Prop strike Sonex
11 min read

Life is full of little adventures and lessons learned. Early in 2016 I got another taste of both.

I have a homebuilt Sonex with a tailwheel, an AeroVee (WV conversion) engine, and a composite propeller. On March 1, 2016, I flew an hour from my home airport to Nantucket Island to attend a morning meeting. I would be flying home in the afternoon. The winds were forecast to top out at 14kts, decreasing as the day went on. With crossing runways at Nantucket, that was acceptable per my personal minimums.

When I got near the island and heard the ATIS, the winds were 14kts and gusting. The control tower told me the current winds were 14 gusting to 20. Yikes. I didn’t like that gust factor. But the winds were from 31 and I was landing on 33, so not bad.

I made a perfect wheel landing and rolled to the crossing runway 24, where I was told to take a left turn on the crossing runway to taxi to parking. The winds were now 70 degrees off my nose, and I was moving at a slow walking pace. Holding the stick to “climb into, and dive away from” the wind, I had the stick back and to the right, which puts the elevator up, and the right aileron up. That should have helped to keep the gear on the ground.

Prop strike Sonex

That happened fast…

The crosswind was causing the tailwheel to skid, but I was nearly to the parking area. Suddenly I heard a wind gust and the tail lifted into the air until “WHAP!” the prop struck the ground. It happened so quickly I barely had time for the event to even register in my brain. The airplane settled back on its tail and I called the tower to tell them I had a prop strike and was stopped on the runway.

The airport facilities people came out in their truck to help. One prop blade had broken off and departed the area. We found it about 200 ft. away in the grass. The other blade was still attached to the hub, but the tip was cracked through.

I pulled the airplane to the tie-downs so I could at least get to my morning meeting. I did not have my canopy cover with me so I knew I would need to put the plane in a hangar until I could get back to the island with my cover. The hangar cost was $50/day! Note to self: when traveling, carry a canopy cover. (The Sonex is a VFR aircraft, and its canopy is not water tight, so a cover is required to keep water out when it’s outdoors.) I filled out a quick report at the Fire/Rescue building and went on my way.

During the day I spoke with the folks at Sonex Aircraft to ask if a tear-down was in order. Since the engine did stop from the strike (even though it made at least a half revolution after the first blade struck), we both agreed that to be on the safe side I should have the crank inspected, or replace it. Either option would require tearing down the engine.

With that decision made I finished my meetings and took the ferry to the mainland, which is 2 hours from my home. My wife picked me up and I started looking at ferry schedules so I could return to the island in my car to retrieve the engine.

Testing the crank takes time and money, so replacing it was going to be the fastest and best way to proceed, at a cost of $350. As soon as I got home I ordered my parts: a new crank, main bearings, cam gear, prop (8-10 week lead time), spinner, and rear oil seal. Thankfully Sonex put a rush on the parts since it was costing a lot to keep the plane on the island

Ferry ride

A decidedly less efficient way to get to Nantucket.

The weekend after the event my friend Dave and I took my wife’s station wagon on the vehicle ferry to Nantucket ($280 round trip!) with all my tools and my home-made engine hoist (made of 2x4s and a 2×8 cross member with a light-weight chain hoist from Harbor Freight). Since the plane was already in a hangar we did the work there. We drained the oil, disconnected everything and put the engine in the car. Having removed the engine several times before, we had it off the engine mount and in the car in 90 minutes.

Now that I had my canopy cover we took the plane to the tie-downs, where the cost was only $10/day. As we did that I noticed the rudder was very close to the tail wheel. Upon further inspection I found that the titanium tail wheel rod was bent. The tailwheel and steering were usable, but the rod would need to be bent back into shape, or replaced. Since it was operable I decided I’d leave that until a future date.

We left the island and took the engine home. The next day I began to disassemble the engine, splitting the case to remove the crank. I found the forward woodruff key (connecting the prop hub and the crank) was sheared, and had scored both the end of the crank and the inside of the prop hub. So I ordered a new prop hub and bushings. Unfortunately, that meant more time to wait for parts. But it did prove as wise my earlier decision to buy a new crank.

Engine rebuild on Sonex

Pull it apart and put it back together.

In two evenings I had the engine apart and cleaned up, and by the end of the week I had the remainder of the parts. It took two evenings (a Sunday and Monday) to get the engine fully back together and ready to go. Since I had already booked the ferry for a Tuesday crossing, I really had to finish Monday night!

Once again my friend Dave Plathe was at my side to help. Nineteen years ago, before I was a pilot, Dave was flying right seat in the Cessna 172 that took my (future) wife and me out for a $100 hamburger to… Nantucket Island! Flying out and back for dinner made me feel like a rock star, so that night I decided I had to get my pilot’s license. Since I finished my Sonex three years ago, I have had to remove and disassemble my AeroVee engine a couple of times. Each time Dave was there to help me. He knows that engine almost as well as I do.

Tuesday at 6:30 in the morning Dave and I loaded the engine and tools into the car and headed for the ferry (another $280 round trip). It was a rainy morning and rather windy, which isn’t good for ferries. Sure enough, when we arrived we found the 9:15 am ferry had been cancelled due to high winds. So we booked ourselves on a standby basis for the 2:15 ferry. We had already planned to spend the night on Nantucket, so this would just mean a late start and working into the evening.

We spent the next 3 hours looking for things to do in Hyannis on Cape Cod, including walking the local mall for an early lunch, then going to the Cape Code Potato Chip factory for the self-guided tour of the plant. Very interesting, but it only killed a half hour.

Since standby status is first-come-first-served, we got in line with our car at 12:30. We slept in the car until the ferry began to load up at 2:00. After much tense waiting as the booked vehicles embarked, we finally got the go-ahead to get on (we were sweating it!). There were only 2 other vehicles behind us that got on.

The ferry ride takes just over 2 hours, so around 4:30 we arrived on the island. We checked into our hotel (another $175) and headed straight for the airport. We had packed bag lunches which now became our dinners. The airport staff got us into the hangar and we got to work.

Engine back on Sonex

Back on the Sonex and ready to go.

Getting the engine on the mounts only took 11 minutes. It took another 5-1/2 hours to get everything hooked up and secured. Since my new prop was weeks away I had borrowed an identical prop from another AeroVee Sonex. We cleaned up and left the hangar just after midnight, then headed back to the hotel.

In the morning we arrived at the hangar, added oil, did a final gapping of the valve rockers, and gave everything the once over. We opened the hangar door and did a run-up. The engine started right up and all the numbers looked good. The engine seemed to be in good shape, with no leaks.

The plan was for Dave to take the 11:30 return ferry and then drive the car home, and I would fly the plane off the island that afternoon as soon as the weather improved. Dave did take the ferry, but the weather never improved for me to fly. The weather for the next day looked like it was going to be good soon after sunrise, and so I got another room for the night. In the morning I took a cab to the airport, did another run-up, and taxied to a tie-down to wait for the good weather to arrive. But as the morning wore on the weather wasn’t improving. On the mainland everything was clear, but here there was a 600 ft. ceiling with mist.

I had to decide whether to continue to wait for the weather, which was supposed to improve at any moment, or to call it quits. There is a small commuter operation (Cape Air) that flies between the island and Boston, at a cost of $135. It was going to cost more than that to stay in a hotel, and I’d miss another day of work. So I decided to cut my losses and get out of there. I flew to Boston and had my wife pick me up, and was able to work a half day. By the time the weather broke on Nantucket (7 hours after forecast!) new storm clouds and a 30 kt wind blew across the mainland. I made the right call! It was Thursday, just 2 1/2 days since Dave and I had left to retrieve the plane.

Saturday looked like it was going to be a very nice day, so I arranged for one of my EAA chapter members to fly me to the island Saturday afternoon. I would have gone in the morning but I had my BFR (biennial flight review) scheduled in a Citabria, and I didn’t want to miss that! So I finished my BFR at noon, grabbed a quick lunch, then flew through clear skies to Nantucket in a C-182, arriving just before 2:00.

Tailwheel fix on Sonex

One last part to fix.

I fired up the AeroVee engine, did another run-up, and taxied out. I requested to remain in the pattern and make low passes so I could verify the engine at high and low power. Everything was in the green so I headed west, climbing to 4,500 ft. The most direct route is northwest toward Cape Cod. But that would take me over 23 miles of open water. So I opted to island hop, going from Nantucket, over two small islands to the west, then over the big island of Martha’s Vineyard, just 6 miles further. After the Vineyard it was another 3 miles or so across open water to the mainland, where I was able to make a bee line for home.

1.4 hours of flight time later, and 18 days since the prop strike, I arrived back to my home airport in Stow, MA (6B6). A week later I fixed the tailwheel.

The blessing of a VW engine is how easy it is to remove, repair and reinstall, not to mention the low cost of parts and ownership. Not including the prop, all my parts for this repair were about $1,000. The insurance agent couldn’t believe it. He said, “you can barely get a bag of screws for that price for a certified aircraft.” The insurance company paid for all the parts and the storage and travel costs, and even paid me $45/hour for my time repairing the engine. I do love amateur-built aviation!

I’ve flown my Sonex and the repaired engine for just over 80 hours now, and it’s running better than ever.

So what did I learn?

  1. A 20-knot quartering wind is beyond the capacity of my tailwheel Sonex to handle. If there is any chance of those kinds of winds in the future, I’ll stay home.
  2. If I inadvertently end up in conditions like this again I’ll simply shut down the engine while still facing into the wind, and pull the airplane to parking. It may be a bit ignominious, but it’s obviously better than the possible alternative.
  3. Winds and weather on an island are far less predictable than on the mainland, so you need to take any weather forecast with a grain of salt.

If I had that March day to do over again I would have stayed home. But for better or worse it became another of those adventures and lessons learned that make life, and flying, rich and interesting.

4 replies
  1. Michael Smith
    Michael Smith says:

    My regular ole hull and liability insurance paid for it, no questions asked. I pay $1,300/year for $35K of hull insurance. It would be less if I had tricycle gear.

  2. John
    John says:

    FWIW, I think insurance is a “must” item. I’ve seen some high risk maneuvers (engine cutting in/out and the pilot/owner/builder) streeettttcccchhhhhheeeeeedddddd the glide (with his wife in the right seat) because he didn’t want to bend his ‘baby’. Good insurance helps me (and I think other pilots) make good decisions. I carry 45K for $500 per year on my tricycle gear Cessna. I’ve only tapped it one time for $12K to fix a prop strike and wing tip in a prop strike (quartering tail wind in taxi) about 20 years ago. By my calculations I’ve got another five years on that FAA ‘incident’ before I’m paying the annual insurance bill with my own money and not that of my old insurance company.

  3. George "ED" King
    George "ED" King says:

    Good story but most of all, A good lesson. and the advantage of a homebuilt, in repair cost’s.

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