Common Errors in Straight-and-Level Flight

Pitch

Pitch errors usually result from the following faults:



Improper adjustment of the attitude indicator's miniature aircraft to

the wings-level attitude. Following your initial level-off from a climb,

check the attitude indicator and make any necessary adjustment in the

miniature aircraft for level flight indication at normal cruise

airspeed.

Insufficient cross-check and interpretation of pitch instruments. For

example, the airspeed indication is low. Believing you are in a

nose-high attitude, you react with forward pressure without noting that

a low power setting is the cause of the airspeed discrepancy. Increase

your cross-check speed to include all relevant instrument indications

before you make a control response.

Uncaging the attitude indicator (if it has a caging feature) when the

airplane is not in level flight. The altimeter and heading indicator

must be stabilized with airspeed indication at normal cruise when you

pull out the caging knob, if you expect the instrument to read

straight-and-level at normal cruise airspeed.

Failure to interpret the attitude indicator in terms of the existing

airspeed.

Late pitch corrections. Pilots commonly like to leave well enough alone.

When the altimeter shows a 20-foot error, there is a reluctance to

correct it, perhaps because of fear of overcontrolling. If

overcontrolling is the error, the more you practice small corrections

and find out the cause of overcontrolling, the closer you will be able

to hold your altitude. If you tolerate a deviation, your errors will

increase.

Chasing the vertical-speed indications. This tendency can be corrected

by proper cross-check of other pitch instruments, as well as by

increasing your understanding of the instrument characteristics.

Using excessive pitch corrections for the altimeter evaluation. Rushing

a pitch correction by making a large pitch change usually aggravates the

existing error and saves neither time nor effort.

Failure to maintain established pitch corrections. This is a common

error associated with cross-check and trim errors. For example, having

established a pitch change to correct an altitude error, you tend to

slow down your crosscheck, waiting for the airplane to stabilize in the

new pitch attitude. To maintain the attitude, you must continue to

cross-check and trim off the pressures you are holding.

Fixations during cross-check. After initiating a heading correction, for

example, you become preoccupied with bank control and neglect to notice

a pitch error. Likewise, during an airspeed change, unnecessary gazing

at the power instrument is common. Bear in mind that a small error in

power setting is of less consequence than large altitude and heading

errors. The airplane will not decelerate any faster if you stare at the

manifold pressure gauge than if you continue your cross-check.



Trim: Adjusting the aerodynamic forces on the control surfaces so that the

aircraft maintains the set attitude without any control input.



Uncaging: Unlocking the gimbals of a gyroscopic instrument, making it

susceptible to damage by abrupt flight maneuvers or rough handling.



Heading

Heading errors usually result from the following faults:



Failure to cross-check the heading indicator, especially during changes

in power or pitch attitude.

Misinterpretation of changes in heading, with resulting corrections in

the wrong direction.

Failure to note, and remember, a preselected heading.

Failure to observe the rate of heading change and its relation to bank

attitude.

Overcontrolling in response to heading changes, especially during

changes in power settings.

Anticipating heading changes with premature application of rudder

control.

Failure to correct small heading deviations. Unless zero error in

heading is your goal, you will find yourself tolerating larger and

larger deviations. Correction of a 1° error takes a lot less time and

concentration than correction of a 20° error.

Correcting with improper bank attitude. If you correct a 10° heading

error with a 20° bank correction, you can roll past the desired heading

before you have the bank established, requiring another correction in

the opposite direction. Do not multiply existing errors with errors in

corrective technique.

Failure to note the cause of a previous heading error and thus repeating

the same error. For example, your airplane is out of trim, with a left

wing low tendency. You repeatedly correct for a slight left turn, yet do

nothing about trim.

Failure to set the heading indicator properly, or failure to uncage it.



Power

Power errors usually result from the following faults:



Failure to know the power settings and pitch attitudes appropriate to

various airspeeds and airplane configurations.

Abrupt use of throttle.

Failure to lead the airspeed when making power changes. For example,

during an airspeed reduction in level flight, especially with gear and

flaps extended, adjust the throttle to maintain the slower speed before

the airspeed reaches the desired speed. Otherwise, the airplane will

decelerate to a speed lower than that desired, resulting in further

power adjustments. How much you lead the airspeed depends upon how fast

the airplane responds to power changes.

Fixation on airspeed or manifold pressure instruments during airspeed

changes, resulting in erratic control of both airspeed and power.



Trim

Trim errors usually result from the following faults:



Improper adjustment of seat or rudder pedals for comfortable position of

legs and feet. Tension in the ankles makes it difficult to relax rudder

pressures.

Confusion as to the operation of trim devices, which differ among

various airplane types. Some trim wheels are aligned appropriately with

the airplane's axes; others are not. Some rotate in a direction contrary

to what you expect.

Faulty sequence in trim technique. Trim should be used, not as a

substitute for control with the wheel (stick) and rudders, but to

relieve pressures already held to stabilize attitude. As you gain

proficiency, you become familiar with trim settings, just as you do with

power settings. With little conscious effort, you trim off pressures

continually as they occur.

Excessive trim control. This induces control pressures that must be held

until you retrim properly. Use trim frequently and in small amounts.

Failure to understand the cause of trim changes. If you do not

understand the basic aerodynamics related to the basic instrument

skills, you will continually lag behind the airplane.

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