AADs and highly loaded reserves (was: Arizona 200-way collision)

[grue 1]

ChrisD

Stereotypes exist for a reason. That's because at some point there is truth behind the stereotype.

There is also the big sky, stereotype. The big sky theory is that there are relatively few collisions between objects in the sky, the Air Force is a big believer in this. As many others, but nonetheless it's still a stereotype.

The AAD is there when you can't pull or when you have forgotten to pull.

We in fact do have a body of knowledge regarding very successful low deployments as a result of proper AAD function. We have a rather large and repeatable series of incidents each and every year of individuals that didn't pull.

The numbers have shown that there are more fatal no-pulls than being rendered unconscious in the air. (that's because the big sky theory works...)

The AAD is a chance, and personally I would always want to avail myself of every chance at success that I can get.

C

So even implying something like I don't use an AAD because my wing loading is this or that is actually choosing to ignore the reliable information that we already have.

People that chose to NOT use an AAD are in the same category as those that pull low so that others can see how good they really are. The same category of those that swoop, not because they enjoy the mastery of the skill, but to show off and they choose to do this only in front of others. Etc,.... Perhaps this is what skydiving has become,...

not something that rational beings do for the intrinsic enjoyment of jumping ,....

I think that's a very narrowminded view. Yes, in the majority of cases it's probably good to have an AAD, but for several years I had a choice: Buy an AAD and not have money to jump, or don't buy an AAD, and use the money to jump.

It wasn't a hard choice.

I didn't give a shit what people thought of my decision, because I didn't throw the information out there. If someone asked which AAD I use, I'd say "none", and if they wanted to know why, I'd tell them. Otherwise I thought of AADs like religion and penises: If you have one, great. Just don't wave it around in my face and try and shove it down my throat.

cavete terrae.

[wmw999 2,130]

Well, I happen to agree than an AAD is a choice. I'd rather have one, but only recently have I had more jumps with one than without.

That said, while I agree that a highly-loaded reserve with an AAD is kind of silly most of the time (I'd rather not land my 1.1 reserve without steering or flaring, never mind something much smaller), it does increase by about 15-20 seconds the amount of time that someone has to wake up and realize they're about to be seriously fucked up.

But if I were to change reserves, I'd upsize long, long, before I downsized.

Wendy P.

There is nothing more dangerous than breaking a basic safety rule and getting away with it. It removes fear of the consequences and builds false confidence. (tbrown)

[grue 1]

wmw999

That said, while I agree that a highly-loaded reserve with an AAD is kind of silly most of the time (I'd rather not land my 1.1 reserve without steering or flaring, never mind something much smaller), it does increase by about 15-20 seconds the amount of time that someone has to wake up and realize they're about to be seriously fucked up.

But if I were to change reserves, I'd upsize long, long, before I downsized.

Wendy P.

Yeah, my 220sqft reserve is loaded around the 1.1 range (and dropping!), and while I'd rather NOT land it without doing anything, I bet I'd come out of it "reasonably" ok, at least compared to what it'd be like if I were jumping a 176 or something to have a cute small rig :P

cavete terrae.

[labrys 0]

Quote

That said, while I agree that a highly-loaded reserve with an AAD is kind of silly most of the time

I don't disagree in general, but "most of the time" might be inaccurate. Almost every AAD activation I've seen (including my own, FWIW) has happened to a conscious but "otherwise majorly fucking something up" skydiver. The vast minority have been incapacitated skydivers. I realize that isn't the marketed use for AADs, but it does seem to be more likely.

Again, I don't think that having a reserve that'll probably seriously injure or kill you if you're incapacitated is a good idea..

Owned by Remi #?

[dirtbox 0]

I gave this some thought before buying a new rig/reserve and came to the conclusion that it didn't really matter too much. I read incident reports of people loading around 1.1:1 and higher loading (~1.6:1) and they all got pretty equally messed up after hitting solid objects/the ground while out under reserve …ended up matching my reserve to my main (120 smart)…chances are if I am out under reserve I am already messed up from the free fall collision and .5:1 different in WL isn't going to make a huge difference to the outcome of a collision with a solid object under canopy

2c worth

[JeffCa 0]

I just bought my first reserve at 0.83 WL because of just this scenario. I spent the extra money to get the Optimum so I could fit a bigger canopy in the same space. I don't know if I'll ever move off that size, because I'll never by skygod enough to handle a smaller canopy while being unconscious at the same time. I'm hoping it's enough to get me down with only minor injuries if I'm unconscious, but maybe that's naively optimistic?

"So many fatalities and injuries are caused by decisions jumpers make before even getting into the aircraft. Skydiving can be safe AND fun at the same time...Honest." - Bill Booth

[Trev_S 0]

Do we need to take into account the possibility of a two out situation when choosing reserve size? Or should we pick a conservative reserve and deal with a difficult two out if/when it happens? Or is having a big difference between main and reserve size not that big of a deal?

[ChrisD 0]

Trev_S

Do we need to take into account the possibility of a two out situation when choosing reserve size? Or should we pick a conservative reserve and deal with a difficult two out if/when it happens? Or is having a big difference between main and reserve size not that big of a deal?

A bit off topic cause Grue is trying to tease out some of the AAD and high wing loading stuff and big way jumps.... assumption that everyone is rich, see what an ass I make of myself from time to time!

But since you asked and this will take up the same amount of space, and trying not to hijack the thread,...

This: PIA report

I humbly suggest this be taken to a different thread /post whatever....
Read the Report, a lot of stuff comes at you very fast, and just one sentence means a lot in that thing and then ask again

But what do I know, "I only have one tandem jump."

[councilman24 36]

The size of reserve shouldn't influence the decision to have an AAD or not. You might die unconscious under a little reserve. I guarantee you'll die unconscious under no reserve. Decide on an AAD or not. Pick a reserve and either accept unconscious you'll get fucked up or pick a bigger reserve and lessen that chance. I won't get into vegetable versus dead debate. Too many variables.

I know I wish my friend knocked unconscious on the door of a DC-3 in 1985 had an AAD. And I'm glad some other friends did have them. And I still have 4 rigs and one AAD.

BTW the dual square report reference above was 1997. Canopy performance wasn't as drastically different as it is now. I'm not sure it matters what the relative sizes are when one is a velocity and one is a Raven.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[piisfish 135]

the silly thing in the story is the highly loaded reserve (guilty)

still better to land unconscious under and AAD deployed highly loaded reserve rather than under a coded rig.

scissors beat paper, paper beat rock, rock beat wingsuit - KarlM

[SethInMI 145]

Does anyone have an idea of what the descent rate of a reserve with brakes stowed is at low (1.1) and/or high (1.8) wingloadings?

Seth

It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

[RiggerLee 61]

I don't think there is any way to say. Too many variables of trim angle, break setting, and air foil. As I understand it there will be standards for this in the new TSO standards so in future there will be a number that will probable dictate the maximum loading of the canopy. They seem to be going round and round with the FAA over this. I'm not sure how it will settle.

Lee

Lee
[email protected]
www.velocitysportswear.com

[JerryBaumchen 1,050]

Hi Lee,

Quote

They seem to be going round and round with the FAA over this. I'm not sure how it will settle.

IMO it has been settled. In the TSO standard ( PIA TS-135 ) for TSO C23f the FAA removed the section on the alternate method of conformance.

I wrote about this in another thread and I'm too busy to go get all of the details.

Anyone can get on the faa.gov site and the PIA site & look this stuff up for themselves. OK, it was fairly easy; see below.

JerryBaumchen

http://www.pia.com/piapubs/TSDocuments/TS-135v1.4.pdf

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgTSO.nsf/0/1a8b18fa46db168786257a830054d117/$FILE/TSO-C23f.pdf

[SethInMI 145]

Thanks Jerry.

From the PIA document, the max brakes stowed descent rate is 24 ft/sec or 7.3 m/s. This is the same as jumping off an object 2.7m or 9ft off the ground. Feels to me unlikely to be fatal.

Interesting to know what that does to the max weights; what the max wingloading turns out to be to meet that rate.

It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

[wmw999 2,130]

However, the max forward speed is 36 f/s, which is equivalent to 25 mph or 40 k/h -- that's pretty brisk.

Wendy P.

There is nothing more dangerous than breaking a basic safety rule and getting away with it. It removes fear of the consequences and builds false confidence. (tbrown)

[RiggerLee 61]

So if that is now locked in stone, what are your thoughts? Will it become the limiting factor on the suspended weight for the canopy as opposed to 254 lb. or what ever the structural weight turns out to be from the heavy drops. Will we see the next generation moving towards the minimal structural requirements be cause there is now no point in pushing for higher weights and speeds when you can no longer placard them for more then say.... 1.2 lb./sq.ft.?

And of the canopies we have now. Where do you think they would fall on this. What would a 126 do at 254 lb. for a total speed? How low do you have to go on your wing loading to get down to 36 ft./sec. over all?

Lee

Lee
[email protected]
www.velocitysportswear.com

[SethInMI 145]

Lee,

My uninformed read of the requirement means it is for brakes stowed flight, not full drive. I don't have a good feel for relative speeds, but my feeling is even high loaded parachutes slow down quite a bit in stowed configuration.

I doubt my 1.5 loaded main is going that fast in stowed brakes, the wind in my face feels more like a 10-15mph breeze than a 25mph breeze.

It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

[JerryBaumchen 1,050]

Hi Wendy,

Quote

However, the max forward speed is 36 f/s, which is equivalent to 25 mph or 40 k/h -- that's pretty brisk.

Actually, not correct. From the PIA document:

"The average rate of descent shall not exceed 24 ft/s (7.3 m/s) and the total velocity shall not exceed 36 ft/s (11.0 m/s) in an unaltered post deployment configuration"

The 36 ft/s is total velocity. That means no more than 24 downward and 36 down its slope. No specific limit on forward speed. It is limited by the vertical speed & the total speed.

JerryBaumchen

[JerryBaumchen 1,050]

Hi Lee,

Quote

what are your thoughts?

At my age I would not want to land a canopy that met this criteria. When I was younger & tougher, I thought nothing about coming in downwind on my ParaCommander; did it many times.

Those days are gone for good.

Quote

Will it become the limiting factor on the suspended weight for the canopy as opposed to 254 lb. or what ever the structural weight turns out to be from the heavy drops.

It says: "Per Table 3, there shall be not less than 6 drops, with an individual and/or dummy in each harness weighing not less than the maximum operating weight2."

There you go.

JerryBaumchen

[JerryBaumchen 1,050]

Hi Seth,

Quote

Thanks Jerry.

Absolutely no thanks necessary.

I think it is very important that people make an educated decision whenever they buy parachute equipment.

As a genuine old fart, we did have many choices 'back in the day.' But now everyone does; read, learn, think & then decide. It might just keep you out of a wheelchair.

JerryBaumchen

[RiggerLee 61]

What if the weight it can support at that decent rate is lower then the min drop weight for the heavy drops? Does the lower weight to comply with the decent become the maximum suspended weight. And where is the incentive to build a stronger canopy?

Lee

Lee
[email protected]
www.velocitysportswear.com

[nigel99 144]

Trev_S

Do we need to take into account the possibility of a two out situation when choosing reserve size? Or should we pick a conservative reserve and deal with a difficult two out if/when it happens? Or is having a big difference between main and reserve size not that big of a deal?

As an Aussie, you have one of the most knowledgeable people in the world on this topic available to you. Look up when Michael Vaughan will be doing a canopy course and hook up with him. He has a presentation on two outs that goes way beyond the outdated dual canopy report that people point you to.

Experienced jumper - someone who has made mistakes more often than I have and lived.

[JerryBaumchen 1,050]

Hi Lee,

I have not been on the TSO committee for over 20 yrs.

But the best place to ask those questions actually is the FAA.

And good luck with getting a coherent written response.



JerryBaumchen

PS)

Quote

What if the weight it can support at that decent rate is lower then the min drop weight for the heavy drops?

IMO it does not make any difference, it says at the Maximum Operating Weight. Pretty clear to me.

[riggerrob 558]

RiggerLee

What if the weight it can support at that decent rate is lower then the min drop weight for the heavy drops? Does the lower weight to comply with the decent become the maximum suspended weight. And where is the incentive to build a stronger canopy?

Lee

............................................................................

There is little incentive to building a stronger canopy, but all certified canopies (e.g. reserves) must still all pass the heavy weight/high speed drop tests.
After a canopy has passed the stress tests, then they measure the rate of descent and decide what maximum weight to placard it. Look at the label on any PD reserve and you will see that the smallest ones (e.g. PD113) is placarded for much less than 254 pounds.
That is because PD expects the canopy to survive a high-speed opening at 254 pounds, but does not expect a fat (254 pound) guy's ankles to survive landing a PD 113 reserve.

[RiggerLee 61]

But such a label is often written as a "Recommended Maximum" based on it's flight characteristics. PD even gives it by experience level. It's generally blatantly ignored. It's a good way for them to doge liability. But this would actually make it a TSO restriction. It would change the true legal maximum with the FAA. Now if you have a small rig you are violating the TSO and both you and the pilot can be violated for every jump made from the airplane.

Lee

Lee
[email protected]
www.velocitysportswear.com