Alright, let's pick this up — Page 257, Lesson 212

Alright, let's pick this up. We're now deep into the practical side of thunderstorm avoidance. We've already decided to avoid the storm, but now we're looking at the specific, step-by-step procedure for what to do if you have to penetrate one. This is a critical, high-workload situation, so the procedure is very structured. First, and this is a human factors point as much as a technical one: you must ensure that everyone on board is safe from the violent motion. I want you to make sure that all passengers and crew are securely strapped in. This isn't just about seat belts; it specifically mentions that loose equipment, like cabin trolleys and galley containers, must be firmly secured. Remember, as a pilot, you need to know that turbulence is normally worse in the rear of the aircraft than it is on the flight deck. So the cabin crew and passengers aft are going to feel it more. Next, the crew coordination. One pilot should be the sole person controlling the aircraft. Their entire focus is on flying. The other pilot must be continually monitoring all the flight instruments. This is a classic split of duties: one hand on the controls, one set of eyes on the panel. Now, the most strategic decision: you must select an altitude for penetration. This isn't just any altitude. You have to bear in mind the critical importance of ensuring adequate terrain clearance in likely downdraughts. The book is very clear on this: investigations have shown that in some thunderstorms there is very little turbulence at the lower levels, but in others there is a great deal. The key takeaway is that altitude is not necessarily a guide to the degree of turbulence. There's another aerodynamic factor here: increasing your height will decrease your buffet margin. That's the margin between your current speed and the stall. And up-currents within the storm may force the aircraft into a buffet because they increase the angle of attack, bringing you closer to the stall. Then, you set the power. You want to set the power to give the recommended speed for flight in turbulence. This is a specific speed, often called turbulence penetration speed. You then adjust the trim to that speed and note its position. Why? So that if the autopilot or the Mach trim system makes an excessive change, you can quickly assess it and correct it. The turbulence speeds quoted in your flight or operations manuals will provide either a single speed or a speed bracket. After that, you do a quick but thorough check. Check all flight instruments and electrical supplies. Ensure that the pitot heaters are switched on. This is non-negotiable in any visible moisture or icing conditions, and a thunderstorm certainly qualifies. Finally, you must check the operation of all anti-icing and de-icing equipment. And then you must operate all these systems in accordance with the manufacturer’s or operator’s instructions. The book gives a specific example: the operation of leading edge, expanding boot type de-icers. That's a specific system, but the principle applies to all your ice protection. You don't just turn it on; you follow the procedure.