Nailing The Straight-In Approach

A good portion of our first few hours of flight instruction-the ones coming after learning basic control-involve getting to know the traffic pattern and perfecting what little takeoff and landing technique we can muster. Using the traffic pattern is convenient: We stay in a relatively small area yet experience one takeoff, a climb, a descent and turns, along with a brief period of straight-and-level flight. One outcome of staying in the traffic pattern and doing touch-and-goes is we get to practice many of the basic VFR skills-along with takeoffs and landings-in a

relatively short period of time.

The educational law of primacy tells us learning to fly a traffic pattern also teaches us it is the only way to properly approach a landing area in an airplane and-to some extent-it is. Flying a standard pattern affords us an opportunity to scan the landing area for its characteristics-obstructions, wind-and use it as a reference to properly position the airplane so an uneventful landing can be made. But flying a standard pattern isnt the only way to approach a landing area, nor is it always the best. And at a towered airport, it may not be what ATC wants. Putting aside the relative merits and usefulness of overhead approaches and abbreviated patterns, theres also the straight-in approach, which can save both time and airspace but also comes with its own challenges.

Straight-in approaches have often been sort of “third rail” among many hangar-flying denizens, who preach the almost-mandatory standard pattern at non-towered airports and rail against anyone with the temerity to fly something else. In almost the same breath, theyll claim its illegal and unsafe, a risk to every airborne thing in the immediate vicinity. And fattening, too. The reality is a little bit different. Instead, straight-in approaches not only have their value, but their purpose as well.

In fact, straight-ins are the rule for precision instrument approaches-the ILS-and for WAAS-supplemented RNAV (GPS) near-precision procedures. And, since we have to practice them, often in visual conditions, theyre recognized as not only appropriate but necessary, even when the weather isnt below IFR minimums.

Most of the hangar-flyers were thinking about, of course, dont fly IFR. So they have no formal need for a straight-in and were never trained to fly them. They also rarely frequent towered airports. In reality, they were never trained to fly the airplane down what should be a relatively constant descent angle (of at least three degrees, something well get to in a moment) for a few miles. Quite the opposite, in fact: They were trained to fly abeam the runway, in the opposite direction, and use various visual cues to help them decide when to reduce power, when to deploy wing flaps, if any, or drop the landing gear, and when to turn.

When flying a straight-in, however, few of the visual cues on which they-and we-over the years have come to depend are present. As one result, some pilots have trouble deciding when to reduce power, slow down, begin a descent or configure the airplane for landing when flying a straight-in. The results can be entertaining, but thats only because pilots arent thinking of the straight-in as a miles-long final pattern segment, one starting out above pattern altitude. When we think of the straight-in as just a really long final, things start to get easier.

On a normal final approach, one following a trip around the traffic pattern, we should be almost finished configuring the airplane for a landing by the time we turn and align ourselves with the runway. Most of us were trained to drop a notch of flaps and the gear, if flying a retractable, abeam the numbers as we reduced power and slowed to our initial approach speed. After turning base and final, we also were trained to drop additional flaps, complete the pre-landing checklist and adjust pitch and power to arrive over the pre-determined landing spot at an altitude and speed from which a normal flare results in a normal landing. Simple, right?

The principal difference between a straight-in and a normal pattern is we dont have those turns and procedures to fall back on. Instead, weve got to use some judgment, skill and experience to decide, for example, when to drop the gear, make the initial power reduction and start slowing down. Without the procedural cues of being abeam the numbers and making turns, we dont know when to do all that. Or do we?

Among the various other characteristics they share, one thing thats consistent between straight-ins and full traffic patterns is the time elapsed between being, say, at midfield on the downwind and touching down versus being two or three miles out on final and the touchdown. Put another way, we have at least the same amount of time to configure and slow the airplane while descending when were flying a full pattern as we do when flying a straight-in. The tasks are the same, the average speed is the same and the distance we fly is the same. The only real challenge is deciding when to do all these things without the visual and procedural cues present when flying the pattern.

The problem, then, becomes gauging the time and distance we have to fly before touching down, plus making decisions on when to configure the airplane. If we think about it, its relatively easy to know when to perform these tasks.

The average personal airplane flying the average traffic pattern at the average airport will fly about three miles from midfield on the downwind until touching down on the runway. At an average speed of, say 80 knots, our rusty E6B whiz wheel tells us this will require two minutes and 15 seconds.

So, while on a straight-in approach, if we plan to start reducing power, slowing and configuring the airplane when were three miles out, 1000 feet above and 2:15 from the runway, well pretty much be doing things in the same sequence and with the same results as would be the case if we were flying a full pattern. Easy, right?

Well, maybe. First off, how do we determine were three miles out? A simple answer is to use our GPS navigator. Generally-there are exceptions-a GPS database uses an airports geographic center as the waypoint for that facility. So, if the runway were approaching is, say, 6000 feet long and the GPS says were 3.5 nm from it, were roughly three miles from touchdown.

Dont have a GPS navigator? No problem: Another answer is to use prominent landmarks displayed on a chart. You can identify these points as part of your pre-flight planning before takeoff or in real-time, as you approach the airport. The best answer, of course, is to know what an airport environment and runway looks like from three or so miles out and 1000 feet. You dont need us to tell you how to figure that out for yourself.

Another challenge with straight-in approaches we dont have when flying a full traffic pattern is determining the correct altitude from which to begin our descent to the runway. Generally, traffic pattern altitudes are 1000 feet above the runway, though this can vary from airport to airport (check the appropriate sources to verify this value for airports you plan to use). So, to make the straight-in work the same as a normal pattern, we want to be 1000 feet above the runway and three miles out when we begin our approach in earnest, right?

Again, the answer is, “Maybe.” As the sidebar on the opposite page highlights, straight-ins are imminently legal, at least presuming we start them far enough out from the runway. How far is far enough? That depends, although a good rule of thumb is at least five nautical miles. As the sidebar notes, starting that far out has the benefit of an NTSB administrative law judges blessing and also precludes the need to make any turns, regardless of direction, while were within what would be considered Class D airspace at the average towered airport.

But if were starting the straight-in from five or more miles out and 1000 feet above the runway, well also be flying a relatively flat approach. Thats not our first choice when flying a personal airplane, although it might be correct in some circumstances and with some airplanes. Instead, I usually want a steeper approach, one at least as steep as the standard three-degree glideslope presented by the average ILS procedure.

The sidebar on page 17 presents a typical profile view of a standard ILS approach, along with a standard descent-rate table from an FAA/Aeronav approach plate booklet. Using some basic math-along with our average groundspeed down the straight-in final over with the distance well cover-its fairly easy to figure out when we should configure the airplane. Since everyones tastes are different, along with their airplane, Ill leave to the reader the decisions he or she will want to make on resolving these variables.

But, no matter what speeds or descent rates we choose to fly, theres one constant we need to keep in mind on the straight-in, which not coincidentally applies when weve turned final after flying a normal pattern: Keep the intended landing spot in the same place in the windshield.

Remember way back when your primary flight instructor preached about “sight pictures” as you struggled to get the airplane close to the runway? He or she was talking about using the view out the airplanes windshield to determine whether the intended landing spot was moving up or down. If it was moving up, we were trending low on the approach and needed to slow our rate of descent with pitch, power or both. If the spot was trending low in the windshield, we needed to increase our rate of descent by reducing power, pitching down, adding drag or some combination. The funny thing about straight-in approaches, at least when theyre compared to normal patterns is this: The same techniques apply, only for a longer period of time.

When starting out on the straight-in from five or so miles out, we need to aim the airplane at the runways end and configure it to keep that sight picture steady. As we drop gear, add flaps, and adjust pitch and power, itll move around a little bit. It always should return to the original spot, however, after we make the appropriate adjustments.

Keeping the intended landing spot in the same place in the windshield means thats pretty close to where were going to hit the ground. The idea of course, is to be slow enough and at the right altitude and configuration so we can pull off the greaser of a landing weve worked hard for. Ill say it again: In this way, flying the straight-in is no different from flying a final leg of a normal traffic pattern.

Yes, there are other things going on when we fly a straight-in versus a normal pattern: We need to pay extra attention in watching for traffic, for example, and deal with changing winds as we descend from a higher altitude for the runway. But at the end of the day, flying a straight-in approach really shouldnt be treated as anything more than an extended final after a normal pattern.