Safety Publications/Articles

Professionally Speaking

One simple test

Rigging mistakes happen

In July we lost two experienced test pilots and a very light jet prototype aircraft. The accident received much attention throughout the industry. The airplane had been in the shop for maintenance that involved disconnecting the aileron controls. To make a long story short, it appears that the controls were reconnected backwards. The airplane crashed on takeoff.

Controls aren't rigged wrong very often. My only personal experience was 30 years ago in a Piper Super Cub in which the trim operated backward. It was scary, but manageable in that small airplane.

Simulator tests indicate that pilots cannot control the airplane when ailerons operate backwards. That is true even when the pilots are warned in advance--they know that turning left will produce a right turn and vice versa. Still, they crash. Our instincts, experience, and training lead us to exaggerate the error by turning even harder in the wrong direction.

It seems that misrigging will occasionally happen. The resulting potential accident could be prevented by the manufacturer, the maintenance people, and the pilot. You, the CFI, can teach students one little test that could--if practiced religiously--put a stop to this.

This is an old technique that bears repeating. During the part of the checklist that says "Flight controls free and correct," add one test. Teach your students to grasp the controls with either hand, put their thumbs in the usual "thumbs-up" signal, and position the yoke or stick for a full right or left turn. Hold it and check the ailerons. The pilot's thumbs should be pointed in the direction of the "up" aileron. If not, a further check is justified and necessary.

Will it work on every airplane? Only if you can see the ailerons from the cockpit. In some jets you cannot. For the airplanes that most of us fly, however, it will indeed work every time.

It's a great idea to visually inspect the elevator or stabilator for proper movement, too, although it's often more difficult to see the tail from the cockpit. Perhaps you can reach the yoke from outside the cockpit, or enlist an outside observer.

If we could just get all pilots to practice this on every preflight checklist, it might save a life once in a long flying career, and that is a worthwhile goal.

I know some highly experienced pilots who say that you needn't do this test every time you fly, but only when the airplane has been in maintenance. I disagree. There is great value in following exactly the same routine on every flight. If you pick and choose the flights, you may well forget it on the one flight that matters.

Besides, most pilots fly rental aircraft. They don't even know when an airplane has been in the shop. Yes, they should know, but many do not check the logbook to find out.

Besides all that, this check is so simple and takes so little time that the question is not should I do it every time, but why not do it every time?

As a CFI, you teach many students who will--collectively--fly many thousand of hours. If just one of them encounters misrigging on one airplane on one flight, you will be glad you taught this simple test.

Ralph Hood, an aviation speaker and writer, has been flying since 1971 and has amassed more than 3,000 hours of flight time. He is a multiengine commercial pilot with an instrument rating. Visit his Web site.

By Ralph Hood

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