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-   -   CAF Dakota crash, Burnet, TX 21-7-18 (https://www.pprune.org/rumours-news/611358-caf-dakota-crash-burnet-tx-21-7-18-a.html)

oxenos 29th Jul 2018 10:21

Pretty much a carbon copy of an accident at Enstone, U.K. 20 years ago.
In both cases:-
1. A large, twin engined tailwheel vintage aircraft.
2 En route to an air display, with passengers on board.
3. Light winds.
4.Less experienced pilot handling, from right hand seat.
5. A swing developed, not controlled.
6.PIC took control, failed to correct swing.
7. Aircraft about to depart runway, pilot elected to pull it off the ground.
8. Stalled, wing dropped, wingtip struck ground, cartwheeled.
9. No fatalities, aircraft written off.

In the Enstone accident, the aircraft written off was the last flying example worldwide.

https://aviation-safety.net/database...?id=19960718-0

Old Boeing Driver 29th Jul 2018 13:03

As the aircraft gets abeam of the guy filming, there is a puff of dirt from the tail wheel as it comes off the ground and back down. Is he off the side of the runway at that point?

Also, there is no deflection in the elevators at that point. I realize they are drooping in the post fire pictures.

Has there been any publication or interview with the guy filming. He sees something early in the take off and seems to know something is wrong.

donotdespisethesnake 29th Jul 2018 17:42


Originally Posted by Old Boeing Driver (Post 10209272)
He sees something early in the take off and seems to know something is wrong.

That's been asked and answered twice already.

Old Boeing Driver 29th Jul 2018 18:37


Originally Posted by donotdespisethesnake (Post 10209422)
That's been asked and answered twice already.

Sorry. Did not see an interview with him. Can you supply a link, or a post Number?

Thanks.

EDIT: I looked through all the posts, and see a few with mentions of being off the runway, but nothing definitive. A few gust lock comments, too. I still don't see anyone quoting the person filming as to what he saw early in the roll.

M.Mouse 29th Jul 2018 19:20

OBD, to save you actually having to read what has gone before try this: More info on what happened

Chris Scott 29th Jul 2018 23:11


Originally Posted by ehwatezedoing (Post 10208523)

Hello Chris, having them pre-selected into the wind is of course a good course of action. What I mean is your ailerons alone can counteract a swerve by themselves if used properly (they are the size of a Caravan’s wing)

On DC3’s wheels on the ground your ailerons are very effective for directional control. It’s a great arrow in your quiver of arrows things to use (like your rudder) to stay centered. And it is something that seems to seems to be more and more forgotten as new people embark flying this type. Turbine version included.

Again, while wheels are touching ground. Yanking them in the air at a speed that can barely sustain yourself will most probably have a poor outcome.

Hi ehwat,

This discussion about the use of aileron to help counter a swing - rather than helping prevent one happening in the first place - has been most interesting and enlightening for me, but I doubt it has much relevance in this particular case. I'm sure you'd agree that the primary means of directional control on take-off and landing remains the rudder. Judging from the information in the video linked above, the conditions were such that secondary techniques - such as aileron, asymmetric power, differential brake or the locked tail-wheel - would have been unnecessary to keep the a/c straight above taxiing speed.

Several posters with more (and more recent) experience of the type than I have experienced difficulty in getting the tail up, which would normally be at 40 kt IAS or soon after - well before flying speed. The public-transport, C-47 operation I was involved with consisted of five freighters and one passenger a/c, using a MTOW of 28,000 lb. A load and trim sheet was prepared for each take-off and, in my limited experience (500 hrs), I never experienced a take-off where the tail was reluctant to fly.

Yes, it goes without saying that the tail must be lifted well before the a/c reaches flying speed to avoid getting airborne prematurely. In any case, to state the obvious: if the tail remains on the ground, no pilot-commanded rotation in the nose-up sense is possible, so I don't understand your final point. The poor outcome is likely to happen because the a/c then flies itself off in a semi-stalled condition, which is what may have happened here.

radfordc 30th Jul 2018 00:03

I'm not able to post the link but the guy who trained the pilots posted a video on Facebook explaining what happened. Look up "Dan Gryder" on Facebook.

Old Boeing Driver 30th Jul 2018 01:36


Originally Posted by M.Mouse (Post 10209493)
OBD, to save you actually having to read what has gone before try this: More info on what happened

MM. Thanks. I have watched that, and his description is probably accurate. I have also read a lot of the expert posts here. Lots of guys with great experience.

I was just asking about what the guy who was filming saw that caused him to get excited. I would have thought some news outlet would have interviewed him by now.

Thanks for your response. I'll wait and see what turns up.

Have a great evening.

ehwatezedoing 30th Jul 2018 15:09


Originally Posted by Chris Scott (Post 10209644)
Hi ehwat,

This discussion about the use of aileron to help counter a swing - rather than helping prevent one happening in the first place - has been most interesting and enlightening for me, but I doubt it has much relevance in this particular case. I'm sure you'd agree that the primary means of directional control on take-off and landing remains the rudder. Judging from the information in the video linked above, the conditions were such that secondary techniques - such as aileron, asymmetric power, differential brake or the locked tail-wheel - would have been unnecessary to keep the a/c straight above taxiing speed.

Correct but knowing where to swing your ailerons on the roll when you run out of rudder authorities, like it seems happened, would have helped.
playing hard with your ailerons while just barely airborne is a recipe for disaster, even if a DC-3 can pull itself away and go flying from a very slow speed. This as long as (once in the air) you don’t play with your controls and keep a decent angle of attack.


They were an obstacle on their way at some point, hence the yanking up and wing walking.
Sh!t happen, nobody is immune to it. That was a pretty good one though..

Wingnuts 3rd Aug 2018 03:31

It appears that aircraft begins to fish tail with increasing amplitude as it accelerates. Perhaps this is what alarms video man.
The tail wheel is castoring type and the last item on Take Off checklist is to ensure it is locked straight.
I wonder if initial swing was caused by application of take off power and unlocked tail wheel?

Old Boeing Driver 3rd Aug 2018 12:26

Thanks
 

Originally Posted by Wingnuts (Post 10213251)
It appears that aircraft begins to fish tail with increasing amplitude as it accelerates. Perhaps this is what alarms video man.
The tail wheel is castoring type and the last item on Take Off checklist is to ensure it is locked straight.
I wonder if initial swing was caused by application of take off power and unlocked tail wheel?

I think you may be right. I looked at the video several more times and it does appear to fish tail early in the takeoff. There are are several comments above from some very experienced DC-3/C47 pilots, which discuss the tail wheel issue.

Thanks for noticing that and posting.

Super VC-10 3rd Aug 2018 20:34

Some of the speculation seems to have been off target.

https://www.ntsb.gov/_layouts/ntsb.a...20180721X41413

ehwatezedoing 4th Aug 2018 13:14


Originally Posted by Super VC-10 (Post 10213932)
Some of the speculation seems to have been off target.

https://www.ntsb.gov/_layouts/ntsb.a...20180721X41413

If you are referring to speculation about tail wheel being unlocked. Yes and no.

They mention in your link that: «The tailwheel locking pin was found in place and was sheered into multiple pieces»
Which means that at some point their tail wheel became free casting as its shearing locking pin did its job by breaking under heavy side load tensions.

It is pretty obvious it happened during their take off roll while trying to straight things up.







Pilot DAR 4th Aug 2018 14:13

The tailwheel locking pin can also be sheared during careless ground handling with a tow bar. In such a case, it is possible that the pilot could select it to the locked position, and be unaware that the tailwheel was not effectively locked. It's certainly nice to have a locked tailwheel, though a safe takeoff is still possible with it unlocked, the rudder will steer the plane if used with purpose.

D-OCHO 4th Aug 2018 15:11


Originally Posted by Pilot DAR (Post 10214421)
The tailwheel locking pin can also be sheared during careless ground handling with a tow bar.

If that is the case you would have noticed during taxi.
Take off without a locking pin is possible if you would know it. If not the moment you add power the aircraft would turn due p-factor.
(About my experience. 1.500 hours in it's little brother the BE-18 including as an instructor and a couple of hours in the DC-3)

Hotel Tango 4th Aug 2018 15:15


the rudder will steer the plane if used with purpose.
Just a question and nothing more. Could overzealous application/correction of the rudder with an unlocked tail wheel easily lead to a loss of control?

3wheels 4th Aug 2018 16:01

It will be very interesting to see the co-pilots total Dakota experience, AND his recency on type.

See my post #22...

D-OCHO 4th Aug 2018 17:20


Originally Posted by Hotel Tango (Post 10214463)
Just a question and nothing more. Could overzealous application/correction of the rudder with an unlocked tail wheel easily lead to a loss of control?

No.not enough airflow over the rudder at that speed. Plus most of the rudder is behind the wing.
Problem doing a take-off with a low wing taildragger is that there are 3 phases in the take-off roll:
  1. All the time the tailwheel is on the ground.
  2. The transition fase between lifting the tailwheel and rolling with the fuselage level.
  3. From that time until lift off.
In Phase 1 the tailwheel will do most of the tracking of the aircraft. Also correct use of the aileron and differential power if needed helps. The rudder is mostly in the shadow of the wing so there will be almost NO clean airflow over it. Only the top part will experience clean airflow.

In Phase 3 The rudder is completely exposed to the airflow so it is at that time your primary runway tracking device.

The most difficult part is the transition Phase 2. Your tailwheel is lifting off the ground so you will loose its tracking capability. The rudder is still in the wing shadow. So the only means of keeping the aircraft straight is differential power, aileron and a little-bit of rudder.

The BE-18 was in that respect a b!tch. It had a very small rudder and a very short fuselage.

So what was the reason for the crash. I can not say. But I can say that what I see in the video is that the aircraft is not ready to fly jet.

Like other people say if there was any kind off problem (flight control, engine) they should have aborted the take-off.

I hope the investigation come with e definite answer.

Hotel Tango 4th Aug 2018 18:17

OK, thank you for that D-OCHO

Eric Janson 4th Aug 2018 21:34

Don't agree with what D-OCHO has written.

There is plenty of airflow over the rudder with the engines running - the rudder is effective when taxiing the aircraft,

@Hotel Tango - the answer to your question is yes. The correct thing to do in this situation is to get the tailwheel off the ground ASAP.


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