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Training Tip: The biggest bumpTraining Tip: The biggest bump

I know it’s a stretch to refer to a 1,700-foot-high hill as a mountain, but two pilots with thousands of hours in the air experienced the worst single jolt of turbulence of their flying lives passing a petite peak on a super-smooth night.

It's always a good idea to be prepared for turbulence. Photo by Mike Fizer.

That big bump—and the sight of a heavy piece of baggage floating weightless in the cabin—made the molehill a mountain in my book, and reflections on the encounter have affected my flying ever since.

That brief bout of turbulence I’d call severe probably wasn’t as unpredictable as it seemed to me and the other pilot aboard our company’s Cessna 172 when we passed about a mile south of the peak at an altitude roughly equal to its summit’s.

The air was smooth, but it was windy-smooth, not calm smooth, and there’s a difference perceptible in groundspeed, a correction angle to maintain course, and perhaps a crosswind for landing. Also, when the wind is strong down low it’s smart to get the surface winds early, compare them, and prepare for possible wind shear on descent.

Afterward we theorized that the strong wind spilling over the peak had created a rotor-like disturbance on the downwind side that was just waiting to perturb (get it?) a little airplane. When the bump hit, the boss’s unsecured flight case went weightless briefly as the aircraft’s floor was forced down from under it.

And this was odd: The bump had an audible aspect—a muffled, metallic noise that emanated the rear of the aircraft cabin. Had the turbulence warped the aircraft’s aluminum skin?

No. Turned out the sound was that of our rear-seat passenger’s head connecting with the Cessna’s ceiling. We’d seen him latch his lap belt, but plainly he had not taken the exercise too seriously, leaving it loose despite being a student pilot.

Such opportunities to bump up your learning are worth analyzing:

  • I knew terrain and strong wind can produce strong localized turbulence effects; however, I have since generously increased my horizontal and vertical margins of separation, and I encourage other pilots to do likewise.
  • Every item placed on an unoccupied seat gets the seat belt treatment—even any really heavy cargo.
  • Observing a passenger buckle in before flight means making extra certain they strap in tightly—and there’s no such thing as a passenger you can trust to do so unsupervised.
Dan Namowitz

Dan Namowitz

Associate Editor Web
Associate Editor Web Dan Namowitz has been writing for AOPA in a variety of capacities since 1991. He has been a flight instructor since 1990 and is a 30-year AOPA member.
Topics: Training and Safety, Training and Safety, Training and Safety
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