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I recently saw a video that I believe was filmed in Turkey where a skydiver was prevented from jumping out of a hot air balloon by the operator/pilot.

Man tries to jump out of a hot air balloon (YouTube video)

His rationale for stopping the jumper was:

  1. the balloon could go out of control and fly up unexpectedly
  2. he could lose his licensing.

He goes into a long explanation of the dangers of someone unexpectedly jumping out but something seems off to me. I have done balloon jumps and the basket is incredibly stable when people jump. The basket and people must weight a couple thousand pounds so I can't see how a person with a parachute could have the dramatic effect that is described in his explanation. I am in no way arguing that he should have been allowed to jump, just saying I am not buying the potential danger described.

Does the description of the danger hold any air?

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    $\begingroup$ Re "His rationale for stopping the jumper was 1) the balloon could go out of control and fly up unexpectedly, 2) he could lose his licensing."-- I haven't watched the video, but it seems from this description that there should have been more of a pre-flight discussion. What, was the existence of the parachute and the intention to jump not revealed until the flight was already underway? ??!!?? $\endgroup$ Commented Feb 28 at 17:34
  • $\begingroup$ After watching the video-- perhaps he had the chute hidden under a jacket or coat that he removed in the middle of a flight? (Edit) sounds like they were at around 3000' AGL when this all happened-- $\endgroup$ Commented Feb 28 at 17:48
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    $\begingroup$ In the UK, the ANO says "the dropping of persons by parachute and which is made under and in accordance with the terms of a parachuting permission granted by the CAA under article 90" so you'd need a permit for a parachute jump. Turkey is a member of the ICAO so I'd guess something similar applies there. $\endgroup$ Commented Feb 29 at 11:03
  • $\begingroup$ The balloon pilot should have just yanked the wannabe skydiver's D-ring so the chute would fall out in a clump on the floor of the balloon basket! (I guess the springy thing in the pilot chute could have been a problem though :( ) Maybe in the future all balloon pilots should carry a bicycle cable lock to lock the skydiving rig to the balloon basket; that would be a way to instantly end the issue -- $\endgroup$ Commented Mar 1 at 17:15
  • $\begingroup$ @quietflyer That adds much more danger than it takes away. If he was able to get a chute out while in the basket there is no telling what would happen. If he was able to pull his pilot chute all the way out, the main parachute would probably just fall out in the deployment bag. If he pulled the reserve handle, it could get ugly as that is spring loaded and could potentially inflate. For the most part D-rings are going the way of the dinosaur being replaced by padded handles. $\endgroup$
    – SDH
    Commented Mar 1 at 19:01

2 Answers 2

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The basket and people must weight a couple thousand pounds so I can't see how a person with a parachute could have the dramatic effect that is described in his explanation. I am in no way arguing that he should have been allowed to jump, just saying I am not buying the potential danger described.

Does the description of the danger hold any air?

The explanation starting at 2:30 in the video (

) is enlightening. By "parachute" he is referring to the round top of the balloon which is only held in place by some velcro, plus the upward pressure of the hot air which forces the "parachute" upwards against the load tapes. Normally the "parachute" is only pulled slightly downward occasionally on one side to spill a small amount of hot air, until after touchdown when it is pulled completely down to deflate the envelope as soon as possible to prevent the wind from dragging the balloon along on the ground. A downward aerodynamic load on the top of the balloon due to an abnormally high ascent rate could dislodge the "parachute" entirely and let all the hot air out. This is why skydivers should normally only be allowed to exit when the balloon has zero vertical speed, or is in a descent. Likewise for hang glider drops.

The "parachute" or "parachute valve" can be seen on a diagram on this web page: https://hotairflight.com/blog/parts-of-a-hot-air-balloon?expand_article=1

This link has some interesting reading about skydiving from balloons: https://www.droplyne.com/skydivers

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  • $\begingroup$ Last link is really more about logistics than flight dynamics/safety but still is an interesting (and kind of funny) read-- some more links could surely be found that more directly address the flight dynamics/safety issues-- $\endgroup$ Commented Feb 29 at 13:57
  • $\begingroup$ So if: 1) The balloon is moving upwards. 2) The person jumping is a large percentage of the total weight to have maximum effect(small balloon and basket with few passengers etc.) -- a danger exists. I believe the pilot in the video may have been overstating the danger but he probably did that to scare off any additional morons that would want to try this without permission. $\endgroup$
    – SDH
    Commented Feb 29 at 18:13
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Yes, the danger is real. A hot air balloon basket weighs very little, and can often be easily carried by two people. I haven't seen your video but the total payload can be less then 750 pounds so having two hundred pounds of ballast jump out can make a real difference, causing the balloon to gain a lot of height and potentially putting it into very different wind conditions.

At the end of the day, everything that happens is the pilots responsibility. If they are unsure of any aspect of the flight, they must take the least risky option.

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    $\begingroup$ Even if the payload plus basket weighs only 750 lb, the entire aircraft must weigh roughly double that to stay buoyant (it must displace 750 lb of atmosphere, with something not much lighter). 200 / 1500 isn't quite so dramatic. $\endgroup$ Commented Feb 27 at 23:38
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    $\begingroup$ Re "(it must displace 750 lb of atmosphere, with something not much lighter)" -- if the buoyant lift is to be x pounds (say 750) and density rato of the displacing gas (air) to the surrounding gas (air) is y which you are suggesting is not much less than 1, then doesn't the total weight z of the displacing gas (air) have to be such that (z/y) -z = x? If y is not much less than one, then the weight of the displacing gas must be much larger than x. Source cited above lists an envelope volume of 77,000 cubic feet to lift 550 pounds of ballon, plus the occupants which might typcially be 2. $\endgroup$ Commented Feb 28 at 14:18
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    $\begingroup$ (Ctd) So, total weight is way more than double the uninflated weight + occupants! That helps to explain how it can ever be safe to allow a skydive, or a hang glider drop (google it for some cool videos!) $\endgroup$ Commented Feb 28 at 14:43
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    $\begingroup$ That's not research, that's a class exercise where the total mass or weight is specified up front. My point was simply that C.G.'s comment hugely underestimated the total weight of a 2-3 occupant balloon, by incorrectly suggesting that the total weight including weight of air in envelope should be about double the weight of empty envelope+basket+occupants. Also see links to actual figures for typical envelope volumes within comments. $\endgroup$ Commented Feb 28 at 16:58
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    $\begingroup$ @PaulSmith I agree the jumper in the linked video was an ass but my question has nothing to do with him. I have jumped multiple times but never the last person to leave. At no point have I ever experienced any sudden motion or instability that the pilot mentions in his explanation. Are you speaking from experience when you say the movement 'is significant'? $\endgroup$
    – SDH
    Commented Feb 28 at 17:04

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