Ground loop and aftermath

[Utah-Jay]

Huge thanks to 500AGL and John Meade for helping me find the correct lifting eye as FA Dodge calls them.

This is a GREAT community

[Tyler]

So very sorry to hear this. Hard to believe when just a few days ago I saw your first flight post. Glad to hear you can repair and get back at it.

[Bissetg]

To add to Marks comments.

It is gut wrenching for a builder to read of someone else’s demise because we all know what it took to get airborne in the first place.

My view is that we should do everything we can to stack the odds in our favour. I’ve said this stuff before but ….

Grass is way more forgiving than pavement (yes we call it tar seal).

The fundamental issue is keeping straight until you are stopped. Keep the wind on your nose, don’t do first flights in a X wind until you’ve really got the feel of the aircraft.

Do stop and gos not touch and gos.

This is a taildragger issue, not a Bearhawk issue.

Don’t think it won’t happen to you, it can happen to any one of us.

Sound training, currency, and good discipline are critical elements to a successful phase 1 completion. Go and see Jared and get him to beat you into shape!

[Battson]

Great comments Grant, I couldn't agree more.

[jaredyates]

My first takeaway is that I'm glad Luke shared about this situation so that we can learn from it. I think we can search for some lessons in this case above and beyond the usual plain old ground loop.

First, Luke is the third case that I know of where the builder hired someone for flying and that other person was responsible for substantial damage after a loss of directional control. Even when another person is experienced, it is still possible for them to get in over their head.

Second, with any flying and whenever possible, we should try to advance incrementally. For example, we taxi a lot before we takeoff. We take off before we land. In a takeoff, directional control starts out easy and it gets harder, landing is the opposite. In this particular case there were not strong winds, which is one of the many things that Luke did right. I don't know the specifics of this situation, but I would wonder what experience on the pedals the instructor had before attempting the landing. It would not have been prudent for the first time on the pedals to have been a landing, unless there was a second person in position to take over. I hope that wasn't the case here. Another big challenge when transitioning is memorizing the sight picture of a straight track along the runway. It would be very unlikely to establish this with only two takeoffs and landings as an observer. There is no time in type requirement for USA instructors in light singles, but there is a 5 hour requirement in twins. My advice in the past has included finding an experienced local tail wheel guru for support, but I think I might change that advice to qualify what type and recency of experience should be considered.

Third, I think that the multi-pilot phase 1 is a net safety gain, but crew coordination is not trivial. Those of us that do it for a living have a lot of training and regular upkeep to keep things going smoothly. In a multi-pilot situation, we always have the extra bandwidth of managing the resources. Luke had 5+ hours and dozens of landings in type. He was extremely solid directional control. He was the best equipped resource in the airplane for takeoff and landing operations. But it can be hard in the moment to make these calculations, especially for folks who haven't had the practice and experience to know that they need to manage this element.

[Luke68]

My instructor taxied for close to a mile that morning and did the takeoff which was about like my first takeoff with you and maybe should have been an
indication of things to come. the rest of the flight went smoothly even the landing was almost perfect and I was confident he had it under control until he didn’t.
I’m still angry with myself for having my feet on the floor when we landed, by the time I realized things were going wrong it was to to late, I don’t know if it would have made any difference but at least I would have
tried.
I realize now that there is a big difference between experience and proficiency

[Battson]

I have always found that two pairs of feet touching the pedals is a bad thing, in my limited experience with an instructor in the Bearhawk. It just results in the pedals losing all their feeling - which is the most important thing in my opinion - and the two pilots tend to interfere with each other and the pedals "lock up". I am always fast to ask the passenger / copilot to get their feet off the pedals when I am flying, in any stage of flight.

[rkennell]

Like the others, My heart breaks for you Luke. Thanks so much for sharing your experience. I am learning a lot from your sharing and the comments of Mark, Jared, Grant and others. Experience in type goes a long ways. I also remember setting at Flight Safety and getting CRM (Crew Resource Management) hammered into my head both in a single pilot and multi pilot situations. It seems like the role of instructor got switched in this incident. As an instructor, the decision as to when to intervene can be a difficult one and you may only have micro seconds to make that decision. It makes it even harder when the roles have not been clearly defined. I would not be to hard on yourself for being put in a very difficult position. It was the instructor's responsibility to know his limitations and to clearly communicate any change in roles.

Your comment about experience and proficiency is a wise one. I have experience in many different types aircraft but have a long ways to go to be proficient in tail wheel aircraft.

Thanks again for sharing.

[arborite]

Condolences to you after all that hard work. i’m sure you will get lots of helpful advice from experienced members on how to proceed. On a purely emotional level, though, You may enjoy watching the link below of another builder who had more than a few challenges. I found the video really inspiring in that he persevered through so many setbacks and continues to enjoy the journey even though it’s not done yet.

Remember we are builders first and pilots second. the joy of building is a huge part of the objective. Hope you can look past the damage and tackle that rebuild with the same energy you did the first time.

https://youtu.be/aKchDn9FXEU?si=MsWCB_KLEQ4oHf37

[Nev]

As Jared has already said, we are very lucky that Luke has shared this incident with us so we can all learn from it. There has been a lot of previous discussion on the forum regarding Loss of Directional Control on Ground incidents and how to best minimize them. Grant also gives excellent advice on learning to fly tailwheel aircraft. In this case it is easy to see that Luke has done everything possible to stack the odds in his favor.

Luke mentions that on his aircraft he had the original Aerodynamic Strut tubing.

It's worth taking a look at the Bearhawk Safety Notices HERE.

In Jan 2010 there was a Mandatory Engineering Change Notice issued HERE titled "Alternate shock strut design for resisting increased side loads during a ground loop on asphalt". That notice has a line through it, indicating (somewhat confusingly) that possibly it no longer applies, and possibly why Luke and others might still have original oleo tubing in place. However I think the intent was that it applied at the time it was issued. It's also important to note that Bob issued this change notice due to a number of previous oleo strut collapses on asphalt.

This notice appears to have been superseded by a June 2016 non-mandatory Engineering Notice HERE.

If I'm understanding correctly, then I gather the intent is that all of the aerodynamic profiled oleo tubing should have been replaced in accordance with the Jan 2010 notice, although it's not clear from the safety notice whether this still applies.

My point being that perhaps we should go a little easy on Lukes instructor - not to say he didn't contribute to the incident, but as Luke says in his original post :

Everything was a textbook landing until the roll out when in an instant we were sliding sideways

02F3577F-49F6-4B23-93AC-532D435E9117.jpg

[rkennell]

You are right Nev. It is not fair to make a judgement sitting in a desk chair with limited experience and knowledge of the incident. The statement about the instructor detracted from the main points I wanted to make:
1. I am very grateful for Luke sharing.
2. I am very thankful for the insights you, Mark, Jared and others share on this forum.
3. And to agree with Jared's point about CRM and the importance of coordination and communication in the cockpit.
Even at 72 there are still many things to learn and building this Bearhawk project has given me many opportunities to learn. The people on this forum have been an invaluable resource. Thanks.

[alaskabearhawk]

I've been following this thread with great interest as "the day" is creeping closer. First, Luke, I'm sorry that this happened to you and your BH...really sorry. I think I have an idea of how much work you put into such a nice airplane and it can't be easy. The good news is that it sounds like the repairs won't be akin to recreating your airplane. The instructor that was flying feels terrible too I'm sure. There are so many moving parts in the first few hours of flight testing and so many things to consider.

I appreciate very much you sharing about this mishap. It really brings home the point that once the airframe is finished there is a lot of training to be accomplished before that first flight. I also really appreciate everyone that has provided information in this forum. It is so helpful in so many ways. "As iron sharpens iron, so one man sharpens another."

[kestrel]

My point being that perhaps we should go a little easy on Lukes instructor - not to say he didn't contribute to the incident, but as Luke says in his original post :

> Everything was a textbook landing until the roll out when in an instant we were sliding sideways

I'm also not passing judgement as I wasn't there. What I will say is that a properly functioning Bearhawk (like most taildraggers) won't instantly go from "fine" to sideways. A lack of proficiency will overwhelm senses and result in the perception that something suddenly happened, when in fact it had been progressing for "a while" but went unnoticed due to sensory overload.

I expect that either something failed or the CFI wasn't proficient, but there may be many things that I don't know that I don't know about the event.

[Battson]

I tend to agree, ground loops are not a sudden unavoidable event. There are plenty of warning signs.

I also think the strength of the shock struts is seldom the issue. The plane is already way out of control already by that point - often too far gone. I have done enough to know the aerofoil struts will withstand an scary-high level of side load. To bend one you really have to be out of control. Although I am aware that in some cases people believe they could have recovered the situation had the struts remained intact, but by that point all bets are off.

[kestrel]

Agreed on the airfoiled struts. I think it is a red herring and the damage would have been essentially the same with the round struts. The strut won't fail until after control is lost and significant damage is going to happen.

[Luke68]

I maybe should rephrase my original comment (emotions were a little high at that point), when I finally realized things were going wrong it only took a few seconds for us to be sideways and not completely sideways but the nose was definitely not pointing down the runway, but like you said I’m sure it was already well on its way by that time I just didn’t realize it partially due to not being at the controls and partially to my inexperience.
We didn’t measure the skid mark left by the right side tire but it is close to 200 feet and progressively gets darker until it left the pavement then skid another 20-30’ feet through the grass before the strut gave out so yes it took plenty of punishment. My reason for thinking the heavier strut might have saved it was the fact that we were not moving very fast at the end maybe 15-20 mph

[AZBearhawk272]

Luke,

My condolences, a difficult experience to resolve internally and more unplanned work dropped in your journey. Be not discouraged, the repair will progress quickly with a bit of focused effort.

I have had an event in a Bearhawk that is the doppelganger of your experience.
The comments by others are insightful, my point of view was from the cockpit.
Returning to the home field after a morning of bounces in the desert.
Paved runway, left crosswind 60 deg 14 kts.
Three point landing,
Then the sickening feeling of WTF.
It felt like the right wing was going down. ( NOT left wing coming up. )
Full left aileron, absolutely no effect.
Then the smell of burning rubber.
Sound of prop chewing asphalt.
Ground to a stop 3 feet left of the runway CL.

The nose always pointing straight down the runway.
There was no swerve, or yaw.

Takeaways.
Be hot wired for a Go Around, milliseconds matter.
Make sure the gear geometry is correct. Unweighted gear should not be canted excessively inward and under the airplane.
In X wind always make sure the upwind wheel touches first. Emphasize the wing low, the correction into the wind, always load the upwind wheel.
Absolutley no lateral drift allowed, that will load the downwind wheel. Which will want to tuck under toward the CL. And buckling of the streamlined strut.
Airplane CL axis straight down and parallel with the runway.
Upgrade to Round Shock Strut Tube.


Kevin D
#272
KCHD

[Mark Goldberg]

There are a lot of good comments / thoughts from all the guys posting. I just want to clarify Bob's thinking when he changed the shock strut design.

Most every structure has a designed in failure point. In this instance it is the shock struts/landing gear. If you keep a BH with S/L tube shock struts going straight down the runway - you should never have a problem. Bob's 4 place and Patrol have over 1,000 hours each. However, he saw how guys were swerving and putting side load or compression on the shock struts which the streamline tubing does not handle as well as a round tube. So he changed the design to a tube that can handle more side load/compression.

HOWEVER, this is not without some potential negative results. It is way better to replace L/G and shock struts than have significant fuselage damage which requires replacing damaged fuselage tubing and perhaps a recover with fabric. Much more expensive repairs.

I know of some cases where Bearhawks with the s/l tubing shock struts landed in UGLY/ROUGH places. Sometimes on purpose and sometimes due to engine failures. If the pilots keep the plane going straight, the shock struts hold up pretty dam well. So there is somewhat of a fine line between situations where the stronger (in compression) shock struts might prevent a collapse. But if it really gets out of hand the round tube struts will not save the day and may potentially result in fuselage damage which might not occur with the original shock struts.

Like everything - it is a compromise. Mark

[unixxx]

Thanks for that explanation Mark

[OhioLSA]

I'm sorry for Luke to have to experience this. Hopefully you can move beyond the darkness of the event, and begin to brighten up about making the repairs and getting a fresh start. Thank you for posting, and many thanks to all who have contributed advice. This inspires me to want to get very serious about getting all the training and experience I can get before it's time for my plane to fly.

[Bcone1381]

by Theodore Roosevelt,

It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better.

The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again, because there is no effort without error and shortcoming; but who does actually strive to do the deeds; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of high achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid souls who neither know victory nor defeat. Shame on the man of cultivated taste who lets refinement to develop in to fastidiousness that unfits him for doing the rough work of a work day world

[fairchild1934]

those lifting eyes are a GREAT idea. I have seen pictures of planes that have had off airport emergency landings where the people attempting to recover
the plane do more damage than the landing did. sometimes even totaling an otherwise repairable airframe.
Would it be good to move the two up front a few inches forward and all a third over that baggage area--- so it would be a 3 point lift ?
Of coarse--- you may want to use the eyes in the hanger for tire changes and other routine chores. would a 3-rd eye help or hurt overall ?
(hope your damage is mostly confined to the gear----)

[kestrel]

A third point on the engine/engine mount would be another option that wouldn't apply bending loads to the spar. Extending forward of the spar will bend it unless somehow supported.

[Luke68]

In my situation the two on the main spar bolts worked fine you just have to get your cg to match up with the lifting eyes.
I watched a you tube video of Rob from Alaska putting his on floats and he has four lifting eyes one on each spar bolt which looked like it worked great. You definitely need to build a spreader bar regardless of how you do it.