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Tragic loss

erich weaver

erich weaver

Well Known Member
Van Snow, a highly respected equine veterinarian and pilot from the Santa Ynez CA area lost his life this last Thursday flying his Harmon Rocket. Van was in Borrego Springs, practicing for an aerobatics competition. I have only second-hand information, but he is reported to have radioed in before the crash that he had lost elevator control. IZA has lost a good one.

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That airplane had been at Santa Paula a few times lately. He was taking aerobatic instruction from a guy that use to rent hangar space from me. I had a chance to talk to him and he seemed like a real likable guy.
 
"In a twist of fate, Stevens noted, it was Snow who sold the plane to John Denver in which the pop singer crashed in October 1997."
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Wow, that's a little creepy.

Condolences to anyone who knew him... I hope they can eventually determine the cause.
 
If someone who follows this accident more closely could post the NTSB report or link when available, I would be very interested to know what part of the control system that failed. Could be a safety item we may need to look into.

Glenn Wilkinson
 
According to the article in the Bakersfield Californian last Saturday, it said that he radioed a friend that his stick had broke. Paper said F 1 Rocket.
 
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mark manda said:
According to the article in the Bakersfield Californian last Saturday, it said that he radioed a friend that his stick had broke.
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That's scary just reading it. It makes me want to carry a wooden dowel with a tapered tip that I could jam down into the weldment for leverage. I wonder if a canopy breaker would have a tip that could jam in there?

Hmm... On second thought, in an emergency I suppose I could get my -6 under control by manipulating the passenger stick. I'll have to try that next time i'm up.
 
Snowflake said:
That's scary just reading it. It makes me want to carry a wooden dowel with a tapered tip that I could jam down into the weldment for leverage. I wonder if a canopy breaker would have a tip that could jam in there?

Hmm... On second thought, in an emergency I suppose I could get my -6 under control by manipulating the passenger stick. I'll have to try that next time i'm up.
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There has been some discussion in the forums about weakening the stick by drilling a hole to pass through the stick grip wiring.

The conclusion was that it's a bad thing to do near the pivot point. I don't know if this was the root cause, but the NTSB report will clarify it.

Vern
 
Stick wiring, elevator trim...

When I wired my PTT on the control stick, I made sure to use a small gauge wire and some heat shrink on both wires as it passed the bolt at the bottom. I did not drill any hole in the stick.

Does anyone know if he had electric elevator trim in the F1 Rocket? If the trim wires going down the stick, that could have also shorted and driven the trim tab to one end of travel, making pitch control impossible.

I put the elevator manual trim cable in my RV-9A just to avoid a trim servo runaway condition. It would also allow pitch control via the trim tab in the event of a bolt shearing or falling out of the linkages from the stick to the elevator.

I never considered flying the airplane using the passenger stick should the pilot control stick break off. That would not be possible in an RV-4 or RV-8. Of course with my RV-9A, I would not be doing any aerobatics at all to create those kind of stick pressures.

My condolences to the family. Let's be safe out there!
 
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n2prise said:
I never considered flying the airplane using the passenger stick should the pilot control stick break off. That would not be possible in an RV-4 or RV-8.
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I think I read where somebody had presence of mind in a tandem (I’m thinking RV-4) to reach back and try the passenger stick to land the plane when he lost up and down movement with his stick, and was able to land successfully. I wish I remembered more of the details.
 
n2prise said:
Does anyone know if he had electric elevator trim in the F1 Rocket? If the trim wires going down the stick, that could have also shorted and driven the trim tab to one end of travel, making pitch control impossible.

I put the elevator manual trim cable in my RV-9A just to avoid a trim servo runaway condition. It would also allow pitch control via the trim tab in the event of a bolt shearing or falling out of the linkages from the stick to the elevator.
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I have a "trim disable" switch in a red shield just above the joystick.
 
wrongway john said:
I think I read where somebody had presence of mind in a tandem (I?m thinking RV-4) to reach back and try the passenger stick to land the plane when he lost up and down movement with his stick, and was able to land successfully. I wish I remembered more of the details.
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It happened many years ago in an RV-4. Because of a construction error (rivets missing in the interconnect tube between the fwd and aft sticks and the tube pulled apart) the fwd stick became disconnected from the pitch control circuit but still worked in roll. Pilot was able to successfully land by reaching behind the seat and push aft on the rear stick to raise the AOA during approach and landing.
 
Thanks Scott for refreshing my memory. I looked everywhere trying to find the article I read that in, but came up short.

Man, if that happened to me I would be on Defcon 2! Of all the controls that could go out, the up and down is the one scares me the most.
 
CONTROL FAILURE

Having survived an elevator control failure in a homebuilt airplane some 47 years ago, this subject is of great interest to me.
A much more frquent problem is control blockage. The tech inspectors at aerobatic contests are usually very diligent about inspection for foreign objects loose in the airplane, especially the aft fuselage. In all the Pitts aircraft, a small screw can get trapped near the elevator horn and restrict or block elevator control. When was the last time you checked the aft fuselage for foreign objects???
Runaway electric trim: I do not believe that either full up or down elevator trim should cause a loss of control. If runaway trim is an issue in any of the RV's, then an emergency disconnect switch should be provided, preferably on the stick.
In the early days of the Red Devils Aerobatic Team(Eagles), mechanics from the EAA Museum were doing much of the maintenence on the Team Pitts's. One of the mechanics ran a 1/16" cable from the bottom of the stick to the top of the elevator horn. Ty wrapped and taped in place. So if any part of the elevator system aft of the stick failed you would have up elevator available. This setup would have saved Shaun Tuckers airplane a few years ago when he had a elevator rod end bearing fail.
Since my incident in 1964, I have frequently practiced flying a wide variety of airplanes with pitch trim and rudder only. I have practiced landing approaches as low as two feet off the ground.
Control stick failure: This has happened on at least one Pitts. The airplane was landed sucessfully. Prevention is the only viable option here, don't drill holes in your control stick, AND DON'T CHROME PLATE IT.
Finally a war story: Most Cassutt racers do not have pitch trim. Tom Cassutt was flying Cassutt #1 in the vicinity of Pittsburg, PA when he lost elevator control. There was at least one runway complete at Pittsburg but the airport was not open. After some testing at altitude, he landed sucessfully by shifting his weight in the cockpit. No damage to airplane.
None of the above should be interpreted as speculation about the Borrego accident.
 
One of my A&P mechanic instructors back in school used to fly banner towing out of Long Beach. I can't remember for sure, but I believe it was a Citabria or the like. In banner towing, they approach low, hook the tow line, and then go into a steep (near vertical) climb to 'peel' the banner up so it doesn't tear. He had just hooked the banner and pulled vertical (probably 100' off the deck) when he felt a pop and the stick came all the way back and elevator control was lost. He was able to trim the thing out of the climb, go out over the harbor for a while and practice, then return for a safe landing.

My condolences to the family of the lost pilot. At least he went doing something he loved.
 
PITCH TRIM

One of the big factors is what kind of a pitch trim you have. The Citabria is a lever that allows immediate full trim. The Pipers with a hand crank which usually slips would be a problem.
 
As part of phase I testing it is recommended you explore flying the aircraft at trim extremes. I did this in my 9A to determine if the airplane was flyable at full up and down trim to simulate a runaway trim condition. The airplane WAS flyable although I had to slow WAY down to keep the stick forces managable. I assume other RV models are similar, actually the RV9 has a larger HS, elevator and trim tab so it could be the 9 would be most difficult of the models to control at extreme trim settings. Also, regarding a disconnect switch for the electric trim system; from a typical neutral trim position to max up or down only takes a few seconds and I seriously doubt if I could detect the runaway condition and have the presence of mind to kill the power before the trim reached maximum. Of course once at maximum, killing the power wont help. I really think it's a good idea to experiment flying our airplanes at trim extremes to make sure we can handle the situation. I'm pretty sure all of the RV models can be flown at maximum trim settings but you need to verify that for yourself.
 
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Recovery practice

After hearing about this accident, later that day I decided to go out and practice power/pitch trim/rudder control only.

I used a Rans S-7 Courier which has a low landing speed. Started with a recovery with trim and rudder only from unusual attitude, then stabilized level flight, then set up a descent and a long final into a local low-use airport. Using rudder to correct both direction and roll is a bit of work, and there was a lot of lag in pitch response to the trim at low airspeed. I was able to use large power changes to arrest/dampen the phugoid resulting from a pitch trim change.

Anyway, the approach was stable enough that I was able to touch down into a wheel landing (while covering the stick of course) and come to a stop. Rollout was quite extended because it takes a long time to wind electric trim up and down to put the tail where it needed to be. I think it would have been much easier with manual trim.

I'm seriously thinking this should be part of my own personal checkout in any airplane (perhaps not to landing) - and knowing whether you can reach back or across to use a passenger stick seems like good advice.

Oh and P.S. if you are (un)lucky enough to have the stick freeze in a relatively pitch neutral position, don't forget that reverse trim can be used to affect pitch attitude.
 
As a Technical Inspector at our IAC competition in KLBT this coming weekend, I am planning to visually inspect all control sticks. Unfortunatelly, without proper NDT inspection, I will not be able to see beyond the welds and paint. Any cracks will have to be obvious.

In my aerobatic ride, we had a SB issued in regards to the stick thickness. http://www.aviataircraft.com/pix/pbulletins/sb23.pdf which became an AD 96-10-12. I know this does not apply to Vans. However, the building practices still doess and might help you guys to inspect your control sticks as well if you incorporate in your next condition inspection.

Still sad for the loss....I wonder why he didnt Bail Out?...He was wearing a parachute!
 
Last weekend I visited a shop where an F1 Rocket was under construction. The control sticks (front and back) were laying on a work bench, powder coated with handles installed. I picked one up to take a closer look and was surprised to see they were made out of aluminum tubing rather than steel like RVs. All the flight and control surfaces on the F1 are beefed up substantially to handle the extra horsepower and performance so having lightweight aluminum contol sticks was really surprising. I have no idea whether this is standard or had anything to do with the tragic accident of N28VS, just an observation I made.
 
Bob,

I didn't measure the tubes but I think they were 1" and the wall thickness seemed about normal, nothing very beefy. The arrangement was the same as an RV where the stick fits into a receptical near the base where the pivoting occurs and the receptical was steel, just the sticks were aluminum with a slight gentle bend. Perhaps someone more familiar with F1's could comment.
 
At least 1 RV-4 has been landed by a quick thinking pilot who lost elevator control and landed by reaching behind and using the aft stick to control pitch.

In this case the front stick did not break but became disconnected.
 
Read this:

Several years ago, a friend asked an acro pilot to put his -4 through the paces while he watched it do rolls, loops and such, from the ground.

After landing, the pilot was standing beside the airplane, peering into the rear cockpit and froze! There were no rivets holding the threaded aluminum cone with the ball end to the pushrod:eek: back to the elevator...only friction kept it in place....yep...Providence.

Be very careful,
 
pierre smith said:
Several years ago, a friend asked an acro pilot to put his -4 through the paces while he watched it do rolls, loops and such, from the ground.

After landing, the pilot was standing beside the airplane, peering into the rear cockpit and froze! There were no rivets holding the threaded aluminum cone with the ball end to the pushrod:eek: back to the elevator...only friction kept it in place....yep...Providence.

Be very careful,
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Scary indeed! All the more reason to have as many folks as possible look at your airplane before you commit aviation.
 
How 'bout part numbers, Mitch..

mv031161 said:
As a Technical Inspector at our IAC competition in KLBT this coming weekend, I am planning to visually inspect all control sticks.

Still sad for the loss....I wonder why he didnt Bail Out?...He was wearing a parachute!
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....since Sean Tucker had a ball-end break in half in his elevator pull-rod? As you know, on the Pitts/Christen Eagle, the pullrod is above the elevator hinge line and pulls during snap type maneuvers. The NTSB report I read, said that some ball-ends didn't meet spec. It'd be great to find out which part numbers they were, so no more Tucker type bailouts.

Best,
 
F1 control stick material

647jc said:
Bob,

I didn't measure the tubes but I think they were 1" and the wall thickness seemed about normal, nothing very beefy. The arrangement was the same as an RV where the stick fits into a receptical near the base where the pivoting occurs and the receptical was steel, just the sticks were aluminum with a slight gentle bend. Perhaps someone more familiar with F1's could comment.
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The sticks are made from 7/8 x .049 wall 6061T6 tubing. I use a 2' extension to form 'em around a die; the material is very stout. Forming those parts wears me out pretty quickly. The lower pivot is made from 1" x .058 wall 4130 - also a very tough part.

Before you start in with the advantages of 4130 (the RVs use 1" x .035 wall to the best of my knowledge - user comments welcome), best you make yourself aware of the stick failures in the welded assemblies -- there are quite a few, ranging from bad welds to simple cyclic overloads.

The Sport wing ships have about 6lbs/G stick forces. So, max G takes about a 36lb pull on the stick -- not very much. I will suggest that the stick will last forever with this being the case, even with a wiring hole just above the socket.

Something else is involved in this crash -- my feeling is that the broken stick is a symptom, not a cause.

Test sequence for any of you to perform: put your ship in a 20-30 deg dive (from a reasonable altitude, please), leaving the trim set as it was in level flight: just push over using the stick. Your ship should start to pitch up (hands off) after accelerating ~20MPH or so. The ship should not descend much more than 500' before it recovers on it's own. Obviously, this ship did not do that, and the question is why.

My ship is an Evo, with a completely different foil, so I cannot perform this test: the Evo foil has just enough pitching moment in its foil to allow a very wide trim band (pitch neutral), whereas the 23013.5 on the RV4/6/7/8 & Sport wing F1s have a more positive pitch response, forcing the nose up due to it's much narrower trim band. Neither trait is better then the other, unless you prefer, or do not prefer, a ship that needs less trimming in its normal speed ranges. You can read Doug Rozendaal's F1 flight report on the Team Rocket website for a description of how this feels to the pilot.

The NTSB will have a look at the wreckage this week -- I talked to the inspector last week, and he knows his stuff. We'll have a better picture soon enough, so please stand by.

Carry on!
Mark
 
?Before you start in with the advantages of 4130 (the RVs use 1" x .035 wall to the best of my knowledge - user comments welcome), best you make yourself aware of the stick failures in the welded assemblies -- there are quite a few, ranging from bad welds to simple cyclic overloads?

Hay Mark, make your self more clear please!!! I have never heard of an RV stick failure. I build those sticks. Are you saying my welds are bad? You must be talking about the GA fleet having failures not RV?s, right???
 
DOH! insert foot...

Russ McCutcheon said:
?Before you start in with the advantages of 4130 (the RVs use 1" x .035 wall to the best of my knowledge - user comments welcome), best you make yourself aware of the stick failures in the welded assemblies -- there are quite a few, ranging from bad welds to simple cyclic overloads?

Hay Mark, make your self more clear please!!! I have never heard of an RV stick failure. I build those sticks. Are you saying my welds are bad? You must be talking about the GA fleet having failures not RV?s, right???
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Hey Russ:

Lemme see if the other foot will fit....

Not referring to any of your work, that's for sure. The RV series have very light elev forces, so the chances of a stick failure are remote. Indeed, I have heard of none, tho other control system SNAFUs have popped up. As an example of other stick 'problems', look at the SB for the sticks mentioned further up in this thread.

Can you confirm the stick tubing size for me?

Carry on!
Mark
 
pierre smith said:
....since Sean Tucker had a ball-end break in half in his elevator pull-rod? As you know, on the Pitts/Christen Eagle, the pullrod is above the elevator hinge line and pulls during snap type maneuvers. The NTSB report I read, said that some ball-ends didn't meet spec. It'd be great to find out which part numbers they were, so no more Tucker type bailouts.

Best,
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It does pull in snap type manuevers, HOWEVER, no one has failed on a certified or factory built aircraft. Only has failed on experimentals Pitts or any versions of them...

Bailing out is an option I like to have with me at all time...That's why I always wear a chute.

In regards to the SB I listed, the source of the crack developed from a unauthorized drilled hole.... For every action there is a reaction and we as owner/pilot/operators need to be aware of our great ideas are not always the best.
 
No problem Mark,

I figured you where talking about something else but just wanted it to be more clear.

Yes the RV?s use 1? .035? 4130 for the sticks.

I also wondered how the aircraft would not have recovered from a 30 degree (upright??) down line from 3500 feet on its own. Maybe the roll trim was off so it was turning as it descended, or the linkage was jammed, (might explain a broken stick)? Maybe we will know some day.
 
ROD END BEARING

Shaun Tuckers failure was a poor quality rod end bearing that got mixed in with some of the good bearings, apparently by the vendor. The safe bet for an aerobatic airplane is Fafner bearings. There were some failures on early Pitts control sticks. The S1 is 7/8 x .049 and I believe the S2B is 7/8 x .058.
 
Sean Tucker

Sean's failure happened on takeoff at Coushatta, LA on an intended practice flight. He was able to fly the airplane with trim long enough to burn off most of the fuel. I think with a stock Pitts he could have landed with just the trim, but Seans airplanes are optimized for tumbling maneuvers and probably much more difficult to fly with just trim than a stock Pitts.
 
OT:

Russ,

Thanks for all the work you do on RV weldments....I know some of these are not easy to make.

Mine were great that I received in my kits!!!

Russ McCutcheon said:
?Before you start in with the advantages of 4130 (the RVs use 1" x .035 wall to the best of my knowledge - user comments welcome), best you make yourself aware of the stick failures in the welded assemblies -- there are quite a few, ranging from bad welds to simple cyclic overloads?

Hay Mark, make your self more clear please!!! I have never heard of an RV stick failure. I build those sticks. Are you saying my welds are bad? You must be talking about the GA fleet having failures not RV?s, right???
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Others still commenting on the RV-4 control stick failure (builder mistake, not design flaw), can read about it in the RVator , sixth issue, 2007, page 13 (finally found it!). It was a reprint from an earlier RVator that many felt needed to be told again. One of the most horrifying stories I’ve ever read, but what a cool thinking pilot to reach in the back to control the up and down with that stick, while using his front control stick to still control the ailerons. The mechanic that was flying it was asked by the pilot to check it out for carb problems. So he did several pull ups and snap rolls, after which coming out of one of those, he discovered he had no more pitch, but landed successfully by keeping his cool wits.

I like this man’s suggestion earlier, and think I want to do something similar on my 4 for peace of mind.

jrs14855 said:
In the early days of the Red Devils Aerobatic Team(Eagles), mechanics from the EAA Museum were doing much of the maintenence on the Team Pitts's. One of the mechanics ran a 1/16" cable from the bottom of the stick to the top of the elevator horn. Ty wrapped and taped in place. So if any part of the elevator system aft of the stick failed you would have up elevator available. This setup would have saved Shaun Tuckers airplane a few years ago when he had a elevator rod end bearing fail.
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