2010-11-Windsocks-Downwind-Landings

Vintage Instructor THE

BY Steve Krog, CFI

Windsocks and downwind landings Fly in the little end and out the big end The airport at which I am based, Miles Field, Hartford, Wisconsin (HXF), is a nontowered airport with both hard-surface and turf runways. It is surrounded by a half-dozen “improved” airports with long runways and, in some cases, control towers . . . all no more than 15 or 20 minutes away. It is an easy airport to fly to and from, and flight instructors from the surrounding airports like to bring students to HXF to practice shortand soft-field takeoffs and landings.

Hartford also has a 24-hour self-ser vice fuel facility. So, in addition to the student flight activity, a number of area pilots like to fly into HXF for fuel, as it is usually less expensive than at the surrounding airports. We have no fixed-base operator on the field, so the UNICOM is not monitored continuously during daylight hours. But we do have the old original standby for determining surface winds—a large orange windsock—located at the midpoint of the hard-surface runway, about 300 feet south of the centerline.

On a daily basis we observe a number of airplanes arriving at the Hartford airport with the intention of landing. Dutifully, they announce their intentions: “Hartford traffic, this is Cessna 12345 entering left downwind for landing on Runway 11, Hartford.”

A quick glance at the windsock from my hangar door indicates the surface wind to be from a westerly direction at about 10-12 knots, clearly favoring Runway 29.

The student, with whom I am conducting ground school at the moment, and I exchange knowing glances, both deciding we need a short break, and move to the open hangar door to watch what will almost assuredly be a five-minute excellent visual student-training exercise. Let the circus begin!

As an active instructor with ready access to the UNICOM, I struggle at this point. Do I listen to the little “angel” sitting on my right shoulder who is saying, “Pick up the microphone and tell the arriving

30 NOVEMBER 2010

airplane it is landing downwind.” Or should I listen to the little “devil” sitting on my left shoulder telling me, “No, don’t tell them anything. Besides, when they’re all done there might be some salvage parts we can use!” I decide to listen to the devil today, because the arriving aircraft appears to be a student and instructor from a nearby tower-controlled airport.

The first attempt at landing is a confirmed goaround as the airplane is still at 500 feet above ground level when crossing the runway numbers. You can almost hear the conversation taking place between the student and the certificated flight instructor (CFI): Student: What did I do wrong? I was really high on that approach.

CFI: You should have brought the power back a little sooner and maybe added some flaps.

The next attempt at landing is not much better, and another go-around is initiated.

Student: I was still too high even after adding 20 degrees of flaps. What am I doing wrong?

CFI: Well, it appears to me that you still need to get the power reduced sooner, and this time use full flaps. And your airspeed is too fast.

The student is becoming quite confused at this point. He (or she) has been doing ever ything exactly the way he or she was taught, and it just isn’t working, but the student is determined to nail it on the next attempt.

At this point the local hangar fliers begin placing bets on the spot of touchdown. Loser buys the next round of coffee.

This time the student has done everything he or she was taught to perfection. Carb heat was applied, power reduced abeam the numbers, a turn to base occurred 45 degrees off the approach end of the runway, 20 degrees of flaps were applied, and a turn to final aligned the airplane perfectly with the centerline. But something is amiss. It doesn’t look right.

Student: I think I’m still too high.

CFI: Add full flaps.

Student: I added full flaps but I’m still too high. What should I do?

CFI: I’ll take it from here.

From the ground it is clearly visible, even to the novice, when the CFI has taken the controls. The wings rock from side to side with the landing gear in search of the runway, and then the nose is pushed over into a dive attitude.

Finally the wheels are in contact with the runway, and tires begin to squeal.

After using approximately 2,900 of the 3,000 feet of runway, the airplane is now under control, and the CFI has the student take the controls for the remaining 100 feet of taxi.

The “angel” on my right shoulder is now telling me, “Do something. Don’t let them try it again.”

At this point I’ll usually pick up the mic and state: “Cessna 12345, we’ve undergone a wind switch in the last hour. You might want to use Runway 29 for your departure.” The student pilot didn’t pick up on the cryptic phrase “in the last hour,” but I’m sure the CFI did. The CFI will usually reply: “Uh, thanks. Cessna 12345 will depart Runway 29 and leave the pattern.” The CFI’s credibility has been saved, and the student’s question about what went wrong has been answered. The approach and landing were made with a tail wind.

All of the gyrations experienced in the example could have been avoided had both student and CFI simply looked at the windsock and determined what it was telling them.

I remember vividly a learning experience I had very early in my flight training. I was having a hard time determining the wind direction by looking at the windsock. My instructor picked up on my confusion and in one short statement gave me advice that I use and share with every student. He said, “Look at the windsock and fly into the little opening and out the big opening.” From that time forward I’ve never had a problem determining wind direction and runway preference. I share that statement with every student beginning with the first lesson.

In addition to the windsock, there are two other surface-wind indicators commonly found on airports: the wind tee, which is a free-swinging T-shaped marker that resembles an airplane, and the tetrahedron, a four-sided object that resembles an arrowhead when seen from the air.

If you’re inexperienced with either of these two indicators, it’s easy to get confused unless you remember a couple of easy statements. Think of the

wind tee as an airplane. The way it’s heading is into the wind. And when seeing a tetrahedron, think of it as an arrowhead pointing the way for you to take off or land.

Included in the flight-training course I provide are downwind landings, a part of the emergencylanding segment of training. To make the downwind landing a true learning experience, first I have the student make a normal takeoff and landing on a day when we have an approximate 10-knot head wind. We’ll note both the takeoff and landing distance.

Then I’ll have the student repeat the normal takeoff and landing, but this time with the 10-knot wind on our tail. The students are quite amazed, not only in the feel of the aircraft but also in the extended distances required.

On final approach with a tail wind, it will sometimes feel as if the airplane is climbing and/or just won’t come down.

H e r e ’s a n e x a m p l e f o r calculating how a 10-knot tail wind will affect your landing distance: At 70 knots, the airplane is traveling at 118 feet per second (fps); at 60 knots, at 101 fps. Let’s say the approach speed is 60 knots and groundspeed is 70 knots. If it takes five seconds to dissipate the extra speed, the airplane will have traveled approximately 550 feet in the float. Not a firm rule of thumb, but an additional10 knots on the approach groundspeed will generally use about 500 additional feet of runway.

It doesn’t take a control tower operator to help you fly safely. Rather, it takes you—the pilot in command—using and applying common sense to every aspect of your flight. And that includes the traffic pattern and landing. Look at the windsock, make a safe landing, and don’t be the deciding factor when it comes to who is paying for the next round of coffee!

At this point the local hangar fliers begin

placing bets on the spot

of touchdown. Loser buys the next round of coffee.

VINTAGE AIRPLANE 31