A good landing comes from a good approach. Its hard to make a good landing from a bad approach. Ive heard both these axioms many times during my ongoing quest for the perfect flight (and have repeated them often to my students) because for the most part its true. A good, and more importantly safe, arrival depends on the process we use to get there. In a perfect world wed have the airplane trimmed up on speed and in configuration for landing from quite a ways out, and simple glide down to touchdown. In practice we do things a little differently. Depending on aircraft type it may be advantageous to delay the final landing configuration until on short final. In most non-transport category airplanes we do not drive down to the pavement, we fly to a point just above the runway and then decelerate to touchdown speed in a flare. And at times operational necessity requires we change configuration closer to the airport. But the further we fly from the optimal, “stabilized” approach, the greater the risk well jeopardize that perfect arrival. Stabilized approach “Operational experience,” according to FAA Order 8400.10, “has shown that the stabilized approach concept is essential for safe operations with turbojet aircraft, and it is strongly recommended for all other aircraft.” Why is a stabilized approach desirable? Two words: workload management. Approach and landing in an airplane, especially in IMC, is a very high-workload event. The airplane is by design flying at a fairly low indicated airspeed (e.g., high angle of attack and reduced control effectiveness) on a path converging with the ground. The need for navigational precision is acute, the opportunity for distraction high. If in addition to everything else the airplane is not trimmed to maintain a desired glidepath or the airplane needs configuration or large power changes, the pilot may quickly find him/herself “behind the airplane” with little room to compensate for deviations. The record shows especially with runway overruns, Controlled Flight Into Terrain (CFIT) and stalls on the missed approach that unstabilized approaches often correlate to approach and landing accidents. Flying at a stable, predictable speed also provides the best opportunity to recognize dangerous wind shear by detecting uncommanded airspeed deviations. Its safer, then, to fly a stabilized approach whenever possible. John Sampson of the International Aviation Safety Association calls stabilized approaches “the accepted airmanship standard” for safe flight. Flying “stable” limits the variables the pilot must contend with in what is already a high-workload environment. Achieving stability Stabilizing your approach is a matter of knowing your airplane. With just a little practice you can learn the “numbers” for your type of aircraft recommendations for power, configuration and airspeeds for various phases of flight. “Flying by the numbers” has become the way most type-specific instructors teach, because its easily learned and most airplanes have very predictable performance for a combination of power, flap and gear settings. With the numbers established, flying is more an exercise in guiding the airplane using its natural tendencies than a struggle against the airplane and the elements to force it to fly the way you want. With this knowledge you can derive an “approach-level” configuration to set up before reaching the FAF inbound, a modification to this technique for the stabilized portion of the descent, and a third technique for flying the missed approach procedure with minimal changes that could overload you at this high-workload time. If you fly a FAA Practical Test Standards-style, “dive and drive” nonprecision approach (as opposed to the growing technique of flying a constant-rate, glideslope-like descent on nonprecision approaches as well), youll need a fourth configuration for flying in the draggy, level-flight condition at Minimum Descent Altitude. Says the FSF: “With complex airplanes, a good practice is to approach the FAF with the first increment of flaps extended (to help slow the airplane), then lower the landing gear at glideslope intercept. The resultant drag will help to begin the descent down the final approach course.” The salvage mindset Pilots are overwhelmingly optimistic and the culture of aviation places great value on innovating to recover from nearly hopeless situations. The result is a mindset that we can salvage any situation, no matter how bad. For example, when training in a twin for my ATP certificate, my instructor simulated a failed engine at the precise moment the glideslope was centering on an ILS approach. In level flight at about 1500 feet agl and destabilizing radically at the very moment I was to extend the landing gear and descend and with my opinion colored by years of studying accident reports I held heading and altitude, kept the gear up, retracted flaps and continued tracking the localizer while I trouble-shot and simulated securing the “dead” engine. Trimmed, stable and on-altitude, I simulated declaring an emergency and asked for vectors back around for the approach. That gave me time to rebrief and then fly the approach without the immediate distraction of the engine failure and its accordant workload. My instructor, on the other hand, was firmly sold on the “salvage” mindset and fairly aggressively told me I should have extended the gear, continued the approach while processing the Engine Failure in Flight procedure as I flew down the ILS. “Youll never pass the checkride if you break off the approach,” he told me. I contended it was safer under almost all possible conditions to abandon the approach, deal with the emergency, then re-enter the approach under precise control. (And also, I passed the checkride.) My point is that we all are taught and tempted to fly on as status and workload build on top of each other, until through some great piloting skill or more likely, sheer luck we make it safely to the ground. Else things dont go our way and we end up in the accident reports. We all know accidents rarely result from a single event, but instead tend to be the culmination of a combination of small distractions that eventually overcome the pilots abilities or the airplanes capability. “Breaking the accident chain” means that we should not attempt to “salvage” approaches and landings, but instead recover from the distraction or emergency while at a safe altitude and then resume the approach or landing attempt. If you find yourself saying variations of “I think we can make it,” “Im high on glidepath, but I can get it down,” or “Im just a couple dots right of course, so Ill keep going and look for the airport out the left side,” recognize youre in potential trouble but are relying at least in part on luck to get down safely. Purposeful instability There are times when an unstable approach is required, at least temporarily. Examples include: The “dive and drive” non-precision approach required under current FAA practical test standards a rapid descent followed by level-off at MDA until sighting the runway environment or missing the approach. Although the trend in training and day-to-day operations is toward a constant-rate, glideslope-like descent from the FAF, obstacles on the final approach course can result in lower minimums for the dive-and-drive than are possible in a glide-type descent. The “high-speed approach” when requested by ATC. This will necessitate configuration, power and airspeed changes inside the FAF and much closer to the ground. The circling or side-step approach variations of the “dive and drive” non-precision technique. When conditions require an unstabilized approach, do what you can to make the approach as close to “normal, stabilized” as possible. For instance, fly the “dive and drive” approach at a constant trimmed airspeed, removing one of the biggest variables. For the high-speed approach, use target “numbers” for power, configuration and airspeed that incrementally evolve to a “normal” approach closer to the airport. In all cases, achieve the 500-foot AGL short final stability targets before you permit yourself to land. Planned or not, recognize that an unstabilized approach means a much higher level of risk. To counter that risk, when unstabilized consider using higher personal minimums to give yourself more room to stabilize on short final. Combating the risk Flying a stabilized approach dramatically reduces pilot workload and improves safety. Theres a demonstrable correlation between unstabilized approaches, CFIT and landing mishaps. Combat the high risk of an unstabilized approach and: Fly stabilized approaches whenever possible. Establish personal missed approach/go-around criteria, and hold yourself to them. Brief and set up the approach well before actually beginning it. Fly “by the numbers” using a constant-airspeed, constant-trim technique. Transition to a 500-ft agl stable condition once visual or when making a VFR landing. One last time: A good landing comes from a good approach. Its hard to make a good landing from a bad approach.
