Dumping skydivers from a helicopter

[double_barrel]

Forgive a dumb question from someone who knows next to nothing about helicopters.

I have been watching a medium size military helicopter (possibly an Aerospatiale SA.330L Puma) dropping skydivers from a rear ramp, from perhaps 2,000'. I see that before dropping, it goes into a hover, facing into the wind, with little or no forward movement. Is there a reason that it isn't done on the run? I can imagine that the military would like to minimise the exposure of the machine, so I might expect them to practice deploying their jumpers at speed. Is it perhaps something to do with risk to (and from) the tail rotor ?

Thanks[/size]

[megan]

Jumping from the hover is similar to jumping from a balloon, you have no slipstream to use to stabilise yourself, it then become necessary to build up speed in free fall in order to establish control, though doubt much, if any, free fall from 2,000. They may have other considerations.

[Trim Stab]

Were they freefall or static line? FWIW when we used to jump from Chinook back ramp on static line, it was done at low forwards speed I think partly so that the used static lines could be recovered between jumpers and partly so that we didn’t end up too far apart when we hit the deck. It can be hard enough finding the rest of your troop at night on a normal drop, let alone when wearing NBC kit on the Chinook drops.

[PlasticCabDriver]

If it’s from a ramp, it’s not a Puma. NH90 or Merlin maybe, depending on where you are in the world?

We used to drop them from the Puma from the cabin door steps. Been a few (!) years now, but I’m pretty sure we never hovered. Maybe 60-ish knots, slow enough to appear hover-like from the ground, especially with some headwind.

[treadigraph]

Kenya - they have a couple of Mil 17s, presumably one of those.

[double_barrel]

Kenya - they have a couple of Mil 17s, presumably one of those.


Definitely not a Mil-17, I've seen those often. I guessed a Puma by looking online to see what Kenyan military have, it looked about right, but obviously not. It looks new and shiny, and sleeker than the ugly old Mil-17. Maybe a new toy for them.

I don't think it's a static line, they freefall for perhaps 5 seconds before opening modern looking steerable chutes.

[RMK]

I've done quite a bit of jumping from helicopters; it's nearly always with some slow forward speed (circa 60kts).

However, 2000ft is really too low for safe jumping with a skydiving rig; so they must be using either base rigs or static line as noted above. Base rigs don't have sliders and open immediately, whereas skydiving rigs open more gradually ("snivel") for up to around 500 before fully opened.

[meleagertoo]

I've done very few parachute drops, thankfully, but the team we used to work with said that helicopter drops were a big aspiration of skydivers, and zero-speed drops were the ultimate thrill - as megan said above something to do with pure freefall until velocity built up that cannot be experienced from normal forward flight. Balloons or base jumping are the only comparable examples and both are understandably unusual). Hovering a jetranger at 3000' scared the crap out of me at first (strangely in RN training we were never shown, let alone trained in high altitude true hover - I'd never even considered doing that until these goons demanded it.) The disturbance as each jumper went was quite alarming.
I was glad when they stopped chartering us!

[Gordy]

Hovering a jetranger at 3000' scared the crap out of me at first . The disturbance as each jumper went was quite alarming.


Have done it a few times over Salt Lake City, but it requires about 7 or 8k jus to get the agl altitude they needed. As long as both sides just fall off, or step the skids in unison without pushing off it s not a problem. Same goes for rappelling from Long Rangers....if both sides arrive at the ground together, it is not a problem. The problem occurs when the rappeller on the left gets down and the one on the right gets knotted up or simulated tie off---then you can be out of lateral CG if he spotter moves to the right side also. Fun times.....

[roscoe1]

Jumping from a helicopter in n a hover is a totally different feeling than having 50 to 70 knots or more of forward speed from an airplane. There is not enough relative wind to control your body until vertical speed picks up after 4 or 5 seconds. You want to be belly to earth if you are ripcord deploying your parachute with a spring loaded pilot chute and this is even more important if you are hand deploying a soft pilot chute as in a sport parachute rig. Uless you have some stability in the relative wind it can be dicey deploying a parachute. Perhaps that is why the short delay you see. 2000 feet is plenty for static line jumps which may be safely done even below 1000 feet if there is enough forward speed. 2000 feet is also plenty for a base rig. Never heard of "base" jumping from a helicopter but it wouldn't be too much different from a real base jump except for the noise. Typically those folks do not have reserve canopies as part of a base rig.

If you see a slider on the suspension lines, a rectangular or x shaped piece of cloth with 4 corner grommets that is packed at the top of the suspension lines and slides down during deployment to slow the opening, then they are not base rigs, although you can pack with the slider down and it basically does nothing and gives a quicker opening. The slider can be seen just above the jumpers head after deployment if there is one. BSBD.

[RMK]

if you are ripcord deploying your parachute with a spring loaded pilot chute .I’ve been skydiving for 20 years and have only ever seen “ripcords” or spring-loaded main pilot chutes in old photographs – this doesn’t exist in civilian jumping.

I don’t know about the military; I assume they can do as they please. But for civilian jumping, most countries have a minimum legal opening height of 2500 AGL for C or D licence holders (1500ft for display jumps with authorisation of BPA/USPA). Round parachutes have been illegal to jump for decades.

The main safety item for helicopter pilots taking jumpers is to stress the importance of the jumpers doing their pre-jump checks – reserve pins & handles and pilot chute handles. Pilot chute handles (leather hackeys or formed soft handles) are on the bottom left side of rigs, so could get caught/pulled for jumpers existing on left side of helicopter causing pre-mature openings and/or entanglement with helicopter.

[aa777888]

But for civilian jumping, most countries have a minimum legal opening height of 2500 AGL for C or D licence holders (1500ft for display jumps with authorisation of BPA/USPA). Round parachutes have been illegal to jump for decades.Minor point of clarification for US readers: in the US skydiving is almost entirely self-regulated. There is only FAR Part 105 for actual, governmental regulations, and there aren't very many. You can jump anything you want as a main parachute, including round parachutes. You can jump from any altitude you want. You can deploy your parachute at any altitude you want.

That said, in the US the United States Parachute Association pretty much has a stranglehold on the industry, much like PADI, NAUI and SSI do on the scuba diving industry, another self-regulated sport in the US. If you jump at a USPA affiliated drop zone, and they pretty much all are, you'll be subject to USPA regulations which are much more extensive. But if you can find a willing pilot and some public land (or private land with permission), you can go crazy and do whatever you like within the bounds of Parts 91 and 105.

P.S. I hold a USPA D-license but hate that they call it a "license" since it certainly isn't a government issued document.

[212man]

2000 feet is plenty for static line jumps which may be safely done even below 1000 feet if there is enough forward speed
Not much forward speed from a moored balloon at 800 ft......
https://www.youtube.com/watch?v=5zxFNp0d37E

[roscoe1]

The OP saId it was military and who knows which military or what gear they were using. I was never saying tthey were using spring loaded pilot chutes, just trying to clarify what he was seeing. Never said you can't jump below a grand and be "safe" but the video didn't show how much canopy time he had before he landed. You won't likley see sport jumpers doing their baloon jumps from 800 feet. I also have a D license and was a tandem master and AFF jumpmaster. Ive seen a guy stuff a T10 into a paper sac and jump from a 182 at 900 feet with no reserve canopy . Fastest opening you'd ever want, but not too smart unless the plane was on fire. Please feel free to nit pick what I say or interpret it how you want. The tone here seems to have changed a bit so I'll sign off, y'all stay safe.

[Flugplatz]

The SA330 Puma (original versions) has a hatch at the rear of the fuselage/junction tail boom. I know the French used to do mil. parachute that way with rounds (mainly exercise only for re-qualification purposes otherwise it was C-160 Transal). So static line and limited sticks

[John Eacott]

https://www.pprune.org/rotorheads/546742-parachute-jump-hell.html

[megan]

Problem without airspeed, or trying to open too early.

https://www.youtube.com/watch?v=ADOyQDnmwrw

[roscoe1]

Did you notice that in the footage near the end his cutaway handle was off the velcro? Could have gotten even more interesting if it hat gotten pulled while his pilot chute was in tow, wrapped around his camera mount.

[ShyTorque]

The SA330 Puma (original versions) has a hatch at the rear of the fuselage/junction tail boom. I know the French used to do mil. parachute that way with rounds (mainly exercise only for re-qualification purposes otherwise it was C-160 Transal). So static line and limited sticks

The RAF certainly didn’t use the rear hatch. We had a servicing ladder on brackets over the bubble window, held in place by pip pins. As far as I’m aware, the only thing to go through it was a load pole, accidentally of course. It fell on someone’s balcony in Guildford.