Constant Rate Climbs and Descents (CRC/D)

T-34C INSTRUMENTS

CHAPTER THREE

Common Errors

Not transitioning to VPS.

Not accomplishing entire sequence on the attitude gyroshifting scan to attitude

crosscheck instrument before transition is complete and trimmed.

Overcorrecting the nose attitude for airspeed or making corrections too rapidly, before

airspeed has a chance to settle down. Remember the airspeed indicator lags behind nose

movement and it will not react immediately after a gyro change is made. Retrim.

Not trimming the rudder, resulting in heading drift.

Fixating on the torque gauge.

306.

CONSTANT RATE CLIMBS AND DESCENTS (CRC/D)

Proficiency in performing climbs and descents at a definite vertical speed is very important

in actual instrument flight. The vertical speed as well as airspeed must be controlled accurately

during a precision Ground Controlled Approach (GCA), ILS approach, instrument takeoff, etc.

The standard rate for climbs and descents has been established at 500 feet per minute.

However, since jet powered aircraft operate most efficiently at high altitudes, a higher rate of

altitude change may be used by these aircraft, often as high as 4000 feet per minute. In this

manual, we shall consider primarily descents and climbs at 1000 feet per minute. By using the

same principles, the procedures for different rate of change may be derived.

A constantrate descent is in reality a constantairspeed descent, performed at an exact

rate. In other words, attitude (airspeed) is the primary consideration and performance (rate)

secondary. You learned in the previous section that nose attitude controls airspeed; now you will

learn to maintain a constant airspeed and vary your rate of descent by use of power adjustment.

Power controls rate of descent or climb.

Constantrate climbs and descents are performed in VPS configuration. They are started

on a numbered heading using a threesecond lead prior to the clock's second hand reaching a six

or twelve to compensate for attitude change. The transitions, scan, power settings, and trim are

the same as constant airspeed climbs and descents with the inclusion of the VSI and clock as

additional performance indicators.

In order to check the performance in a 1000 FPM descent, crosscheck the VSI and utilize

checkpoints on the altimeter. For every 250 feet of altitude change, check the clock for 15

seconds of elapsed time or every 500 feet, 30 seconds of elapsed time.

If the descent becomes less than 1000 FPM, the rate of descent must be increased to a value

greater than 1000 FPM in order to catch up with the time schedule. By decreasing power and

changing nose attitude (to maintain constant airspeed), you will increase the rate of descent. As

soon as a checkpoint indicates that the aircraft is back on performance, attitude and power are

BASIC INSTRUMENTS FLIGHT PROCEDURES 3-17