xcrmckenna

Turbulence + V = chicken

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Unlike most pilots I get scared hitting turbulence at cruise. It doesn’t take much turbulence before I’m slowing down to Va.

 

I was wondering what is a reasonable amount of turbulence or severity of turbulence it takes you guys to start slowing down in your Mooney? And if my concern is really valid.

 

This last weekend I flew down to KSAC. 40 minutes of the flight I was getting tossed around pretty good. And I missed the benefit of a nice tail wind. The sectional even indicates the area of extreme turbulence, on Sunday it was spot on.

 

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For me it depends on who is with me. By myself or with my son we would have to get tossed around really good in cruise before I'm slowing down. However with my wife if it is more than a few bumps I'm going to power back and slow down some. 

I haven't been in more than what consider to be moderate turbulence. The only time I have slowed down by myself isn't in cruise because at 8,500-9,500 my IAS doesn't get into the yellow, I have intentionally pulled power in descent if it got bouncy but only because I'm not comfortable with the bumps and an IAS of 160-180 when Vne is 189.

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4 hours ago, Skates97 said:

For me it depends on who is with me. By myself or with my son we would have to get tossed around really good in cruise before I'm slowing down. However with my wife if it is more than a few bumps I'm going to power back and slow down some. 

I haven't been in more than what consider to be moderate turbulence. The only time I have slowed down by myself isn't in cruise because at 8,500-9,500 my IAS doesn't get into the yellow, I have intentionally pulled power in descent if it got bouncy but only because I'm not comfortable with the bumps and an IAS of 160-180 when Vne is 189.

Be careful, Va (maneuvering speed) is where the structure is happy not the people. 160~180 is well above Va. 

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Skates - Your plane is 54 years old right?  Personally I'd be on the conservative side of Va.    

This is an interesting thread on the topic - 

 

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For me expected turbulence = no go. One thing to get it passing through some clouds, but widespread, no thanks.

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I'm with @Skates97. If I'm solo or with a friend, we'll just push on through. But if my wife is with me or it's an Angel Flight, I'll slow it down.

 

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A month ago I went up with my instructor for my yearly Instrument proficiency check. I do that every year both for me and to keep in touch with my instructor. Despite it being CAVU, I knew it would be bumpy because of forecast winds 60kts at 6000, but at the same time it would be a challenge rather than another easy IPC flight. We tried to level off at 4,500 and could not hold altitude and I'm not sure I had complete control a few times. Planned on flying 6 but due to continuous moderate occasionally more than that we landed after the first one. I knew it would be bumpy but it was CAVU.  With the strong winds at 6,000 ft I figure we were right in a wind shear area at 4,500 and others said it was smooth above. 

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I have never flown in anything I would call more adverse than light chop.  For sure on a hot summer day I have experienced intermittent bumps that might even get the head close to ceiling, but would never rate it as moderate and definitely NOT severe.  I fly in the yellow arc primarily and on decent 180 is my personal VNE, so when I am at 170 I modify pitch or reduce airspeed (500’/min).  If I get more than a couple cloud jolts at those speeds in decent I will slow down.  Never concerned about airframe.  My concern is my and passengers comfort.  The yellow Arc is there for a reason, but our planes are stout and the yellow is conservative in vintage Mooney’s.  That said, if I got into moderate sustained turbulence I am getting to top of green.  For comfort.

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My J the green arch ends at 200mph cruise is normally 170mph and Va at max weight is 130mph. 40mph above Va seems like a lot to me. And most of the time I’m a good 150-200lbs below max weight. So Va is normally slower. Am I still being to cautious? Because I would say Ive flown through moderate turbulence a hand full of times.


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Vertical gusts independent of control inputs can overload the structure.  

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8 minutes ago, bluehighwayflyer said:

Va is all about maximum control inputs. Not turbulence. Just keep it out of the yellow in turbulence and you will be fine.  Common sense prevails, though, if the turbulence is really bad, which thankfully for me at least is a rare occurrence.  Then I let comfort be my guide. 

I disagree.  Va is for anything that causes the airplane to create maximum lift.  That could be control inputs or turbulence.  The idea is to have the plane stall before it breaks.

Now back to the original question....

If there is forecast moderate turbulence, I'll cancel the flight.

If there is any non-pilot in the plane with me and I encounter any turbulence, I'll slow down.

If I'm solo and I encounter continuous light turbulence, I'll slow down.

If there is even an occasional bump that is bordering on moderate, I'll slow to Va.

And don't forget, the lighter you are, the slower Va is.

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With a little weather experience it is reasonably easy to predict the occurrence of turbulence.  In the past 26 years of airplane ownership I have been stopped by turbulence once.  it was over Wyoming in the afternoon and there was no option to mitigate it.  I've attach an article I wrote a while back that might be of interest on flying turbulence.   Nobody really likes it and flying a 3,000 pound airplane in expected moderate turbulence is no fun and in my opinion should be avoided if you want passengers to fly with you again.

The Mooney structure is really strong and remember it is certified for 3.8g meaning the wing can carry a load of 3.8 x 3,000 pounds or 11,400 pounds.  Turbulence would have to be strong to load the wing to that amount.  Having said that, if there is a significant amount of turbulence and I've used all the mitigating choices discussed in the attached paper before I call it quits and land, I'm definitely not flying above the top of the green arc.  If it's uncomfortable enough to slow to maneuvering speed, it's time to land and call it a day.   As a private pilot, do you really need to be flying in those conditions?

On Flying Turbulence.pdf

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Often, forecasted turbulence is not encountered.  If I want to get somewhere, as opposed to a fun lunch run, then I will check PIREPS, and make a go/no-go.  Moderate turbulence is tiring and annoying.  I slow down for moderate, but mostly for my passengers comfort.  I found Don Kaye's article on how to mitigate the effects to be very useful.  If I get anything more than moderate, I will land.

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Just curious what do people believe the Va is for their Mooney

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Don Kaye gives good general advice...having flown your route in the past and experienced late afternoon turbulence in that same general area ,the only solution was to climb above the overcast layer ,probably low to mid teens would do it.You had a pretty strong tail wind out of south west and combined with the Sierra Escarpment and Eagle peak ,is a fine recipe for a rough ride.Had you been able to climb higher than 11k ,my experience is a pretty smooth ride and even better tailwind.That being said,after 5000 hrs I have never gotten use to turbulence.Sometimes you just have to slow down and grin and bear it

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Thanks guys. I read the thread@rpcc posted and a thread started earlier this year. I don’t know how I missed it but would have saved some time, and your article@donkaye. A little more info my cross country turbulence encounters are all clear air because I’m only vfr rated. The first encounter I had in the Mooney with turbulence over Va was flying it home from Texas. I was going across Arizona at 14,500 and still had my iPhone hit me in the face twice. The flight from Sacramento I expected turbulence because of thunderstorms in the area. But it had been two hours and I was behind their path. It sounds like slowing down was the best course of action. 90% of the time the only ga pireps in eastern Oregon come from me:)

Turbulence on take off and landing doesn’t bother me. I’m more worried about airplane damage in cruise and have images of the tail being ripped off. But if that isn’t likely I will relax a little. Unless I’m going through severe turbulence.


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Just curious what do people believe the Va is for their Mooney

I sense this is a trick question. But my poh says at gross my Va is 130mph. I normally take off about 200lbs below gross at take off and guess my Va is about 125mph and gets lower the further my flight is as fuel burns off.


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5 hours ago, RLCarter said:

Be careful, Va (maneuvering speed) is where the structure is happy not the people. 160~180 is well above Va. 

 

4 hours ago, rpcc said:

Skates - Your plane is 54 years old right?  Personally I'd be on the conservative side of Va.    

I appreciate the concern guys. I thought I was clear in what I wrote but I suppose I could have been clearer.

10 hours ago, Skates97 said:

The only time I have slowed down by myself isn't in cruise because at 8,500-9,500 my IAS doesn't get into the yellow, I have intentionally pulled power in descent if it got bouncy but only because I'm not comfortable with the bumps and an IAS of 160-180 when Vne is 189.

On a 2-500nm trip I typically cruise at 8,500, 9,500, or 10,500 (any lower and you run into rocks most directions out here) and my IAS at those altitudes is usually right around 135mph, sometimes 138mph at 2,400rpm. Va in my plane is 132mph so I'm not terribly concerned with the plane breaking up if I encounter some bumps when my IAS is 3-6mph above Va. (Again, never been in anything more than what I consider to be moderate, and that's a subjective term although I've never had anything get tossed around the cabin, nor had my butt come out of the seat).

The yellow arc in my plane starts at 150mph. In descent I push the nose over and slowly walk the throttle back to keep that same apprx 20" that I saw in flight if the air is smooth. If it is smooth I don't have a problem with an IAS in descent between 160-180mph when the Vne is 189mph. If it is bumpy I am not comfortable with an IAS of 160-180mph so I pull power back more to keep it slower.

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Flying in a Velocity once, I was very concerned that each and every little bump had the canard on the front bouncing. It was very disconcerting and there is no way I could sit there and watch it move around no matter how sure I was it wouldn't ever brake off.

I'm confident there's no turbulence that would take a wing off a Mooney. We do however, need to keep the tail on as well. But that is very stout and as @donkaye said, certified to 3.8g's.

 

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3 hours ago, Yetti said:

Just curious what do people believe the Va is for their Mooney

I try to skip belief and trust in science ;)

For the Ovation (per the AFM)

MANEUVERING SPEED -- The maximum speed at which application of
full available aerodynamic control will not overstress the airplane.

Maneuvering Speed at:
lbs. /Kg.
2232/1012 . . . . . . . . . 104/103
2430/1102 . . . . . . . . . 109/108
3300/1497 . . . . . . . . . 127/126
3368/1528 . . . . . . . . . 128/127

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My CFI would say check the POH.  Here's what my owner's manual says: "The yellow arc indicates speeds at which the pilot must exercise caution when encountering rough air or severe gusts.  Rough air is considered to be a condition uncomfortable to pilot and passengers.  Therefore, under these conditions, do not operate at airspeeds within the yellow arc."

Sounds like they are saying, if you can take it, the plane can take it.  On the other hand, I've had passengers who were uncomfortable with the bump of the landing gear coming up.

Edited by skydvrboy
spellimg
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On 5/11/2018 at 4:54 AM, teejayevans said:

For me expected turbulence = no go. One thing to get it passing through some clouds, but widespread, no thanks.

You wouldn't be flying 9 months of the year in AZ.

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I had one memorable flight from Las Vegas to Tucson in my Mooney Bravo. The winds were howling over the mountains. One definition of severe turbulence is loss of control of the aircraft. I had ten such episodes in a ten minute period staying under the Bravo airspace of Las Vegas until I could climb.

Has another episode in my F model downwind in the pattern to land at Scottsdale. I hit my head on the ceiling hard enough that I was surprised I remained conscious. Bled like the dickens too.

The joys of flying in the afternoon in the summer in Arizona.

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Turbulence not only affect the airframe but also items attached to it. Under high turbulence the wings may not fell off but maybe your rusty engine mount, floor attachment, avionics, batteries and other components.

José 

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