IAD vs. S/L - Instability Risk (Was: What's the correct order of the instructor ratings?)

[dgw 8]

*THREAD HIJACK*

Tom, I did both SL and AFF, and on one SL jump, which was a dummy pull from a PAC750 ( four jumps) with the door on the left, I got my arm over the static line, and then wrapped up in the risers (which funked up my shoulder for ages). On a previous jump from the PAC, the SL got in the way of my dummy pull, but just pushed my arm away. On planes with right hand doors, (13 SL jumps) the potential for this didn't seem to exist.

In IAD, is there a greater risk of instability during dummy pulls and potential entanglements?

[slotperfect 7]

So you knew you were hijacking the thread and did it anyway? Why not start another one and just refer to the first?

From the Forum Rules:

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Off Topic Replies and "Thread Hijacking"

"Drifting" threads are subject to locking or deleting. Replies to topics started by another user should remain within the context of the initial post. While we recognize that discussions often diverge and evolve, threads or responses that are completely irrelevant to the initial post will most likely be deleted or split into two different threads.

Please don't do it again.

Arrive Safely

John

[tombuch 0]

The side of the door shouldn't matter. It's the instructors job to rig the static line to keep it out of the way, and then to control it throughout the exit. That's tougher if the door is on the same side as the practice ripcord.

With an IAD there is more time between exit and opening, so there is a greater risk of instability, but there is also more time for a stable student to pull the practice handle without being disrupted by opening.

In my experience as both an instructor and a pretend student, the openings of a square main are much better with the IAD system, and more similar to what we expect on conventional equipment. It's actually pretty tough (and annoying) to remain completely stable as a static line is ripping stuff off your back. And trying to do a practice ripcord pull under those conditions is unpleasant. The military makes appropriate use of static lines to deliver troops into battle with big round parachutes, but i don't think it's as effective as a training tool with squares. That's just my opinion.

The entanglement part is interesting. There are actually two basic kinds of static line rigs. The first is direct bag, in which the static line is attached to the bag, and it doesn't release until the canopy is extracted from the bag. The other version of static line is pilot chute assist. With that version the static line is attached to the pin, and then to the top of the pilot chute, or in some cases just the pin and a spring loaded pilot chute is used. With a pilot chute assist there is a greater chance of an unstable student grabbing the pilot chute...it happened to one of my students years ago, as I watched helplessly. With a direct bag there is a greater chance of a student being in tow behind the airplane. An instructor needs to know the specific kind of equipment being used, and the pluses and minuses of that system.

Tom Buchanan
Instructor Emeritus
Comm Pilot MSEL,G
Author: JUMP! Skydiving Made Fun and Easy

[Andrewwhyte 1]

The primary argument for IAD over S/L is that the opening is in sequence and so the stresses are in line with a normal opening. This means that any instability during a dummy pull happens later in the process and any entanglement risk is entirely due to the student's body position.
It is a bit more work for the instructor but in my view a far superior system from the point of view of the student.

[phoenixlpr 0]

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With a pilot chute assist there is a greater chance of an unstable student grabbing the pilot chute...

We have some fix for that. There is a velcro on the pin end of the static line which is mated to its pair attached to the spring loaded PC. I can make some pictures about it if its needed.

[speedy 0]

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With a pilot chute assist there is a greater chance of an unstable student grabbing the pilot chute...

We have some fix for that. There is a velcro on the pin end of the static line which is mated to its pair attached to the spring loaded PC. I can make some pictures about it if its needed.

We also have velcro attaching the spring loaded PC to the static line. It did not fix anything. The student still caught the PC, the reserve (cypres activated) fired in to the mess.
Since then the first jumps are made with direct bag. Once the student shows the ability to make a stable exit we then progress onto pilot chute assist with static line.

Dave

Fallschirmsport Marl

[phoenixlpr 0]

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We also have velcro attaching the spring loaded PC to the static line. It did not fix anything. The student still caught the PC, the reserve (cypres activated) fired in to the mess.

Students are creative .

I was really creative too.

[tombuch 0]

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With a pilot chute assist there is a greater chance of an unstable student grabbing the pilot chute...

We have some fix for that. There is a velcro on the pin end of the static line which is mated to its pair attached to the spring loaded PC. I can make some pictures about it if its needed.

We also have Velcro attaching the spring loaded PC to the static line. It did not fix anything. The student still caught the PC, the reserve (cypres activated) fired in to the mess.

Oh yeah!

It was um-teen million years ago, but I can still see my first jump student aggressively push off the Cessna, roll on his back, grab at the first thing he saw (the pilot chute), then go full fetal until the AAD fired. I don't think he had a clue what was happening, but I was plenty scared.

That jump involved a poised exit from a Cessna 182. Following that incident we changed to a hanging exit. There is less chance of an aggressive student back flipping with a hanging exit, but it can still happen.

Once the student grabs the pilot cute bridle the games up unless the AAD does it's job. With a direct bag the deployment, the process keeps going. So, I'm happier with a direct bag and a hanging exit.

Tom Buchanan
Instructor Emeritus
Comm Pilot MSEL,G
Author: JUMP! Skydiving Made Fun and Easy

[Yossarian 0]

you say there is a greater risk with the direct bag method of a static-line hang-up, but how often does this really happen? and i know mistakes get made and shit happens every once in a while but shouldnt a misrouted static line be very easy to spot? are there any other causes of a hangup other than a misrouted s/l?

[tombuch 0]

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you say there is a greater risk with the direct bag method of a static-line hang-up, but how often does this really happen? and i know mistakes get made and shit happens every once in a while but shouldnt a misrouted static line be very easy to spot? are there any other causes of a hangup other than a misrouted s/l?

It's very rare. Some of the things that can cause it are a misrouting to the pin, a bag lock, or a connection between the bag and canopy that won't release. Back in the day it was common to use breakcord, rather than Velcro to attach a static line to the apex of the canopy, and sometimes that breakcord would be either the wrong type, or wrapped too many times, and that would cause an in tow situation. Velcro makes that less likely. You can find some basic technical specs for static lines under FAR 105.47.

Tom Buchanan
Instructor Emeritus
Comm Pilot MSEL,G
Author: JUMP! Skydiving Made Fun and Easy

[riggerrob 558]

With any static-line system, there is a slim chance that a student will wrap a static-line around his reserve, neck, or arm, etc. and get towed behind the airplane.

For example: the last Canadian soldier - who wrapped a static-line around his neck, didn't get towed behind the airplane, but the broken neck sure killed him!
Before you criticize the dear departed too harshly, try to picture yourself standing - correction: trying to stand - in a harness that is too tight, in a bouncing C-130, in the dark, for half an hour, with a rucksack, rifle and snowshoes.

[dgw 8]

"It's actually pretty tough (and annoying) to remain completely stable as a static line is ripping stuff off your back. And trying to do a practice ripcord pull under those conditions is unpleasant."

I agree . So does my shoulder.

When I originally started doing the SL progression, I used rigs with hip mounted ripcords. My AFF was with a similar deployment system. On dummy pulls with the hip mounted ripcord, the SL deployment didn't really affect the handle position, and I found this helpful for dummy pulls and early freefall, particularly in light of later efforts on BOC dummy pulls, where the container and handle move during deployment.

I thought that the transition from hip to BOC (after 40 jumps) was no great leap, although I appreciate early freefalls are a picnic short of a picnic.

I haven't got a strong view on the matter, but I do think that hip mounted ripcords are way more easily reached on dummy pulls, and, consequently, allow a student to develop more confidence in deployment procedures. By comparison, on a first freefall with a BOC progression, a student could be forgiven for grabbing where the handle was on the dummy pulls - it won't be there.

Thanks for the response.

[kevinwhelan 0]

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Back in the day it was common to use breakcord, rather than Velcro to attach a static line to the apex of the canopy

I trained on static line and have never seen the static line attached to the canopy at all. We just have the line attached to the bag.
What are the advantages of having it attached to the canopy?

"be honest with yourself. Why do I want to go smaller? It is not going to make my penis longer." ~Brian Germain, on downsizing

[tombuch 0]

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What are the advantages of having it attached to the canopy?

Staged deployment. I'm thinking mostly of round parachutes with pilot chutes. The static line is attached to the bag, and a piece of Velcro then attaches the inside of the bag to the pilot chute or the apex of the canopy. It simply ensures the canopy and lines are deployed in sequence, rather than bag strip. I'm not sure how most DZ's are rigging their squares with a direct bag these days.

Tom Buchanan
Instructor Emeritus
Comm Pilot MSEL,G
Author: JUMP! Skydiving Made Fun and Easy

[riggerrob 558]

A piece of break cord or Velcro attaching a round canopy to the static line is mandatory.
This is because rounds are very sensitive to slack during the opening sequence.
They are also very sensitive to the cross-winds (across the skirt) that often occur during S/L deployments, making it doubly important to keep a bit of tension on the apex.
Ergo, many countries have federal air regulations demanding some sort of break cord or Velcro on s/l deployed rounds.

Squares - on the other hand - don't care if there is any tension on their top skin/bridle attachment during deployment. As soon as wind hits the bottom skin, they want to OPEN.

[BIGUN 1,053]

Why would one do IAD -S/L out of a PAC, King Air or Otter? IMO, the instructional methodology should fit the A/C. Personally, I would fit the IAD - S/L method to C-182's, but think it would be an easy and safer sell for AFF or AFP for PACs, King Airs or Otters.

Nobody has time to listen; because they're desperately chasing the need of being heard.

[tombuch 0]

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Why would one do IAD -S/L out of a PAC, King Air or Otter? IMO, the instructional methodology should fit the A/C. Personally, I would fit the IAD - S/L method to C-182's, but think it would be an easy and safer sell for AFF or AFP for PACs, King Airs or Otters.

The Otter is a fine static line aircraft as long as the operator wants to use it for low passes. It has a big door, flys slow, has a high tail, and is super easy to rig and jump from. Sure, it's more efficient for high altitude jumps, but it works for a static line program too.

Tom Buchanan
Instructor Emeritus
Comm Pilot MSEL,G
Author: JUMP! Skydiving Made Fun and Easy

[riggerrob 558]

Twin Otters are surprisingly graceful for static-lining or IAD.
I suspect that PAC 750s are equally graceful.
However, King Airs are simply too fast.

[BIGUN 1,053]

I've been thinking about this since Tom's thread and I can kinda see the S/L working on an Otter. I guess it's no different than a poised exit off the 182, just on a different side. I do know that I'd have someone experienced show me before I did one myself. I do have one question - is it necessary to duct tape the door frame or just run your hands down it to ensure there's no nicks?

Nobody has time to listen; because they're desperately chasing the need of being heard.

[NelKel 0]

Twin Otters are surprisingly graceful for static-lining or IAD.
I suspect that PAC 750s are equally graceful.
However, King Airs are simply too fast. <<<

I agree, Otters are capable of slower flight.
DO you think hanging off the strut of a C-182 gives the student a better chance of sucess for a stable exit? It just seem to me that Staticline=C182 and AFF=Otter.
It just seems to me also that if a DZ could afford to operate an Otter then they would also have an AFF program. Most DZ that have an AFF program shy away from S/L traning. Sometimes it is nessary during crossover training when a student comes from a different DZ that only offered S/L training. It may be nessary for the student to complete a catogory in their original training program before starting the AFF program. At the begining of each Catogory of section 4 of the SIM's there are requirments and reminders for crossover training.

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Someone dies, someone says how stupid, someone says it was avoidable, someone says how to avoid it, someone calls them an idiot, someone proposes rule chan

[NelKel 0]

In IAD, is there a greater risk of instability during dummy pulls and potential entanglements? <<<

I know you asked Tom B. but I wanted to point out something to you about S/L and IAD.
When I train my student on PRCP's , I teach that they will not beat the S/L deployment. They will usually feel the S/L slight jerk while they are reaching for the PRCP. This is during an exit from a C-182 strut. Also the S/L prevents the student from completing a belly to earth position before deployment. On IAD it is more possibale for the student to reach a belly to earth orentation prior to deployment. But only slightly more than S/L. Ofcorse these senerios are from hanging C-182 exits.
However the chance of instability depends on the student, not the method

_________________________________________

Someone dies, someone says how stupid, someone says it was avoidable, someone says how to avoid it, someone calls them an idiot, someone proposes rule chan

[Andrewwhyte 1]

As Tom said the slower deployment sequence of IAD allows for a slightly higher instability risk. I definitely feel, however, that the entanglement risk is significantly higher during a S/L deployment. The reason is the out of sequence deployment inherent in the S/L system. During an IAD deployment everything is coming out in order and downwind of the student whether they are stable or not. Since the static line is attached to the plane it must be upwind of the student when the canopy separates from the D-bag, or the pilot chute separates from its static device, depending on which method is used. I think it is this "sail effect" combined with an unstable student which provides the most significant entanglement risk.

[riggerrob 558]

When I train my student on PRCP's , I teach that they will not beat the S/L deployment. They will usually feel the S/L slight jerk while they are reaching for the PRCP.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

And I tell my students that this jerking around/minor instability is an additional test.
We want to test if they can remain focused on opening their own parachute even with that distraction.

[zero-hero 0]

My 4th IAD jump was terrifying for me. But managed to shake off my pilot that was around left my arm. Did 5 thousand count down. While i could feel a light pressure there too. At 5 thousand count. Did visual check and couldn't believe my eyes. Just my tiny little white pilot hanging off my arm. LOL

Everything went ok after pilot managed to shake loose. And canopy opened perfectly. Phew. ...

Does this happen a lot? Or the instructor trying to kill me (joking, but seriously) The instructor said i squished him as i was leaving door. Plus he said i was free falling for 7 seconds. From 3500ft.

I'm just being paranoid too. I noticed the instructor didn't or i think he didn't put the parachute on right? And noticed i think he got retraining on exit procedures. Was watching the experts i think give shit to my instructor. Any expert advise to calm m my nerves would help me for my next safe jump.

[gowlerk 1,911]

zero-hero

My 4th IAD jump was terrifying for me. But managed to shake off my pilot that was around left my arm. Did 5 thousand count down. While i could feel a light pressure there too. At 5 thousand count. Did visual check and couldn't believe my eyes. Just my tiny little white pilot hanging off my arm. LOL

Everything went ok after pilot managed to shake loose. And canopy opened perfectly. Phew. ...

Does this happen a lot? Or the instructor trying to kill me (joking, but seriously) The instructor said i squished him as i was leaving door. Plus he said i was free falling for 7 seconds. From 3500ft.

I'm just being paranoid too. I noticed the instructor didn't or i think he didn't put the parachute on right? And noticed i think he got retraining on exit procedures. Was watching the experts i think give shit to my instructor. Any expert advise to calm m my nerves would help me for my next safe jump.

It's hard to say from your description exactly what happened. But it is fair to say that the instructor made an error. We are all human. It does not happen a lot, but it does happen. Your instructor is not trying to kill you, he is probably very embarrassed about the mistake.

You did a nice job dealing with your situation. You identified the problem and cleared it before your AAD fired. If I were you I would ask to talk to the head instructor about the incident. You are owed an honest explanation of what happened.

Always remember the brave children who died defending your right to bear arms. Freedom is not free.