It sure can cause a crash
 

A recent re-run of air-crash investigations ( or was is seconds-from-disaster?) on NatGeo was about TWO B737 crashes in the US ( Colorado springs in 1991 and another five years later ) that nearly led to grounding of 737's worldwide! The first was due to severe CAT and the other due to a turbulent wake of another jet! A THIRD plane could have crashed, but survived to tell the tale. It finally offered the clue to NTSB about those yet-unsolved crashes. Turned out it was a hydraulic servo valve that actually reversed the rudder! (Can you even imagine driving and you turn the wheel right and the car goes left?)

The crashes were turbulence triggered. The pilots used the rudder to correct, the valve turned fiendish and 150 humans met their maker.

NOAA (or is it NASA) routinely flies airplanes into hurricanes. If they can withstand that, they can withstand turbulence.

My most memorable turbulence experience was at the start of "parked at the gate for four hours" weather delay. A massive thunderstorm rolled through right before we were scheduled to push back, with high winds and hail. That's the only time I've felt turbulence on the ground, and the plinking of the hail on the hull was pretty memorable too. Once we finally took off I had fabulous window-seat views of the storm all the way from MSP to ATL. Over Hartsfield we did a spectacular high-speed dive through a hole in the clouds to get back under the weather.

We got in so late they sent a special train just for us; it was an express that took us from Concourse D to the main terminal without stopping at C, B, or A. ^ But we still had to wait just as long at the baggage carousel.

So interesting you mention this. I love to fly but am not the best at handling turbulence (well, anything more than moderate) ever since a bad experience a few years ago. Whilst my uncle's been an airline pilot for 37 years and I know, I really do, that turbulence is neither anything to be afraid of nor a particular safety issue, I still get anxious. I don't mind the bumps up and down, but it's that feeling that the aircraft could "flip" sideways that makes my body go into "flight" mode. Ridiculous and annoying :mad:

The point is that turbulence didn't actually cause these crashes -- the real cause was the flaw in the servo valve. The turbulence in itself wasn't really dangerous; it just happened to cause a situation that exposed a flaw in the 737's mechanical systems.

And to the OP: because of the NTSB investigation, that flaw has been fixed in all 737's for a long time now. So rest easy on your flights.

Turbulence #'s
 

I was recently on a UA 757 from JFK to SFO. While over the rockies we encountered some moderate turbulence where the plane got banged around for about 15 seconds. Listening on the ATC channel I heard the pilot report to ATC that we encountered a minus 18 and a plus 10. I believe he was refering to the turbulence. Anyone know what he was actully refering to?

There was one crash due to turbulence...in Japan in 1960..but the pilot went off plan to give the pax a special view of mount Fuji and got caught in a freak mountain wave.

Windshear on take off or approach can be a problem..but that's a different story.

Turbulence feels worse than it is. The aircraft, even in heavy turb, rarely moves more than 50ft. Our inner ears are sensitive to negative g acceleration and that's why pax always over estimate turbulence's severity.
The plane is not going to fall out of the sky, flip over, or break up.

If you want to reduce the sensation, there are some tricks. I use them all the time:

Get an aisle seat in the middle of the aircraft, this part moves less than the extremities, and less than the window seats.

Close your eyes. Part of the icky feeling is disparity between the information your eyes, ears, and nerve endings give your brain. Closing your eyes eliminates 1/3 of the problem.

Lift your feet off the floor during bumps. This slightly reduces contact points between yourself and the aircraft, and reduces the sensations by about 15%.

Dramamine, Benzodiazepines, even alcohol...but never together! Sleeping helps, and if you are somewhat sedated you don't feel it as much. Or care.

Morning flights..especially in summer..are less turbulent in general. Cold air is a bit more stable than rising warm air. But look at your times and routes. For example, NEVER book a flight into PHX between 1pm and 8pm during July and August...monsoonal mosture and storms pop up. Avoid flying over northern Texas in Feb when the jet stream drops down from central Canada.

Not 100% sure, but that might have referred to loss/gain of indicated airspeed in kts. If the aircraft encountered an area of shifting wind direction both could happen in sequence.

^ I don't know why but I kinda like turbulence, it makes the flight a little more fun, specially if you are flying +10 hours and your IFE is not working.

You like that 'rollercoaster' feeling inflight? :D

There was a case not more than 8 months ago I think, on UA in which a pax suffered a spinal injury and died later.

Of course, after investigation and witness statements UA was cleared of responsibility because the flight was bumpy and the pilot turned on the Fasten Seat Belts sign and made an annoucement for the FA's to take their seats also, more than 25 minutes before the injury.

The woman (victim) was one of those "Signs don't apply to me" types and got out of her seat anyhow and went to the lav. The aircraft experienced a few seconds of moderate to extreme turb while she was in there and she was thrown against the ceiling of the lav where she got the spinal injury.

The UA crew complied with all regulations and issued all warnings, and she still got out of her seat.

I've experienced my share of light chop to mod chop, but, I actually experienced Mod-Sev once on a dash-8 from YYC-YEG in January of this year. It's a short hop (45 mins) and about 8 people got sick on the plane. It was the worst and longest 45 mins of my life and the only time I've actually be terrified on a plane. All I remember was the smell of vomit and constant thrashing around inside the plane.. It was very relieving when we landed that's for sure... Everyone was pale as they got off..

My cousin was also flying from YVR-YEG the same evening on a different airline (737) and they had to have an ambulance meet their plane as they had some injured pax.

Best info ever on how to deal with turb.
 

Are you a saint, or something?
You have made my day--and I am sure thousands of people will feel less fearful of turb.
This is really ingenious and useful information. Brilliant.
Thanks. I am a very frequent flyer, and not fearful. Always buckled in when seated, always...espec when sleeping. I have flown everywhere, and experienced severe turb with px screaming. White knuckles. Things falling and flying.
Flying into Palm Springs in summer--thunderheads--like being in a paperbag in the hands of a giant. Go with the flow. Small plane.
Flying over India during monsoon...tossed around, not comfortable...
It's all flying. It's travel. It's what happens when you are on your way to somewhere wonderful.
Thanks so much for your brilliant and practical insight.
Keep up these great posts.

Flying over the Gulf of Bengal in the summer or autumn time is usually pretty rough, too. Most flights from Europe to Singapore/Kuala Lumpur have to fly that way.

Flying over the Intertropical Convergence Zone is rough, as well.
Air France Airbus A330-200 most probably crashed within that very active weather zone into the Atlantic Ocean.

Not to be Debbie Downer, but..wasn't the 2001 AA crash out of JFK determined to be due to pilot error (excessive rudder movement) and structural failure, overreacting to wake turbulence?

Preliminary AF data seems to indicate icing of the pitot tubes, causing the pilots to not know their actual airspeed. Reports I've read say the plane was intact at impact.

I have found that turning my head 90 degrees helps alleviate the sensations of turbulence and associated motion sickness. My theory is the our bodies are used to g forces in the fore/aft and up/down directions based on walking, driving, etc. but the side to side motions from turbulence are not normal. Turning my head to the side (and thus, the motion sensors in the ears), the side-to-side is turned to fore/aft, and turbulence rarely causes changes in the speed of the aircraft (now side-to-side).

Or it's just psychological. But it works for me.

That would be in reference to an airspeed loss of 18 knots and a gain of 10 knots. Pretty classic example of mountain wave turbulence.

Checko