Safety Publications/Articles

CFI Tips

First things first

Getting the seat height right

One simple but often-overlooked consideration in primary flight instruction involves proper seat height. After witnessing some students attempt to fly the airplane from the "low rider" position, I am convinced improper seat height is responsible for a number of landing difficulties and erratic learning curves. Most brand-new students need a little initial help adjusting the seat forward and aft, but the topic of seat height might never arise until specific landing problems or inconsistencies develop.

Since the human factors experts tell us that 80 percent of the learning process is visual, it makes sense to invest a few training minutes in discussion of how to properly see from the cockpit - and that means you need to talk about how to sit in the airplane.

Why is seat height important? The short answer is more accurate: pitch control. You might think that so long as students can see out the windscreen, sitting height isn't a big deal. Consider this - the absolute key to consistency in landing and through the pattern is being able to set proper pitch attitudes, in conjunction with airspeed control. Therefore, a consistent sitting height along with instruction about the proper outside references is crucial. If you aren't talking about the proper pitch attitudes for rotation, VX, VY, and the landing attitude, your student's training will certainly suffer delays and possibly regression.

Purists will note that when power is constant, pitch determines airspeed and therefore on-speed takeoffs and landings. A good demo really pays off when teaching these benchmark pitch attitudes. Take the time to show a student where the horizon is supposed to meet the windscreen and glareshield. Then teach her how to consistently duplicate these references. Likewise, when you use the time-honored chalkboard drawing of the glareshield and the horizon you are assuming that the student is seeing approximately the same attitudes at approximately the same airspeeds for a given trainer make and model, but that is only true if he or she sits in the same seat position (height) each time. Experienced pilots and instructors are usually so sensitive to disruptions to normal pitch cues that a bad seat position is cause for an immediate search for seat cushions or even an aircraft change. Unfortunately, students simply may not be aware of the differences between seat positions in different aircraft.

With heavy use by many different people, a trainer's cushions break down, seat brackets weaken, and the seat in one Cessna Skyhawk or Piper Cherokee can be quite different than the one in a sister ship the next spot over.

So how do you teach the student to "assume the position" correctly each time?

The best method to get the same sight picture on each flight is to initially adjust height from the top of the cabin and then fine-tune as required. First, teach the pilot how to get the proper fore/aft distance from the rudder pedals, i.e., knees slightly bent with balls of feet on the bottom of the pedals. I periodically check to see that students are not placing their entire size 12s on the rudder pedals. Unless you are watching, you might not realize the mistake until your student tries to use full rudder and inadvertently hits the brake on a crosswind landing.

Next, help the student set the correct seat height required to view the proper outside horizon pitch reference. Have her check the space between the top of her head and the roof of the cabin. To remember this reference, place a flat palm, a fist, or a specific number of closed or spread fingers between the top of the head and the roof of the cabin. If the aircraft doesn't have a roof or one you can reach, use some type of reference to the horizon. A fist or fingers on the glareshield sometimes works as well. Although some seats have good vertical adjustment mechanisms, it may be necessary to revert to additional seat cushions to get enough height for an intermediate position.

It's important to note that, unlike taildraggers, most tricycle-gear training aircraft (with properly inflated struts) are usually pretty close to a level cruise-flight pitch attitude while stationary in the chocks. The old rule of two-thirds sky with the horizon one-third of the way up the windscreen stills works well as a tool to teach level-flight pitch reference. Make sure that your student can describe what he should be seeing from the seat. When your lessons begin to concentrate more on takeoffs and landings, his ability to describe the roundout and flare in terms of changing pitch references will accelerate his feel for handling the aircraft correctly prior to touchdown. Likewise, short-field and soft-field takeoffs are much easier to teach if the student understands she needs to obtain a specific outside pitch reference.

Another tip involves aim point control. If a student is experiencing difficulty holding an aim point on final, pull out the trusty old grease pencil and mark a small but visible "x" in the center of the pilot-side windscreen. The mark can be used like a gunsight to aim the aircraft at a specific point on the runway. This can quickly help get rid of shifting aim-point problems.

Seat height problems often go unnoticed by both students and instructors. Although the usual tendency is toward incomplete flares with a lower-than-normal sitting height, minor problems can arise that aren't as apparent. Also, we are certainly more prone to seat adjustment errors when rushed or starting a new or more complex flight profile. Night, marginal VFR, or instrument meteorological conditions make it easier to overlook something as basic as starting out with the proper sitting height.

Whenever there is a poor horizon reference, pay extra attention to where you're sitting. I once flew a night currency ride with a 20,000-hour-plus instructor who was making fast, firm touchdowns very uncharacteristic of his usual excellence. Near the end of the ride he announced, "I am just sitting too low!" Sure enough, the airplane's previous pilot had adjusted the seat lower than normal. The darkness made this simple oversight hard to detect, and after all, there isn't a checklist item for seat adjustment.

The seat adjustment step is so simple that it seldom is addressed. It might not even be discussed at all unless a student asks questions. Nevertheless, it can sure throw your student off or embarrass you on a demo if you let it. One final thought - improper adjustment may not be the reason your student has suddenly developed problems in the flare. There could be any combination of other elements that can contribute to substandard landings, and landing regression sure can be a tricky problem to sort out. Proper seat position is, however, one of the easiest things to check and correct. In conventional aviation wisdom, it is good practice to identify and fix the simplest things first.

Dave Hensley is manager of standards and curriculum at Regional Airline Academy in DeLand, Florida. A former Air Force U-2 pilot, he is an aviation safety counselor, a Master CFI, and a Civil Air Patrol check pilot. He has 7,600 flight hours.

By Dave Hensley

Back to the Index of Instructor Reports