Trouble ahead

This old school advice of “tighten your seatbelt, turn up the cabin lights, and continue to fly straight ahead” dates back to the 1940s before we knew how dangerous thunderstorms could be. Even the old TV show Sky King touts the ability to penetrate thunderstorms. In episode 16, Sky says, “Fasten your seatbelt. Looks like we are headed into a storm.”

“Why don’t we turn back?” Penny asks.

“We’ll be through it in no time.”

“What do we do?”

“Just what we’ve been doing...Don’t be frightened, young lady. You can rely on the Songbird.”

Many pilots have died this way.

In 1969 I almost lost my life because of an inadvertent encounter with a thunderstorm. Fortunately, I was in communication with a controller at Wurtsmith Air Force Base, (a Michigan B–52 Strategic Air Command base at the time) who was tracking my plight on radar and strongly suggested an immediate 180-degree turn. Had I ignored their instructions and continued without turning, as per Advisory Circular AC 00-24C, I am sure my life would have ended.

The following reasons for initiating an immediate 180-degree turn rather than continuing to fly straight ahead assume the pilot does not have access to onboard radar or datalink radar and he/she has accidently blundered into a storm.

The initial turbulence encountered from a thunderstorm is almost always before the aircraft has entered the cell itself. In my case, visibility was only 3 miles in haze when I experienced severe turbulence about 3 miles from the edge of the storm. If you happen to be flying in instrument conditions, you most likely would think you are already inside the cell when in fact you have not yet entered the edge of the storm. What you are experiencing is turbulence whirling around the edges of the storm. Continuing to fly straight ahead would certainly make matters worse as you enter the actual cell heading toward its core. Not only would turbulence increase dramatically, but you would have to deal with the greater possibility of hail and lightning strikes.

At this point, you have no immediate information regarding the intensity of the cell, its size, shape, or movement. For all you know, you may be entering the backside of a cell which may increase in intensity as you proceed to the front of the cell. You may be dealing with the first of several cells and have no idea of their location, intensity, or anything else.

The only information you have is your own pirep—“I was flying in smooth air just a few seconds ago and now I can barely control the airplane.” Based on this information alone there is only one thing you should do: turn around and fly out of your situation.

The key argument for not turning in the advisory circular is the additional stress added to the aircraft while making the turn. If you initiate a 180-degree turn without holding altitude, however, the aircraft won’t be stressed any greater than if you remained in level flight. Simply make a 1-G, 180-degree turn. Certainly, continuing straight ahead the long way down a squall line will stress the aircraft to a much higher degree than a quick one-minute, 180-degree turn. One could even argue overall wing area exposure to the vertical updrafts and downdrafts would be less in a turn, but that’s not something you should bank on.

What you should do to maximize your chance of survival:

• Slow to maneuvering speed.
• Leave the autopilot on and in heading mode only to help you control roll. Make sure you turn off altitude hold. If the autopilot disengages because of turbulence, turn it back on.
• Turn the heading bug 180 degrees (or if you know a heading for the shortest way out).
• Don’t hold altitude. Let the aircraft descend (or climb) at maneuvering speed to maintain the same airframe load as in level flight.
• If you have datalink NEXRAD (you must have had it turned off) find the shortest way out which, most likely, will be a 180-degree turn.

My recommendations to update Advisory Circular AC-00-24C were sent to Gordon Rother, AFS-220 Air Carrier Operations, FAA. He responded that it and other weather advisor circulars will be integrated into one weather source document. “Once we have the handbook developed, we will cross reference the Instrument Flying Handbook and make the changes required to the new document. Thank you for the education and I totally agree…penetrating a thunderstorm is never the best course of action.”

Then COVID-19 hit, and as far as I know, nothing has changed.

Research in the air and on the ground has led me to conclude that the tactics above maximize your ability to survive an inadvertent encounter with a thunderstorm. I sincerely hope you never have to face this situation, but if you do, turn around! Dr. David Strahle is a flight instructor and nationally recognized weather radar spokesperson who educates pilots on the proper use of datalink radar. He is also executive producer of the upcoming film Grounded.