Instrument Training

Advanced Instrument Maneuvers

Constant-rate climbs and descents, stalls, and recovery from unusual attitudes complete the first stage of instrument training, which consists of basic, intermediate, and advanced maneuvers. Don't rush through this seemingly simple, but often neglected, stage of instruction. If these skills are not mastered, radio navigation and cross-country instrument flying will be difficult. The instrument workload is hard to handle if you must continually think about aircraft control.

Constant-Rate Climbs And Descents

These maneuvers (called rate climbs and descents in the instrument-rating practical test standards) have two pitch requirements: airspeed and vertical speed. The primary instruments are the vertical speed indicator for pitch, airspeed indicator for power, and heading indicator (constant heading) or turn coordinator (standard-rate turn) for bank.

An important relationship exists between pitch and power. If airspeed is correct, pitch and power must work together because both affect airspeed and altitude or vertical speed. However, when two pitch requirements exist and airspeed is incorrect, you must override normal throttle movement in order to correct airspeed while you adjust pitch to maintain vertical speed or altitude.

Constant-rate climbs and descents are taught for two reasons: They reinforce instrument interpretation and control coordination skills, and the constant-rate descent is a prerequisite for ILS instrument approaches.

For training purposes, constant-rate climbs and descents should use attitudes and power settings that maintain slow-cruise airspeed while climbing or de-scending at 500 feet per minute. Slow-cruise airspeed is the airspeed you use when maneuvering during an instrument approach, and it should be just below the maximum flap extension speed, VFE.

You should check the vertical speed indicator's accuracy before starting constant-rate maneuvers. If it does not read zero during level flight, use the instrument's indication on the ground or in level flight as its zero point. Now establish a 500-foot-per-minute climb or descent, and time the altimeter's movement to be sure the airplane is climbing or descending at the desired rate.

Assume that slow-cruise airspeed is 110 knots. To start a constant-rate climb, increase pitch and power simultaneously so that the target pitch attitude and power setting are established at the same instant. The correct attitude and power setting will generate 110 knots and a 500-foot-per-minute climb. To start a constant-rate descent, decrease pitch and power simultaneously so that the target pitch attitude and power setting are established at the same instant. Again, the correct attitude and power setting will generate 110 knots and a 500-foot-per-minute descent.

Adjusting pitch and power simultaneously is called elevator-throttle coordination, a critical skill for precise instrument flight. Most instructors know several exercises that will develop the proper coordination, so if you're having trouble, ask for help.

Intermediate level-offs can be imposed at any time during constant-rate climbs or descents, but this can be confusing, particularly when the intermediate level-off occurs during a climbing or descending turn. When you are approaching the assigned heading and/or altitude, look at the attitude indicator and establish the attitude and power setting that's required for the next objective-level off and stop turning or level off and continue turning. This action simplifies the complex task of trying to scan flight instruments that are lagging behind actual aircraft movement.

Stalls

Stall training is not required for the instrument rating, but all instructors should include this confidence-building maneuver in their training syllabus. You should perform clean, power-on stalls with and without the attitude indicator, while maintaining heading and while turning. The objective is to recover with minimum altitude loss.

Recovery From Unusual Attitudes

The next procedures teach you to regain control after attitude has be-come abnormal. Recoveries must be performed with and without the attitude and heading indicators. Covering these instruments simulates vacuum system failure.

Your instructor may subject you to vertigo, a false impression of airplane movement caused by misleading sensations of motion and/or vision. You will experience the confusion that results when your mind and the flight instruments generate conflicting information. When vertigo occurs-and it will-concentrate on the attitude indicator until the sensation subsides. To do this safely, you must know how to validate the attitude indicator and make certain that it's working properly.

To induce vertigo, I have the student sit in a normal position with his eyes closed. Then, while I slowly roll the airplane into a steep turn, I ask him to lean forward as if picking something up from the cockpit floor. He remains in that position while I perform at least two, 360-degree steep turns and ease the airplane into the desired unusual attitude. Before I say "recover," I have him turn his head to the right for a few seconds and then to the left.

Here is the recovery procedure:

• Step 1-Look at the airspeed indicator. If airspeed is increasing, select idle power. If it is decreasing, select full power.
• Step 2-Look at the attitude indicator. From a nose-high attitude, lower the nose to the level-flight attitude, and then level the wings. From a nose-low attitude, level the wings and then raise the nose to the level-flight attitude. (If the attitude and heading indicators are inoperative, look at the vertical speed indicator. If the aircraft is climbing, lower the nose until the instrument reverses its trend of movement (starts moving toward zero). Then look at the turn coordinator. Use ailerons to stop the turn (zero the turn rate) and use rudder to center the ball (slip indicator). If the aircraft is descending, look at the turn coordinator. Stop the turn and center the ball, then look at the vertical speed indicator and raise the nose until the trend of movement is reversed. Whenever the vertical speed indicator's trend of movement is reversed, the airplane is near the level pitch attitude.

This use of the turn coordinator is not valid if the situation degrades into a spin, because the ball is then pulled away from the airplane's centerline by centrifugal force. Right spin or left spin, it makes no difference. With the turn coordinator mounted on the left side of the instrument panel, the ball will always be to the left.

A spin will not occur unless the airplane is stalled, which implies complete loss of control. This may be the result of severe turbulence, airframe ice, or a malfunctioning airspeed indicator.

A blocked pitot tube or static source can generate abnormal airspeed indications, so most pilots should turn on the pitot heat whenever they fly in the clouds-especially when the outside air temperature is within 10 degrees of freezing. If, however, you know the correct attitudes and power settings for each flight regime, erroneous airspeed indications can be an annoyance, not a crisis that leads to loss of control.