by Brian Johnson
From time to time, every pilot has a streak of bad landings. Sometimes the results are embarrassing; occasionally something gets bent. Landing difficulties date back to the dawn of powered flight on December 17, 1903. Orville and Wilber made a total of four flights that day. On the first flight, Orville cracked one of the skids. On the last flight of the day, Wilber flew 852 feet in 59 seconds before breaking the elevator frame on landing.
At the end of the first day of powered flight, the accident rate was an astounding 50%. Fortunately the Wright Brothers did not have to worry about the FAA, the NTSB, or insurance premiums.
Now dont be too hard on Orville and Wilber. Keep in mind that they did not have current flight reviews, not to mention pilot certificates. They did not even have three landings within the preceding 90 days. Glider landings do not count; category and class are required. On top of that, the Wright flyer was an unstable airplane and very difficult to fly.
These mitigating circumstances no longer apply. Today, every pilot has the option to be current and legal for each flight. Technology and airplane stability have improved dramatically. In-depth knowledge of aerodynamics is required for every pilot certificate. Nevertheless, problems with landings persist.
The overall accident rates have improved, but landings are still a problem. According to the NTSB data, from 1995 through 1997, a quarter of all general aviation accidents occurred in the landing phase of flight. There is clearly room for improvement.
Perfecting your landings, then, is a good way to reduce the likelihood of contributing to the accident statistics. Practice seems like a logical solution. Unfortunately, practicing poor techniques will cement improper procedures and make it even more difficult to break your bad habits. You could fly with a CFI, but that can get expensive. Even if the lessons were free, ego would probably still prevent many experienced pilots from asking a CFI for landing advice.
An unlikely alternative comes from the FAA, which has unwittingly provided you with a very valuable exercise that could dramatically improve your landings.
In August 2002, the FAA added a few surprises to the PTS for Commercial and CFI applicants. They brought back the power-off 180-degree accuracy approach and landing. Those who put off their commercial or CFI training have a price to pay for procrastinating. While this is an excellent training maneuver, the practical test standards border on unreasonable.
The maneuver begins at 1,000 feet agl or less on the downwind leg in the traffic pattern. Abeam the specified touchdown point, close the throttle and pitch for the best glide speed. Lower the gear if applicable; you do not want to practice gear-up landings. Here is the tough part, taken directly from the PTS; touch down in a normal landing attitude, at or within 200 feet beyond the specified touchdown point.
No, that does not mean your first bounce occurs within 200 feet. You cannot slam the nose down or dump the flaps either. You must land in a normal landing attitude and you cannot land short of the touchdown point. On a calm day, this is feasible. On a gusty day with variable wind conditions, you might want to reschedule your check ride or prepare yourself for the possibility of a pink slip.
While the PTS for this maneuver may be extreme, the 180-degree power-off accuracy landing is still an excellent training tool for honing your landing skills. With the exception of crosswind landings, landing problems typically start with poor altitude and speed control. Often the approach is high and fast or low and slow. Both of these combinations can lead to serious problems.
To practice this maneuver, try to find an uncontrolled field that is not too busy. Hopefully you can find one with a reasonably long, wide runway. Try it first with moderate winds that are closely aligned with the runway. You can add the complexity of a crosswind after you master the maneuver. Pick a touchdown point 1,000 to 1,500 feet down the runway. You want to avoid clipping the approach lights if you are short but still have enough room to stop if you overshoot.
By eliminating the variables of power and crosswinds, you will become more conscious of the glide path of the airplane. You will undoubtedly notice that the power-off approach is steeper than your typical approach. A steeper approach provides better obstacle clearance and it also increases your odds of making it to the airport if the engine quits. A steeper approach can provide an additional margin of safety when flying into congested areas.
Holding best glide speed will force you to fly a stabilized approach. Flying at a constant airspeed with an idle power setting, your pitch attitude and descent rate should remain constant until short final. In addition to reinforcing stabilized approaches at an appropriate airspeed, this maneuver will also restrict the size of your pattern. If you start at 1,000 feet agl, you will not be able to fly the unreasonably popular three-mile downwind leg before turning base. The size of the pattern will be affected by the wind, but you will probably find that the resulting pattern size is much smaller than the one you are currently flying.
With even a moderate amount of wind, consistently landing within the specified touchdown zone is very difficult. As you turn final, you will be forced to continuously evaluate your position relative to your touchdown point. With practice, you will become increasingly aware of the effects of a headwind on your glide path. A steady wind will not change your descent rate, but it will change your angle of descent. If you find yourself either too high or too low, you will need to make adjustments.
If you are too high, you have several options. You can sequentially add flaps or execute a slip. In a 172SP, adding flaps will initially boost you farther above the glideslope. Over a long enough distance, flaps will result in a steeper angle of descent. Take the time to establish and evaluate the new angle of descent before adding another notch of flaps. As you practice this maneuver, experiment with different levels of flaps at various distances from the touchdown point. You will learn a great deal about the lift and drag characteristics of your airplane in a single practice session.
Instead of using flaps, you also have the opportunity to practice the lost art of slipping. A forward slip increases drag without changing the shape of the wing. The increased drag is immediately eliminated as soon as you return to coordinated flight. As a result, you can repeatedly enter and exit the slip to fine-tune your position relative to the desired glide path.
If you are too low, you only have one option, two if you count prayer. Assuming that you are in the vicinity of the runway, you can increase your descent rate and fly directly above the runway in ground effect. Remember that ground effect can reduce induced drag by as much as 50 percent.
Your increased airspeed and the reduction in drag might allow you to float to your touchdown point. In a 172SP, if you are still going to come up short, add flaps in increments as your airspeed bleeds off. In ground effect, adding flaps can actually increase your gliding distance. You will not find this information in your POH, but you can empirically estimate the significance of ground effect at various flap settings and airspeeds in your own airplane.
Unless your actual touchdown spot appears to be unsafe, complete each power-off approach to touchdown. An important benefit of this maneuver is that your actual touchdown spot provides you instant feedback on your performance, even without a flight instructor on board.
As you have probably already realized, another significant benefit of this exercise is the opportunity to repeatedly practice engine-out emergency landings, all the way to touchdown. While you will not be going through emergency checklists and restart procedures, you will still become much more proficient and confident in safely and precisely landing your airplane in the event of an actual engine failure.
As you repeat this maneuver, if the wind is relatively constant, your performance will rapidly improve. However, if you practice this maneuver on different days in different wind conditions, you will immediately discover that the pattern size changes significantly as a function of the wind. That means that altitude and distance references and even the sight picture out the windshield will change for each approach.
The Airplane Flying Handbook suggests that the turn onto the base leg should be made at an altitude high enough and close enough to permit the airplane to glide to what would normally be the base key position in a 90 power-off approach. Aside from not being very helpful, the writer has missed the point that there is no key position on the base leg. The position on the base leg will vary as a function of the actual winds. The only key or consistent positions for this maneuver are at 1,000 feet agl abeam the touchdown point and at the touchdown point. Everything else is variable.
A Better Approach
So what do you do if you are taking your checkride or even worse, have an actual engine failure and need to get it right the first time? There is hope. It turns out that there is a simple mathematical relationship between the required outbound time (after passing abeam the touchdown point) and the headwind component on final. It is even easy enough to apply in the airplane.
The formula for a 172SP at maximum gross weight and 1,000 feet agl can be expressed easily as: The time outbound (in seconds) equals 25 minus six-tenths of the headwind component on final. A generalized formula applicable to other airplanes and altitudes is presented in the sidebar.
As mathematical formulas go, this one is easy to use. For example, lets say the local ASOS, AWOS or ATIS says the wind is 10 knots directly down the runway. The required outbound time is 25 – 0.6(10), or 19 seconds.
Ignoring crosswinds for a moment, you begin the procedure at 1,000 feet agl on the downwind leg. You set the power to maintain level flight at 68 knots, the best glide speed for the 172. Passing abeam the touchdown point, you start your time, reduce power to idle and reduce pitch to maintain 68 knots.
After 19 seconds, you execute a 180-degree standard-rate turn, roll out on final and land the airplane. Yes, you will probably still need to make some adjustments on short final. However, if you can fly precise headings, airspeeds, and standard rate turns, you will consistently be in position to land in your touchdown zone.
Note that you will not be flying a standard base leg. The commercial and CFI practical test standards do not require you to fly a standard traffic pattern for this maneuver and you are obviously free to use the pattern of your choice in the event of an actual emergency.
The procedure above more closely resembles flying three descending legs of a holding pattern. In fact, that similarity is the impetus for the mathematical derivation.
What about crosswinds? Through trial and error, adjust the width of your downwind leg to find some reference mark on the wing strut (or wing on a low-wing airplane) that will return you to the touchdown point in calm winds. Since you will always be entering this maneuver at 1,000 feet agl, this reference mark will consistently line up with the runway and with your touchdown point when you fly a pattern of the appropriate width. Use the same procedure to identify a new reference point for a 10-knot crosswind component and interpolate or extrapolate as necessary in actual conditions. This would be considered the key position in the power-off approach.
It is easy enough to hit this key position when flying in the pattern, but reaching this point in an actual engine-out emergency is aided by the other new maneuver: the steep spiral.
After identifying and flying toward your desired touchdown point, the steep spiral allows you to descend in a constant radius around a specified point, at idle power and a constant airspeed. If you descend at best glide speed, you will be properly configured to execute the 180-degree power-off accuracy landing when you pass abeam your touchdown point at 1,000 feet agl.
Just start your clock, maintain your heading and airspeed, and put it down on your touchdown point.
Many commercial pilots are still trying to figure out a practical application for chandelles and lazy eights, but practicing 180-degree power-off accuracy landings not only will improve your landing technique, it might just save your life in an engine-out emergency.
Brian Johnson is a CFII and MEII who is flying a Cessna 172SP until Lancair delivers his Columbia 350.