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Very dangerous mistake!

A

AirbusPilot

Well Known Member
Hi Folks,

Yesterday I was flying with a passenger in my 8 who is not a pilot but he has flown with me a few time before, I always let him to fly the plane because he wants to become a pilot (he is rebuilding an ultralight) also he helped me when I was building.

My passenger was flying and I was teaching him how to trim the plane (I have infinity grips with electric flaps and trim), we were flying at 140kt when I felt the plane strange so I said "I have control" and started to trim in again but the plane still feel strange, there were I saw my flaps down about 20 degrees:mad:

Max speed with flaps down is 87kts and I was flying at 140kts, I have a kill switch for the rear stick button but I leave it on, I checked the flaps after landing and everything looks fine but only thinking about what could happens if he lower all flap down:confused:

I feel very bad because what I have done, a big flap failure and I could lost control of my plane with terrible result for me, my family and the entire expirimental group, maybe thinking their is a problem with the plane.

Leasson learned, that switch must be off all time and no more non pilot passenger flying my 8!!!
 
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Wouldn't worry about it too much. Probably check for any stress damage. If you can find an NDI guy to help you that should give you peace of mind. More than once I've oversped flaps in jets by accidentally hitting the flap switch while putting on a flak jacket up into the higher mock numbers. They just pull an access pannell and run an NDI xray thinngey over it for about 10 seconds
 
Based only upon my limited experience in the -8, I doubt that the motor has enough strength to deflect the flaps far enough to cause structural damage. Now, if you were to throw the flaps out all the way at slow speed, and then roll into a vertical dive like a Stuka, then you might hurt something.
 
Sounds like you are being too hard on yourself to me. Not that it's good, but that sort of thing happens in rental airplanes everyday. Letting a buddy think he is flying the airplane isn't a crime either. :)
 
Well, we now know that 8?s have been field tested to 140 kts at 20 degrees flaps the hard way.

I was leery about electric flaps not necessarily for that reason, but possibly because an electrical short or problem of some sorts could possibly activate it. I hope there are redundant safeguards built into the electronics for this. I was told in the RV-4 electric flaps would allow more room for the passenger, so it made sense to me to go that route, otherwise, I like just keeping it as simple as possible.
 
We have a flap controller that has an air speed switch. It's adjustable and you would set it to 87 knots and if you hit the flap switch at over that speed nothing happens. We love ours.
 
Ron B. said:
We have a flap controller that has an air speed switch. It's adjustable and you would set it to 87 knots and if you hit the flap switch at over that speed nothing happens. We love ours.
Click to expand...

I have that switch too that came with my flap and trim controller from TCW but I have not installed yet:(
 
I like that idea, in the absctract at least.

But let's take it that line of thinking to its logical conclusion. Accidental flap deployment seems like a bona fide safety issue. But are inoperable flaps ever such a big deal?

This leads to a question; why do we have flaps in RVs? I know that must be heresy to some of you, but bear with me. Sure, there are plenty of cases when flaps are a great convenience and there may even be a few fileds that some of us would have to exclude without them, but how many, really? And many instrument approaches are simplified somewhat, but how many cannot be safely flown without them. Maybe it depends on wind...

Now think of the weight, build time, complexity, maintenance issues, and failure mode issues....

Are they really worth it? Okay, here's a non-rhetorical question: If you built one without how hard would it be, and would Vans support it?

Here's a riddle. When is a Skylane faster than an RV? Answer: With one notch of flaps. You can drop one notch in a Skylane up to 140kias. But, then, I guess Fernando's friend has now matched that...
 
You are not the first

cropdusterdave said:
Wouldn't worry about it too much. Probably check for any stress damage. If you can find an NDI guy to help you that should give you peace of mind. More than once I've oversped flaps in jets by accidentally hitting the flap switch while putting on a flak jacket up into the higher mock numbers. They just pull an access pannell and run an NDI xray thinngey over it for about 10 seconds
Click to expand...
My son (young teen at the time) hit 50% flaps accidentally in a cruise descent on my Cirrus SR22. I don't recall the speed, but normally in that profile I would be 180 or faster TAS (max flaps are 119 indicated). No damage, but flap motor has a clutch and I bet it got worked hard.

But now that you brought it up I will consider a flap disconnect switch in the co pilots grip (Infinity grip where I will put the flap switch).
 
This problem is easily avoided: Just put the flap switch by the throttle (Hmm - I guess flap switch location can become a new primer war :eek: )
 
flaps

Well, we may have the youngest pax who deployed flaps. My daughter, then 11.5 months, hit the down flaps switch in a T-34A in full cruise with her flailing foot. What a weird feeling; we decelerated so fast I thought something really bad had happened. It was dramatic but we found no damage and the plane is still flying very well. My wife Jane, who was holding our daughter on her lap, never saw the offending move!
 
delusional said:
Accidental flap deployment seems like a bona fide safety issue. But are inoperable flaps ever such a big deal?
Click to expand...

Completely inoperable, probably not that big of a deal. But having flaps accidentally fully deploy at 190 mph+ might have the potential to rip your flaps off, or possibly cause other damage, I would think.
 
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The flap controller

is on first glance a nice convenience. Vertical Power has the same type of system on their box. While at Oshkosh I asked if there is an override to the flap lockout, I was told no. I can envision an emergency situation where I would be in severe turbulence and may consider stablizing and slowing down by deploying the flaps at a higher speed than the recommended velocity.

Just food for thought.
 
passengers in a tandem aircraft

Flying any passenger in a tandem aircraft with controls requires quite a bit of trust. Flap deployment is probably not the worst thing an uninformed passenger can do back there in an 8 with controls in the rear. My plan is to have a removable rear control stick.
 
I bought & sold a RV-10 that had a "grandpa switch" on the panel. When it was clicked towards the pilot the flaps and trim controls were on the pilots stick, and when it was switched the other way the controls on the co-pilots stick were in command. Very cool idea, that worked, if you remembered to move the switch after letting someone fly. :rolleyes:

The owner called it a "grandpa switch" so grandpa was in control.
 
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Not flaps, but I recently had a bad experience with a pilot as passenger. I was trying to raise SoCalApp for over two minutes. Finally when I did reach them they said I had had a stuck mike for two minutes. I was totally puzzled! Later when I was making an approach to the field we were going to it took me three tries before I got the plane on the ground. 'Turns out the stuck mike was due to the passenger resting the map book on the stick on his side with its PTT, and the squirrly approaches were due to his having the map book leaning against the stick. The stick is going to be made removable. I never had this problem with non-flying passengers!
 
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Inspection after flap overspeed on the RV-8

There are two things I would inspect closely after a overspeed event on the flaps.

First, if you have aluminum pushrods on the flaps, I would inspect them very carefully, or consider just replacing them. The aluminum tubing with internal thread as per the plans is strong "enough" for normal use with some margin. 140 kt would use up most of that margin.

My pushrods are 4130 steel tubing - a very very small weight penalty for a big increase in safety margin.

Second, the one-piece rod-end/ball joint fittings supplied with the kit do not have any protection for remaining captive if the bearing fails, and more important, the steel that the ball-joint stud is made from is not as strong as an AN3 bolt. (ask me how I know). Instead, I used a normal rod end bearing, with an AN bolt, AN970 washer to keep the rod end captive, and a steel sleeve spacer to position it inboard from the flap attach rib a little - allowed a nicer path for the pushrod without cutting a huge hole in the fuselage too.
 
Flap Speeds

If you look at most any spam can, they have a different flap speed for the approach flap setting than for full flap deployment. This makes sense because the stresses on the flaps at 20 degrees deployment is considerably less than at 40 degrees for that same speed. Vans only provides a single speed for full deployment.
At one time I tried to find out from Vans what speeds would be appropriate to a one-notch or two-notch (rv-6) deployment. Although they (I can't remember who it was) said that it would make sense that the speeds would be different, they had never figured out what those speeds might be. At the time, I also querried the blogs as to how this might be calculated based on the assumption that 40 degrees has a speed limit of 100 mph. What would be a safe speed for a 20 or 30 degree deployment? I got a lot of agreement that it should be doable but no suggestions on how to properly calculate the speed. Is there an aeronautical principal that can be applied here?
With a manual flap handle, you can 'feel' how much force it takes to deploy various flap positions at various speeds. It is fairly easy for the first notch and fairly hard for the last notch when done at the same speed. It takes a fair amount of 'pull' to get that last notch in at 100 mph. Would this not translate (unscientifically) to an equivalent amount of 'pull' at a higher speed for 20 degrees of flaps resulting in the no more stress on the flap mechanism? It certainly seems to work that way for Cessna, Cirrus, KingAir, etc based on the allowable flap position to acceptable speed markings.
Certainly designing in differences in the levarage of the flap mechanism would/could affect this equation. However, the flap linkage on the RVs all seem to be fairly linear, in that the linkage doesn't "appear" to try to change the leverage as more flaps are applied. Does anybody see this differently?
 
Nick Leonard said:
If you look at most any spam can, they have a different flap speed for the approach flap setting than for full flap deployment. This makes sense because the stresses on the flaps at 20 degrees deployment is considerably less than at 40 degrees for that same speed.
Click to expand...


My C-172 (2001 vintage) is placarded for 10 degrees at 110 IAS, the rest of the flap travel is 85 IAS.
 
RV-10 flap speeds

Somewhere in our RV-10 kit literature, there is actually two flap speeds listed. I think 87 kts limit for full flaps, but 94 kits for something less than that.
 
yooper said:
Somewhere in our RV-10 kit literature, there is actually two flap speeds listed. I think 87 kts limit for full flaps, but 94 kits for something less than that.
Click to expand...

The RV-7 build manual from vans also has some similar speeds listed.
 
This is an age old problem and the folks at the Grumman Iron works had a elegant solution that they employed in the F-6 Hellcat.... They put a pressure relief valve in the system... In the Hellcat you can put the flaps down at any speed you like and as you slow down they extend farther.... If you have them down and push the nose over they will blow up as you accelerate......

It works great, The Hellcat is a wonderful airplane in many ways and this is just one of them.....

Replacing the electric screw jack with a pneumatic cylinder and a small compresser in a system that employed a pressure relief valve.....

Just kidding.....

Tailwinds,
Doug Rozendaal
 
Flap switch on the stick?

When did putting the flap control on the stick become the norm. Placing it on the control stick, where there is all ready a push-to-talk, elevator trim, aileron trim, xponder ident, radio toggle switch and what else can be thought of is not good. I have flown over 75 different models of aircraft and not one had the flap control on the stick. It was located on the panel complete with an position indicator. Put it back on the panel where it belongs and not where a Flight Simulator nerd thought it would be cool.

Paul
N277PM
LAF
Fuselage
 
What Paul said....

...I too, have flown several dozen different airplanes and none had the flap control there.

IMO, it's asking for trouble.

Best,
 
Pbr47906 said:
When did putting the flap control on the stick become the norm. Placing it on the control stick, where there is all ready a push-to-talk, elevator trim, aileron trim, xponder ident, radio toggle switch and what else can be thought of is not good. I have flown over 75 different models of aircraft and not one had the flap control on the stick. It was located on the panel complete with an position indicator. Put it back on the panel where it belongs and not where a Flight Simulator nerd thought it would be cool.
Click to expand...

One of the nice things about experimental aviation is that we have the ability to customize things the way we want them. Where the flap switch goes is one of those areas where pilots are going to agree to disagree - I too have flown MANY types of airplanes in my career,and have had flap switches on the stick in more than a few cases. I have it there on my -8 as a matter of fact. It works well, and there were/are many other examples of RV's (and other planes) flying with it here without any problems.

A lot of how "safe" this is depends on your stick grip. In the case of the Infinity grip, remember that in order to get the flaps to come down, you have to physically lift your thumb, hook it OVER the switch bat, and pull back (My installation has an "up" limit switch, so the switch bat is always "up" in flight, not neutral - takes two clicks to go "down"). This is not a simple thing to do, and almost impossible to "bump" accidentally. It can be done with an absent-minded motion of course, which is what usually happens. I submit, however, that there are many things in an airplane that - if you do them absent-mindedly - are pretty dangerous! It's nice to make an airplane goof proof, certainly, but it is reasonable to assume that a pilot will take a certain amount of care.

As they say - if you make something fool-proof, someone is going to come along and invent a better fool.....;)

Paul
 
Ironflight said:
it is reasonable to assume that a pilot will take a certain amount of care.
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But, in the case that started this thread, the passenger stick grip apparently also has a flap switch if I understand correctly. It probably isn't reasonable to expect every passenger to take care to avoid such a switch. I put the minimum amount of controls and switches in the rear cockpit, to minimize the number of ways a passenger can try to kill me. My main trim power switch has three positions, OFF, FRONT ONLY, FRONT & REAR. That allows me to only enable the rear trim switch when I have someone back there that I trust. If I had a rear seat Infinity stick grip with a mitt full of switches, I'd have some means to disable that stick grip from the front seat.
 
Sorry, Paul, I hate that statement...

Ironflight said:
One of the nice things about experimental aviation is that we have the ability to customize things the way we want them.
Paul
Click to expand...

I see it used to justify poor decisions all them time (not picking on you as I have a great deal of respect).
However, just because we can, doesn't mean we should. Yes, it is one of the "nice" things about experimental aviation. It has also contributed to some accidents and deaths. (John Denver fuel selector). http://www.avweb.com/other/ntsb9905.html
Here is an example of a builder customizing things the way they want them, and ending up in tradgedy. I am a firm believer in standardization of critical instrumentation and systems.
I think one can easily argue that panel mounted flap switches, next to the throttle, could be considered standard on most aircraft. However, I dont think anybody is going to die if they do put it on the stick.
 
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JonJay said:
I see it used to justify poor decisions all them time (not picking on you as I have a great deal of respect).
However, just because we can, doesn't mean we should. Yes, it is one of the "nice" things about experimental aviation. It has also contributed to some accidents and deaths. (John Denver fuel selector). http://www.avweb.com/other/ntsb9905.html
Here is an example of a builder customizing things the way they want them, and ending up in tragedy. I am a firm believer in standardization of critical instrumentation and systems.
I think one can easily argue that panel mounted flap switches, next to the throttle, could be considered standard on most aircraft. However, I don't think anybody is going to die if they do put it on the stick.
Click to expand...

Well of course, I was overgeneralizing - sorry. Certainly the John Denver case is a great example of a poorly placed fuel selector. But....the airplane flew for quite a few hours before the incident that killed the NEW pilot in a plane NEW TO HIM, and who knows what kind of transition work and practice he had done. Be adaptable, and practice with what you have. I have flown many airplanes that didn't have things exactly the way I would want them, but that didn't mean they were dangerous - just different. Some people feel that a tailwheel is just too dangerous, others think a nosewheel is a problem.

You need to decide if the airplane is adequate for your purposes, and if you can train yourself sufficiently to be safe in it. If you build an airplane with abnormal configurations, you don't let someone else borrow it, and you make sure that a buyer is fully aware of how it works, and what it's limitations must be - doing other than that is irresponsible.

And giving the passenger controls that could be dangerous is a bad idea in my book - at least if the pilot can't disable them. Others might differ with that opinion, but it is the one I hold.

Paul
 
I flew an airplane yesterday that had a vernier throttle as well as mixture - definitely not "standard" but I loved it for taxi power control and got completely used to it in about 2 seconds. My dad flew left seat in the same airplane a little while later and hated it, had trouble applying power smoothly and had to get on the brakes hard at one point because he couldn't pull the power off fast enough.

Good for me, bad for him - it's all in what you like and what you are prepared to work with. What's good for one is not good for all.
 
Pbr47906 said:
When did putting the flap control on the stick become the norm.
Click to expand...

The RV-8 prototype was set up this way circa 1995. I believe the same was done with the RV-8A prototype. Vans has long sold a flap control relay specifically for the purpose.

I have my flap switch on the stick (Infinity) and it hasn't ever caused a problem (~650 hrs). The main disadvantage is that the relay adds complexity; I might go for the simpler approach if doing it again.
 
Pbr47906 said:
When did putting the flap control on the stick become the norm.
Click to expand...
You can probably trace it pretty closely to the release of the Infinity stick grip, which offered lots of switch options to be placed on the stick to give the Amateur-Built pilots the HOTAS feel of a fighter.

Not saying that was a bad thing, but IMO it was an incomplete solution. What was needed is a matching throttle grip. Then you could have less functions on the stick, and some on the throttle. Putting the flaps on the throttle makes more sense, many here have even suggested putting the switch next to the throttle. Certainly getting it away from the trim is a good idea to avoid confusion.

I seem to recall being told once that the military philosophy for controls were that you control the amount of power with one hand (your throttle) and you direct the power with another (your stick). Flaps, in that system, would be more closely related to the amount of power, I would think. And it's common to see the "speed brake" switch on the throttle in military aircraft that have them.
 
Kevin Horton said:
.....If I had a rear seat Infinity stick grip with a mitt full of switches, I'd have some means to disable that stick grip from the front seat.
Click to expand...
I agree. Disabling all electrical functions on the rear seat Infinity (and other grips as well) is as simple as running its ground wires through a "kill" switch.

s1501v.jpg
 
Rick6a said:
I agree.
Click to expand...

Me too. Except I am going to get fancy and have a second switch. First one gives them trims, second gives everything else (flaps, stick-mounted PTT, starter (gasp!) AP disconnect (or should this be always hot?), and remote smoke).

Sorry about the bad CAD drawing...I'm still banging away on the wings.

copilot-enable.jpg
 
Confusing placard.

Rick6a said:
I agree. Disabling all electrical functions on the rear seat Infinity (and other grips as well) is as simple as running its ground wires through a "kill" switch.

s1501v.jpg
Click to expand...

Does this mean that the co-pilot controls are "enabled" with the switch "down"?
 
Correct

[I seem to recall being told once that the military philosophy for controls were that you control the amount of power with one hand (your throttle) and you direct the power with another (your stick). Flaps, in that system, would be more closely related to the amount of power, I would think. And it's common to see the "speed brake" switch on the throttle in military aircraft that have them.]

Yes, that is correct. And remember your primary slow flight and/or instrument training; Pitch to airspeed, power to rate of decent.

Interesting question, has anyone ever considered retrofitting the speed brakes off a Mooney onto an RV? I've flown Frank Smidler's 6, and darn that thing will not slow down. I've slipped it and even slipped it with flaps. Way slick. It would be nice to charge into the pattern, throw out the boards, and keep it close in.

Paul
LAF (Battleground)
N277PM
Fuselage.
 
Interesting question, has anyone ever considered retrofitting the speed brakes off a Mooney onto an RV? I've flown Frank Smidler's 6, and darn that thing will not slow down. I've slipped it and even slipped it with flaps. Way slick. It would be nice to charge into the pattern, throw out the boards, and keep it close in.
Click to expand...

6's with constant speed props.........slow down real well!

L.Adamson ---- RV6A
 
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