Instrument Flight
Safety/Emergency Procedures
TURBULENCE AND THUNDERSTORMS
If you should find yourself in a thunderstorm, unusual attitudes and structural damage could result.
However, if you follow NATOPS procedures, you can successfully survive inadvertent thunderstorm
penetration. You should establish a power setting and pitch attitude for penetration prior to entering the
storm. In moderate turbulence, changes in attitude are not violent, but some changes in altitude are
unavoidable and pressure instruments will fluctuate. In severe turbulence, these effects are greatly
increased in amplitude and intensity. Preparation before entering a thunderstorm may be generalized into
four basic steps. The first letter of each step spells HALT: Heat, Airspeed/Attitude, Light, and Tight.
1.
Heat
a.
Pitot heat switch - CHECK ON
2.
Airspeed/Attitude
a.
Maintain airspeed of 250 KIAS.
b.
Go on instruments and stabilize airspeed and attitude prior to penetrating the
storm.
c.
Adjust ADI reference.
d.
Fly on a heading calculated to provide the quickest passage through the storm at
an altitude affording the least turbulence and icing while clearing all ground
obstacles by a wide margin.
e.
Avoid the upper 2/3 of a mature cell (turbulence and hail) and freezing level +/-
2,000 ft (lightning).
3.
Light
a.
Turn all cockpit lights to bright including floodlights.
4.
Tight
a.
Lower the seat to prevent striking the head against the canopy and to reduce the
blinding effect of lightning.
b.
Tighten lap belts.
While in a storm, you should proceed as follows:
1.
Maintain constant power and pitch attitude.
2.
Concentrate on maintaining a straight and level aircraft attitude by referencing the ADI.
3.
Be prepared for turbulence, hail, rain, and lightning.
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