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kr2 incident


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Guest rocketdriver

Hi guys

 

thanks for your concerns and well wishes ... and, Yes, 2POB .... it is, after all a KR2 ..... and within wt and balance limits .....

 

FWIW, here is the text of my accident report and what happened .....

 

After a short flight of about 30 minutes, I rejoined the circuit crosswind and observed a very slack windsock with other a/c using runway 22. Flew a standard LH circuit and was a little high on short final so reduced RPM to idle. At this time I had full flap selected as used on previous flights. Flared the a/c with a little late correction to the sink rate. Touched down in a tail low wheeler attitude and allowed the tail to sink a little causing a skip. Both touchdowns were light. The aircraft deviated from a straight path requiring large helpings of rudder and brake to control. After possibly two quick waggles right and left, the aircraft appeared to be running straight but at angled towards the left of the runway and would not straighten up. As we left the tarmac surface I released the brakes as I knew the ground was likely to be soft. Shortly after the a/c left the tarmac surface it started to tip over and we stopped inverted in very soft ground, still within the runway boundaries.

 

Upon inspection immediately after I was released from the aircraft, I noted that the starboard wheel axle was badly bent upwards with the wheel having about 45 degrees of negative camber. I don’t know if this was a cause of the ground instability or not. The aircraft had sunk beyond its axles in very soft ground.

 

The following day we noted that, as it departed the tarmac centre strip, the aircraft ran about 7 or 8 meters on a soft mossy / grass that had a firm underlying surface. At this time the aircraft was running in a straight line at an angle of about 30 degrees to the runway alignment, pointing off to the east (left hand) side. The right hand brake was on or the wheel was dragging at this point as evidenced by the mossy grass surface being torn up in small tufts in the wheel track. The right hand wheel track then matched the indentation in the surface produced by the left wheel for another 4 or 5 meters, still running straight, with no scuffed grass tufts, indicating that the wheels were just rolling at this stage. After this the main wheels began to dig in evenly on both sides until they stopped abruptly after another 10 meters approx. The spinner witness mark in the ground was about 10cm deep and 30 to 40 cm long before it too stopped. The witness mark from the tail fin (a straight simple vertical slice into the ground) seems to indicate that the aircraft had zero forward speed at the point of impact. We recovered one broken propeller blade from about 15cm under the surface at which level there was free water present in the soil.

 

This was my fourth flight in this aircraft and the first with two occupants. On take off I had noted that I needed considerably more forward stick to raise the tail and also feel that the initial bounce was caused by the tail dropping quicker than I anticipated in this configuration. Although with difficulty, the aircraft swing had been stopped before the tarmac boundary was reached but at this point I could not turn the aircraft right to realign with the runway. Had the grass within the runway boundaries been firm, we would not be making this report.

 

With the wisdom of hindsight it was foolish for me to fly from a runway where the margins for either pilot error or mechanical failure had been so reduced by the wet ground conditions that there was only a narrow safe surface left for operatons..

 

 

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Thanx for the report rocket, we are all glad to hear you are both ok. This sort of thing happens, as youd know before this bingle.

 

It may have been a little bold of you to take a pax on the 4th flight, but thats not for us to comment on. Im just glad you are here to cop a ribbing...hehe

 

cheers

 

 

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Guest davidh10

Sorry to read of your mishap, but thanks for posting the report and glad you are both unhurt. A bit of heartbreak about the aircraft, but that will repair.

 

 

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  • 2 weeks later...
Guest rocketdriver

For some reason, I have not been getting alerts to your comments, guys, so aplologies for the delays .....

 

Motz ..."It may have been a little bold of you to take a pax on the 4th flight" clearly true in hindsight! and definately a contributary factor. The changed aircraft performance, climb rate and extreme pitch sensitivity in particular, led to a high work load on short final. Although the approach was adequate and stabalised (good speed, a little high so we were a little long in landing (about 200 metres in out of 1000 approx I guess) and no pilot induced oscillations) I didn't feel confident that I had a go around option if one was needed ........ Perhaps the ground run would have been more stable with a little throttle to give airflow over the tail ...... and so on ..... I think I have relived / reviewed what went on about a million times, and the ultimate answer still comes back to "should not have decided to fly out of a runway that was so restricted in width". With the full width available (including the grass) we would perhaps have been reporting a bent axle at the worst and I would still have an intact aeroplane (and ego)......

 

David I "Sitting here I can just imagine the slow motion sensation as she would have nosed over."

 

Yes .... I realised she was going up on her nose and watched the prop destroy itself in the black soil ... very memorable view that .... grass and black soil completely filling the windscreen and a lovely golden prop chopping itself in pieces (three actually, 2 tips and one hub!)...... But once she was past the vertical, she seemed to come down quite quickly .... witnesses says she nearly didn't go all the way ..... when she came down it seemed a very hard impact .......

 

"Out of curiosity, would you have been able to get out without the assistance of bystanders?"

 

My mate could and pretty much did by kicking and shoving against the broken canopy and the cockpit interior, but his harness was not properly tightened which is why he got a cut on the head .... he said after that he didn't bother to tighten it because he didn't believe we were going to have a prang ..... silly boy! I was jammed in somehow and couldn't move. My chin was jammed to my chest .. most uncomfortable ... and I couldn't get to my straps to loosen / undo them. When the tail was lifted, I was able to free my arms, take my weight on one of them and get the straps undone. Then it was easy ...... I think the a/c, whilst on its back, was also leaning on the wing tip on my side, leaving me rather less room to move .....

 

Its quite lucky that, during the refurbishment, we decided to do away with the upholstered cardboard panel that formed the rear "bulkhead" to the cockpit. We replaced iti with a piece of 3 mm ply screwed to the foam former that defines the shape of the rear turtledeck. This ply remained fully intact despite both the roll over ridge in the canopy frame and the fuselage cross bracing behind the seat having failed on impact. So, despite the non structural nature of the turtleback, it did not fully collapse which would have pushed us both further into the soft soil ... not a happy thought!

 

So there we are ... a little wiser, still a little sore in the neck and considerably less wealthy .... but alive!

 

Thank you again for all your kind wishes .....

 

cheers

 

RD

 

 

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Guest rocketdriver
You didn't say if your going to rebuild her, you have another one I believe , but I would be keen to follow the progress if you do fix her up!

Don't know yet ... have only just started to have a look .....Interestingly, it looks to me as if the broken longeron just behind the cockpit might have been fractureed 3/4 of the way through during construction as most of the cross section is quite dark in comparison to what is obviously the fresh break ..... Also interestingly, the fin structure itself appears to be intact but a sideways twist perhaps as the aircraft settled appears to have broken the fin structure out of the that of the fuselage. (fin was dug into the soil by about 200mm holding it firm and forcing the joints to break as the a/c settled onto one wing tip I guess .....)

 

Then there is the disapproval of "she indoors "to be considered ......

 

time will tell .....

 

Cheers

 

RD

 

 

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Guest rocketdriver

Hi everyone ... for those that want to see what she was and what she now is like I have posted a few pics here ...http://www.recreationalflying.com/useralbums/wasnt-she-pretty.20/view ..

 

cheers

 

RD

 

 

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  • 1 year later...

Rocketdriver, I know this happened more than a year ago but I just came across it.

 

Sorry for your loss but glad you are ok! Did you sell or fix your baby?

 

I know how you feel having "dinged" a KR2 as well........

 

Fly safe,

 

Rudi

 

 

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Guest rocketdriver

Hi Rudi ... Thank you for your thoughts ...

 

I'm in the middle of modifying/ fixing the a/c. I have converted it to tricycle and have fixed the structural stuff (one broken fuse longeron and ply panel just behind the cockpit and have splinted the broken fin main spar and replaced a ply panel under the HS). I'm currently awaiting a new canopy transparency so I can complete a rebuild of the canopy and the rear turtledeck. ....

 

Its taken a bit longer than it should of as it took a while to decide what to do ..... and my best mate (we met flying hang giders back in the '70's) died suddenly from complications following minior surgery and that took the wind out of the sails a bit ....

 

Anyway ... How, when/where did you ding your KR2? .... they seem to be a very survivable aircraft as the occupants seem always to walk away ... hope you did too!

 

Cheers

 

Martin

 

 

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Thanks for bringing this thread back to the top of the pile, Rudix. I must add my thanks to you RD for posting such a comprehensive report so soon after the bingle. We so rarely find out anything concrete after an accident, so your report is a valued contribution to our education.

 

I hope your pretty little plane is soon ready to fly again.

 

P.S. get that trainer wheel as far forward as you can!

 

 

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Hi Rudi ... Thank you for your thoughts ...I'm in the middle of modifying/ fixing the a/c. I have converted it to tricycle and have fixed the structural stuff (one broken fuse longeron and ply panel just behind the cockpit and have splinted the broken fin main spar and replaced a ply panel under the HS). I'm currently awaiting a new canopy transparency so I can complete a rebuild of the canopy and the rear turtledeck. ....

Its taken a bit longer than it should of as it took a while to decide what to do ..... and my best mate (we met flying hang giders back in the '70's) died suddenly from complications following minior surgery and that took the wind out of the sails a bit ....

 

Anyway ... How, when/where did you ding your KR2? .... they seem to be a very survivable aircraft as the occupants seem always to walk away ... hope you did too!

 

Cheers

 

Martin

Hi Martin!

 

Great news that you are fixing the KR2! Yes, even small jobs can take a lot of time, especially when you have to wait for bits like canopies. I was fortunate that the damage to my plane was minor, it could have been a LOT worse. Yes, I did walk away with no more than a few scratches! Flew again (another plane), less than an hour later.....

 

Here is a full account of what happened with photos:

 

http://rudix.zxq.net/ZS-VYZ/Stories/oops.htm

 

Hope your KR will be flying again soon!

 

Cheers,

 

Rudi

 

 

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Thanks for posting this very instructive story, Rudi. My own canopy has issues; I am still working on a better type of latch. It slides at the front and hinges on short arms from the back, to eliminate the need for an ugly long pair of tracks. In flight the canopy has popped open a few times, and slides back about 50mm to a point of equilibrium. I designed it to be fully openable in flight but I haven't been game enough to try it so far. Your experience adds to my misgivings.

 

 

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Guest rocketdriver

Hi Rudi

 

Glad you were ok ..... tough little birds aren't they! Lucky you didn't go over the top ... thats where most of my damage came from ... plus I found out that you need really solid roll over protection together with a canopy that breaks so you a). survive the inversion and b). can get out (room to move plus an open exit!). (I actually think that the broken longeron occured when my passenger mate kicked it to enlarge his exit path and the fin spar broke when the inverted aircraft rolled to rest its port wing tip on the ground whilst the fin top was firmly stabbed about 200mm into soft mud ....)

 

cheers

 

Martin

 

 

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Hi Martin!Great news that you are fixing the KR2! Yes, even small jobs can take a lot of time, especially when you have to wait for bits like canopies. I was fortunate that the damage to my plane was minor, it could have been a LOT worse. Yes, I did walk away with no more than a few scratches! Flew again (another plane), less than an hour later.....

 

Here is a full account of what happened with photos:

 

http://rudix.zxq.net/ZS-VYZ/Stories/oops.htm

 

Hope your KR will be flying again soon!

 

Cheers,

 

Rudi

Hi Guys,

 

Just read this - glad you are both OK.

 

I fly a Sonerai and there is a story on the Sonerai Owners site of a canopy opening in flight - same unstable inablity to fly - with the canopy open to one side - the only way that one landed was to grab the canopy and try to close it - similar story to Rudy - I'd suggest that neither aircraft will fly without a canopy at all! That's the conclusion the other Sonerai owner came to - but I've never seen any research data to back that opinion up.

 

Hope the repairs go OK and you both get up - certainly emphasises the need to check that the canopy latches actaully keep the canopy closed!!!!

 

Regards,

 

Mike S

 

 

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They really are strong little planes Martin!

 

I agree Mike, I would not like to fly it without a canopy, I was told the airflow over the tail becomes so disturbed that controlling the plane, and preventing a spin, becomes a mayor problem. I know of a KR that spun in from 8000' after loosing the canopy, the pilot was injured but survived!

 

I think I will make sure my canopy stays on in the future......

 

BTW, I love the Sonorias and I am busy negotiating a deal on one (2L) at the moment!

 

Regards,

 

Rudi

 

 

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