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Deep Stall in a modified 4-place Cozy
CG error nearly kills pilot
From CP87, Page 3 (January 1997)

The following was posted on the Internet by Jeff Russell at the request of writer Pat Young. The mistakes admitted by the builder here are not limited to any single aircraft type, and should be of concern to all pilots. RAF is reprinting this story in hopes that it will prevent a similar accident in the future. Knowledge Is everything.

by Pat Young

     I would like to write about an accident in my homebuilt airplane. I know its been awhile since it happened (October 4, 1996) but it has been hard for me to come to grips with it and put down in writing just what took place.
     It has come to my attention that quite a few inaccuracies have been published and circulated and I feel that I should speak up on the matter. I can't believe that there are those that would use someone else's tragedy to benefit by distorting the facts in such a manner to deface and discredit others. I see no reason that anyone else should suffer due to mistakes made by myself.
     I would like to first describe the plane that took just over 3 years of dedicated effort to complete. The fuselage was built by myself, and other than widening the backseat by four inches, it was built to plans. The canard was built to plans. I had installed the canopy to open forward ala Cozy Classic and used a Q-200 1/4" thick glass to fit my requirements. When I built the nose I exercised my option to omit the ballast compartment due to previous nose heavy tendencies in my Cozy three-place. This was a wrong assumption on my part as the four-place is somewhat heavier in the tail. I customized the instrument panel to resemble the Glassair which seems to accept a few more switches and knobs. I designed the turtle back to contour from the canopy to the Velocity type cowlings I purchased from the AeroCanard. I also used the pre-molded strakes and main gear from AeroCad's AeroCanard. These units were superb and all worked very well. The engine was an 0-360 Lycoming with the after market fuel injection mounted on a Weldtech mount. Another superb piece of work, if you know welding.

     I had been test flying the airplane for 17 hours prior to the accident, doing the normal flight test maneuvers: stalls, speed envelope expansion, C.G. range expansion, etc. with no adverse tendencies. One thing I was concerned over during flight was some instability in the pitch characteristics. The elevator was between 34 degrees down in cruise which fooled me into thinking I had plenty of weight in the nose. I actually believed that the canard incidence was not correct and could stand to be increased. After thorough investigation of the incidence and mounting templates, I concluded that I needed to increase the angle. The templates are very critical and very hard to distinguish such a small (.86 to I degree) angle.
     The day of the accident I had removed three vortilons that I believed were causing a yaw problem that I had been working on. After exhausting all other possibilities I decided they were the last possibility. Low and behold, after @g to the skies the yaw problem was corrected. Level flight and 160 kts indicated at 6500 MSL and ball in the middle. Yeaaaah! I was exhilarated.
     A person with good sense would have gone back and put the little vortilons back on straight before going any farther, but this is my second composite airplane and what about all those late-night epoxy fumes. Juuuust kidding.
     What I did next was a steep climb to 10,000+ feet which puts me at 6,000 feet AGL. Without leveling to stabilize I commenced an accelerated stall - lik. before the canard stalled and the nose came down to the horizon.
     At this point I pulled power off to go into an approach stall. Immediately the airspeed fell to the bottom of the curve and the nose pitched back up. It felt as if I was doing a reverse tailslide.
     All this happened at speeds of 58 to 60 mph. With the nose pointing at the sky about I- to 20 degrees, VSI indicating 3000 feet down I had established myself in a deep stall, NOT MY INTENT by any means.

     What I remember about the plummet was the initial stall and a very empty feeling in my stomach accompanied by terror. Trying to recover by full forward and aft stick netted about a 5-degree nose bob. Ailerons caused only yaw with no roff. The rudders were ineffective. Cycling power affected forward movement only slightly and the biggest change was to noise level. I believe that the prop was cavitating in the vacuum caused by the plane surface blocking an airflow. if you have ever heard an airplane prop cavitate its a sound you don't forget
     One other attempt that could have made, but don't recall - I had departed with my shoulder harness buckled. While in the stall I could have taken these off to throw a 25-pound shot bag in the nose. The shot bag was on the floor, copilot side, in case of a problem. When I was recovered only my lap belt was buckled. @ shot bag was wrapped around the right side rudder pedal.
     Luckily I don't recall the impact or much that followed. Fortunately I in a ravine sloping downhill. This was (text omitted here in CP article) looked to these people, and if they wondered if it was some alien. Thanks for coming over guys.

     I was able to piece together what happened when I got home from the hospital by looking at the wreckage in my hangar. I know that the major impact was absorbed by the main gear and propeller/engine. The main gear snapped in the middle and the engine mount was bent 12-15 degrees to the left, engine still hanging on with only bends in the tubes and slight tube stress cracks around the tip -left dynofocal mount. The propeller was in splinters. The main axles sheared off at the bolts and went flying but were recovered within 50 feet of the plane. Both gear mount studs were bent slightly along with all of the engine mount bolts both at the firewall and engine. No damage to gear and engine mount box on the airframe.
     After initial impact the plane then cartwheeled to the left from one winglet to the other smashing the tops and twisting and delaminating them from the wingtips. The right winglet was barely hanging on by the bottom skin and laying on the ground. Once on the right wing the nose came down on the canard tearing it out of the airframe shearing the mount tabs' at the bolt holes. The canard was laying on theground parallel to the nose of the airplane. The plane came to rest on its belly after th e canard departed and smashed down on the right side. of the nose.
     Other damage was to the instrument panel, collapsed left seat bottom, left armrest and center keel. The nose from the instrument panel forward was destroyed from the longerons down due to twisting and delamination but still somewhat intact
     There was much delamination on bottom of fuselage and around gear legs. Gear access panel was hanging on by three screws.
     Left intact was the canopy, strakes, main spar and most of the fuselage aft of the front seat. The top cowling was undamaged and the bottom cowling was scratched with some small holes from the alternator and starter. I ended up with a few broken ribs, punctured lung, fractured left ankle, (and) some scratches. Hey, I'm still here thanks to the Rutan design, and just crazy enough to try it again. But no stalls, please!
     This brings me to sum up what I believed caused this mess. First off when I weighed the plane I unknowingly had a 50-pound block in the front seal No big problem just subtract weight at its station and refigure empty e.g. This is what I did. I should have left it alone. I also subtracted the weight from total on gear in another calculation, and came up with a number that was much closer to example in the operational handbook. Since the weight of the plane was only 3lbs different than the example in the handbook I figured that the empty e.g. should also be close. Wrong choice. Very wrong by almost two inches, I know, I know, looking back you couldn't have convinced me with a 9 MM to my head.
     When I realized this, it was a little too late. It did help to explain the nose instability problem. All this time I had been flying around with my c.g. at the aft end of the envelope. I was still trying to explain the down-elevator situation, I think that the canard incidence being in error contributed, but did not cause the stall. If it had been the sole problem, I don't believe this could have happened. However, if the c.g. had been at 100? Oh well.
     After an extended steep climb and not leveling off, the fuel (25 gal) could have been at the aft of the tank causing an even more aggravated c.g. problem. All the baffles were in place according to plans.
     Last but not least, the missing vortilons probably contributed to the wing stalling when it had not before with them attached. It those little tabs out there can cause the entire plane to yaw when on a few degrees crooked, they certainly must be doing the job that they were meant to do when on straight I never doubted it Burt.
     So there is your deep stall in a nutshell. Well, maybe a big nut. I hope and pray that this never happens to anyone else. I hope that my experience can keep it from happening in some way, shape or form. Those gremlins are out there looking for us all at the most inopportune times. Even though I made some disastrous mistakes, at the time I had no idea. And I usually listen to all sides, look at all the angles.
     I would like to give my sincere thanks to all those who were concerned during this time. My special thanks to Jeff Ru&sefl of AeroCad for his concern and support during this period. I can not speak highly enough on the work and advancements he and his Dad Greg have made to this design. Besides that, their just "plane" great folk. To my wife Jeannine who has been the stronghold though it all. If It wasn't for her recovery efforts I don't know what I would have got back out of that ravine. She is still the best partner ever.
     So we are in the process of rebuilding the four-place canard. Maybe in a year or so we will once more take to the skies.

Happy Skies to you all,
Pat and Jeannine Young