On the Record: Zenith CH 750—Tennessee

May 22, 2016

The sport pilot was conducting the airplane’s first test flight and had a passenger on board. After takeoff, he applied right rudder to maintain runway heading, but the airplane continued to the left. As he applied more right rudder, the severity of the turn increased. The airplane departed the left side of the runway and the airport property and struck trees and terrain before it came to rest. Postaccident examination of the wreckage revealed that the rudder was rigged backward, which would have resulted in a left turn upon right pedal application and vice versa.

NTSB Final Report

NTSB Docket

FAA
Ron Wanttaja
Ron Wanttaja
Ron Wanttaja is a retired space systems engineer. During a 40-year career, he helped design, build, test, launch, and operate 18 spacecraft, including the International Space Station. On the aviation side, he has owned a Bowers Fly Baby since 1996 and flew the original prototype for seven years before acquiring his own. He lives just outside of Portland, Oregon, with his wife, romance novelist Lisa McAllister.

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Dan Marotta
Dan Marotta
19 days ago

…A thorough preflight, especially before the first flight!

airguy
airguy
Reply to  Dan Marotta
19 days ago

And a passenger on the first test flight?!?

Ron Wanttaja
Reply to  airguy
19 days ago

Well…the rules say no one but required flight crew. The FAA doesn’t not totally prohibit a second person onboard, but they have to have a definite function.

We had a very experienced homebuilt pilot in our chapter who had built a T-18 and often made first flights for builders. He’d station the builder in the right seat to monitor the engine and gauges while he flew the aircraft. A reasonable split of functions, I think, and probably within the letter of the FAA requirements. Whether a passing FSDO inspector would have thought the same, well….

There was one case where he was making the first flight with the builder aboard and the engine quit…fortunately, with plenty of altitude. He let the builder fiddle with the engine while he set up for the forced landing (at the airport they’d taken off from). All came out OK.

Dan Marotta
Dan Marotta
Reply to  Ron Wanttaja
18 days ago

Yup. The owner of the build assist program where I built my gyro insisted on all first flights. I went along, in the pilot’s seat, to record temperatures, pressures, etc. Then he got out and I completed the 40 hour Phase I test flying before flying home from TX to NM.

Tom Waarne
Tom Waarne
19 days ago

Reversed controls can happen to anyone when assembly/disassembly is required. A second set of eyes is not a guarantee of correctness but as close as you can get for most lighter aircraft.

Ron Wanttaja
Reply to  Tom Waarne
19 days ago

Best story I heard concerns the two Thurston Seafires built by Dave Woodcock and Bob Hammer. Very complex aircraft; four-seat amphibians with retractable gear, constant speed props. Took them a decade to build the two, side-by-side. EAA chapter members regularly came out to view the production. As the first flight day neared, that attention was even more intense. The FAA DAR came by, took hours to examine the builds, and signed off.

Finally, the day of the first flight came by. Woodcock taxied to the runup pad. He’d always used the CIGAR acronym for his final check. “Controls free and correct….” he moved the stick to the side, watching the ailerons.

Hey, wait a minute….

He stared at the wing in disbelief.  After a moment, he taxied back to the ramp, shut down the engine, and popped open the door.

“What’s wrong?” asked Hammer.

“Either I’m crazy,” said Woodcock, “Or these ailerons are reversed!”

Woodcock wasn’t crazy. Dozens of homebuilders, three EAA Tech Counselors, the DAR, and Woodcock and Hammer themselves (both having built previous airplanes, including an original-design jet) had missed it.

They pulled out the plans to see where they’d gone wrong.

The point was…they hadn’t. The plane was built totally per the plans.

The airplane had been designed for a yoke, and the two had asked the designer to give a modification for joysticks, instead. He’d sent the plans for the modifications. They called the designer, he checked…and they were right. The modification plans were wrong.

It’s something ANY aircraft owner… production, plans-built, or kit-built homebuilt…has to keep in mind.

One thing to consider is that if the swap had been to the rudder (like this Zenith) instead of the aileron, Woodcock probably wouldn’t have caught it. Most Cessnas have a nice rear window, but few other planes do. I’m happy to fly an open-cockpit plane that lets me strain my neck around and watch the rudder jiggle.

Yes, the Zenith builder should have caught the problem. But it’s an easy one to miss. the odd chain of responsibility for the aircraft made it even worse.

Last edited 19 days ago by Ron Wanttaja
Dan Marotta
Dan Marotta
Reply to  Ron Wanttaja
18 days ago

My Cessna 180K is kept in my locked hangar so, before most takeoffs, I simply verify “Controls – Free and Clear”. During preflight, it’s readily apparent that the controls are connected to the yoke.

But after any work done on the airplane, especially Annual Inspection, I verify VISUALLY, that the left aileron goes up when the wheel is moved left AND that the right aileron goes down at the same time. Then I look at the other wing and do the same test.

I also verify the same for the elevators and stabilizer trim. I can’t see the rudder from the cockpit but I’m quick to abort any takeoff where yaw makes me uncomfortable.

Greg A Kulosa
Greg A Kulosa
Reply to  Dan Marotta
18 days ago

It’s easy to lift the nose (assuming nosegear) off the ground, and push on a pedal, and ensure that the rudder goes the correct direction. (and that the nose wheel turns the other way for that matter).

This is something that you verify BEFORE that final “controls free & clear” check before takeoff.

It shouldn’t matter that you can’t see the rudder from the cockpit. If it’s newly built, or just undergone maintenance, that’s the time to check it.

Shary
Shary
Reply to  Greg A Kulosa
18 days ago

I do both checking free and CORRECT per checklist at runup. But, I also check free and correct — by manipulating the control SURFACES and watching the yoke/pedals from outside the aircraft during the walkaround — EVERY FLIGHT

Shary
Shary
Reply to  Ron Wanttaja
18 days ago

Same thing happened with my plane — but it was the electric stab trim that was backwards. Mere switch of the wires was all that was needed (and change to the schematic.) Noticed during the build preflight — LONG before the 1st flight.

Joseph Robert Hopwood
Joseph Robert Hopwood
Reply to  Tom Waarne
18 days ago

While reverse assembly is possible. Take off with reversed is impossible with a proper preflight.

Tom Waarne
Tom Waarne
Reply to  Joseph Robert Hopwood
17 days ago

Sounds wonderfull, but it isn’t.

Joseph R Hopwood
Joseph R Hopwood
Reply to  Tom Waarne
17 days ago

Control check before takeoff is mandatory. And it actually saved my life once. I landed and taxi back. Before pulling on runway ran before takeoff check list and discovered ailerons only went one direction. Very puzzling since I had just landed and they were working. Taxi to hangar and discovered ailerons only piece of balsa wood used for stream lining had came loose and jammed ailerons in one direction. When checklist followed properly, impossible to take off with controls reversed. In this case since had not completed a test plan, he probably did have a checklist either.

Voyager
Voyager
18 days ago

The DAR who inspected this has some explaining to do also, unless the owner R&Red the rudder post inspection. This is one thing that should be pretty hard to miss.

Ron Wanttaja
Reply to  Voyager
18 days ago

The full NTSB report (link with the article above) has a few ambiguities. It notes that the builder completed the Condition Inspection about two months before the accident. It notes the DAR signoff, but doesn’t give the date. The owner had bought it partially assembled. Ideally, a logbook entry would be made for any work, but it’s possible the rudder was removed (for one reason or the other) after the DAR inspection.

Thought this bit was interesting…

Approximately 13 months prior to the accident flight, a maintenance facility had performed a considerable amount of construction and modification on the airplane, including “installation” of the rudder. After that, the pilot/owner decided that the work performed did not meet his liking or the kit specifications, and undid or modified the work performed by the maintenance facility. It could not be determined who performed the most recent work on the rudder and rudder control system prior to the accident flight.

There were a lot of cooks’ hands in this broth, with no obvious way to pin the error on anybody.

Last edited 18 days ago by Ron Wanttaja
Darrin
Darrin
Reply to  Voyager
17 days ago

There are a few DARS out there that seem to be only checking paperwork. I looked over an expermental that a DAR had signed off on and it was not airworthy. Took 3 guys and a weekends worth of work to get it ready for the first flight.

gregc
gregc
18 days ago

Checklist:

  • “Flight controls free and correct?”
Shary
Shary
Reply to  gregc
18 days ago

Yeahbut — watch people! Most get to that bullet and “stir the controls” but RARELY check for correctness. “Yeah, they’re free [and I mouth “and correct”]

Ron Wanttaja
Reply to  gregc
18 days ago

But can the pilot see the rudder from the cockpit of a CH-750 to verify the “correct” part?

Yes, that should have been done in the hangar before mounting up. But the normal CIGAR test at the runup pad won’t catch this problem.

Testing in the hangar shouldn’t be difficult, but it would require someone else to visually confirm proper motion. Personally, I’d set up a cell phone video pointed at the rudder while I loudly call out the rudder pedal being pressed.

Jerry Kemp
Jerry Kemp
18 days ago

A good reason to check the proper operation of all flight controls before every takeoff.

Lumpy
18 days ago

In a book about the history of the Travel Air company, I read that Clyde Cessna intentionally had the rudders rigged backwards whenever he flew check flights of new Travel Air airplanes. Apparently the pedal movement seemed more natural to him that way. Of course they were re-rigged in the conventional manner prior to delivery.