Parachuting incident 1

[Alistair_Heaton]

https://youtu.be/2XMESBk0dJw

Sorry reds if it brings up things.

But this shows quiet well what happens when aft CoG and low airspeed occur.

There are a few more things going on with it because it's a twin.

There is some quiet informed comments on that vid

 

[TugboatEng]

It's as if they should have hired an engineer to evaluate the jump.

All of that aside, props to the pilot for continuing to push the nose down to avoid crashing in to the skydivers. It looks like the pilot regained control quickly but then put the plane back in to a dive to avoid the group.

The again, it looks as if, and I hope, another skydiver fell from the plane during the dive. That plane had a whole lot of airspeed at that moment. I hope the diver was uninjured.

For the skydivers... Maybe they didn't realize what had just happened before getting in to formation? Oh well, why waste a jump?

 

[Alistair_Heaton]

In a spin there is nothing you can do to stop the nose going down.

The only control that's not stalled is the rudder.

Power off stick neutral oppersite rudder and wait to the rotation stops and everything else unstalls. I might add I don't know what the official recovery technique is for that type it may include forward stick at some point.

The pilot did do well. But I doudt they had a clue where the divers were it's more luck than anything else nobody was killed.

 

[TugboatEng]

Between 1:35 and 1:36 it does appear that the pilot makes a large correction to slide the plane away. Then again, the pilot may have just been shifting the rudder to steer in to the stall.

 

[Alistair_Heaton]

I think the aircraft was still in recovery at that point. If you look later it starts kicking into 90 plus Deg rolls.

The g forces would be quiet high at that point to boot.

 

[MintJulep]

Aft and left CG.

A fair amount of flaps down.

I couldn't really see the aelieron.

 

[LittleInch]

The comments below the video are in part from one of the people trapped inside the plane....

They did then say they now restrict the number of people outside the aircraft to 5 instead of 6. Usually the pilot would just increase throttle and blow the skydivers off or start to push the nose down.

I think the loss of air flow over the left stabiliser would be a key issue not normally thought about.

I also doubt the pilot had anything other than a screen full of green to deal with never mind avoiding his recently departed passengers.

I experienced it in a Skyvan once when it bucked like a bronco as we overloaded the tail a bit too much. But that had a huge square door at the back so was rather easier to get out.

The worst I ever heard when I first started jumping (1983) was a lode star (nicknamed a lodestall), which went into a stall and then spin and nearly everyone left on board died. I heard an flat inverted spin in nearly impossible to get out of which is what I thought this one was, but maybe just a straightforward spin.

https://www.baaa-acro.com/crash/crash-lockheed-18-56-lodestar-silvana-11-killed

The linked report showed it had happened several times before.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Alistair_Heaton]

They bring the power right back on the side that the jumpers are on to lower the prop wash.

Flaps to fly slower.


It's very hard to get out of trim laterally. You basically have to run a wing fuel tank very low.

 

[RedSnake]

It is okey Alistair.
Things popup all the time, at least it looked as everyone was okey.
Last week there where some intervju with one forensic pathologists here in Umeå on a evenings show produced live here.
Even if it wasn't because of the accident it still came up since she was one of them who identified the dead, not CH though it was a guy and they showed pictures from the crash site.

Still waiting for the preliminary report from Örebro, they have sent the motor of to Canada everything takes longer because of Covid.
A vittnes says it sounded as the motor wasn't running.

A fair amount of flaps down.

First thing I noticed when I saw the video too.
On the SE-MES they would only had been out at lift off.

This cradling motion after he gets out of the spin wiggling from side to side I guess is because the flaps are out, if they where in the plane hade been more streamlined and going more strait forward and being easier to get control over.



“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Alistair_Heaton]

Problem they have is its a twin turboprop they were using c90 kingair.

Quick google gives a clean stall speed of 94 knts and dirty (flaps out) of 75 knts.

Drag increase at V sqrt so the jumpers will want it as low as possible to be able to hang onto the side of the aircraft.

I don't agree on single engine light aircraft you only put them out for takeoff and landing. You put them out when you want them and need them. When I was doing photography I had them out because it gave a better aircraft angle and stall margin.

As for the spinning with the flaps out, The pilot was lucky they didn't come off depending on what speed he got up to. Although they may well be hydraulic and have a blow back safety feature on them which is basically just a pressure relief valve on the hydraulic lock keeping them out. So as soon as things got fast they came up due to loading.

Spinning a FAR23 twin turboprop is not in any of the certification programs or in pilot training. As its Australia and its a turbo prop the pilot will not be in the same league as the pilots of the single engine petrol aircraft. They will have been flying commercially for 5 plus years and have over 2000 hours.

I don't know what's causing the cradling motion. Twin engine spinning dynamics I really have never thought about or experienced. There will all sorts be going on with asymmetric thrust. They did extremely well recovering it although luck did play a part as well.

 

[RedSnake]

I don't agree on single engine light aircraft you only put them out for takeoff and landing.

Just what it said in the flight manual, what pilots do in reality I don't know.
The video sade Mosselbay, South Africa.. ?

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Alistair_Heaton]

Don't have a clue. But south Africa is similar to Australia that a King air turbo prop will require a relatively experienced pilot. Even in europe well will quiet happily stick a 200 hour in a multi crew environment but single crew turboprop they will be of similar experience mainly because of insurance reasons.

In general on an A to B flight then it is correct other "missions" you use them when you need them or want them within the aircraft limitations.

 

[Sparweb]

For those who want to watch it frame by frame, it's nice to know Youtube does it with the period and comma keys.

Left aileron is definitely down (attempting a bank to the right) making the problem worse.

Flaps seem to be all the way down, not partial.

That's a really high angle of attack at the last moment before the stall.

Not a lot of skydivers get to see the top of the plane after they jump out.

 

[Alistair_Heaton]

He has the rudder full over though but they may have trimmed it that way.

This pulling back the power on one engine on a twin is to be honest lining up so many slices of cheese. Especially with a turboprop.

If you go below about 10-15% torque you create more drag than if the engine is feathered. The king air was one of the few that could keep the speed with the Jetstream and dump the energy off on approach. Both planes could keep Vmo of about 230knts until 4 Nm on a 3 deg glide and still land at 115ish knts. There is no way I can do that on the jet. If I am not back to 180 knts with flap out when we descend on the glide I have no chance of landing.

So torque at flight idle on one side which gives higher drag than engine shutdown feathered and high torque setting on the other to maintain just above stall level flight requires loads of rudder input talking 45 lbs of force to be held on one leg with fine control. Again not something which is normally trained for. Which is why they are likely to have trimmed it. But if you trim it and need opposite direction you have to fight against the trimmed force plus what you need to get it over the other side. Which may account for the snap rolling later on.

Its very hard to stop yourself using alerion to correct roll. And you are right before the spin it made matters worse and possibly triggered the spin with one wing stalling before the other. Once in the spin both wings will be stalled anyway. Once the rudder unstalls the wings it will again become an issue as the wings will have different AoA which may throw you into a spin again.

To be honest and the way I read it. I am surprised the aircraft flew again in the next couple of days. I would have thought Beechcraft would have insisted on a C check (which is the big one where they strip the cabin out to have a good look at the structure)

 

[LittleInch]

It's interesting to me that it looks like the pilot is trying to maintain level flight during the climb out / exit mode.

My experience was that they usually start a shallow dive once they throttle back to give them some leeway in avoiding stall. It also incentivised people to get a move on getting out of the door to avoid loss of jump altitude. It also needs to be said though that a bigger fear when you're climbing out was letting go or not getting a good grip and leaving early. Then your dive has gone down the toilet before it even started..... So you took your time as much as you could to not get blown off as you search for a hand hold you can't see with cold / frozen fingers.

But for sure, the stall warning hooter often goes off on exit. I used to get a bit nervous if I was at the front of the cabin and the hooter went off for more than 3-4 seconds as it was me that wouldn't get out.... Not everyone seemed to realise what that strange noise was but I did and it scared the living daylights out of me to hear it going on for several seconds. I wonder how long it was going off on that flight for?? No one's saying.

I did see somewhere on the you tube comments or similar that the pilot knew it was going wrong when he was on the stops of the elevator. Guess he had run out of options at that point as the turbine wouldn't spool up fast enough to save him.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Alistair_Heaton]

Its surprising to me they are running it that close that the stall warner goes off as routine.

The engines on a Kingair are free turbine they respond instantly compared to everything else bar petrol piston fixed prop aircraft.

Those new GE engines I use it takes over 10 seconds for them to spool up those huge fans from an approach power setting which needs to be set by 1000ft AGL which is approximately 40% N1. The jetstream it was 1 second max from zero to everything.

The PT6 engine is a truly superb bit of engineering. It takes so much abuse and shrugs it off. Saved many a life by giving way more performance than it should on paper be able to do.

 

[MacGyverS2000]

Would anyone mind posting the original Youtube link? Work doesn't like shortened URLs, and all of the URL expanders are blocked.

And on that note, was anything really saved using a shortened URL compared to the original, which is pretty much the same length?

Dan - Owner

http://www.Hi-TecDesigns.com

 

[Alistair_Heaton]

Here you go

https://www.youtube.com/watch?v=2XMESBk0dJw

Sorry I posted it off my smart phone and its easier to share and copy the link to then post it.

I will bare it in mind if I post a youtube link again.

 

[LittleInch]

It wasn't every lift, but when you had a full plane and a group trying to get out and hang off the door and everyone shuffling down the plane ignoring all the lines painted on the walls.... The good jump jockeys knew what was going on and usually put the plane into a gentle dive as soon as they throttled back. Or just gave it more throttle and blew everyone off if they were out there too long. I once jumped a jet powered min troop transporter whose slowest speed was about 150 knots at altitude. Getting out of that was something else when you slow down to terminal velocity instead of speeding up.... I think that was still slower than the imortal DB cooper so how he survived I'll never know.

Given that the plane did actually stall the hooter must have been going for at least a few seconds before it finally gave up the battle with physics

The other thing is that on exit the standard is a call "Ready, Set, Gooooooo. Those at the front of the plane start moving backward on the "Ready" so you can get a sudden increase in load just before the first group lets go.

It's amazing how far the person in front disappears when you get into freefall. They can be 1m away from you but you're 0.5 seconds later getting out and they end up 50 m away from you and 100m down once you all reach terminal.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Sparweb]

I made up my mind after seeing the video, based on my own opinions, and very limited flying experience. Then I shared it with some other pilots/engineers that I know.
One offered a very interesting counterpoint. He was a long-time pilot who flew skydivers for years:

Not likely a stall but intentional. Pilot would drop the nose immediately everyone was gone and then roll so as not to lose sight of the jumpers until he was below them. Airplane should always beat the jumpers to the ground. Generally the drop zone is on the airport so the shortest distance is a straight line. When I was flying the jump plane there were bragging rights associated with the fastest time from 10000 ft to wheels on the runway.

We called it a “lump out” so that everyone starts off together at the same altitude. A lot more interesting for the pilot when you have 4 skydivers hanging onto the right side strut of a 172 hovering just above stall.
See the sky-diving door. I did one of those on a QueenAir but it didn’t move nearly that smoothly.
Note that the KingAir descents faster than the skydivers in freefall. They’re paying for the airplane by the minute and an empty jump plane is just wasting money.

The comment about the door is in reference to designs he did to modify aircraft later in his career.

So, in his opinion, BTDT!