pliers, snips, and other tools.  At Ace I bought a rivet hand tool, rivets, backing plates (washers), and minor items.  At Family Dollar I bought markers and replacement USB charging cord for my phone.  The suction from open hole during the drop sucked out a pen from my pocket, and at first I thought got my phone.  After the drop and when controlled, instead of suction, the hole let air in to act as a drag.  Turned out my phone was on the floor near my pedals.  It started on the right side on top of bags as I was texting Mary when on AP and checking Google map to be sure I was roughly following I-90.  I had the major road lines on the Dynon, but wanted to double check it was I-90 and not another freeway I was following.


Tuesday was a 14 hr work day, cutting the Plexiglass, cutting the metal, installing and removing the patch about 8X to measure and make adjustments.  I wanted patch on the inside as canopy is an airfoil that if intact pulls up.  It was very hard, mostly working from the limited space inside the cockpit, to cut and fit, drill, Cleco, remove, and do it again.  I missed by a bit and had to add another small patch on the pax side.  I had riveted from the inside as I figured I wanted the flat part of the rivet inside cockpit in case I hit my head on canopy.  The stub of the rivets sticking outside would reduce speed and climb performance, but might be safer.  The stubs aren’t very high anyway.  At the end of the day I was exhausted, sore, but happy to have it done.  All in all, I was happy with repair with just rivets, when Justin said I should Gorilla tape all along both inside and outside along edges of the patch.  Can’t hurt, and weight was minimal, so I did as he suggested.  Finished some time after 9 pm Monday.  Returned Tues am, Justin was scheduled to spray and I wanted fuel, had to clean up the mess, and wanted his blessing on the repair.  Turns out am winds were about 10 kts, not bad for flying but too much for spraying.  Justin provided a broom, shop vac, and blessed the repair.  I cleaned up, vac’d the plane, loaded, tested canopy latch, and went flying.  I figured if something wasn’t right I would go around and land, if all was OK, just continue.  Took off at about 9:30 am.  All was OK.  Mild winds over the Rockies and I was through at 12:30.  Rockies is about a 3 hr flight to cross.  Cascades are about an hour or less.  Depends on how often and how slow I have to slow down to maneuvering speed in case winds are a factor.  That’s true even when plane is undamaged.  Turns out the patch was fine.  Speeds seemed OK in level flight, but I had a hard time climbing above 7,000 MSL.  Maybe patch and rivets, maybe density altitude.  I crossed Rockies with max 7,500 ft and then Cascades at 6,700 ft. 


I could have netted the back baggage area.  Steve (other pilot who flies this plane) and I have talked about this.  There’s no hooks for this, but could be added.  But this is the 4th time crossing the Rockies, and I wasn’t even crossing yet.  Had there been a net, I doubt it would have prevented canopy breaking as nets have give.  It may have prevented battery from exiting plane, but then there’s a good chance it could have fallen back down and hit me in the head.  Maybe with enough force to knock me out???  Hindsight.  Really, even when loading, and during the flight east, and now west, I thought the light weight stuff might shift, and a 10# battery would be stable.  I did block it to prevent lateral movement, but not movement up.  Who’d a thunk it needed it??


Even commercial jets occasionally have severe turbulence that hurts people and causes damage.  It can happen to any aircraft, obviously at any altitude, without warning.  Winds were 8 to 13 kts with gusts about 6 kts higher.  Nothing severe or enough to land.  Winds can be 10+ kts at 6 am and at 9 pm, as I found out while in Big Timber.  I had used the AP about 70% of the trip east, and about 30% on the trip west.  The gusting winds weren’t severe, but enough that it upset the AP and a couple times, not anywhere near when this event happened, but a couple times, the AP suddenly announced “Auto Pilot disengaged.”  Then it was recover from a minor unusual attitude as each time the plane quickly entered a dive and rolled left; I had to react quickly.  From then on, I always kept a hand on controls even with AP engaged, except when it was calm and then I could take a drink of water or write something down.  Occasionally I would turn off AP and see how controls were, trimming for hands off flying, then engage AP again.  When this event happened I was hand flying.


Many thnx to Justin Ferguson of Yellowstone Air Service in Big Timber (6S0) for his help.  Could not have repaired without him.  Now ordering new canopy today.  And back to work so I can pay for this.


Jim McGauhey

President SnoFly Flying Club

President EAA Chapter 84

Snohomish, WA

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Comment by Gary Reed on August 7, 2019 at 8:18pm

Just a reminder, since you encountered such a severe negative G loading on the aircraft, please do a thorough structural inspection, including the engine mount.  Something might have got bent,twisted, or misaligned or mount and attachment bolts might have been stressed, especially in light of your performance issues after the incident.
Better to be safe than sorry.

Comment by Jonathan Fay on August 5, 2019 at 10:23am

Wow. This was crazy Jim. I am glad you are ok. I guess you will have something to report during the "Interesting flights" section of our next EAA meeting!


Comment by Jim McGauhey on August 2, 2019 at 6:58pm

Mack, I used a 18 amphr battery from Pacific Batteries; $90.  Harbor Freight 4 panel 100 watt solar charger, but I just brought 1 panel with me.  Battery went through the night and was recharged by 1 pm every day.  Plus it has USB sockets and comes with bright LED bulbs.  Can buy 1 panel, but those don't come with controller and connections, so for about $40 more I bought 4 panel kit.  Canopy is on the way.  Zenith treated me well.

Comment by Mack P. Kreizenbeck on August 2, 2019 at 2:46pm

Thanks for sharing. It opened my mind that a net is stretchable, so I'll act accordingly. You are to be commended on keeping your cool and flying the plane. 

Some questions: What kind of battery did you use for the CPAP and what was the solar panel? 

I have a ResMed and their recommended 90W DC converter that I've been able to get 4 days of service out of a 12V 170 cold cranking amps without recharging, but car batteries are heavy.

Good luck on your new canopy

Mack, the poor ol unemployed farm boy from Idaho 

Comment by Damon Brantley on August 2, 2019 at 11:23am

Definitely a scary experience and you handled it well.

When I get to the point of working on the fuselage of my plane I am going to invesgtiate installing some kind of tie down rings in the baggage area so I can secure everything down with a cargo net. Also some kind of tie down for items in the passenger seat.

Comment by Dave Gardea on August 2, 2019 at 9:06am

Glad you made it home safely. Thanks for sharing this story.

Comment by Joe Harrington on August 1, 2019 at 11:37pm

Wow, that was an incident that you will not want to repeat, I am sure. I was also flying through Montana on Sunday on my way back from Oshkosh. I was further north than you but the air was quite rowdy where I was (landed at Cutbank, MT before turning north to cross the border). I am quite careful to tie down all heavier baggage but your incident will have me being even more diligent in the future. Thank you for sharing your experience! BTW, good job of piloting and the making a field repair!

Comment by Daniel Niendorff on August 1, 2019 at 6:13pm
Incredible story. Thanks for such a detailed account. A lesson for us all.
Comment by Jimmy Young on August 1, 2019 at 6:13pm

I’m glad you came through this ok. I am going to secure everything in my plane that has enough mass to go through plexiglass or AL skin from now on. I’ve never experienced anything anywhere close to that, but reading your story is enough warning for me. Thanks for the post.

Comment by Zenith Aero on August 1, 2019 at 2:05pm

Wow! Thanks for sharing

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