aspin! (asminnow.bsky.social)

“Are you comfortable being so close to that storm?” We were approaching Gander en route to LHR when the Pilot Flying elected to narrowly skirt the downwind side of towering cumulus clouds with visible lightning. He shrugged. “It’ll be fine.” “I'll tell the flight attendants to expect severe turbulence.” By the time I had the interphone to my ear, he adjusted our heading for further distance. That's a conversation worth having in any cockpit. Thunderstorm avoidance isn't a matter of personal bravado or how close you've gotten away with flying before. Here's what the FAA and the Air Force have to say about the issue: FAA “Never regard any thunderstorm lightly, even when radar echoes are of light intensity. Avoiding thunderstorms is the best policy.” FAA AIM, §7-1-27 (a) Predictably, the Air Force turns the suggestion into a rule. “The PIC will not intentionally fly into a thunderstorm.” AFMAN 11-202V3 Now let’s go one level deeper. FAA “Avoid by at least 20 miles any thunderstorm identified as severe or giving an intense radar echo.” “Regard as extremely hazardous any thunderstorm with tops 35,000 feet or higher whether the top is visually sighted or determined by radar.” FAA AIM, §7-1-27 Leave it to a government agency not to explicitly connect the dots—so I will. My interpretation: Any thunderstorm with tops at or above 35,000 feet gets 20 miles. The Air Force is even more conservative: Avoid a thunderstorm at FL230 by 20 miles Below FL230 avoid them by 10 miles The Air Force adds additional guidance about flying OVER thunderstorms: “A rule of thumb is to fly an additional 1,000 feet higher for every 10 knots of wind speed at cloud top level." AFH 11-203, Volume 1, Weather for Aircrews Forty knots of wind at cloud-top level? That's 4,000 feet above the storm top. Don’t mistake that calculation for a recommendation to overfly thunderstorms. The handbook specifically cautions against interpreting it that way. "Storms can grow faster than an airplane can climb, and their tops can be difficult to assess accurately. This is guidance for exceptional circumstances, not a safe-overflight formula." Distance from the storm isn’t the only consideration. Wind direction/velocity Anvil location Maneuvering room Vertical development Fuel remaining Aircraft maximum altitude These all matter when deciding how much separation is enough. My experience has been that many pilots are more comfortable skirting thunderstorms—or flying over them—than they should be. A history of successful close encounters isn't proof that the risk was acceptable. After 38 years in military and airline cockpits, my philosophy is pretty simple: Pilot Flying: Give thunderstorms a wide berth. I err to the conservative. Pilot Monitoring: Speak up. I highly recommend reading Malcolm Gladwell’s book, Outliers: Chapter 7—The Ethnic Theory of Plane Crashes He examines several accidents in which communication, authority gradients, and a reluctance to challenge the person in command played a role. His point is worth remembering: A Pilot Monitoring’s responsibility isn't simply to assist the Pilot Flying. It's to speak up when something doesn't look right. I'd recommend the chapter to every pilot, particularly those early in their careers. Don't let a schedule, a shortcut, or a desire to stay on course turn a manageable deviation into a bad day. Cue the “I’ll never get where I’m going …” remarks in 3, 2, 1 … Your jet. Your call. There is no prize for getting close—and most of us get paid by the minute.