Forums: Skydiving: Safety and Training:
AAD and reserve deployments

 


reyno_gr  (C License)

Mar 27, 2005, 2:06 PM
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AAD and reserve deployments Can't Post

I've just been reading some bits in 'The Skydiver's Handbook' by Dan Poynter and Mike Turoff.
It suggests that a main will open within 3 to 4 seconds with a reserve taking slightly less. The book suggests this equates to about 700 feet (assuming the freefaller is at terminal i.e. 120 mph). <p143>
An expert Cypres fires at 750 feet which, by my logic means that if a skydiver lost altitude awareness and had a Cypres fire they would have about 50 feet to find the toggles and select a safe landing area. Now that's a very small margin!! Is this statement correct or am I missing the point?
With regards to aircraft emergencies it suggests that expert jumpers may elect to jump from a stricken plane between 500 and 1000 feet. <p119> From a personal point of view the plane would have to be pretty much engulfed in flames to get me out at 500 feet, especially if the reserve takes about 700 feet to deploy (although I accept this assumes terminal velocity not an enforced hop and pop).
Any views regarding the accuracy of this information?


AggieDave  (D License)

Mar 27, 2005, 2:18 PM
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Re: [reyno_gr] AAD and reserve deployments [In reply to] Can't Post

A reserve should open within 300-400ft, a main opens anywhere from 400-1000ft. My XF2 consistantly takes 900ft to open, for instance.

As for when to get out in an AC during an emergancy. Depends on the plane and the pilot. When a 182 I was in lost the engine at 200ft I stayed in and the pilot landed us perfectly in a cow pasture (no injuries, not even a bump or a bruise).

However, the wing falls off or some other random (probably not going to happen) incident along those lines I'd rather take my chances with my reserve.

That's just IMO, so please talk to your S&TA and/or your instructors about these scenerios!


ryoder  (D 6663)

Mar 27, 2005, 2:33 PM
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Re: [reyno_gr] AAD and reserve deployments [In reply to] Can't Post

Bear in mind there is a huge difference in altitude lost when you deploy at a specified altitude at terminal, vs doing a hop & pop from an aircraft at that altitude. In the latter case, you will be starting with a vertical velocity of zero, but you will have plenty of airspeed (from the a/c) to deploy the canopy, so you will open with much less altitude loss than if you had been at terminal at that altitude.


mark  (D 6108)

Mar 27, 2005, 2:34 PM
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Re: [reyno_gr] AAD and reserve deployments [In reply to] Can't Post

Check your assumptions. If your reserve takes 4 seconds to open, do you think you'll be falling at 120 mph at the 3-second point?

And if you exit an airplane moving horizontally at 80 or 100 mph 500 feet above the surface, what is the length of your trajectory to the ground?

Mark


tdog  (D 28800)

Mar 27, 2005, 6:54 PM
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Re: [ryoder] AAD and reserve deployments [In reply to] Can't Post

In reply to:
In the latter case, you will be starting with a vertical velocity of zero, but you will have plenty of airspeed (from the a/c) to deploy the canopy, so you will open with much less altitude loss than if you had been at terminal at that altitude.

So at a low altitude bailout - the faster the airspeed of the aircraft the better - so you can use the forward throw of the plane to give you airspeed to fill your reserve the quickest????

Side question... Faster you go, the harder the reserve opens - I.E. "terminal opening". But, that does not mean you are using the least distance to get to stable canopy flight. Specifically, does a longer, softer opening at, let say 80MPH relative wind speed take more or less distance than a harder opening at 130 MPH relative wind speed?


Kris  (D 26033)

Mar 27, 2005, 9:06 PM
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Re: [reyno_gr] AAD and reserve deployments [In reply to] Can't Post

Another thing you're forgetting as well....as soon as that bag comes off your back you're already starting to decelerate. Same thing when your canopy is snivelling.

This is a big reason why people think they have 1000' openings, although they're very rare. A really slow opening on my Stiletto, where it snivels for 2-4 seconds, is usually only chewing up about 400-600 feet.

I watched someone deploy about 300' away from me and they swore they had a 1000' opening, it was maybe 400'.Wink

It's more of a perception thing.


Andrewwhyte  (C 1988)

Mar 27, 2005, 10:53 PM
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Re: [Kris] AAD and reserve deployments [In reply to] Can't Post

I've had 1500' openings on tandems and they really do take a long time (like fifteen seconds).


Kris  (D 26033)

Mar 27, 2005, 11:05 PM
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Re: [Andrewwhyte] AAD and reserve deployments [In reply to] Can't Post

In reply to:
I've had 1500' openings on tandems and they really do take a long time (like fifteen seconds).

Another reason why I'm not getting a tandem rating.Tongue Tandem mains and reserves are different animals, I'll grant you that.

If my Stiletto isn't open after 5-6 seconds of snivel, I'm tugging on the rears to speed things up then chopping it if it still wants to just stay all compressed and pouty about opening.Cool

But, thanks for proving my point, 15 seconds for 1500 feet is roughly half belly terminal speed.


JohnMitchell  (D 6462)

Mar 28, 2005, 8:17 AM
Post #9 of 25 (1196 views)
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Re: [Kris] AAD and reserve deployments [In reply to] Can't Post

In reply to:
Another reason why I'm not getting a tandem rating.Tongue Tandem mains and reserves are different animals, I'll grant you that.
That's why we pull so dang high all the time.Smile I wouldn't ever want to get deep in the beeps with a tandem rig.


riggerrob  (D 14840)

Mar 28, 2005, 8:19 AM
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Re: [AggieDave] AAD and reserve deployments [In reply to] Can't Post

According to TSO standards, reserves are supposed to open in less than 3 seconds and less than 300 feet.
Tandem reserves are allowed slightly more time and distance for inflation.


Premier billvon  (D 16479)
Moderator
Mar 28, 2005, 10:02 AM
Post #11 of 25 (1174 views)
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Re: [reyno_gr] AAD and reserve deployments [In reply to] Can't Post

>An expert Cypres fires at 750 feet which, by my logic means that if a
>skydiver lost altitude awareness and had a Cypres fire they would have
> about 50 feet to find the toggles and select a safe landing area. Now
>that's a very small margin!! Is this statement correct or am I missing the
> point?

Well, reserves open faster than that, but also cypreses can fire lower than that. They have simple barometric triggers which sense altitude, and they can easily be off by a few hundred feet. We had a very low cypres firing at Perris a few weeks back, and the jumper only had about 10 seconds under canopy before he landed.

A cypres is intended as impact prevention, little more. It's not designed to give you altitude to release your toggles, do a few practice flares, find a landing area etc.

>From a personal point of view the plane would have to be pretty much
> engulfed in flames to get me out at 500 feet . . .

If the plane were on fire and going down I'd get out at 100 feet. If I could really get out at 100 feet (i.e. not start to open the door at 100 feet and get out just before impact) then I figure my reserve would at least stand a chance at slowing me down to a survivable speed before impact. It would depend on how bad the aircraft emergency was.


reyno_gr  (C License)

Mar 28, 2005, 2:13 PM
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Re: [billvon] AAD and reserve deployments [In reply to] Can't Post

I never considered that AAD'S would be less than 100% accurate in their activation altitude. A difference of a hundred feet is a sobering thought but I guess the bottom line is at least they get a canopy over your head.
Another issue arising from this (and yet another thing I'd never considered - thank god for thought provoking forums) is can AAD's be adjusted (like altimeters) if the emplaning point is different from the DZ (i.e there is an altitude difference between the two) or is there no requirement to do so?


jakee  (C License)

Mar 28, 2005, 4:16 PM
Post #13 of 25 (1108 views)
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Re: [reyno_gr] AAD and reserve deployments [In reply to] Can't Post

The Cypres can be set for offset landing areas when you turn it on. I would ASSumeTongue other AAD's use a very similar process.

Seriously though, more jumps than me and you didn't know that? (Don't mean to be rudeSmile).

There is a one or two week old incident thread from Perris that might be an eye opener to you. I strongly recommend you find it and learn from anothers mistakeUnsure.


(This post was edited by jakee on Mar 28, 2005, 4:18 PM)


Premier billvon  (D 16479)
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Mar 28, 2005, 4:19 PM
Post #14 of 25 (1106 views)
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Re: [reyno_gr] AAD and reserve deployments [In reply to] Can't Post

>can AAD's be adjusted (like altimeters) if the emplaning point is different from the DZ?

I was going to answer "very funny" but I have a sinking feeling you are asking a serious question.

Yes. A recent fatality occurred when a woman did not pull in time at Perris. Her cypres did not fire because she turned it on at a different location (a lower elevation) than she jumped at. The instructions on how to turn on the cypres, and how to rezero it or reset it to a different LZ location are contained in the cypres manual.


Premier NWFlyer  (D License)

Mar 28, 2005, 5:28 PM
Post #15 of 25 (1097 views)
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Re: [jakee] AAD and reserve deployments [In reply to] Can't Post

In reply to:
The Cypres can be set for offset landing areas when you turn it on. I would ASSumeTongue other AAD's use a very similar process.Unsure.

The Vigil has that capability as well.


mjosparky  (D 5476)

Mar 28, 2005, 11:27 PM
Post #16 of 25 (1060 views)
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Re: [reyno_gr] AAD and reserve deployments [In reply to] Can't Post

If you go through 1,000 feet at terminal, you have about 5/6 seconds until impact. If you step out of an airplane doing 80 to 90 mph at 500 feet, you have about 5/6 seconds until impact.

From the time your container opens at terminal you start slowing down and as soon as you step out of the airplane you start slowing down. The difference is that when you step out of the airplane you will only slow down at first then you will speed up. That is if you don't pull.

Most reserve canopies are tested to open in 3 seconds. And 3 seconds is 3 seconds no matter how fast you are going.

I have stepped out of an airplane at 600 feet and would take that over going through 1,000 feet at terminal anytime. (And BillVon is right, I went for my main.Tongue)

When your cypres fires it is just about to late for you to do anything useful.

Sparky


diablopilot  (D License)

Mar 29, 2005, 8:41 AM
Post #17 of 25 (1001 views)
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Re: [reyno_gr] AAD and reserve deployments [In reply to] Can't Post

Quote:
I guess the bottom line is at least they get a canopy over your head.

No, the bottom line is when the work properly they activate the reserve deployment (cut a loop, or pull a pin).


reyno_gr  (C License)

Mar 29, 2005, 12:38 PM
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Re: [billvon] AAD and reserve deployments [In reply to] Can't Post

Your sinking 'feeling' was right. It was a serious question and apperantly (judging by some of the comments one I should have known the answer too) Blush
However, as this information was never imparted to me on my AFF course, and I never received a Cypres manual when I brought my rig (it was second hand) I genuinely didn't know the answer. I haven't come across it in any publication (I've read so far), and as I've always taken off and landed at the same DZ I've never had cause to pose the question till it arose in this forum. Was it missed (by me or my instructors on the AFF course) or am I just dense?Unsure
At least I know the answer now (and I will get a copy of the Cypres manual too). Thanks for enlightening me.


Premier wmw999  (D 6296)

Mar 29, 2005, 12:47 PM
Post #19 of 25 (962 views)
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Re: [reyno_gr] AAD and reserve deployments [In reply to] Can't Post

There's no way that your FJC and even subsequent AFF training can cover everything you might need to know. If you're not near water, you probably haven't had much in the way of water training, but the assumption is that if you get closer to water, you should take the responsibility of asking.

Your life is in your hands. It's not in the hands of the gear maker, the Cypres, or anything else. Because you can learn about everything that you jump with, enough to KNOW why it works, and what will reduce its chance of working.

Not that you have to. Plenty of people don't. But it's all something you can learn about, and you should know enough to know what you haven't learned. Yes, that sounds weird. But it's your life.

Wendy W.


AndyMan  (D 25698)

Mar 29, 2005, 1:10 PM
Post #20 of 25 (955 views)
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Re: [reyno_gr] AAD and reserve deployments [In reply to] Can't Post

You can download the Cypres Manual here: http://www.cypres.cc/

_Am


Premier billvon  (D 16479)
Moderator
Mar 29, 2005, 2:55 PM
Post #21 of 25 (932 views)
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Re: [reyno_gr] AAD and reserve deployments [In reply to] Can't Post

>However, as this information was never imparted to me on my AFF course,
> and I never received a Cypres manual when I brought my rig (it was
>second hand) I genuinely didn't know the answer.

Your AFF course taught you everything you needed to make it through AFF, but only about 10% of what you need to survive in this sport. Some other good sources of info/ways to learn:

1. Read Parachutist, especially the incident reports.
2. Ask people questions when it's raining.
3. Get the manuals for all the gear you own and read them. Most are available online. Pay special attention to your harness/container manual.
4. Buy your beer for firsts. When you give it out, make sure you tell people why you bought it. You will likely get some good advice/observations/stories about what happened when they had their first X too.
5. Get a SIM and read it. It will make license tests easier and contains useful stuff.
6. Go to new DZ's and ask people there why they do things differently.

>Was it missed (by me or my instructors on the AFF course) or am I just dense?

I think this happens a lot - once people are off AFF they don't get much further education. The ISP was intended as a way to get more education out there but it is of limited effectiveness since not all DZ's implement it. When there's no ISP you have to be more aggressive in learning stuff yourself.


riggerrob  (D 14840)

Apr 1, 2005, 7:35 PM
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Re: [JohnMitchell] AAD and reserve deployments [In reply to] Can't Post

In reply to:
In reply to:
Another reason why I'm not getting a tandem rating.Tongue Tandem mains and reserves are different animals, I'll grant you that.
That's why we pull so dang high all the time.Smile I wouldn't ever want to get deep in the beeps with a tandem rig.

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

Just to amuse myself, I used to play "beat the beeper" by setting my Dytter to 5,000 feet and trying to time my pull so that my Dytter would "dyt" during line stretch.


bodypilot1  (D 16037)

Apr 1, 2005, 8:54 PM
Post #23 of 25 (844 views)
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Re: [Andrewwhyte] AAD and reserve deployments [In reply to] Can't Post

In reply to:
I've had 1500' openings on tandems and they really do take a long time (like fifteen seconds).

Holly shit! 15 seconds?

I know POSITIVELY that I'd never ride any tandem canopy that took 15 seconds to open. Crazy

That's WAY too long if your pulling at 5000ft, I'd look at the trim of the canopies.


Be safe.
Ed


Andrewwhyte  (C 1988)

Apr 1, 2005, 9:59 PM
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Re: [bodypilot1] AAD and reserve deployments [In reply to] Can't Post

It has happened a few times, ususally with tiny passengers. Trim's usually ok, but on older canopies for sure. I leave that stuff up to riggerrob.


tbrown  (D 6533)

Apr 2, 2005, 11:51 PM
Post #25 of 25 (795 views)
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Re: [reyno_gr] AAD and reserve deployments [In reply to] Can't Post

People shouldn't forget that a Cypres will not arm itself until 1500 ft of climbout from takeoff. So if you have to bail from less than 1500 ft, the Cypres isn't going to do ANYTHING at all. Because that's the way they're programmed. Once again, you'll have to pull silver yourself.

In the olde days of the seventies, 500 ft used to be considered the minimum acceptable altitude for bailing out, below 500 you kissed your ass goodbye and trusted the pilot. Nowadays it seems more like 1000 ft is the bail or kiss altitude. Personally, if the plane's on fire, falling apart, or in a steep dive, I'll be clawing at the door to get it open and I'll bail at 50 ft because I'd rather bounce than burn. But if the pilot's got the plane in a glide, I'll stay buckled and kiss my ass goodbye, and maybe the ass next to me if she's pretty...



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