Chopslapped at 9500 ft

We've all been there, I imagine: that out-of-the-blue headwhack against the canopy during an otherwise routine flight - similar to driving placidly along the interstate only to be jarred out of our reverie by an unseen, Texas-sized pothole.

I was recently flying in light chop at 9500 ft with my RV-14A when - BAM! - the airplane dropped from under me and my head hit the canopy with a force that would have had me seeing stars had it not been for my trusty flight helmet. The bottom edge of the instrument panel hit my left shin hard enough to skin it through the pant leg.

Call me conservative, but I've gotten into the habit of throttling back even in light chop to keep IAS well within the green just in case something like this happens. I doubt this was anywhere near the -14's +6/-3g limit, but the hit was enough to make me glad I was far, far away from the yellow arc.

Can any WX buffs explain the phenomenon here? It's almost like colliding with a random invisible object, only the impact is vertical not horizontal.

I have experienced this in corporate jets near busy airports. Mine was wake turbulence or as I call it, used air. As a sailplane pilot, I know the energy of strong thermals, they can be very rough with no warning.

You mean the downdraft you encountered? BTDT. No G meter on board? You "Front Range" pilot are tough. Not sure what the pic represents.?

rmarshall234 said:

Not sure what the pic represents.?

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Band aide on a cadaver leg is my guess. ;-)

Second guess would be a band aide on the poster's leg, with poor light quality.

If u don’t have the crotch strap, I suggest u install em and use em. It’s gonna happen again.

Am guessing clear air turbulence. Not that familiar with it, but a recognized phenomena. Sorry, but don't know the science behind it. I once flew through the very top of a cumulus cloud. Got a very severe jarring and hit my head on the 10 cabin top, which is several inches above my head. Definately not the typical bumps found in CU clouds. Sometimes the air just does unpredictable stuff. Any chance you were only a couple thou below a crossing jet? Have heard similar events from wake turbulence aloft. Very violent.

rmarshall234 said:

You mean the downdraft you encountered?

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I usually think of downdrafts as more sustained downward currents, lasting five seconds or more. This one was instantaneous with no post-event downward air.

rmarshall234 said:

Not sure what the pic represents?

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I figured it'd be in poor taste to post a color, pre Band-Aid photo of the leg injury; suffice it to say I was very surprised to see blood showing thru my pant leg a few minutes after this close encounter of the turbulent kind.

pilotkms said:

If u don’t have the crotch strap, I suggest u install em and use em. It’s gonna happen again.

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Thanks, Keith, for some sound wisdom - from now on the seatbelt crotch strap is getting my full attention.

Gotta love Boeing

I’ve experienced this phenomenon twice in the Air Force flying the KC-135. First time was flying out of Guam on a typhoon evacuation. For over 30 minutes after climbing out the aircraft couldn’t stay within 4,000’ of assigned altitude. I’d slowly reach assigned altitude then all of a sudden drop or climb 3,000 to 4,000’. Icing would cover the wind screen then immediately clear only to repeat the cycle. EPR readings (A model) would climb then immediately fall back indicating engine inlet icing/clearing. Wings looked like they were flapping.

I just set fuel flows and rode it out until clear of the weather. What a ride!! After getting into normal sky’s I got up to check on the 40+ passengers in back expecting to see a lot of sick and scared folks. Discovered most we’re sleeping! One passenger said, “he’d experienced worse on a hurricane evac last year.” Go figure!

Second time was flying about 20+ miles downstream of a line of thunderstorms in east Texas around FL 280. The air was clear where we were at as we stayed well clear of a line of severe weather. All of a sudden it was like the floor fell out and the airplane just fell around 4,000’ hitting with a bang as we found real air again. Called center begging forgiveness and explained what happened as we returned to assigned altitude. They immediately notified other aircraft in the area of severe clear air turbulence. Ya think?

Both times I was super impressed with the Boeing Aircraft Company and how ruggedly the 135 was built!

I’ve had this happen in a Mooney. Cruising along and before I knew what happened my head hit the ceiling as did the clip board I had in my lap. It was instantaneous “wham!”

G meter

Did anybody get a G meter reading from their experience? When it happened to me in my RV3, IIRC, it was pretty near the design limit of -3 Gs but maybe I'm misremembering. I do recall doing an airframe inspection afterwards. As well as a chiropractor visit to straighten my neck back out Man,, where did that come from??

Sudden DOWN elevator.....

PandaCub said:

I was recently flying in light chop at 9500 ft with my RV-14A when - BAM! - the airplane dropped from under me and my head hit the canopy with a force that would have had me seeing stars had it not been for my trusty flight helmet. The bottom edge of the instrument panel hit my left shin hard enough to skin it through the pant leg.Can any WX buffs explain the phenomenon here? It's almost like colliding with a random invisible object, only the impact is vertical not horizontal.

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Being from the Front Range, how close to the Mountains were you (although sometimes that doesn't matter). As you know, mountains can produce their own "rapids" and sometimes MILES from the peaks themselves. If you happen to hit a small "roller" off the Mountains just right, it can be a sudden "smackdown" that might do what you experienced. A miniature "air waterfall", if you will. WHAM!

I have flown a lot between Colorado and Montana which means a trip through Wyoming. Much better in SuzieQ than the Cub as it is faster and handles turbulence better. My harness in either airplane is snugged down any time I am over The Barren State. For those unfamiliar, the Wind is almost always blowing through central to Southern Wyoming. (If the Wind should suddenly stop blowing in Casper, everyone would fall over... Their Windsock is a logging chain on a telephone pole....). I'm not sure how many times I've had those smackdowns but it's been quite a few. One in particular in the Cub (when it had the nose tank) I was West of Cody and was suddenly being SHOVED down enough I was watching fuel come out of the fuel cap! That was a downflow off a ridge after following the UP air for quite a while. Did not get to West Yellowstone that day.

Crotch strap: I have one in SuzieQ but not the Cub. The type of bump you hit might not bring that into play as that is more for keeping you in place going forward and not submarining out of the lap belt. Snug belts in turbulence in either airplane is my common practice. Helmet: me, too! Love mine for multiple reasons...!

Yep, you Front Range Flyers are tough! My hat's off to you.

All in the belts

With a 5 point harness I've never hit my head. Got a few stitches from my prop, once.

I’ve hit CAT twice that I remember. Both were in clear, smooth air, before and after, with a very sharp drop at, I presume, the boundary between two air masses moving in different directions up/down.
First time was in an older V tail. First thing I did, after putting my headset back on, was to look out the side window to see if the wing was still attached.
Second time was in cruise, on autopilot, in the -10. Nearly simultaneous with the drop there was a warning beep from the Trio - it had auto-disconnected. I forget what the disconnect setting was set to, maybe 2.5g?