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  #61  
Old 11-11-2013, 09:56 PM
gossend gossend is offline
 
Join Date: Dec 2011
Location: Georgetown, Texas
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Exclamation Not due to a problem with the aircraft??

Gee...i cant let that one slip by! What do you think happened?
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  #62  
Old 11-12-2013, 12:36 AM
rgmwa rgmwa is offline
 
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Location: Perth, Western Australia
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Quote:
Originally Posted by gossend View Post
Gee...i cant let that one slip by! What do you think happened?
I don't know exactly what happened but based on the information I have concerning this accident and those involved in it, it seems highly unlikely to me that a problem with the design, the preparation of the plane, weather or pilot error caused the crash. That doesn't leave too many other possibilities. You may also want to go back and read post #22. When the investigation results are eventually published, we will all know the details.
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  #63  
Old 12-04-2013, 08:39 PM
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RV10inOz RV10inOz is offline
 
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Location: Brisbane Qld. Aust.
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Post #22 http://www.vansairforce.com/communit...6&postcount=22


And here I my comments based on the data available from the ATSB report done for the NSW Police.
http://atsb.gov.au/media/4469487/AE-2013-069_Final.pdf

I have a few comments to make here; My opinion based on the data.

Take off roll starts at 50:23 approx
Gets going at 50:28
Takeoff speed starts around 50:33
IAS peaks at about 80 Knots @ 50:42
Pitch is steady through the roll until 50:42
PA is steady from 33-42s as well, with a short dip, typical of a positive pitch up (static port sinking)
Trim is repeatedly pitched down during the acceleration and then pitched up prior to the rapid climb, then trimmed back down again
Full power applied in the time up to 50:28
Distance travelled approx 380m in the 50:25 > 50:42 sec range.

I have flown Dick VanGrunsven's own personal RV12, and even with two of us, (he is very tall & I am errr..more solid) the takeoff distance is half that.

I have made my comments known on this before. There is nothing to suggest this is anything other than the result of deliberate and foolish acts by the pilot.

I might be proven wrong when the NSW police evidence is presented to the coroner. But it looks unlikely.

Make your own mind up after studying that.
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  #64  
Old 12-04-2013, 09:38 PM
rgmwa rgmwa is offline
 
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I had suspected pilot incapacitation as the most reasonable explanation based on accounts of what happened and assuming that a test pilot would have acted responsibly. Looks like I was wrong in that assumption.
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RV-12LR 912ULS
120346
  #65  
Old 12-05-2013, 08:08 AM
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Geico266 Geico266 is offline
 
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The detailed and straight forward accident reports from AU are amazing.
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  #66  
Old 12-05-2013, 08:20 AM
sailvi767 sailvi767 is offline
 
Join Date: Sep 2010
Location: Charlotte NC
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I must be missing something. All I see is data showing a aircraft taxi out, make a return back to the hangar and then go back out takeoff and pitch up to a very high deck angle where it appears to depart controlled flight. There are so many things that could cause that I could write for hours listing them.
David provides a lot of great information on the forum but has a strange habit of talking in riddles at times. What is he trying to say and what is the apparent cause?

George
  #67  
Old 12-05-2013, 10:24 AM
cactusman cactusman is offline
 
Join Date: Oct 2012
Posts: 421
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Quote:
Originally Posted by RV10inOz View Post
Post #22 http://www.vansairforce.com/communit...6&postcount=22


And here I my comments based on the data available from the ATSB report done for the NSW Police.
http://atsb.gov.au/media/4469487/AE-2013-069_Final.pdf

I have a few comments to make here; My opinion based on the data.

Take off roll starts at 50:23 approx
Gets going at 50:28
Takeoff speed starts around 50:33
IAS peaks at about 80 Knots @ 50:42
Pitch is steady through the roll until 50:42
PA is steady from 33-42s as well, with a short dip, typical of a positive pitch up (static port sinking)
Trim is repeatedly pitched down during the acceleration and then pitched up prior to the rapid climb, then trimmed back down again
Full power applied in the time up to 50:28
Distance travelled approx 380m in the 50:25 > 50:42 sec range.

I have flown Dick VanGrunsven's own personal RV12, and even with two of us, (he is very tall & I am errr..more solid) the takeoff distance is half that.

I have made my comments known on this before. There is nothing to suggest this is anything other than the result of deliberate and foolish acts by the pilot.

I might be proven wrong when the NSW police evidence is presented to the coroner. But it looks unlikely.

Make your own mind up after studying that.
I think that blaming a dead pilot not able to defend themselves is inappropriate.

The RV-12 does not have manual trim, and is rather dependent on a trim motor with wire connections.

The data does not show the position of the trim switch or the actions of the pilot or if the trim was running away. The final report will improve instructive, but as someone who is quite familiar with the political nature of accident investigations carefully structured under the guise of safety, I can tell you that I intend to be pretty darn careful with the trim settings as runaway/improperly set trim has caused a lot of accident and incidents in aviation in general, and the numerous problems and posts on here have proven very instructive to later builders to learn from the problems others have faced in this regard.
  #68  
Old 12-05-2013, 11:33 AM
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rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
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Quote:
Originally Posted by cactuspilot View Post
The data does not show the position of the trim switch or the actions of the pilot or if the trim was running away. and the numerous problems and posts on here have proven very instructive to later builders to learn from the problems others have faced in this regard.
I agree that the data doesn't show specific trim position but it does show changes in the pitch trim control and changes were made in both directions so (to me anyway) it appears highly unlikely there was any type of pitch trim runaway.

I am not going to allow anyone to accuse me of playing the blame game, but I will point out a couple things that may not be obvious to everyone looking at the data of this report.
I understand and respect Doug's policy regarding waiting for a final accident report... my understanding is this will be the only report ever published for public consumption. The ATSB got involved with the investigation to help assist with data acquisition only. The local authorities were leading the investigation, and it is my understanding that their report will never be made public (though I may be wrong).

The data indicates that the airplane lifted off after about an 8 second long take-off run (about what would be expected).

It then leveled off at 20 ft (because of instrument errors of some type, it started out indicating a Neg. 50 ft altitude for some reason but it doesn't matter, we can still see a delta increase of 20 ft)

It flew level at 20 ft (with a pretty high level of precision, that for me doesn't indicate that it was severely out of trim in pitch... you decide for your self) for about 13 seconds.



During the level flight at 20 ft it accelerated pretty much linearly to about 89 MPH (converted from Meters/Second).
During this time the pitch trim was being constantly adjusted. Fully expected since the pitch trim would be changing the entire time the airplane was accelerating. NOTE: The actual calibrated trim range is noted to be from 1 to -1 so the amount of pitch trim change indicated in the chart is a small percentage of the entire range.

At the end of the 13 seconds level at 20 altitude, the airplane made an abrupt pitch up. The stall indicator activated at the beginning of the pitch up, probably as a result of it not yet being calibrated properly.

Airplane decelerates during the steep climb until it appears to stall at about 125 ft AGL, where during the stall it both yaws and rolls abruptly to the right
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RV-6A (aka "Junkyard Special ")

Last edited by rvbuilder2002 : 12-05-2013 at 11:38 AM.
  #69  
Old 12-05-2013, 11:48 AM
nauga nauga is offline
 
Join Date: Jan 2007
Location: AOTP
Posts: 192
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Quote:
Originally Posted by RV10inOz View Post
Trim is repeatedly pitched down during the acceleration and then pitched up prior to the rapid climb, then trimmed back down again
From the report:
Quote:
The elevator trim position appeared to have been mapped from -1 to 1; this range represents the travel of the motor arm attached to the pitch trim servo. Further information is required to convert this value into elevator trim position
The trim motor *indication* changes just a hair over 1.5% of its full range during the trace. There's no assurance that the trim tab itself moved at all as a result, and there's no calibration or even a sign convention to tell what that means in any meaningful sense. I wouldn't read anything into such a small variation. Others might.
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2004 RV-4
  #70  
Old 12-05-2013, 12:21 PM
cactusman cactusman is offline
 
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