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  #1  
Old 06-24-2010, 11:28 AM
JohnF JohnF is offline
 
Join Date: Jan 2005
Posts: 458
Default Crunch !!!!

N29CX took off this morning for the initial flight. It lasted not more than two seconds. The plane accelerated smoothly and I noticed the RPM passing through 4950 when there was an uncommanded pitch of what I am guessing was 60-degrees, and full force forward on the stick didn't do anything and then there was a stall. Fortunately there was still forward momenten when the nose wheel hit the dirt at the side of the runway.

The nose wheel fork separated from the wheel. The nose leg severed at the point where it attaches to the bottom of the fuselage.

The exhaust pipe was a bit squeezed, and one exhaust pipe popped out of the muffler.

There were no oil, coolant, or fuel leaks. The ELT went off, and within perhaps 3 minutes I was out of the plane, stopped the ELT and disconnected the ELT antenna. The satellite still picked up the squawk.

The fuselage at the firewall is probably beyone repair, because of some rips in the skin. The firewall bottom is a bit curled up.
An aircraft mechanic helped me get the plane back into the hangar, and he found that the Ray Allen servo was damaged; the back of the servo box is broken out and there are broken gears showing. The linkage from the servo to the anti-servo tab, and to the point where it anchors to the tail cone area is in perfect condition - no scratches, no distortions, nothing broken, all in perfect shape, but the servo itself has its case broken at one side, and the part of the servo that screws out is jammed.

Was it an uncontrolled servo activation? The suspection right now is that it was, but that will be further investigated.

The prop broke away at the hub on one side, and broke off about 10-inches on the other side. NO damage to the pitot tube, nor the spinner. The oil cooler is perfectly OK, as is the muffler and the gascolator.

I know the engine will have to be removed, broken down, and I just hope that the crank is OK, but that will have to be determined.

The airworthiness inspection was on June 11th and I know the inspector took a lot of time looking at the anti-servo system (he had not seen an LSA or an RV-12 before) and he was satisfied.

I got as small scratch on my right index finger, but no other damage, nor even any shock.

My preliminary inspection makes me think that the entire 'fuselage' section will have to be replaced...wings are all OK, and tail section is fine, except where a plastic pipe that had reflective material on it to mark a taxi way edge poked a hole in the bottom of the fuselage...but that is an easy patch.

I will post more as I learn it. Only real damage is to my ego, and to a lesser extent, to the check book.

Does a 2-second lift off count as another RV-12 in the air? Darn, I took a lot of photos before the flight, and many more of the damage ... being an old FAA retiree and an attorney the back of my mind said take a LOT of photos of everything, including the Ray Allen servo...bad day at back rock, but at least I am OK, there was no property damage, and noone else was hurt.
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  #2  
Old 06-24-2010, 11:34 AM
TSwezey TSwezey is offline
 
Join Date: Oct 2005
Location: Savannah, GA
Posts: 1,849
Default

Sorry to hear about your short flight. We had a servo lock but luckily we caught long before we ever flew. We were just playing with it on the ground. Glad you're alright!
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Todd
N110TD
RV-10 Vesta V8 LS2/BMA EFIS/One formerly flying at 3J1 Hobbs stopped at 150 hours
Savannah, GA and Ridgeland, SC
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  #3  
Old 06-24-2010, 11:36 AM
JBPILOT JBPILOT is offline
 
Join Date: Nov 2007
Location: Jesup, Iowa
Posts: 1,673
Default Sorry to hear

For sure let us all know what you feel is the final estimate as to what may have happened. Glad you are OK !

John Bender
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  #4  
Old 06-24-2010, 11:39 AM
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kentb kentb is offline
 
Join Date: May 2005
Location: Canby, Oregon
Posts: 1,785
Default Ouch!

Sorry to hear about the plane, but glad to hear that you are OK.

Kent
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Kent Byerley
RV9A N94KJ - IO320, CS, tipup
AFS 3500, TT AP, FLYING....
Canby, Or
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  #5  
Old 06-24-2010, 12:52 PM
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apkp777 apkp777 is offline
 
Join Date: Oct 2008
Location: Schaumburg, IL
Posts: 2,053
Default

Wow, sorry to hear about that!
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Tony Phillips
N524AP, RV 9 (tail wheel)
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  #6  
Old 06-24-2010, 12:53 PM
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Brantel Brantel is offline
 
Join Date: Mar 2006
Location: Newport, TN
Posts: 7,509
Default

Wow...glad you are OK and sorry for the damage to your craft...

I am not familiar with the control system for pitch on the 12.

Why would a busted trim servo cause this? 60° pitch up with full down stick????

edit..

I just took a look at the plan revisions on Van's site that show this area and I now see how the mechanism works for the stabilator and anti-servo/trim tab....

Does anyone know if the 12 would even be stable enough to fly without the anti-servo tab? What is the expected result if it was disconnected and flapping in the breeze? How strong is it's influence changed by full range travel of the trim motor up and down?
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Last edited by Brantel : 06-24-2010 at 01:14 PM.
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  #7  
Old 06-24-2010, 01:20 PM
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RBD RBD is offline
 
Join Date: Apr 2006
Location: Tampa, FL
Posts: 406
Default

Sorry to hear about that, John, but glad you're ok. Things could have turned out much worse.
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Tampa, FL
RV-4 (sold)
RV-8 (sold)
Xtreme Decathlon (borrowing)
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  #8  
Old 06-24-2010, 02:22 PM
tacaruth tacaruth is offline
 
Join Date: Jun 2005
Posts: 121
Default

Sorry to hear about the problem. I cannot imagine the disappointment.

"An aircraft mechanic helped me get the plane back into the hangar"

Are you supposed to move the aircraft or leave it where it was for NTSB/FAA investigation? I'm sure there are alot of interested 12'ers that would like a report.

Good Luck
Tom RV-7A N175TJ Flying
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  #9  
Old 06-24-2010, 03:02 PM
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John Clark John Clark is offline
 
Join Date: May 2005
Location: Santa Barbara, CA
Posts: 1,324
Default NTSB

I doubt that there is a problem with having moved the aircraft, however I would contact the FAA and NTSB. As you will see in the attached, the first item they are interested in is flight control systems. The rules requiring a report are in NTSB 830:

Subpart B--Initial Notification of Aircraft Accidents, Incidents, and Overdue Aircraft

Sec. 830.5 Immediate notification
The operator of an aircraft shall immediately, and by the most expeditious means available, notify the nearest National Transportation Safety Board (Board), field office /1/ when:

(a) An aircraft accident or any of the following listed incidents occur:

(1) Flight control system malfunction or failure;

(2) Inability of any required flight crewmember to perform normal flight duties as a result of injury or illness

(3) Failure of structural components of a turbine engine excluding compressor and turbine blades and vanes;

(4) In-flight fire; or

(5) Aircraft collide in flight.

(6) Damage to property, other than the aircraft, estimated to exceed $25,000 for repair (including materials and labor) or fair market value in the event of total loss, whichever is less.


The usual procedure is for the NTSB to "appoint" the FAA to do the accident investigation when there are minor or no injuries.

John Clark ATP, CFI
FAA FAAST Team Member
EAA Flight Advisor
RV8 N18U "Sunshine"
KSBA
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  #10  
Old 06-24-2010, 03:51 PM
JohnF JohnF is offline
 
Join Date: Jan 2005
Posts: 458
Default Moving the crunched rv-12

The A&E and the airport manager and I all thought the damage was just the prop and the nose gear leg. The tail was out over a narrow taxiway and the nose just in the dirt along side, so it was really blocking the taxi way. When we got the plane back in the hangar and removed the lower cowling we could see that the damage was major. The NTSB and the local FSDO were notified and reports filed over the internet. A lot of photos were sent to the FSDO and they are going to try to have an inspector here this coming week.

The linkage from the servo to the trim tab and back to the tail hard point are all in absolutely perfect condition...not a scratch, but the Ray Allen servo has its aft end busted out and you can see broken plastic gears inside. It is also mechanically jammed.

More as I learn it...but I wish now I had the mechanical trim tab control that my now-sold RV-6A had...heavy but fool-proof. I may try putting something like that in after we get the -12 fixed, since its experimental I could do that.

The plane will sit there in the hangar until the FAA looks at it. I hope they take the servo away and have it analyzed. It did meet the up/down time when it had proper battery voltage as I re-checked it just a few days ago.
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