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.
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.
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: