Common Errors - P-340

CHAPTER THREE

T-34C INSTRUMENTS

again adjusted to maintain a 1000 FPM descent. Now let us consider the corrections necessary

for a rate of descent greater than the desired rate of 1000 FPM. If, for example, after descending

500 feet, only 25 seconds have elapsed, you are ahead of desired performance; power must be

added and nose attitude adjusted to slow the rate of descent to less than 1000 FPM. As soon as

the altitude change and time agree (500 feet at 30 seconds or 750 at 45 seconds), power and

attitude must then be adjusted to a value between the initial setting, which resulted in a descent

greater than 1000 FPM, and the first adjustment, which gave less than 1000 FPM descent. These

power and attitude adjustments will continue to be made until altitude change and elapsed time

coincide with a 1000 FPM descent. A constant rate cannot be maintained without a constant

airspeed (130 KIAS), therefore prior to making power corrections, crosscheck airspeed.

The same principles apply for 1000 FPM climbs. A 1000 FPM climb will normally be

achieved by using 850 ftlbs of torque. However, if you determine that the rate is insufficient

and the addition of power to maximum allowable does not yield a 1000 FPM climb, maintain

130 KIAS, regardless of rate of climb.

Common Errors

Starting the maneuver off altitude.

Not using a threesecond lead. An incorrect or late transition will adversely affect

your arriving at the first checkpoint at the correct time.

Attempting to fly performance scan and neglecting airspeed. Positive performance

checkpoints occur only once every 250 feet. The common tendency is to allow

airspeed to remain off until a performance check indicates a deviation from the

desired rate. If the airspeed is not 130 KIAS, the attitude is incorrect and the

performance cannot possibly be proper. Make appropriate nose correction for

airspeed as soon as any deviation from 130 KIAS is indicated.

Not retrimming after making a correction. Remember, if you correct for airspeed or

change power and ease the nose to maintain airspeed, you have "set" a new attitude.

You must trim to hold it.

Correcting the rate with nose movement: power controls rate.

Correcting for airspeed with power: nose attitude controls airspeed.

NOTE

(e) and (f) are the most common errors.

Overcorrecting for airspeed (equate nose movement to airspeed correction).

3-18 BASIC INSTRUMENTS FLIGHT PROCEDURES