Pilot Says Too Many Jumpers Outside Led to King Air Spin
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I know very little about aviation but this seems like a pretty foolish and avoidable incident. I would have thought there would be a procedure for how many people can leave or hang from the back of the plane as it would very obviously affect how it flies. I can’t imagine that sort of manoeuvre is good for the airframe?
This seems like a weakness of a king air as a jump plane. The pilot has to throttle down the left engine so jumpers aren’t thrown into the tail on exit by the prop wash. I’m happy with our single-engine super caravan with its wide door so not so many people have to be outside to do big groups like this.
I always find it interesting how we underestimate the expanse of 3D space depending on the view: jumpers are exactly between the airplane and camera, which is not surprising since the cameraperson and jumpers came from the direction of the airplane, with the camera going out first.
From another angle (eg satellite view from above or a sideways view), I am sure the distance between jumpers and the plane would be more obvious. Still risky (you wouldn't plan on passing that close), but not as much as it seems.
The question more is what made sure that the airplane didn't re-contact the skydivers. When an airplane after the drop flies on straight and steady you know that they wont hit the skydivers because the skydivers have no propulsion and relatively lot of drag. The skydivers will lose horizontal speed quickly and gain vertical speed downwards even quicker. This basically guarantees that the separation between the squishy humans and the airplane will be maintained.
With the spinning airplane staying close to the divers who knows. Maybe the pilot is an ACE and they kept a mental model of the parachutist's position relative to theirs at all times. Maybe what appears to us as uncontrolled tumbling is anything but. Or maybe it was just up to "luck".
I like to turn question like this on its head: how would you make an airplane hit those skydivers on the way down? If the answer is: "very fricking hard", I think the "luck" plays a small role.
Basically, if they were hit, they would have instead been "very unlucky". :)
The rest of the dynamics fall out from that: during the dive, the engine on the divers' side is already off, and once the stall happens, the pilot cuts off both engines (to avoid a spinning engine hitting anyone), dives to gain speed.
Being inside the plane as a jumper during the recovery was probably the least pleasant -- normally one doesn't have a seatbelt in that scenario. I think at 0:54 one more person falls out the open jump door?
You are right that there is a clear limit to the number of people allowed on the outside step set by the DZ. In the original video you can count the heads on climb-out and these jumpers are exceeding every guideline that I've been subject to. My formations adhere to five outside and one crouched, max - but do note that several bodies may follow the exit with as little delay as possible. We try to exit as a unit. I'm only a coach with ~500 jumps, by no means an authority.
This model plane in particular is less forgiving and the airspeed is high on jump run. As skydivers we are cautioned about the exits and take extra care to maintain a forward CoG. I have experience with aerodynamic modelling and private pilot training but won't speculate other than to say that structural integrity is not an issue. It's more like capsizing a boat than overloading a trailer hitch.
Pilot perspective copied here: https://www.reddit.com/r/aviation/comments/qm1952/an_absolut...
"One of the jumpers [exited later]. She was tossed around inside the aircraft and ended up on the floor next to the door. During the final motions of the aircraft she bounced off the door frame and out the door."
Yikes.
Just to embellish and clarify: During my first jump training, one of the things the instructor drilled into us was "You have a parachute. If something goes wrong and you need to save your life, use it!".
This commercial pilot gives a very thorough explanation of the problem and includes a report from the pilot of the flight.
Asymmetric thrust, flaps down, large group disrupting airflow over horizontal stabilizer and creating a substantial CofG shift to aft, what could go wrong ...
Stall recovery is also something pilots train for as that is highly dangerous during takeoffs and landings. A landing is basically a controlled stall. Spin recovery is less commonly trained for because it basically means you messed up the stall recovery, which should not happen. Sounds like the pilot did the correct thing (eliminate async trust and nose down).
So, not a good incident but it happened at an altitude where there was plenty of time to recover.
Ref Approach (100% flap) -> 85-90kt
Stall (100% flap) - 59kt
And documented stall speeds are when the wingtips and ailerons start losing effectiveness - the wing still generates plenty of lift.
That being said I also heard that this is absolutely not how one should land an airliner. This type of landing would cause a tail strike there. So who knows. Maybe my trainer was old school. Maybe what is correct on a Cessna 150 on a grass field is not correct on your type or airfield.
Velocity landing should be above stall speed, albeit slightly. No one wants the airframe to crash/slam into the ground.
Source: Aeronautical in a previous life
> No multiengine airplane is approved for spins, and their spin recovery characteristics are generally very poor. It is therefore necessary to practice spin avoidance and maintain a high awareness of situations that can result in an inadvertent spin.
In something like a Caravan this might not be such a big deal (though I don't know about their stall-spin characteristics) but deliberately courting stall-spin in a big twin like a King Air by using asymmetrical thrust so close to stall seems extraordinarily dangerous bordering on reckless, even if you aren't counting the presence of skydivers near the out-of-control aircraft. The fact that it's established practice doesn't mean it's safe; it can just as easily be a "normalization of deviance" sort of thing.
As other commenters have mentioned, I think bringing both engines back to low power or idle, and accepting a moderate sink rate during the jump, would be much safer. That way, even if you do stall, you at least aren't doing it in an asymmetrical thrust condition.
^[1] https://www.flightliteracy.com/stalls-in-multiengine-aircraf...
Regarding sink rate, in the absence of a definitive source I don't really buy that a moderate sink rate (again, with the same low airspeed) is going to significantly increase the risk of somebody hitting the tailplane. In the absurd extreme of a vertical dive, I guess a skydiver would probably be outpaced by the aircraft due to their different terminal velocities, but a shallow dive is a very different picture.
Spinning a King Air is, from an aviation safety point of view, unacceptable. Accidents happen, but the point is that great pains must be taken to prevent them from happening again; and if the skydiving community wants to convince the aviation community at large that this procedure is perfectly safe, they really need to show that what happened here was a freak accident rather than a totally predictable one. That will be a tall order, because it was a totally predictable accident.
Safety needs to take precedence over convenience. If the King Air can't run skydiving operations safely and conveniently, maybe it should not be used for skydiving operations.
A stall is when the wing stops producing lift due to reduced air speed. Plane wings do not stall during landing. They produce lift all through the landing process. The plane uses flaps [0] to reduce the stall speed of the wings so they continue producing lift as the plane slows down. In the final stage of landing, the plane uses ground effect to produce lift at even slower speeds.
[0] https://en.wikipedia.org/wiki/Flap_(aeronautics)
[1] https://en.wikipedia.org/wiki/Ground_effect_(aerodynamics)
It's the kind of thing the pilot does in commercial operations (to improve the customer experience) when there's textbook perfect VFR conditions and 10k of margin below you if you run out of power/lift and have to dive out of a stall. It suffices to say marines jumping out of the back of C17s and C130s are not getting that kind of polite treatment. Even if you've got a bunch of well practiced skydivers, having them all get out of the plane quickly and close together is going to make for a much better experience for them.
Everyone is gonna pearl clutch about it being "dangerous" but prop washing the crap out of your skydivers also carries some danger. As the video indicates a stall at 10kft isn't really a big deal for a halfway competent pilot. I wouldn't call it a daily occurrence but elevator pilots (skydive pilots) recover from a stall far more than most because they're constantly climbing as fast as possible (because that's the most economic way to run a skydive operation). Considering the kind of pilots who wind up doing skydive operations I think a lot of them would have been tempted to just take their hands off the controls and see if the plane recovers itself (it should) and then intervene if it doesn't.
There is no real "answer" here because the activities involved have some baseline danger to them and at best you can just shift it around between parties.
Imagine the fallout if someone bumps the horizontal stabilizer on the way out the door and does even the slightest damage to it or gets a minor fracture or something. It's a big f-ing mess. A stall and a bunch of hand wringing is clearly the better outcome for all parties.
That kind of seems to be what happens in the video?
I’ll be the first to admit I know nothing of planes outside of games, but if they’re even marginally accurate being gentle is very important.
I don't know about that. I count at least two secondary stalls while the pilot was trying to recover. Or maybe you are saying the pilot is not halfway competent?
Here is a video of a test pilot giving a talk at MIT on the F-22 and its advanced flying capabilities which --as he puts it-- makes flying an F-22 actually easier than a Cessna.
https://www.youtube.com/watch?v=n068fel-W9I
Apologies in advance for you losing an hour -- the talk is that good!
> skydivers often aren’t well versed in aircraft operations (after all, they have a lot more takeoffs than landings!)
Made me giggle
Nary a King Air has counter-rotating props. As such, they all have a critical engine. Beechcraft as a company is sort of like the black-box storage providers of the 2000s pre-cloud IT world. They're not doing anything better than anyone else, with the exception of marketing...
The terms you wanna google here if you're curious and not familiar are "P-factor" and "adverse yaw."
There are lots of better airplanes to toss parachute jumpers out of than a King Air for this reason. For that matter, there are a lot better airplanes for the owner of this airplane in question to take his family to Aspen or Grand Cayman in, for the exact same reason.
If the aforementioned early 2000s IT storage salesman responds to a question of how you recover from disk failure with "don't have a disk failure," you would probably walk away not not buy his black box, right? Yet people buy King Airs because they bought a Baron before it, and bought the Baron because it was just a Bonanza with two props.
"What's going on with all these King Air crashes?" [1]
1. https://www.bjtonline.com/business-jet-news/whats-going-with...
Sounds like the pilot is talking about the simplest thing in the world. Video makes the pilot seem incredibly calm in the face of the plane moving in a crazy way.
Edit: what would make the plane move that way?--it seems to recover after initial spin only to drop nose down, then start strafing (correct term?) left and right like it's in a half pipe before starting to spin again. It looks almost totally of control, to me it looks like it hit a wall of air. I have no idea. I'm amazed the pilot was so cool. Very impressive
The older CFI's usually seem to be up for it. :D
Perhaps because the training wasn't being well done. It's a pity, because to most pilots a spin will be very disorienting unless you are used to it.
https://www.faa.gov/documentLibrary/media/Advisory_Circular/...
Many commercial pilots (like skydiving pilots) have CFI (because while training, you need to meet a certain number of flight hours, and you might as well spend them on CFI).
Of course all that is with no engines. Assymetric thrust in a twin is more complicated, and I expect you've got less margin before you damage the airframe.
From what I’ve heard it’s actually pretty frightening the first few times, but that’s the point - do it enough to recognize what’s happening and make the response automatic.
I was told that spin was not because it could damage some of the instruments which have gyros.
We did it anyway (in a Cessna 152), and it only took about 1.5 turns to recover. Great fun. Easiest way to induce a spin was flaps down during stall.
Response to your edit: It's yawing because of asymmetric thrust.
Aviate, Navigate, Communicate.
In that order
Get the airframe under controlled flight, then avoid obstacles and fly towards safe landing, then tell control & other aviators about the situation so they can help (or at least not worsen it).
In that order, to save your life.
Pilots remain calm
Only like confused new pilots in groups panic. For the rest, you can basically retrain your ear to tell when a pilot is more-so disillusioned by their self-preservation efforts.
I already have trouble mastering driving a car, and that's removing like half the dimensions a pilot has to deal with.