Spirals

CHAPTER TWO

T-34C OUT-OF-CONTROL FLIGHT

207. SPIRALS

The spiral is characterized by a nose-low attitude, high roll rates, and rapidly increasing airspeed.

A spiral may easily be confused with a spin if the pilot relies solely on the interpretation of

outside references and fails to accomplish a proper analysis of the cockpit flight instruments.

Should the pilot misinterpret a spiral as a spin, it is highly unlikely that anti-spin inputs will

affect a successful recovery.

If performed to the left, the cockpit indications will initially look like those of a Steady-State

Erect Spin, with AOA pegged, airspeed moving into the 80 - 100 knot range, and turn needle

fully deflected left. However, the aircraft is not stalled. This becomes apparent if the spiral is

performed to the right, which makes the AOA hover near 20 units. Even when performed to the

left, the airspeed will soon accelerate through the 80 - 100 knot range and positively indicate the

aircraft is not in a spin. Airspeed will continue to accelerate with a rapid rate of rotation until the

only method of recovery is effected, NATOPS OCF Recovery Procedures. Once the controls

have been neutralized and the absence of spiral indications is confirmed, the pilot must recover

from a nose-low, unusual attitude. Having the power reduced to idle will help slow the rate of

airspeed increase. Excessive airspeed creates a strong tendency for the nose to pitch upward.

This tendency is exaggerated when the aircraft is trimmed for a slower airspeed (i.e., 150 KIAS).

It is critical to emphasize, the pilot must stop the roll and level the wings prior to allowing the

nose to pitch upward. This will prevent a rolling pullout, which imposes additional stress on the

airframe. Failure to prevent a rolling pullout could result in structural failure of the aircraft due

to asymmetrical "G" loading. Prior to attempting a pullout, ensure the wings are level by

referencing the horizon and do not exceed 24 units AOA or 4.5 "G's" (altitude permitting).

The key to a safe recovery from an inadvertent spiral lies in the expeditious recognition of the

aircraft's actual flight condition. The pilot must be able to accomplish a proper analysis of the

cockpit flight instruments and not rely solely on outside references.

208. T-34C ERECT SPIN CHARACTERISTICS

If pro-spin controls are maintained through the PSG phase, a spin will develop. Spin is

characterized by stable pitch attitudes, AOA, vertical velocity, airspeed, and yaw rates. Cockpit

indications of an erect spin are: Airspeed - stabilized between 80 - 100 KIAS, AOA - 30 units,

turn needle - fully deflected in direction of spin. Other characteristics include approximately 45

nose down attitude, a spin rate of 110 - 170 degrees per second, and a 9000 - 12,000 fpm rate of

descent. The Incipient Spin will precede the fully developed spin, with some oscillations in all

parameters present.

Positive recovery controls should be utilized for fully developed spins. If the controls are simply

released, aerodynamic loads will hold the elevator full aft for several turns; the ailerons and

rudder may "float" to near neutral. To neutralize the elevator, a moderate but definite forward

force (approximately 40 lbs. for the T-34C) will be required to overcome the aerodynamic load.

Positive control neutralization may occasionally result in a recovery, but in most cases, the

recovery is slow and may not occur. With anti-spin controls maintained, recovery will occur in

1 - 2 1/2 turns.

UNUSUAL ATTITUDES AND OUT-OF-CONTROL FLIGHT 2-9