When do you slowdown to VA

Kitch

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Kitch
So yesterday I took my wife to Lake George NY for the day. Grabbed a rental car did a boat ride had lunch blah blah blah. We had a great time.

The flight home was a little on the bumpy side. Not excessive but enough that I hand flew instead of using the autopilot most of the way. The question is how much turbulence do you need to encounter before you slowdown to maneuvering speed ?
 
When I fly I don’t mind some bumps but when I can’t click on or twist knobs on the GPS, or my seat starts to feel like it drops out , I pull back to maneuvering speed.

This is a hobby and I don’t get paid to fly. We do have to pay to maintain our aircraft so why push a 45 year old airframe. On the other hand this beat up body of mine doesn’t need the extra pounding, and my bride would rather no bumps so altitude changes may be required.
 
I'm interested to see the answers. I figure as long as I'm not in the yellow I'm good, but I'm prepared to be corrected. Va is for full deflection of the controls, which if you're not aerobatic, would only be if you've lost control and are trying to correct. In my little normal category plane the only time I'm worried about maneuvering speed is when I'm doing maneuvers that bring me close to the edge of my normal envelope like steep turns or unusual attitude recovery. I also tend to slow down if I can't keep my hand on the radios, but that's only happened a couple times. At that point I'm looking for smoother air (or ground), not slowing down to ride it out. I don't feel like slowing down really makes the bumps any more tolerable.
 
Depends on how severe and what model I'm in. Anything Piper I'm probably slowing early. Most any other make, I'm a few knots under yellow arc.

Va is for full deflection of the controls
Some folks (myself included) use Va as an approximation of a rough air penetration speed. IIRC Cirrus has that as an actual speed.
 
Va is for full deflection of the controls,
Note that in your POH it probably defines Va as “rough air or maneuvering speed”.

Below the yellow arc should protect you until you start approaching the load limits for your airplane (+3.8/-1.5?), which is way more than than most people will put up with in general. Mostly I’ve slowed to rough air speed when doing stupid things around thunderstorms.
 
Below the yellow arc should protect you until you start approaching the load limits for your airplane (+3.8/-1.5?), which is way more than than most people will put up with in general.
This is my thought.

Yeah, yeah, piper wing spars...

Va in my plane is 109 knots. I'd rather the wings fall off than fly that slow ;)

Screenshot_20230515-133237_Drive.jpg
 
I’ve gotten waaay too many speeding tickets in VA so I slow down as soon as I cross the border into VA.

Me too, and in VA you have to go to court for them speeding tickets.
 
Below the yellow arc should protect you until you start approaching the load limits for your airplane (+3.8/-1.5?), which is way more than than most people will put up with in general.

I was just talking to my A&P on the phone about something else so I asked him. This is the exact answer he gave me.

Va in my plane is 109 knots. I'd rather the wings fall off than fly that slow ;)
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I slowed down to 110 kia yesterday and said no effin way I'm slowing down more than this :)
 
I’ve gotten waaay too many speeding tickets in VA so I slow down as soon as I cross the border into VA.

I was more of an East West guy when I was driving a truck so I have my share in PA & slowhio from back in 55 mph for trucks days.
 
This is my thought.

Yeah, yeah, piper wing spars...

Va in my plane is 109 knots. I'd rather the wings fall off than fly that slow ;)

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Vno would be for turbulence.

Va would be for full use of flight controls.

If between Va and Vno, how much of a bank turn angle can you make without stressing the airframe?

I think turbulence is generally ok for a few seconds and if you are going too fast you’ll get uncomfortable enough to slow it down automatically without thinking much about it. My thoughts.
 
From Piper Arrow III POH. Indeed, the commentary implies Va is the limit in rough air. I guess Vno is the limit for non-smooth air? Up to pilot discretion the difference between not-smooth and rough. :dunno:
 

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I've always interpreted VNo as it has to be "perfectly smooth" air to go this speed or above, and Va to mean you can fly at this speed when it's vomit-inducingly bad (i.e., getting bumped around to the point where it's damn near equivalent to a full deflection of one of the controls).

In reality comfort is the key dictator (for me at least). There is no chance I'm flying (usually descending) anywhere near the yellow arc in the arrow if it's rough (i.e., where I'm having turb induced attitude changes of more than a few degrees, or altitude changes or serious jolts). Likewise, unless I have pax and I'm doing it for comfort, there's little chance I'm slowing down to Va just because I'm getting bumped around every few minutes.

This is where I've thought about building some kind of arduino sensor g-meter or something to try and quantify my own turbulence experience better (that records the whole flight). It probably already exists in ForeFlight or something. But talking about turbulence is so subjective. I've flown with people who are spoiled in large, heavy aircraft who don't like small bumps and will try to climb to a different altitude to get rid of it -- and people who can get beat up for an hour and they don't even comment on the conditions. It'd be nice to have a sensor that gives me some "standard" rather than anecdotal evidence or personal observations.
 
In the RV-8, I haven’t had to slow for turbulence. At least so far. In moderate turbulence (per the published criteria) the G-meter showed 0.8 - 1.2G at 160 KTAS (Va is 123). With the airframe stressed to +6/-3, I’m comfortable that it isn’t anywhere the limit.
Yeah, yeah, piper wing spars...


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If it wasn’t a Piper flown by some Riddiot repeatedly slamming it onto the runway and doing aerobatics, there won’t be any issues. The AD should have been just on planes flown by that school.
 
If it wasn’t a Piper flown by some Riddiot repeatedly slamming it onto the runway and doing aerobatics, there won’t be any issues. The AD should have been just on planes flown by that school.

I am very suspicious of the data analysis surrounding this AD. The study methodology in the SAIB is tailor-made to cause a panic. I am currently awaiting processing of a raw data FOIA request to do a proper analysis of this.
 
I am very suspicious of the data analysis surrounding this AD. The study methodology in the SAIB is tailor-made to cause a panic. I am currently awaiting processing of a raw data FOIA request to do a proper analysis of this.
I applaud your request for the raw data--always the right starting point--but I'm curious as to what the next steps would be. Would an independent re-analysis of the data need to be done, with results sufficiently compelling to make the FAA re-evaluate their position and amend the AD? That sounds challenging (not the re-analysis so much, but getting the FAA to change their mind...).
Or is there a simpler path that I'm not seeing?
 
I applaud your request for the raw data--always the right starting point--but I'm curious as to what the next steps would be. Would an independent re-analysis of the data need to be done, with results sufficiently compelling to make the FAA re-evaluate their position and amend the AD? That sounds challenging (not the re-analysis so much, but getting the FAA to change their mind...).
Or is there a simpler path that I'm not seeing?

Likely the government will ignore all reason and continue whatever way they were going to anyway. Worth a shot, though. My day job is statistics and data analysis and I have sufficient connections to consult on the engineering side. The biggest issue is that the entire report considers only the incidence of failure as an absolute number and not the actual rate. You'll notice in the charts they only show planes that failed, which effectively looks like a heat map of which planes are most popular. I've requested raw data on all tests reported regardless of outcome. From there, it's just a matter of applying basic statistics to identify actual trends.

I think the ship has sailed on preventing recurring inspections. Even with how potentially harmful such measures have proven to be, the FAA is spring-loaded to foist these on us. A key test I plan to perform is goodness of fit with a memoryless (Poisson) process. If the spar failures are Poisson-distributed then there is no basis for a spar life limit.
 
after the first bump....and we hope it wasn't too late. o_O
Anything more than just bumpiness, I’m slowing down. When startling, I’m also hoping it was not too late.

Mostly I’ve slowed to rough air speed when doing stupid things around thunderstorms.
So have I, but I’m slowing more than VA by at least 10-20 knots to account for lower than gross weight and avoiding the need for calibrated airspeed considerations.

Speaking personally, I think if you own your plane, you will slow down more and faster than if not. Instead of looking at how CFIs (did not) lower airspeed in turbulence as a guide during my early flight hours, I took it as an example of something too avoid as those flights were uncomfortable by memory.
 
If u inadvertently get caught near or in a thunderstorm.
 
Maybe the rules for calculating Va needs to be reviewed as some folks may not be totally clear on meaning.
 
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Hmmm… got my Pietenpol hat on… I have no idea what speed that is. I generally don’t do ANY slowing down until the flare.

In big airplanes, I slow down when I have a hard time doing a crossword.
 
V-g diagram is your friend. This from PHAK.

Basically, below Va you can't cause damage to the airplane regardless of control input. As for when you should use Va - any time you feel the airplane is being bounced around that is equivalent to full control deflections. That would be fairly rare except in severe turbulence. Unable to accurately turn the radio knobs is not that.




Vg.png
 
V-g diagram is your friend. This from PHAK.

Basically, below Va you can't cause damage to the airplane regardless of control input. As for when you should use Va - any time you feel the airplane is being bounced around that is equivalent to full control deflections. That would be fairly rare except in severe turbulence. Unable to accurately turn the radio knobs is not that.




View attachment 117309
With the understanding that I'm probably comparing apples and oranges, but what about that Airbus that crashed in Queens? I, for one, fly C-172 or smaller and I haven't broken them yet.

How Overuse Of The Rudder Downed An Airbus A300 In 2001 (simpleflying.com)
 
It’d be nice if we couldn’t cause damage with control input below Va…
 
V-g diagram is your friend. This from PHAK.

Basically, below Va you can't cause damage to the airplane regardless of control input. As for when you should use Va - any time you feel the airplane is being bounced around that is equivalent to full control deflections. That would be fairly rare except in severe turbulence. Unable to accurately turn the radio knobs is not that.




View attachment 117309

This is all well and good, but the structure know only stress and strain - basically load factor in g * weight. So while the FAA says that as you reduce mass in the airplane Va decreases (i.e. they want you to stay below the g limitations of your plane's certification, all the wing knows is the force it sees. Assuming Va is calculated/certified at MTOW in theory that same speed could be flown at light weight and the wing would still stall at the same force level and still be within the actual structural loads that the wing was certified to (even though a g meter would say that you exceeded the certification limits).

Pedantic, but frustrating (to me at least) when bureaucratic rules trump engineering principals!
 
Tools:”In big airplanes, I slow down when I have a hard time doing a crossword.”

Wouldn’t you be better off in the big or small plane keeping speed up to decrease the crosswind component during landing( but so much that it induces too much float in the small plane)?
 
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This is all well and good, but the structure know only stress and strain - basically load factor in g * weight. So while the FAA says that as you reduce mass in the airplane Va decreases (i.e. they want you to stay below the g limitations of your plane's certification, all the wing knows is the force it sees. Assuming Va is calculated/certified at MTOW in theory that same speed could be flown at light weight and the wing would still stall at the same force level and still be within the actual structural loads that the wing was certified to (even though a g meter would say that you exceeded the certification limits).

Pedantic, but frustrating (to me at least) when bureaucratic rules trump engineering principals!
I thought the idea was the wing stalls, removing the stress, at Va. When the plane is lighter weight, there's a lower stalling speed, so Va is lower.
Airspeed - AOPA
 
This is all well and good, but the structure know only stress and strain - basically load factor in g * weight. So while the FAA says that as you reduce mass in the airplane Va decreases (i.e. they want you to stay below the g limitations of your plane's certification, all the wing knows is the force it sees. Assuming Va is calculated/certified at MTOW in theory that same speed could be flown at light weight and the wing would still stall at the same force level and still be within the actual structural loads that the wing was certified to (even though a g meter would say that you exceeded the certification limits).

Pedantic, but frustrating (to me at least) when bureaucratic rules trump engineering principals!
Not understanding. Do you mean that our aircraft are certified to one set of force limits, but in actuality, those limits are higher than certified ie our aircraft are overbuilt structurally? Good to know, but who of you want to test that hypothesis to its conclusion without a parachute and enough altitude to deploy it.
 
This is all well and good, but the structure know only stress and strain - basically load factor in g * weight. So while the FAA says that as you reduce mass in the airplane Va decreases (i.e. they want you to stay below the g limitations of your plane's certification, all the wing knows is the force it sees. Assuming Va is calculated/certified at MTOW in theory that same speed could be flown at light weight and the wing would still stall at the same force level and still be within the actual structural loads that the wing was certified to (even though a g meter would say that you exceeded the certification limits).

Pedantic, but frustrating (to me at least) when bureaucratic rules trump engineering principals!

Not quite! Of course the G limits translate to strain, but strain on the wings (which varies with g*weight) is not the only strain. For instance the strain on the engine mount varies only with Gs and not weight. So the maneuvering speed w.r.t. the engine mount does decrease as weight decreases.
 
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Not quite! Of course the G limits translate to strain, but strain on the wings (which varies with g*weight) is not the only strain. For instance the strain on the engine mount varies only with Gs and not weight. So the maneuvering speed w.r.t. the engine mount does decrease with as weight decreases.
This is a very good point, and something that I really hadn't considered! I don't like to be wrong, but I like to learn more than I like to be right... so thanks!
 
For the OP - did you have turbulence the whole way, or just on the first third or so of the flight from GF over the Berkshires into central MA? I wasn't flying yesterday, but asking because I do flights similar to that from time to time.
 
Not quite! Of course the G limits translate to strain, but strain on the wings (which varies with g*weight) is not the only strain. For instance the strain on the engine mount varies only with Gs and not weight. So the maneuvering speed w.r.t. the engine mount does decrease as weight decreases.
FAR 23 airplanes are stressed to 3.8G positive. Engine mounts are stressed to 9G positive. They want that engine staying put in a crash. You're not likely to tear it off by yanking on the elevator.

Some airplanes have a habit of failing the horizontal stabilizer before the wing. The Cessna 210 and Bonanza have done that. A VFR pilot flies into IMC, loses control, and pops out of the bottom of the cloud and finds himself spiralling nearly straight down at or over Vne. He pulls back and fails the stab and elevator, and the airplane tucks forward over onto its back and the wings fail in negative G loading.
 
Rumor has it the roads are really, really bad in VA so my advice is to slow down when you cross the border so you don't beat the s**t out of your vehicle. LOL ;)
 
FAR 23 airplanes are stressed to 3.8G positive. Engine mounts are stressed to 9G positive. They want that engine staying put in a crash. You're not likely to tear it off by yanking on the elevator.

Some airplanes have a habit of failing the horizontal stabilizer before the wing. The Cessna 210 and Bonanza have done that. A VFR pilot flies into IMC, loses control, and pops out of the bottom of the cloud and finds himself spiralling nearly straight down at or over Vne. He pulls back and fails the stab and elevator, and the airplane tucks forward over onto its back and the wings fail in negative G loading.

Oops! Bad example. I considered using something more clearly academic like the ashtray. :dunno:
 
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