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-   -   South Africa - Aircraft Stalls as Skydivers Prepare to Jump (https://www.pprune.org/accidents-close-calls/643522-south-africa-aircraft-stalls-skydivers-prepare-jump.html)

Tiger G 3rd Nov 2021 17:39

South Africa - Aircraft Stalls as Skydivers Prepare to Jump
 
Didn't see this one posted, apologies if it's a repeat:


Quote: "Incident info released for general information and educational purposes to the aviation community by videographer Bernard Janse van Rensburg, with the full knowledge of the drop zone operations.

The Beechcraft C90 King Air was trimmed up for the exit procedure at an altitude of 16000’ AGL for the second load of a planned 20x jump event. We opened the door and began the climb out. As is normal, the skydive team was fully focused on achieving correct positioning and exit timing. This intense focus on task resulted in many of the skydivers missing the tell-tale signs of an imminent stall.

From the videographer exit position (outside, most tail-ward end of the jumper line) I felt the plane 'slip' once and then twice after which I knew something was wrong and decided to let go of the now banking aircraft. This all happened inside of just a few seconds. Those on the outside of the door and immediately inside of the door followed. With 9 of us initially in the sky, there were still 5 skydivers inside of the aircraft.

The moment was surreal and I could not believe what I was seeing. Everything happened in slow-motion and I remember thinking 'am I really seeing the plane spinning nose down next to us'. After the spin, the aircraft started to veer underneath us but luckily did not make contact. As the aircraft started to recover from the stall (still unstable) one further skydiver exited, leaving 4 skydivers and the pilot in the aircraft.

After I was satisfied that the aircraft had recovered (it is a fascinating and unusual thing to see your jump aircraft below you in freefall), I searched the sky for my team and found them building the pre-planned formations in a safe and normal manner. The aircraft returned and landed safely on the runway. The incident was promptly reported to the South African CAA and PASA national safety and training officer. The next day the jump team made adjustments to their exit procedure following discussion with the pilot and no further incidents or near-incidents were experienced."

Pilot DAR 3rd Nov 2021 17:58


The next day the jump team made adjustments to their exit procedure following discussion with the pilot
Yeah! It's only fair to tell the pilot when what you're about to do to the plane he's flying will probably put it out of C of G limits, dramatically increase drag, obstruct some airflow over the tail, and cause a sudden unexpected weight change, all while he's flying as slowly as you have asked him to! I had four jumpers do this to me, while I was flying a C 185, resulting in my entering a spin. I remember being very fearful that I would hit them, as I rotated down, but I did not. I had swift words with them afterward, along with a talk with the boss! I extend (for now) the possibility that the pilot was a victim of an unexpected event, which a really good preflight discussion could have prevented. It is noteworthy that jump planes are often stripped down for weight saving. In the case of a King Air, what is stripped out (air conditioning and avionics) is usually in the nose, moving the C of G back already! If the pilot intended to allow that many people to cling outside the plane that far back, I hope he had some authority to permit flight so misloaded!

munnst 3rd Nov 2021 18:58

There is an interesting video on youtube of the same thing happening to a DC3.
Seems to happen quite frequently concidering the potential outcome.

treadigraph 3rd Nov 2021 19:08

I believe on one occasion Martin Caidin inadvertently spun his Ju-52 while parachutists swarmed out onto the wing (it survived to delight joyriders with Lufthansa for many years and I regret not managing to get a seat on flights out of London City before it became grounded...)

munnst 3rd Nov 2021 20:32


Originally Posted by treadigraph (Post 11136785)
I believe on one occasion Martin Caidin inadvertently spun his Ju-52 while parachutists swarmed out onto the wing (it survived to delight joyriders with Lufthansa for many years and I regret not managing to get a seat on flights out of London City before it became grounded...)

That Ju52 used to fly over Kennington where I lived. Must have been 90's?

biscuit74 3rd Nov 2021 21:00

Wow - kudos to the pilot for there being a 'next day' drop !

A good two or two and a half turns of spin and some interesting wing rocks during recovery - perhaps because the pilot was pulling hard to try to stay within the flap limits as (presumably) the flaps motored up.


tdracer 3rd Nov 2021 21:51

Memory is foggy about the details, but there was a crash like this near Seattle back in the late 1980s - IIRC a couple of the jumpers still managed to get out after the aircraft went into a spin, but most were killed in the resultant crash.

West Coast 3rd Nov 2021 21:53


Originally Posted by munnst (Post 11136782)
There is an interesting video on youtube of the same thing happening to a DC3.
Seems to happen quite frequently concidering the potential outcome.


The last few jumpers out got more than they bargained for.

treadigraph 3rd Nov 2021 21:56


Originally Posted by biscuit74 (Post 11136843)
some interesting wing rocks during recovery - perhaps because the pilot was pulling hard to try to stay within the flap limits as (presumably) the flaps motored up.

Flyer has a quote that, according to the pilot, the subsequent wing rocks were due to one engine spooling up more quickly than the other...



tartare 3rd Nov 2021 22:05

I wasn't even aware this was a thing - both of those videos are chilling to watch...

Pilot DAR 3rd Nov 2021 22:28


due to one engine spooling up more quickly than the other..
Yeah, who knows what the props were doing just before he stalled, presuming at a rather low power, and then maybe idle when he went over. PT-6's can spool up a little differently if you rush the power levers and things were not stable to begin with.

As for the DC-3, they have stall characteristics which must be understood, and trained, as the design precedes today's standards for handling. I have errantly done exactly what that video shows, during stall testing of a modified turbine DC-3, yes, it's a thing. Again, everyone crowded at the back of the cabin is terribly destabilizing, and a DC-3 is particularly vulnerable to this!

biscuit74 3rd Nov 2021 22:58

Thanks treadigraph and Pilot DAR. That makes sense. An exciting time. It looks as if the aircraft try to spin again, to the right, on first recovery.

Vessbot 3rd Nov 2021 23:22


Originally Posted by treadigraph (Post 11136867)
Flyer has a quote that, according to the pilot, the subsequent wing rocks were due to one engine spooling up more quickly than the other...

I would put more money on the elevator being held firmly against the aft stop causing the 3 or 4 secondary stalls and incipient spins

Pilot DAR 3rd Nov 2021 23:37

The added challenge of spins in more "sleek" airplanes is that they build up speed very quickly on the way down. The vertical attitude, combined with the buildup of speed causes pilots to want to recover too early, though too late will assure an exceedance. I did a spin program on a modified Cessna Grand Caravan, and without the G meter I installed for the testing, I would have certainly exceeded Vne during the post recovery dive. A "normal" spin recovery in the Grand Caravan at forward C of G and near gross weight was 2.5G pull, and just about Vne, meaning that not pulling the 2.5 would have assured exceeding Vne. The aft C of G spins were an entirely different thing!

fitliker 4th Nov 2021 05:39

The King Air had almost full aileron by the time the jumpers got ready to leave . Hence the left wing stalling more than the right inducing the roll over spin entry . Usually close to a stall in a King air you get a lot of buffeting and loss of lift before any change in attitude . Interesting to watch the rolling moment as the left wing is more stalled by the aileron than the right wing .

Airspeed is life

megan 4th Nov 2021 06:34

Loss of control on the jump run is some thing that should be foremost in the pilots mind. It's not a unknown event, pilot might like to think how he is going to get out as well if all turns to worms, it's why these days he has to wear a parachute, not the case in my day.


Skydiving accident.

https://www.atsb.gov.au/publications...101903_001.pdf

Video of the above accident taking place, note the height when the pilot gets out.


rnzoli 4th Nov 2021 09:46

Not unusual, but always frightening

Pilot DAR 4th Nov 2021 12:07


it's why these days he has to wear a parachute,
Yes, this became a requirement in Canada just as I started flying jumpers. A pilot lost control and spun a Cessna 180 jump plane locally, lost control, and they were all thrown from the plane. The pilot was not wearing a 'chute, though the jumpers were all fine. I had zero intention of ever using the 'chute they provided for me (and never did), but I guess it was reassuring (as was my extra check of my seatbelts!). Though I don't know much about types of parachutes, I suspect that the large pack they provided to me was really not intended for pilot use, as it fit terribly with the seat, and was entirely uncomfortable!

fitliker 4th Nov 2021 13:08

It would be very difficult to egress a plane with no pilot door or hatch . Getting out while being thrown about might take a lot of altitude and having a plan of what ifs . How to use your legs in a g load situation as your arms might not have enough strength to pull you out .

The first king air video shows a tenth person exiting northbound as the plane is recovering heading east .

EFS

ehwatezedoing 4th Nov 2021 13:52


Originally Posted by Vessbot (Post 11136909)
I would put more money on the elevator being held firmly against the aft stop causing the 3 or 4 secondary stalls and incipient spins

The pilot specifically said that the subsequent wing rocks were due to one engine spooling up more quickly than the other and you come up with this theory on your own!?
Pure pilot bashing....

I went very, very close to stall a Beech 18 one time during a jump run and for the exact same reason, way too many far back.
It's a strange feeling when you push your elevator all the way forward to its stop and the aircraft is doing the exact
opposite.


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