Saturday, July 10, 2010

Jacobson's Ladder

Most new instructors start out by teaching student pilots almost exclusively. After several months of watching, correcting, and saving their students (and themselves) from various landing catastrophes, they may begin to wonder "Do I still know how to perform a respectable landing?" Now a seasoned instructor, I still find it challenging to impart the important skills involved in getting a plane safely back on terra firma. There's nothing like teaching a student pilot how to land an aircraft for putting a flight instructor back in touch with beginner's mind.

A crucial trait for flight instructors is being open to new ideas. Truth be told, every week we instructors stand to learn (or re-learn) something important from a pilot that we're supposed to be educating. Then there's the other end of the spectrum: Instructors who think they have seen it all and know it all. After giving hundreds or thousands of hours of dual instruction, falling into a rut is all too easy. And so I found myself feeling a bit skeptical when a student who had been wrestling with inconsistent landing performance introduced me to something he had found on the Internet. It's known as the Jacobson Flare.

Before going any further, let's get this out of the way: The Jacobson Flare is not a parlor trick. It doesn't involve a deck of cards or a pact with the devil. Jacobson uses the pilot's Eye-to-Wheel Height (or EWH, based on the aircraft type), the pilot's offset from the main landing gear (also based on aircraft type), the airplane's approach angle (usually 3 or 4 degrees), and simple geometry to determine visual references on the runway surface where the pilot can aim and begin the landing flare. One of Jacobson's documents even has an appendix that lists the calculations for several transport category aircraft as well as several GA aircraft.

I followed the link my student sent me, downloaded, and then read the various documents. And I watched the two videos, one of which clearly demonstrates the technique in a C172. I was intrigued, but still skeptical.



It helps to understand the dimensions of runway markings when choosing an aiming point and a suitable cutoff point (where the landing flare will commence, based on your aircraft type and descent angle). You can find some important details in AC 150-5340-1J: Standards for Airport Markings.  At most airports you will encounter one or more of three basic types of runways: Precision, non-precision, and visual. The markings and dimensions for each are shown below. Remember that there are airports out there with non-standard runway markings, so be careful about assuming the length of the centerline stripes, how tall the runway number are, or the length of the gaps between the centerline stripes.




The day after reading Jacobson's material, I had the opportunity to try out the technique with a fellow instructor who was doing some instrument currency work. On her first landing, she mentioned she had to suppress some of her normal landing instincts, but the landing was very good (7 out of 10, I'd say). We both felt skeptical until her second landing, which I would describe as a 10. Okay, interesting, but still too small a sample from which to draw any meaningful conclusions.

The second day I flew with an instrument pilot for an aircraft check-out flight. I explained the landing technique and he was game. His first landing was a 7 - not bad considering it involved an 8 knot tailwind component. His next two landings were a 9 and a 10 respectively. This was interesting considering he hadn't flown that particular aircraft type in quite a while.

The third day I flew with a student pilot and saw equally pleasing and consistent results. His normal, short field landings, even a power-off approach, were all 9s. He was excited and so was I. We switched to crosswind landings, his concentration wavered a bit, but the next two landings were a 6 and 7 (not bad considering a 15 knot direct crosswind). I mentioned that he had flared too high on one landing and he immediately recognized the problem and agreed. From an instructional standpoint, this is significant: Instead of a vague sort of Goldilocks process - "That flare was too low, that flare was too high, Oh! That flare was just right, do that again!" - Jacobson provides objective visual references on which the pilot can concentrate.

The past week has provided the most fun I've had watching people do landings in a long, long time. Yesterday, it was my turn to do a couple of landings - one normal, one short field. I don't mean to brag, but my first landing using Jacobson's Flare was an 8. My second landing was a short field effort. I not only touched down on the selected target, it was a very soft touchdown at minimum speed - a definite 10.

It's my considered opinion that pilots who learn to apply Jacobson's techniques can make consistently good landings, provided they know how to configure their aircraft and fly a stable approach at the appropriate airspeed. Pilots still have to develop and maintain a feel for their aircraft and learn how to handle crosswinds and gusty conditions, but Jacobson's procedure is very useful. And when you haven't flown in several weeks or it's your first landing in a new-to-you aircraft type, Jacobson's approach gives you something on which to hang your hat.

From a teaching perspective, there seem to be three main advantages to Jacobson's technique: First, it gives the pilot objective visual criteria for when to begin the landing flare, tailored to their type of airplane. Second, it provides visual cues to concentrate on throughout the flare. Every experienced pilot knows that landing performance improves when they are concentrating or, in the case of challenging conditions, they are forced to concentrate. Last, but not least, applying this technique will undoubtedly save the student time and money (not to mention the wear and tear on training aircraft).

Of course there are exceptions and limitations. It would be foolish to try to apply this approach to every possible landing situation. Simply watching a video will not teach you how to fly and land an airplane. Jacobson's material doesn't contain data for many newer GA aircraft, though I'm putting together a spreadsheet of measurements for some of the aircraft I fly. There are runways and landings surfaces that have no markings, including grass, dirt, and gravel strips not to mention bodies of water used by seaplanes. Anytime you try a new technique, it's wise to consider having an instructor along.

Even with these caveats, I'm excited to have a cool, new tool in my teaching toolbox. I can't shake this feeling of a kid in a candy store. As the instructor I flew with today said after her last landing, "Thanks, Jacobson!"