By definition, a crutch is a temporary support. If you break your leg, you use a crutch to help you walk until the leg heals - then you get rid of the crutch because you don't need it anymore. That's how a crutch should work. It supports the body until the leg is strong enough to function without assistance. If you keep using the crutch after the leg heals, you'll never walk as efficiently as you could without the crutch.
In training, instructors use crutches to help students attain a goal or objective. If they are having difficulty learning a complex task or a new concept, a crutch is the step that leads to the new learning. For example, complex tasks are often broken down into smaller parts, practiced individually, then put together as a whole. Also, mnemonic devices help students (and sometimes instructors) remember information. In both instances, the part-task learning and the mnemonics are used as crutches and are appropriate.
Crutches come in many forms. A checklist is a good crutch. Any complex procedure that has the potential to end in disaster needs a checklist. This is basic safety. But when your student uses a checklist, make sure he (or she) understands that the objective is to complete the procedure correctly, not just to use the checklist to complete the procedure.
Students must understand what they are doing at each step. They must know why they are moving a control, what the control movement causes, and what should be the result of that movement. If they just learn the checklist, they'll flip a switch and move to the next procedure. If the switch fails, they'll never spot it until after the accident.
If the checklist says to check oil pressure after engine start, students will look at the oil pressure gauge. If their instructor hasn't taught them the correct indication, the students will look at the gauge, ignore a zero oil pressure indication, and move to the next item. They followed the checklist, which has now become the objective, and they've just ruined one engine.
Mnemonics are excellent crutches, and aviation has plenty of them. ANDS is one example. Accelerate North, Decelerate South helps students understand compass error while accelerating and decelerating on easterly and westerly headings. When testing students to see if they understand compass errors, you ask them what the compass indicates when the aircraft is on a given heading and accelerates (or decelerates). If they give the correct answer, it means they understand the concept and have accomplished the objective.
If you ask students to repeat the mnemonic, you are testing the crutch, which you have turned into the objective. As a result, you and your students have no idea whether they understand compass error, which was the original objective.
The private pilot (airplane) practical test standards apparently has several objectives that were originally crutches. The Rectangular Course (Area VI, Task A), is one example. The procedure is to enter the course at an angle to the first leg, fly a complete rectangular pattern, then exit the pattern at the point of entry. Terms such as "traffic pattern altitude," and "45 ? to the downwind leg" are clues that this maneuver originally was an exercise for learning traffic patterns. Somehow it became part of the private pilot checkride in addition to flying traffic patterns.
Practicing a rectangular course is excellent part-task training when learning traffic patterns. Another part- task crutch is having the student establish the aircraft in straight and level flight, slow to traffic pattern airspeed, configure it as if on downwind, make a 90-degree turn, configure it as if on base leg, adjust airspeed and descend as required, then turn another 90 degrees, and change to final approach configuration and airspeed. After stabilizing the aircraft in a constant descent rate and airspeed, execute a go-around procedure. After mastering both the rectangular pattern and practice pattern procedure, your student is probably ready to enter a real traffic pattern.
At this point some may ask, "What's wrong with evaluating the crutch? It's part of the objective. If a student can perform the crutch, he can perform the procedure."
Sometimes this is true. Often it's not. If students correctly execute a traffic pattern, they achieve the objective, and the crutches are irrelevant. If you evaluate your students on the crutch and never evaluate them on the original objective, the original objective is defeated, which still makes the crutch irrelevant. Fortunately, many (if not all) examiners observe traffic pattern procedures and evaluate the Rectangular Course task based on the traffic pattern.
Stalls (Area VIII, Tasks B and C) is another example of not understanding the objective, and thus reverting to crutches. During the past 30 years, stall training and evaluation has had many names and procedures. Names included full stalls, partial stalls, imminent stalls, approaches to stalls, gliding stalls, turning stalls, straight-ahead stalls, power-on stalls, power-off stalls, departure stalls, takeoff stalls, approach stalls, and accelerated stalls. Current names are power-on stalls and power-off stalls, but the procedures simulate stalls after takeoff and stalls before landings.
When we teach stalls, the overall objective is to make students aware of what stalls are, what causes them, how to recognize situations that lead to stalls, how to avoid those situations, and how to recover from a stall should one occur. The test standard should reflect this concept. It doesn't. It reflects the crutches. Research indicates that most stall accidents occur in the traffic pattern, on approach and after takeoff, hence the names approach stalls and departure stalls. Current thinking is to simulate an approach and transition to landing, then stall and recover; and to simulate a departure, then stall and recover.
If the objective is to determine whether students recognize situations that lead to stalls and avoid them and to recognize a stall and to recover from it, then that is what you should measure and evaluate.
The PTS expects students to simulate stalls from the approach and departure configurations as a means to prevent traffic pattern stall/spin accidents. The approach and departure procedures, originally a crutch, have become the objective. Stall recognition and recovery are no longer the primary objectives.
The last example demonstrates why objectives are important, and why teaching and evaluation must be directed towards the objective. If you evaluate the wrong concept or procedure, you have failed as an instructor - and the student fails as a pilot. With a poorly defined objective, it's easy for a crutch to become the objective.
How can you avoid this trap? Take a good look at your objectives and instructional techniques. Ask yourself why you teach a particular skill the way you do. Is it effective? Do students understand what they are doing, and understand why they are doing it this way? Can the technique or procedure be transferred to different situations easily, or are students unable to make a positive transfer to a new situation? If the answers to these questions point to a problem, it's time to re-evaluate your objectives, teaching crutches, and teaching techniques.
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