HISTORICAL INFORMATION ON DUAL AAD SYSTEMS FOR AFF/PFF

[Chris_K 0]

I am looking for specific information on incidents involving a dual AAD system (AAD on the main and reserve) for rip cord systems.

Please specify the set up used, dates of incident and a brief description of what happened.

I know that Perris and the air force academy used to use these systems.

My DZO wants to use similar systems for a AFF/PFF program but I have hear some real negatives to the system, as such I need specific mals /incidents that have historically ahppend to these systems.

Ideally if any of the old dogs from Perris of AFA can post it would be appreciated.

Downsizing is not the way to prove your manhood.

[JohnRich 4]

I haven't seen such setups since the early 1980's. The place I jumped then used Sentinels on the reserves, and KAP-3's on the main. The Sentinel is like today's modern AAD's, and the KAP-3 was a Russian mechanical timer that activated a spring-loaded pin pull. For example, if the student was supposed to do a 5-second freefall delay, the KAP-3 would be set to pull at 10 seconds.

I know of no negative incidents from these dual AAD's, but my experience is limited.

[fossg 0]

I was one of the early AFF students in Perris. The setup was a double keel Paradactyl and an aad on the reserve. I have only heard of double aads on military HALO jumps. The aad was a FXC 1200. The guy who would know would be skybill.

[Andrewwhyte 1]

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I am looking for specific information on incidents involving a dual AAD system (AAD on the main and reserve) for rip cord systems.

Please specify the set up used, dates of incident and a brief description of what happened.

I know that Perris and the air force academy used to use these systems.

My DZO wants to use similar systems for a AFF/PFF program but I have hear some real negatives to the system, as such I need specific mals /incidents that have historically ahppend to these systems.

Ideally if any of the old dogs from Perris of AFA can post it would be appreciated.

Doesn't Joe Chow use them now at STI?

[VerticalRush 0]

I think the Air Force Academy in Colorado uses a Cypres reserve and a FXC main combination.

[skypuppy 1]

Joe Chow is his dzo, and yes, right now that is the system his ff students use. Chris is asking about specific incidents which show this system more risky on aff/pff-type jumps.

My opinion is, on an aff jump, isn't the main-side instructor the main aad?

If some old guy can do it then obviously it can't be very extreme. Otherwise he'd already be dead.
Bruce McConkey 'I thought we were gonna die, and I couldn't think of anyone

[Andrewwhyte 1]

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Joe Chow is his dzo, and yes, right now that is the system his ff students use.

Ahh. His profile lists PST.
If you are going to use a ripcord activated main I can see very little downside to using duel AADs.

[koppel 3]

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f you are going to use a ripcord activated main I can see very little downside to using duel AADs.

Depends on the type of AAD.

I learnt on a DZ that uses Cypres (and now Argus as well I believe) on the reserve and FXC1200J on the main.

I am not a fan of this system due to the fact that FXC have a large window firing. The factory talk about a 300'Plus/Minus window on the firing height but I have seen closer to +/- 1000 myself.

I like my canopy...


...it lets me down.

[Andrewwhyte 1]

My own experiences are closer to 300' with the recipient swearing they were higher than that. Regardless it should not be a problem as a student should be activating by 3000' anyway.

[riggerrob 558]

FXC says to leave a 1500 foot margin of error between the AAD setting and planned opening altitude. That means if you tell students to open by 3,000 feet, FXC 12000 AADs should be set to fire at between 1,000 and 1,500 feet.
I have only seen one FXC 12000 miss-fire at 7,000 feet. All the other FXC "miss-fires" happened below 3,000 feet with many of them looking like less than 2,000 feet.

[riggerrob 558]

Holy Freudian slip Batman!

"... using duel AADs..."

If you want to prevent AADs from duelling to the death, set their firing altitudes a long way apart ... ... like 2,000 feet apart.

[riggerrob 558]

History lesson ....

Perris Valley Skydiving School installed (during the 1980s) FXC 12000 AADs on their main containers long before Cypres was invented in 1991.
Once (mid 1990s) Cypres had proven itself, PVSS installed Cypri in all their student reserves.
My last (2001) rigging job in Perris was to remove all the main FACs and sew on double-handled BOCs.

[riggerrob 558]

Another history lesson ...
AADs were invented to save unconscious pilots after they ejected from jets.
First-generation AADs (e.g. Irvin Hite-Finder) were only used by military freefallers and they fired on every jump.
Second-generation ADDs (e.g. FXC 8000) had two sensors to prevent them from pulling if the skydiver opened his main at a reasonable altitude.
Third-generation AADs (e.g. Snyder's Sentinel) used electronic sensors to measure altitude more precisely.
First, second and third-generation AADs all open containers by pulling ripcord pins.
Fourth-generation AADs (eg. Cypres, Astra, Argus, Vigil, etc.) use modern electronics to measure time and pressure more precisely. Fourth-generation AADs are the first "loop-cutters."

[skypuppy 1]

On a test jump on the system last week we had the fxc on the main set for 3000'. I pulled around 4500', and after I had landed it was discovered that the fxc had fired, even tho' I pulled over 1000 ft above it's set altitude....

If some old guy can do it then obviously it can't be very extreme. Otherwise he'd already be dead.
Bruce McConkey 'I thought we were gonna die, and I couldn't think of anyone

[LouDiamond 1]

Quote

Another history lesson ...
AADs were invented to save unconscious pilots after they ejected from jets.
First-generation AADs (e.g. Irvin Hite-Finder) were only used by military freefallers and they fired on every jump.
Second-generation ADDs (e.g. FXC 8000) had two sensors to prevent them from pulling if the skydiver opened his main at a reasonable altitude.
Third-generation AADs (e.g. Snyder's Sentinel) used electronic sensors to measure altitude more precisely.
First, second and third-generation AADs all open containers by pulling ripcord pins.
Fourth-generation AADs (eg. Cypres, Astra, Argus, Vigil, etc.) use modern electronics to measure time and pressure more precisely. Fourth-generation AADs are the first "loop-cutters."

Not busting your balls but you forgot one. The AR2. Another military AAD that has limited use still. This AAD could be hooked up either on the main or the reserve. In either case, the jumper attached the AR2 to the power cable assembly prior to jumping after having manually set the activation altitude which required determining the setting based on barometric pressure on the ground via a AR2 calculator. The jumper was responsible for arming the AR2 by flipping a switch on the side of the AR2 body. This was done at the jumpmasters command normally at 6k feet AGL. Once the jumper landed, he turned the AR2 off by flipping the switch to off.

AUTOMATIC RIPCORD RELEASE, MODEL 451 0004 00
THEORY OF OPERATION
The AR2 senses rate of fall and altitude above mean sea level (not above ground level). When
the AR2 falls through the altitude set on the altitude dial at a rate of fall of over 80 ft/sec, the
power cable will retract two inches (minimum) and at an initial force of 70 pounds. If the rate of
fall is at a slower speed, such as 70 ft/sec, the AR2 will not actuate.

When the AR2 is used on the reserve parachute, the main parachute must be fully deployed at
least 1,500 feet above the actuation altitude for the AR2. While in free fall, if the main parachute
opens within only a few hundred feet above the actuation altitude, the fall rate mechanism may
not have sufficient time to equalize pressure and deactivate. This could result in the deployment
of two parachutes, leading to problems associated therewith. If the fall is initiated below the
altitude set on the altitude dial, the AR2 will definitely actuate, and generally within 1,000 feet of
free fall.

"It's just skydiving..additional drama is not required"
Some people dream about flying, I live my dream
SKYMONKEY PUBLISHING

[Andrewwhyte 1]

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On a test jump on the system last week we had the fxc on the main set for 3000'. I pulled around 4500', and after I had landed it was discovered that the fxc had fired, even tho' I pulled over 1000 ft above it's set altitude....

Put it in the chamber and see if you can reproduce the result.

[pchapman 261]

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it was discovered that the fxc had fired, even tho' I pulled over 1000 ft above it's set altitude....

Put it in the chamber and see if you can reproduce the result.

I believe that's the plan.
The DZ's experience with FXC reliability has generally been good. Over about 10 years, for example, I recall only once hearing of a problem with one firing unexpectedly (under canopy in that case), and needed to go back for manufacturer checks. Probably a couple others were found during DZ chamber tests to be getting a bit out of spec and being sent back. All of the FXCs in use (about 30-35 at one time) do get their proper 2 yr factory checks.