VNE question

B

blooddiamond

Filing Flight Plan
Joined
Jun 19, 2007
Messages
5
Display Name
Display name:
blooddiamond
I went on an aerobatics flight with a buddy recently, and noticed that in an attempt to go inverted he accidentally exceeded the VNE speed by quite a bit (and to correct the situation, he pitched up which was even scarier considering the likely substantial load on the wings).

I've been looking through the FAR's... obviously this is a very undesirable situation, but does it prompt an aircraft inspection or void the airframe or airworthiness certification? Is this a big deal or is it something I should let go? I don't like getting into tenuous situations but if there is a chance that this aircraft or pilot may endanger somebody I have no choice but to involve myself.
 
nothing in the FARs that i know about. common sense rules.
 
I once had a situation where a guy came to me with a Bonanza asking for unusual attitude training.

I inspected his aircraft; there were very small wrinkles about thirty inches outboard of the cabin in the skins. I thought the tail didn't look quite right either, but I didn't measure Vtail tips to wingtip on both sides.

I said, "hmmmn, no flying today". Seems he had an encounter with a thunderstorm and was lucky to be alive.
 
While you didn't witness a failure or see any evidence that could result in a future failure, over-stressing any piece of equipment is a cumulative effect. An airframe is no different.

Navy carrier-based aircraft go through a substantial inspection due to the stress during launches and traps. On the Viking, it was every 112 days. Civil aircraft are no different. They suffer fatigue as well and far too often it goes unnoticed, particularly in GA aircraft. The best example I could site for fatigue issues would be Chalk's Ocean Airways in 2005. It was cumulative and went either unnoticed or ignored.

Tony hit it. Common sense says you don't over-stress to start with. Stay inside the V-G parameters.
 
bbchien said:
I once had a situation where a guy came to me with a Bonanza asking for unusual attitude training.

I inspected his aircraft; there were very small wrinkles about thirty inches outboard of the cabin in the skins. I thought the tail didn't look quite right either, but I didn't measure Vtail tips to wingtip on both sides.

I said, "hmmmn, no flying today". Seems he had an encounter with a thunderstorm and was lucky to be alive.
Click to expand...
YIKES!! What did you say to him and do you know what it took for him to get the plane repaired. That sounds very scary.
 
Vne is usually set by flutter onset, and if flutter didn't develop (believe me, you'd know if it had!), then no harm there. The possible over-g issue is probably more serious than the overspeed issue. Just how many g's showed up on the g-meter?
 
Ron Levy said:
Vne is usually set by flutter onset, and if flutter didn't develop (believe me, you'd know if it had!), then no harm there. The possible over-g issue is probably more serious than the overspeed issue. Just how many g's showed up on the g-meter?
Click to expand...

There are drag limits on airspeed as well so just because no flutter was encountered doesn't guarantee the lack of overspeed induced structural problems. I would agree that in most airplanes you'd have to exceed Vne by a lot to get into a drag issue, but I also believe this is entirely possible without flutter. As to the G issue, I don't think the OP stated that there was any G overload, just that with the high speed there was a "likely substantial load on the wings".
 
What model airplane?
 
The Citabria has an upright Vne and an inverted Vne. I exceeded the upright Vne accidentally once in a maneuver and had my mechanic check it over afterwards.
 
Well, from the back I didn't have a good view of the accelerometer, plus I was pretty glued on that airspeed. I wouldn't be surprised if there were excessive positive G's pulled as the pilot corrected the situation by pitching up pretty hard. I don't even recall if the throttle was all the way back.
The aircraft was a 7KCAB Citabria.
 
Last edited:
40-50 knots, I believe red line was 180? maybe 280, I don't remember.
 
blooddiamond said:
40-50 knots, I believe red line was 180? maybe 280, I don't remember.
Click to expand...
Red line in my Citabria (7GCAA) and also the 7KCAB is 162 mph. Inverted Vne is 135. I don't think that the airspeed indicator goes much higher than 180. Oh, I just found a photo of my panel. See attached.

If he exceeded 162 mph by 40-50 knots while pulling several G's, I'm amazed the airplane is still in one piece and flying.

I asked my mechanic what happens if you exceed the inverted Vne and he said the first thing to happen would be the greenhouse blowing out. Interesting stuff.
 

Attachments

  • Citabria ASI.jpg
    Citabria ASI.jpg
    241 KB · Views: 65
Blooddiamond;
It would, as others have said, be a good thing to have the plane given at least a cursory inspection.

The other part of your last sentence is what I'm concerned about.
"...a chance that this aircraft or pilot may endanger someone..."

I can see botching a vertical maneuver and getting red but for someone to screw a ROLL manuver up so bad that VNE is passed...well...I'd sure like to know what training your "buddy" has.
Though I could be wrong; from your description it sure sounds like either a roll to inverted was tried without any pitchup prior to the roll or that the roll was started OK but he "chickened out" and pulled elevator to regain wings level through the second part of the roll. It's called "dishing out" of a roll and has broken airplanes and killed people in the past (and will in the future unfortunatly).

If you buddy has not had Aerobatic instruction and is attempting to teach himself aerobatics tell him it's safer to study DIY brain surgrey...results will be about the same but he won't be tempted to take anyone with him.

If he owns the plane then the Monkey is on his back as to the inspection. If it's a rental then the owner as well as other pilots deserve to know the plane has been overstressed.

I don't suppose you were wearing a 'chute?

JMPO's
Chris
 
Ok, well looking after looking at that photo I'd say it was more like 15 knots over. We weren't inverted during the overspeed, it was after he failed to maintain the inversion with enough forward pressure on the stick, ditched, and ended up putting us into a nose low attitude while turning upright.

The aircraft is a rental, which is the only reason I am concerned about informing the proper person (which I've already done just in case). I don't know what kind of training he's had, but I assume he's had some sort of training in the aircraft considering it's a taildragger. Negative on the chute, I asked about it before we left and got the impression it wasn't required and nearly useless in Colorado since we can't get far enough off the ground for parachutes to be worth it with 6000 foot ground elevations. Apparently there's some sort of waiver?
 
Last edited:
Blooddiamond;

Just my opinion but your friend knows neither aerobatics nor the FAR's concerning them. The limitations in the FAR's concerning use of parachutes has no reference to height (MSL or AGL). My Softie will fully open in 800'. This last is per the Manufacturer...I myself personally have not verified it...(my Beta testing has it's limits).
Be afraid...be VERY afraid.

Chris
 
Last edited:
Oh I don't plan on going up with him ever again. It was extremely fun despite the overspeed, but yeah I definitely kissed the ground when I got back. Next time I'll be a little more cautious before I just hop in with someone.
 
Don;t let this put you off of aerobatics. There are lots of Flip-Flop-Flyers out there that know what they're doing and love to share the acro experince. Go to the .IAC.org website and see what and who is in your area.

Chris
 
blooddiamond said:
Well, from the back I didn't have a good view of the accelerometer,
Click to expand...
Most accelerometers have an extra pair of hands that show the max positive and max negative loads pulled during flight. Those should be checked after flight to confirm that the g-limits were not exceeded, and if they were, by how much. If your pal reset the max load markers before anyone else could look, you can (based on the sum total of dumb things you've reported he's done/said) be fairly certain that the positive g-limit was significantly exceeded on that pull-out. Therefore, I would not fly with that pilot again at all, or in that plane again until it's had an over-g inspection performed.
 
Hmmm. Sounds like this guy's a prime candidate for a smoking hole. :(

Hopefully he tries to get his next BFR from Rick Durden. :yes: :D
 
These posts are a few months old, but I had to join and say something.
On that deal where the guy exceeded vne and pulled a few g's in the process etc, I noticed that even some of you guys that were alarmed by that, made some comments that made me raise my eyebrows over your grasp of whats going on with an aircraft structure in flight.
I recently got my tail-wheel endorsement in a Super Decathlon after being inactive in flying for about 10 years. Then promptly learned aerobatics , which came pretty natural to me...and even though I haven't been nearly as involved in flying as a lot of you guys, I could instantly see that everyone has a slightly different concept of the mechanics of it and none of you were quite right.
 
wagy55 said:
These posts are a few months old, but I had to join and say something.
On that deal where the guy exceeded vne and pulled a few g's in the process etc, I noticed that even some of you guys that were alarmed by that, made some comments that made me raise my eyebrows over your grasp of whats going on with an aircraft structure in flight.
I recently got my tail-wheel endorsement in a Super Decathlon after being inactive in flying for about 10 years. Then promptly learned aerobatics , which came pretty natural to me...and even though I haven't been nearly as involved in flying as a lot of you guys, I could instantly see that everyone has a slightly different concept of the mechanics of it and none of you were quite right.
Click to expand...

well do you care to explain to us why none of us were quite right?
 
Good Lord, your asking me to go back and re-read all the comments, then do a lot of typing which i hate..Give me a moment...I'm doing several things at once, including petting the damn cat that wont get out of my lap
 
Welcome to the forum. :)

wagy55 said:
Give me a moment...I'm doing several things at once, including petting the damn cat that wont get out of my lap
Click to expand...
Be careful, this is what happens if you let your cat on the keyboard. :redface:

So, what do you fly? :)
 
sorry..dealing with the cat is making a smart alec...start to finish would be c-150,c-172,c-310,few houras in c-401, beechcraft bonanza(various models, 1 hour in a t-34 which was neat. one ultralite which had an engine failure and landed on a mountain highway(got famous for that) and some others I've forgotten about
 
Oh..sorry...just put about 20 hours on a super Decathlon last summer...that is a fun airplane, and it was like going back in time because the first plane i ever flew was an Aeronica champ...except the champ had so little horespower, it did nearly everything at 70 indicated...LOL
 
wagy55 said:
sorry..dealing with the cat is making a smart alec..
Click to expand...
I'll trade you cats. Mine is trained to stay off the aquarium. :D His name is Wilco.
 

Attachments

  • Wilco.JPG
    Wilco.JPG
    238.4 KB · Views: 42
wagy55 said:
one ultralite which had an engine failure and landed on a mountain highway(got famous for that)
Click to expand...
I'd like to hear that story. Is it somewhere on the internet?

Reminds me of the time my husband took off in our Challenger from our farm, but came back home in the back of a neighbor's pickup truck.
 
Last edited:
wagy55 said:
Good Lord, your asking me to go back and re-read all the comments, then do a lot of typing which i hate..Give me a moment...I'm doing several things at once, including petting the damn cat that wont get out of my lap
Click to expand...

We're still waiting for answer.:rolleyes:
 
well.. my experience with over g's and over speeds, and the engineering background that i have... as long as it was not terribly excessive, it shouldnt really pose much of a problem. If it was a wood wing citab... i think there is an ad to have the wings inspected every annual, and if those come up clean, no harm no foul, lesson learned. If its a metal wing, id just log it as an overspeed and keep in mind you just took a few cycles out of the wings life span. Inspections always would seem like a good idea, but engineers design in a faily substantial safety factor into things like that something like 1.5 is the standard for airplanes i think... personally, i would say no big deal, just learn the lesson that comes from it and dont do it again.

I also seem to recall that the bigger issue with the 7 series is that windscreen caves in around Vne.

just my thoughts....
 
wow that is pretty crazy...I mean, if I get up to anything over 135knt at the bottom of a loop I start easing off the back pressure so as to not stack on extra stress. Passed VNE? Jesus....
 
As I search the web tonight to figure out what I am doing wrong I am glad I found these posts. I have taken some basic aerobatic training, loops, aileron rolls, hammerheads and spins in a super decathalon. Everytime I attempt and aileron roll in my Citabria 7GCAA, after picking up airspeed (130 mph) and climbing to 20 degrees, unloadig the plane and cranking in full left aileron, once inverted the nose drops and in the recovering dive as the plane rolls to level I'm picking up way too much airspeed. Today I exceeded VNE for about 5 seconds by 15 mph as I recovered from the dive. Am I dishing out? I know I have forward/nuetral stick and full aileron control. In the decathalon it was so easy. I'm just about ready to call this aerobitic stuff quits before I pull the wings off.
 
joystick said:
As I search the web tonight to figure out what I am doing wrong I am glad I found these posts. I have taken some basic aerobatic training, loops, aileron rolls, hammerheads and spins in a super decathalon. Everytime I attempt and aileron roll in my Citabria 7GCAA, after picking up airspeed (130 mph) and climbing to 20 degrees, unloadig the plane and cranking in full left aileron, once inverted the nose drops and in the recovering dive as the plane rolls to level I'm picking up way too much airspeed. Today I exceeded VNE for about 5 seconds by 15 mph as I recovered from the dive. Am I dishing out? I know I have forward/nuetral stick and full aileron control. In the decathalon it was so easy. I'm just about ready to call this aerobitic stuff quits before I pull the wings off.
Click to expand...

OH, gosh, I don't even know where to start. I have a 7GCAA and had a LOT of problems learning to roll it. And the same things happened to me.

My POM calls for an entry speed of 120 mph for the barrel and slow roll and I use that for the aileron roll as well. I pull up higher than 20 degree normally (except for a competition roll) in the beginning of the roll so that the nose isn't as low when inverted. Yep, it's harder in the Citabria than the Decathlon.

Do you have access to an instructor who can work with you on this? No need to give up. You just need to figure out what you're doing wrong.

joystick said:
I know I have forward/nuetral stick and full aileron control.
Click to expand...
At what point did you have forward stick?

How many G's were you pulling when you exceeded Vne and pulled out?

If you have specific questions about the Citabria and making it do what you want or technical questions, the Citabria forum is also a good place to go to ask questions:

http://groups.yahoo.com/group/CitabriaPilots/
 
joystick said:
As I search the web tonight to figure out what I am doing wrong I am glad I found these posts. I have taken some basic aerobatic training, loops, aileron rolls, hammerheads and spins in a super decathalon. Everytime I attempt and aileron roll in my Citabria 7GCAA, after picking up airspeed (130 mph) and climbing to 20 degrees, unloadig the plane and cranking in full left aileron, once inverted the nose drops and in the recovering dive as the plane rolls to level I'm picking up way too much airspeed. Today I exceeded VNE for about 5 seconds by 15 mph as I recovered from the dive. Am I dishing out? I know I have forward/nuetral stick and full aileron control. In the decathalon it was so easy. I'm just about ready to call this aerobitic stuff quits before I pull the wings off.
Click to expand...

20 degrees nose high initiation point for an aileron roll at 130 in a Citabria isn't high enough unless you are "modifying" the roll a bit with forward elevator through inverted unloading the roll. The airplane has too much drag index using pure aileron to allow recovery on the back side without a deep dish out. The faster roll rate of the Decathlon will allow the same roll using the same numbers with far less dish.

Try raising the nose higher before initiating the roll. That will help you a great deal. Also, and this is extremely important, remember that although you need inside rudder applied with aileron to cancel adverse yaw to initiate the roll , don't forget to ease off that inside rudder once the roll rate is established. Holding the rudder in as you approach your first knife edge will definitely pull the nose DOWN on you, further complicating the back side situation and contributing heavily to your dish out problem.

The Citabria will do a decent aileron roll, but you MUST get that nose a bit higher and remember to ease off that rolling rudder.
 
When I was a pump jockey at the airport a guy I know got a new Citabria.
Two weeks later I climbed my ladder to fuel and asked what happened to his leading edges? They looked like someone took their fist and pounded down the leading edge between ribs. He said he was teaching himself aerobatics and it got really fast and really low and he had to pull really hard. It REALLY screwed up that airplane.
Dave
 
You must log in or register to reply here.
Back
Top