Managing Energy

Practical energy management is a critical skill used for each landing. How to put it on the numbers every time.


by Pat Veillette

Every good landing requires several important ingredients. And, with landings retaining their top spot among flight operations giving pilots the most trouble-and causing the most accidents-its never a bad time to review some of their basic requirements. Recent articles have focused on flying traffic patterns and, among other things, on maintaining control of the airplane all the way to the ramp. Other problem areas regularly demonstrated by pilots include controlling the aim point and managing the energy needed to reach that aim point. In fact, when you look through the landing accident reports, usually one or both of these ingredients is involved. Usually recognition by the pilot that his or her energy management was inadequate for the landing doesnt become obvious until halfway down the runway and realize they wont be able to stop on the remaining runway. By then, its way too late and a go-around may be the best option. Its far preferable to burning up brakes and tire trying to stop.

Every time we fly, we accumulate, store and expend kinetic energy. Altitude is perhaps the best way to measure how much kinetic energy we have: At low altitudes, we have little kinetic energy-we wont be able to glide very far if the engine quits. With, say, 10,000 feet between our seat and the ground, we have an abundance of energy stored up. The truth is that we cant make a good landing without dissipating all that energy. Arriving over the threshold 20 feet high at cruise airspeed is a pretty good indication we havent dissipated all of it. Similarly, salvaging a botched landing by dragging the airplane in over the numbers with cruise power means we used up all our stored energy somewhere else. Trying to land the average airplane from that configuration on the average runway likely means a trip into the weeds at the runways far end.

Good energy management starts with good mental preparation and good mental preparation starts well before entering the pattern. Early in my flying days, especially when flying into an unfamiliar airport with multiple runways, I had a hard time picturing patterns for various runways. Back then I resorted to drawing the runway configuration on my flight log, along with an arrow from my direction of arrival, and a line showing the traffic pattern. That seemed to help me. In years since, Ive learned to make a mental picture of the runway while looking at the horizontal situation indicator and superimposing the wind. Other pilots buy products designed to simplify this process; if these help you out, thats great. Use whatever tools that work well for you. Regardless, you must have a good understanding of the traffic pattern youre about to fly-its dimensions and your position relative to it-well before entering. Of course, the before landing checklist should be accomplished early on, preferably before entering the landing pattern. This allows you to pay more attention to aircraft control and situational awareness as you proceed in the landing pattern, rather than having your head buried in the cockpit during a critical phase of flight.

Location, Location
If you want to make consistently good landings, you need to start with a consistent location on the downwind leg, at a consistent and appropriate airspeed. The downwind leg needs to be positioned at a sufficient altitude and distance from the runway. In high-winged aircraft, usually that places the runway about halfway up the strut. In the low-winged training aircraft, the fuel cap can be a good reference point. Halfway out on the wing works for other low-winged aircraft. Learn to visualize this angle because it will work well no matter if you are at your home airport or at a strange field during a cross-country.

Now, I know some flight training programs that teach canned altitudes and locations with respect to the runway. In fact, I was taught that method at the very start. However, its riddled with potential pitfalls. It works well as long as the pilot is flying at only one airport. Ive consistently seen students from this training situation unable to fly patterns at other airports because they are unable to judge an angle that looks satisfactory for the landing pattern. Besides, whats going to happen if you experience an engine failure over terrain with an unknown ground elevation? How is the pilot trained to fly downwind at a certain altitude going to respond in this situation? And of course there are the constant what-ifs in the pattern: What if the aircraft ahead is flying an extra-wide pattern; what if they extend their downwind leg; what if extra spacing is required because of aircraft on final approach? Additionally, some airports have very high pattern altitudes driven by noise abatement concerns; other airports have altitudes because of nearby controlled airspace or overflying traffic at adjacent airports. And pilots arriving at towered airports may be asked to make abbreviated patterns or fly straight in to the runway. How will a new pilot trained only to fly a full pattern a certain way deal with these challenges? Pilots who have been taught how to judge their energy management using angles are better prepared to handle all of these real world anomalies much better than students who are taught to fly over X point on the ground at Y altitude.

Proactive Wind Corrections
The wind will definitely affect our energy management because it alters our placement with respect to the runway, our turn radius over the ground and our groundspeed. Do you remember those ground-reference maneuvers we all did for our Private pilot certificate? At the time I learned those, I thought they were such a pointless maneuver. What I didnt realize back then is that these maneuvers taught the skills needed to fly good traffic patterns. They require the pilot to accurately determine the aircrafts drift over the ground, make appropriate corrections for the desired ground track, and do all of this while dividing attention between aircraft control and watching outside for traffic.

When the wind is blowing straight down the runway, our alignment on the downwind leg shouldnt vary from the ordinary. Wind blowing from different direction, however, is another story. An overshooting crosswind-crosswind that is blowing from the direction of the downwind leg towards the runway-is potentially the worst condition because our groundspeed will rapidly increase during the base leg. This creates a larger turning radius which, in turn, requires us to plan better the point at which we should start the turn onto the final leg. Historically, many pilots do not proactively lead their turn to final. This has led to many pilots recognizing the aircraft shooting through the runways extended centerline too late and attempting to increase the turn rate (sometimes with bottom rudder). This type of skidding turn onto final approach is to be avoided at all costs, as it will often lead to an unrecoverable stall/spin. If the windsock is indicating a crosswind flowing from the downwind leg towards the runway, you need to remember to use a crab angle to prevent the aircraft from being blown towards the runway. If the winds at pattern altitude are particularly strong, you may want to consider displacing the downwind leg slightly further from the runway.

One of the traits of an expert pilot is the ability to proactively make a control input before the aircraft deviates off course. In the case of wind, the expert pilot will proactively make a crab correction for wind, rather than waiting for the aircraft to drift off course. This means putting in a predicted wind correction angle as soon as turning onto downwind, base and final legs.

Pitch And Power Settings
There is a power setting in every aircraft that keeps the airspeed in a good range for extending the flaps. That power setting will occasionally vary with aircraft loading and weather conditions but it is a good starting point. Before you arrive in the downwind, trim the aircraft to maintain straight and level flight. Having a trimmed aircraft will greatly lessen your workload for maintaining the correct airspeed and altitude, enabling to concentrate on things like your position to the runway, other traffic and the wind. A known pitch and power setting, coupled with a trimmed aircraft, will do wonders for lowering your workload.

Its common practice to extend a notch of flaps abeam the runway numbers, or to extend the landing gear if youre flying a retract. Remember that extending the flaps will add the drag and may often create a pitching moment. You need to know the handling characteristics of your aircraft while extending the flaps so you can proactively counter the drag and pitching moment. This is a another big difference between an expert pilot and an average pilot. The expert pilot, upon extending the flaps (lets assume a high-wing design), knows that the nose of the aircraft will tend to pitch up, and thus applies a slight amount of forward pressure on the yoke as the flaps are extended. This will keep the nose tracking in the exact desired position and is in contrast to the pilot who finds the nose pitching up and only then correcting.

As soon as I align the aircraft on the downwind leg, I am already trying to visualize the descent path Ill take during the downwind, base and final legs. As I fly abeam the numbers, I gauge whether the aircraft is too high or too low for the approach, based on the angle of the runway with respect to the wing, and make a corresponding correction. If the aircraft appears too high with respect to the normal angle on downwind, I know it needs to be angled away from the runway more. If that isnt possible because of nearby clouds or terrain, Ill need to lose more altitude when descending from the downwind leg. This typically means a larger-than-normal power reduction to begin bleeding off the stored energy.

Is there a good point at which to turn onto the base leg? Yes; in general, the point from which you can look back to the runway at about a 45-degree angle is a good time to turn onto the base leg.

Sometimes your pattern has to be modified because of other traffic in the pattern, or due to winds. If several aircraft are on final approach while you are on downwind, you may be forced to extend your downwind to allow sufficient spacing from those aircraft. A recommended technique is to wait for the aircraft on final approach to pass by your wing before you turn onto base leg. With that said, extending the downwind can really screw up the pattern for everyone else, and in turn cause a cascading effect for everyone in the traffic pattern. There comes a time when some noble individual needs to break out of the pattern to allow the downwind leg to shrink back to a normal length.

Base Leg
One disadvantage of flying right-hand patterns or high-wing aircraft is that the runway can be shielded from view during turns. This makes it hard to keep track of the aircrafts relative position to the runway. As I approach the turn onto the base and final legs, I take another look at the runway. If the aircraft appears to be high, I reduce the power slightly and let the aircraft descend at a slightly faster rate during the turn. The goal here is dissipate a little more of that stored energy. At each and every moment in the pattern, its my intent to detect any departure from the optimal glide path and make a correction to get back.

This is where I see a lot of mistakes happening in the traffic pattern. Its much easier making a small correction to the glide path-and, thus, your stored energy-than it is waiting for the deviation to get large and then being forced to make a large power and control input to get back to the middle of the envelope.

Develop an eye for determining whether your present position is within that glide path envelope and make your corrections sooner.

Pitch Plus Power
A popular expression you should remember is pitch plus power equals performance. In general, a change in one requires a change in the other. If you know the approximate pitch and power settings for your aircraft, your airspeed and sink rate should be very close to the normal values. In turn, this will help you remain close to the desired approach envelope. However, what happens when you find the aircraft high on the glide path but slow on airspeed? The common cause is a higher-than-normal pitch. Simply lowering the aircrafts nose (pitch) may be enough to regain the lost airspeed and get reestablished on the glide path. As a matter of technique, however, making such a correction is best done with both pitch and power: Lower the nose while simultaneously reducing power a small amount. When reestablished on the proper glidepath-when youve correctly managed your available energy, in other words-bring the nose back up to its previous position and add back in that power reduction. Making a correction with just pitch or power alone seldom results in stabilized airspeed or pitch and just make the pilot work harder.

Sometimes the circumstances require a different power setting. Headwinds will require higher power settings for the approach simply because the airmass is constantly moving away from the runway and you must swim upstream against the current to get to the runway. Really strong headwinds can require surprisingly high power settings, especially in high-drag (gear and flaps down) configurations.

Energy Goals
Your goal during final approach is to maintain your aim point in the touchdown zone of the runway and to manage your energy so that the aircraft remains on-speed and on-glidepath. If you can place the aircraft at a good position on the downwind leg, and constantly work to keep the aircraft within the middle of the approach envelope at an appropriate target speed, then you should be able to consistently arrive over the numbers in a stable position from which to make a good landing. Mental preparation and proactive adjustments for the winds will aid you in the quest for a good landing.

On the occasions when the landing approach isnt working out, pilots flying powered aircraft have an advantage over their brothers and sisters in sailplanes with the ability to go around so they can try it again. Sailplanes get only one shot at the landing since a go-around is usually impossible. That sort of motivation tends to keep a soaring pilot focused intently on the landing. The learning curve for mistakes in soaring has that rather precipitous consequence if the landing approach is really botched, and it shows up in the accident numbers.

Having a way out is always a good option, something that powered pilots need to appreciate and exercise. Its always better to manage that energy than to it is to try push a bad approach getting worse.

Also With This Article
“Approach: Three-Energy States”
“Real-World Energy Management”

-Pat Veillette is an aviation safety researcher who flies transports for a living.


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