Penetration Procedures

CHAPTER FOUR

AVIATION WEATHER

Penetration Procedures

The faster a plane is going when it strikes an updraft or downdraft, the greater the shock. Refer

to your flight manual for the recommended turbulent air penetration speed.

Once inside the storm, the pilot should let the plane ride out the updrafts and downdrafts and

concentrate on maintaining a level attitude. With power set to maintain the proper airspeed,

maintaining the same attitude will result in only minor airspeed variations. However, the

aircraft's altitude may vary by thousands of feet. The rapidly changing pressure conditions

within the storm will result in unreliable indications and erratic variations in altitude, airspeed,

and rate of climb instruments. Since the attitude gyro is independent of the pitot-static system,

its indications should be considered reliable.

If thunderstorm penetration is unavoidable or you inadvertently fly into a thunderstorm, follow

these procedures:

Secure all loose objects, tighten your lap belt and lock your shoulder harness. Turn cockpit

lights up to highest intensity.

Turn on pitot heat. (If the aircraft is equipped with engine anti-ice, turn it on. Neither the

T-34 nor the T-6 has engine anti-ice.)

If able, plan your course to take you through the storm in minimum time, penetrating below

the freezing level or above -20C to avoid the most critical icing areas.

Establish the recommended turbulent air penetration speed and disengage the autopilot to

minimize control inputs that could increase structural stresses.

Don't chase the airspeed and minimize power changes. Expect significant deviations in

attitude and altitude. Keep your eyes on your instruments.

Don't turn back once in the thunderstorm.

Experience in severe weather flying is gained by necessity more often than by design and

planning. Your first flight experience near a severe thunderstorm will make the dangers listed in

this chapter all too real. Pilots should not knowingly fly into severe weather if the mission does

not demand it. In making a "go/no-go" decision, consider it better to arrive at the destination late

than not at all.

4-16 Thunderstorms