(a) Above all, never think of a thunderstorm as “light” even though the radar shows echoes of light intensity. Avoiding thunderstorms is the best policy. Remember that vivid and frequent lightning indicates a severe activity in the thunderstorm and that any thunderstorm with tops 35 000 ft or higher is severe. Whenever possible:

(i) don’t land or take off when a thunderstorm is approaching. The sudden wind shift of the gust front or low level turbulence could result in loss of control;

(ii) don’t attempt to fly under a thunderstorm even when you can see through to the other side. Turbulence under the storm could be disastrous;

(iii) avoid any area where thunderstorms are covering 5/8 or more of that area;

(iv) don’t fly into a cloud mass containing embedded thunderstorms without airborne radar;

(v) avoid by at least 20 NM any thunderstorm identified as severe or giving intense radar returns. This includes the anvil of a large cumulonimbus; and

(vi) clear the top of a known or suspected severe thunderstorm by at least 1 000 ft altitude for each 10 KT of wind speed at the cloud top.

(b) If you cannot avoid an area of thunderstorms, consider these points:

(i) Tighten your seat belt and shoulder harness; secure all loose objects.

(ii) Plan a course that will take you through the storm area in a minimum time and hold it.

(iii) Avoid the most critical icing areas, by penetrating at an altitude below the freezing level or above the level of -15°C.

(iv) Check that pitot, carburetor or jet inlet heat are on. Icing can be rapid and may result in almost instantaneous power failure or airspeed indication loss.

(v) Set the power settings for turbulence penetration airspeed recommended in your aircraft manual.

(vi) Turn up cockpit lights to its highest intensity to minimize temporary blindness from lightning.

(vii) When using the auto-pilot, disengage the altitude hold mode and the speed hold mode. The automatic altitude and speed controls will increase manoeuvres of the aircraft, thus increasing structural stresses.

(viii) Tilt the airborne radar antenna up and down occasionally. This may detect hail or a growing thunderstorm cell.

(c) If you enter a thunderstorm:

(i) Concentrate on your instruments; looking outside increases the danger of temporary blindness from lightning.

(ii) Don’t change power settings; maintain the settings for turbulence penetration airspeed.

(iii) Don’t attempt to keep a constant rigid altitude; let the aircraft “ride the waves”. Manoeuvres in trying to maintain constant altitude increases stress on the aircraft. If altitude cannot be maintained, inform ATC as soon as possible.

(iv) Don’t turn back once you have entered a thunderstorm. Maintaining heading through the storm will get you out of the storm faster than a turn. In addition, turning manoeuvres increases stress on the aircraft