Instructor Report

If you’re smart—or lucky—you can’t teach your students much about the perils of thunderstorms from direct personal experience. Not only are thunderstorm accidents rare, averaging six per year—but 70 percent are fatal. That stands to reason: Any event violent enough to bend an airplane in midair can be expected to do ugly things to whoever’s inside.

While thunderstorm-penetration accidents are uncommon, they’re not becoming any more so. Some years are better (two in 2001) and some are worse (14 in 1992), but there’s no long-term trend suggesting improvement. There were six in 1993, four of them fatal. In 2012 there were also six. Five were fatal.

The lack of improvement is surprising given how much cheaper and easier it has become to get detailed weather information in flight. Twenty years ago a panel-mounted lightning detector was the state-of-the-art device in the 90 percent of the piston fleet without on-board radar, and the installed cost ran well into five figures. By 2005, a quarter of that—plus a modest monthly subscription—would buy you a portable GPS that superimposed the airplane’s track on a moving map along with radar and lightning-strike imagery showing where the storms were as recently as 15 minutes ago. Now it seems that every pilot can pull up the weather on their telephones, tablets, or both.

So why do pilots still fly into thunderstorms? People seem inclined to accept whatever level of risk they personally find comfortable; rather than increasing margins of safety, technical improvements often are used to provide comparable safety with less margin for error. Drivers follow more closely in cars with antilock brakes. Weather datalink enables pilots to make flights they’d hesitate to attempt without it, and this works if they understand its limitations. Signal and image processing delays mean that datalink shows what areas to stay well away from, not how to squeeze between rapidly developing cells. Recognizing this can be the difference between a safe diversion to another airport and a wreckage trail that runs for miles.

If you’re smart—or lucky—you can’t teach your students much about the perils of thunderstorms from direct personal experience. Not only are thunderstorm accidents rare, averaging six per year—but 70 percent are fatal. That stands to reason: Any event violent enough to bend an airplane in midair can be expected to do ugly things to whoever’s inside.

While thunderstorm-penetration accidents are uncommon, they’re not becoming any more so. Some years are better (two in 2001) and some are worse (14 in 1992), but there’s no long-term trend suggesting improvement. There were six in 1993, four of them fatal. In 2012 there were also six. Five were fatal.

The lack of improvement is surprising given how much cheaper and easier it has become to get detailed weather information in flight. Twenty years ago a panel-mounted lightning detector was the state-of-the-art device in the 90 percent of the piston fleet without on-board radar, and the installed cost ran well into five figures. By 2005, a quarter of that—plus a modest monthly subscription—would buy you a portable GPS that superimposed the airplane’s track on a moving map along with radar and lightning-strike imagery showing where the storms were as recently as 15 minutes ago. Now it seems that every pilot can pull up the weather on their telephones, tablets, or both.

So why do pilots still fly into thunderstorms? People seem inclined to accept whatever level of risk they personally find comfortable; rather than increasing margins of safety, technical improvements often are used to provide comparable safety with less margin for error. Drivers follow more closely in cars with antilock brakes. Weather datalink enables pilots to make flights they’d hesitate to attempt without it, and this works if they understand its limitations. Signal and image processing delays mean that datalink shows what areas to stay well away from, not how to squeeze between rapidly developing cells. Recognizing this can be the difference between a safe diversion to another airport and a wreckage trail that runs for miles.

If you’re smart—or lucky—you can’t teach your students much about the perils of thunderstorms from direct personal experience. Not only are thunderstorm accidents rare, averaging six per year—but 70 percent are fatal. That stands to reason: Any event violent enough to bend an airplane in midair can be expected to do ugly things to whoever’s inside.

While thunderstorm-penetration accidents are uncommon, they’re not becoming any more so. Some years are better (two in 2001) and some are worse (14 in 1992), but there’s no long-term trend suggesting improvement. There were six in 1993, four of them fatal. In 2012 there were also six. Five were fatal.

The lack of improvement is surprising given how much cheaper and easier it has become to get detailed weather information in flight. Twenty years ago a panel-mounted lightning detector was the state-of-the-art device in the 90 percent of the piston fleet without on-board radar, and the installed cost ran well into five figures. By 2005, a quarter of that—plus a modest monthly subscription—would buy you a portable GPS that superimposed the airplane’s track on a moving map along with radar and lightning-strike imagery showing where the storms were as recently as 15 minutes ago. Now it seems that every pilot can pull up the weather on their telephones, tablets, or both.

So why do pilots still fly into thunderstorms? People seem inclined to accept whatever level of risk they personally find comfortable; rather than increasing margins of safety, technical improvements often are used to provide comparable safety with less margin for error. Drivers follow more closely in cars with antilock brakes. Weather datalink enables pilots to make flights they’d hesitate to attempt without it, and this works if they understand its limitations. Signal and image processing delays mean that datalink shows what areas to stay well away from, not how to squeeze between rapidly developing cells. Recognizing this can be the difference between a safe diversion to another airport and a wreckage trail that runs for miles.