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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)

KarlADrage 24th Jul 2018 08:01


Originally Posted by Mach E Avelli (Post 10204469)
It would be interesting to know what it was that had the guy taking the video invoking religion and excrement so early in the take-off run. He appears to have seen something unfolding before it actually did. Let's hope he is a reliable witness.

I read a comment on a thread on the Facebook page where the video was originally shared from someone who claimed to be there at the time. She (I seem to recall!) confirmed that the concern expressed by the man was due to a violent swing to the left when the tail briefly became airborne, which isn't quite so obvious in the video.

sablatnic 24th Jul 2018 08:02


Originally Posted by Three Lima Charlie (Post 10204039)
In this photo you can clearly see the elevators down, no control lock. Later in the fire, the elevators sag to the ground and move upward to a more neutral position.

https://static-16.sinclairstoryline....?1532222524452

Certainly no gust locks here - thanks!!

Chris Scott 24th Jul 2018 09:20


Originally Posted by Airbubba (Post 10202623)
Looks like the tailwheel kicked up a puff of dirt before liftoff, maybe went off the left edge of the runway as the nose yawed right.

Can anyone confirm that the a/c was using the asphalt runway? Very hard to tell from the video - could almost be a grass runway. The asphalt runway is apparently only 75 ft wide - half the standard width. So not much room to recover from a severe swing. Perhaps the first exclamation from the camera operator was a response to the left main-wheel leaving the runway, as I think Airbubba was implying in the above post?

KarlADrage,
I think the tail comes up briefly after the swing has been corrected, but probably with the left main-wheel already on the grass.

Watson1963 24th Jul 2018 09:58

More views
 
https://www.facebook.com/groups/4140...0865617665413/

Pilot DAR 24th Jul 2018 23:49

While riding jump seat in the turbine DC-3 today, I watched carefully what the very experienced pilot did during the takeoff: On the airspeed alive call, control wheel pressed gently forward, and the tail coming up at about 40 knots. Power set and confirmed by 50 knots, and aircraft gently rotated off the runway at the bug speed of 82 knots. My comprehensive stall testing in this aircraft eleven years ago showed a stall speed of 59 to 57 KIAS. The wind was 12G20 right down the runway, and the variability of the headwind seemed very easily compensated by the use of bug speeds from the performance charts. I'm confident that had the winds been more severe, or more variable, the pilot would have allowed a little extra caution speed.

Directional control and pitch attitude control are not really related during takeoff. If the accident aircraft had a directional deviation, it would still have had a better outcome were the tail to be up, and the aircraft at flying speed before being allowed to become airborne. The sudden wing drop visible in the video is exactly what happened to me numerous times during stall testing of a turbine DC-3. Recovery was gentle if initiated before the stall had occurred. If the stall progressed to loss of control, it was demanding to recover with minimum upset. Recovery from a half turn incipient spin in t DC-3 will use up around 2000 feet of altitude for my experience.

Chris Scott 25th Jul 2018 13:27


Originally Posted by Pilot DAR (Post 10205308)
[...] On the airspeed alive call, control wheel pressed gently forward, and the tail coming up at about 40 knots. Power set and confirmed by 50 knots, and aircraft gently rotated off the runway at the bug speed of 82 knots.

Directional control and pitch attitude control are not really related during takeoff. If the accident aircraft had a directional deviation, it would still have had a better outcome were the tail to be up, and the aircraft at flying speed before being allowed to become airborne...

I agree with your analysis, Pilot DAR. Whether the a/c had left the side of the paved runway or not, any attempt to use the locked tail-wheel to regain directional control by deliberately lowering the tail again would have been unnecessary and inappropriate. The rudder is very effective with the tail up, although PIO can be a problem.

That said, what puzzles me most is why, if things were going so badly wrong that the tail could not be lifted, the take-off was not simply aborted.

broadreach 25th Jul 2018 17:59

En route to Oshkosh, full of people looking forward enthusiastically to the show, we can deal with this once we're airborne.
Edit: not suggesting lack of professionalism, just that there may have been some unspoken get-there pressure around. An apparently minor problem rapidly growing into something more serious.

Bobby G 26th Jul 2018 08:21


Originally Posted by Pilot DAR (Post 10205308)
Directional control and pitch attitude control are not really related during takeoff. If the accident aircraft had a directional deviation, it would still have had a better outcome were the tail to be up, and the aircraft at flying speed before being allowed to become airborne. The sudden wing drop visible in the video is exactly what happened to me numerous times during stall testing of a turbine DC-3. Recovery was gentle if initiated before the stall had occurred. If the stall progressed to loss of control, it was demanding to recover with minimum upset. Recovery from a half turn incipient spin in t DC-3 will use up around 2000 feet of altitude for my experience.

In a standard powered DC-3 the forward push to get the tail up can hardly be called "gentle" when heavily loaded. Now this airplane was nowhere near that condition but I have flown them where it takes everything you have to push the tail up. As a matter of fact in those conditions you have to use the trim wheel to get things going. As for directional control, as I mentioned in a separate post, the ailerons are highly effective for directional control and MUST be used, rudder alone cannot overcome a large swing. And we routinely used aggressive differential power when needed to keep the thing straight when aerodynamic control input was not sufficient.

Judd 27th Jul 2018 02:24


In a standard powered DC-3 the forward push to get the tail up can hardly be called "gentle" when heavily loaded. Now this airplane was nowhere near that condition but I have flown them where it takes everything you have to push the tail up. As a matter of fact in those conditions you have to use the trim wheel to get things going. As for directional control, as I mentioned in a separate post, the ailerons are highly effective for directional control and MUST be used, rudder alone cannot overcome a large swing. And we routinely used aggressive differential power when needed to keep the thing straight when aerodynamic control input was not sufficient
That all sounds very dramatic for a DC3 and may I say a little exaggerated? If you have "used everything" then to get the tail up during the early part of the take off run in a standard DC3 it suggests maybe the Centre of Gravity was a problem. The DC3 is a normal tail wheel aircraft with normal take off and landing characteristics. No unusual control forces are needed and the rudder is effective early. We never had to use ailerons for directional control (apart from appropriate aileron into a crosswind) and certainly never use "aggressive" differential power.

Are you sure you are not talking about flying a DC3 Microsoft simulator? Never heard of using the elevator trim to get the tail up. The elevator trim is useless at low speeds anyway. By what you have described is not an average DC3 handling at all. Of course if you have allowed the aircraft to gather momentum in a large swing, that suggests slow pilot reaction to prevent any initial swing from trying to force the tail up. Once you allow that to happen due poor flying ability, then all bets are off in terms of getting the aircraft to straighten up again and you may even have to resort to dabs of appropriate brake pedal to prevent further yaw on the roll. Not trying to rubbish your description but something not quite right IMHO.

Bobby G 27th Jul 2018 05:02


Originally Posted by Judd (Post 10207276)
That all sounds very dramatic for a DC3 and may I say a little exaggerated? If you have "used everything" then to get the tail up during the early part of the take off run in a standard DC3 it suggests maybe the Centre of Gravity was a problem. The DC3 is a normal tail wheel aircraft with normal take off and landing characteristics. No unusual control forces are needed and the rudder is effective early. We never had to use ailerons for directional control (apart from appropriate aileron into a crosswind) and certainly never use "aggressive" differential power.

Are you sure you are not talking about flying a DC3 Microsoft simulator? Never heard of using the elevator trim to get the tail up. The elevator trim is useless at low speeds anyway. By what you have described is not an average DC3 handling at all. Of course if you have allowed the aircraft to gather momentum in a large swing, that suggests slow pilot reaction to prevent any initial swing from trying to force the tail up. Once you allow that to happen due poor flying ability, then all bets are off in terms of getting the aircraft to straighten up again and you may even have to resort to dabs of appropriate brake pedal to prevent further yaw on the roll. Not trying to rubbish your description but something not quite right IMHO.

If you don't believe my story above then you probably think that winds in St. Thomas, USVI cannot possibly be reported as "wind 22 knots gusting to 34, all quadrants" when coming in to land and it is a pretty wild ride that DOES take everything you have including near full aileron deflections on takeoff and landing. And yes, in a DC-3 loaded with 30 passengers, 600 lbs baggage aft and 400 lbs baggage forward it IS hard to keep the tail up when you want it up and yes, some guys roll the trim forward as they accelerate and roll it back once the tail is up. When it is gusty you manhandle the controls, there is nothing gentle about it.

Granted, it is calm in this video but that is deceiving, too. A light crosswind is easier to handle than no wind at all since the airplane is pushed to one side and there is no question about which way to correct. In calm conditions it is easier to swing from side to side.

Not Microsoft simulator but 1600 hrs in DC-3s from 1977 to 1979 in San Juan, Puerto Rico. Air Caribbean. 5 airplanes. They all flew different. "No unusual control forces are needed". Hmmm, not really, did you ever fly one at gross wight in gusty conditions? Some had light controls and others had super heavy controls and were pretty tough to handle. Some flew great on one engine with a load in the back, others were pigs and would barely fly with the good engine at METO power and lightly loaded. We had P&W powered and Wright Powered. We had left door DC-3's and right door DC-3's. My memory is pretty good...

Chris Scott 27th Jul 2018 10:48

Must concur with Judd and Weheka. The aircraft that Bobby G describes above bears little similarity to the C-47s that I flew fifty years ago. I invite Bobby G to explain precisely how - on the aircraft - the ailerons could be used to such high effect in regaining directional control after a swing.

As for differential power, this helps in the early stages before the tail is lifted but, IMHO, could land you in a lot of trouble later on. In our operation the PNF took control of the throttles early on, to ensure that the engines were not over-boosted, and then the PF took charge of them again.

ehwatezedoing 27th Jul 2018 11:09

Where was their abort’s call!?

The ailerons are none the less very effective tail low on a DC-3 for directional control.
Your downward aileron pretty much act like a spoiler in those conditions and is amazingly good at helping you recover from a swerve going the opposite direction. Timming while doing it is everything.

A common rookie mistake when starting an uncommanded swerve is trying to correct it like you would do in a car and its steering wheel (don’t laugh, I’ve seen it) That would just exacerbate your controlling issue.

I was wondering if that was not part of their initial problem. Driving their swerves instead of flying them. Then I realise that the CAF would never put rookies at the control of one of their aircraft, so that simply cannot be.
Keeping its tail low for whatever reason like elevator jammed or partially jammed was definitely one though.











Chris Scott 27th Jul 2018 13:17


Originally Posted by ehwatezedoing (Post 10207592)
[...] The ailerons are none the less very effective tail low on a DC-3 for directional control.
Your downward aileron pretty much act like a spoiler in those conditions and is amazingly good at helping you recover from a swerve going the opposite direction. Timming while doing it is everything.


Interesting. The only point I would offer from my limited experience on the type is that, with the tail still on the ground in a strong crosswind, I would have pre-selected full into-wind aileron anyway. The swing is most likely to be into-wind, and no further deflection would be available. Admittedly, the swing could be in the downwind direction, in which case would you remove the into-wind aileron briefly?

What do you mean by "Timming while doing it is everything."?


A common rookie mistake when starting an uncommanded swerve is trying to correct it like you would do in a car and its steering wheel (don’t laugh, I’ve seen it) That would just exacerbate your controlling issue.


Yes, I've seen that by a rookie on a big jet. Apparently, it had worked in the simulator...

Weheka 28th Jul 2018 00:10

Apologies to Bobby G for doubting his experience in the DC3 aircraft. Still don't understand why the characteristics are not very similar to other tail dragger aircraft but my experience is only in the single engine types. For example in a loaded 185 I would set trim so tail will come up virtually on its own, once six inches or so off the ground, slight back pressure and you are airborne. For you DC3 experienced guys, where is the elevator trim set for take off with a reasonable load?
Sent you PM Bobby but your inbox full?

Bobby G 28th Jul 2018 04:03


Originally Posted by Weheka (Post 10208146)
Apologies to Bobby G for doubting his experience in the DC3 aircraft. Still don't understand why the characteristics are not very similar to other tail dragger aircraft but my experience is only in the single engine types. For example in a loaded 185 I would set trim so tail will come up virtually on its own, once six inches or so off the ground, slight back pressure and you are airborne. For you DC3 experienced guys, where is the elevator trim set for take off with a reasonable load?
Sent you PM Bobby but your inbox full?

Thanks Weheka. I'm new here and don't know why my mailbox shows full with 0 messages.
The trim is set for liftoff speed/weight. But really, that's about the same setting for all weights. The heavier and bigger the airplane, the more out of trim it will be in the early takeoff roll until 60-70 kts, that's just the way it is. In some DC-3s we could "fly the tail" during runup when empty, in others there was no way you could. All of the DC-3s handled different, have their own character. Any of the multi-engine airplanes I sent you pictures of would surprise you the first time you fly it. A few years back I started flying the B-25 and although from a distance it looks like a nimble airplane, it flies the same way as the lumpy C-46. It takes muscle. My point with this is that not every DC-3 takeoff is the same. Bluebonnet Belle was loaded for Oshkosh. I wasn't there but the airplane was likely loaded with a lot of fuel and extra gear, different from the usual load. The takeoff would've been much more challenging than normal. As a former CAF pilot I can tell you that it's difficult to maintain proficiency in those airplanes and through a combination of several factors directional control was lost and the airplane yanked off the ground. It is slow to react to control forces at low speeds and heavy weights. But I cannot see aileron movement which is very suspect in my opinion and is the main reason why I reacted to this thread, nobody mentioned the all important ailerons.

ehwatezedoing 28th Jul 2018 13:57


Originally Posted by Chris Scott (Post 10207685)
Interesting. The only point I would offer from my limited experience on the type is that, with the tail still on the ground in a strong crosswind, I would have pre-selected full into-wind aileron anyway. The swing is most likely to be into-wind, and no further deflection would be available. Admittedly, the swing could be in the downwind direction, in which case would you remove the into-wind aileron briefly?

What do you mean by "Timming while doing it is everything."?

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.


More info on what happened (it is a Facebook video )











Mach E Avelli 28th Jul 2018 18:20

Absolutely agree with the vid guy about where the training emphasis needs to be. Warbird type ops are generally VFR, so learning to fly an engine out ILS at the expense of ground handling is a woftam.
On such training, another pointless exercise in these (and many other transport aircraft) is the touch and go. The takeoff needs to be from a static or slow roll on to the runway, to get the art of pushing tail up etc happening and ditto - landing needs to be to a slow crawl to get the directional control tecnnique as the tail comes down, brake against elevator, etc.
Further, for training the aircraft needs to be ballasted to a fairly aft c of g. When light and with a forward c of g it is generally easy to get the tail up, and it almost pins itself on the ground during landing. Tail heavy it is a quite different beast, as Bobby G has said.
And Bobby is right about how much they can vary in the way they feel. After such a long life, most DC3s have been bent, broken and rebuilt more than once. In one operation we had two almost identical aircraft with very similar weights and c of g. One had been damaged quite badly at some stage. It was definitely a bit twisted, but flew a full 10 knots faster that its sister ship . To prove this was not an indication error we formated and matched power settings.

Eric Janson 28th Jul 2018 19:37

The experiences of both Bobby G and ehwatezedoing are very similar to my experiences flying the DC-3.

Ailerons can be used for directional control. I've seen this demonstrated on landing with the tail up and the rudder neutral - the aircraft was moved left and right using only aileron inputs.

The aircraft can be very tail heavy especially with baggage behind the passengers. It wasn't unusual to have to trim to help reduce the forces to get the tail up. Tail not up by 60 knots was an abort.

It's a beautiful aircraft to fly but it needs to be treated with respect - these old aircraft can bite you hard!

cncpc 28th Jul 2018 20:41

Just to put this out there. Could a slow ASI have come into this chain of events, i.e. alive but not yet up to 40 when the aircraft was well past that?

wanderinwilco 29th Jul 2018 01:59

C of G
 
If the pax had repositioned just prior to t/o, moving the C of G aft, could that have initiated the chain of events?


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