Vigil fire

[pchapman 261]

Cypres must compensate for the burble -- even if they ignore the whole issue in their manuals!

As previously posted in a link, Cliff Schmucker of SSK wrote, in the document on the SSK site:

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The Expert CYPRES activates when a velocity of 35 meter/second (115 feet/sec., 6890 feet/min.) or greater is obtained at an altitude of 750 feet with a skydiver in freefall stable face-to-earth, or tumbling. With a skydiver falling perfectly stable back-to-earth, or with CYPRES in a test chamber, or in a descending aircraft, the activation altitude is approximately 1050 feet. (This 300 ft. difference is due to the low pressure area aft of a freefalling body versus the actual air pressure.)

The NTSB report was written by people who don't understand skydiving and missed that point.

[pasha_justas 0]

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Cypres must compensate for the burble -- even if they ignore the whole issue in their manuals!

I see 2 ways to get true:
1) make an experiment in the chamber (like myth busters ;))
2) make request to Airtec directly. By email for instance.

[billvon 2,400]

>Only Vigil has additional altitude correction.

No AAD has "additional altitude correction." They fire when they sense a given altitude. If the sensor is in the rig it senses a higher altitude when you are belly to earth, and a lower altitude when you are back to earth (or standing up.) The only adjustment AAD manufacturers can make is to change the firing altitude to account for this. They do not have attitude gyros, so they cannot detect what position someone is in and compensate for different body positions.

[pchapman 261]

For what it's worth, I found another document from SSK that mentions the altitude compensation* also from 15+ years ago:

http://www.cypres-usa.com/cyp13.htm


* altitude or pressure or body position
adjustment, correction, compensation, allowance, variance, differential, whatever term you prefer

[pasha_justas 0]

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>Only Vigil has additional altitude correction.

No AAD has "additional altitude correction."

English is not my native language.

I mean this:

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Conclusion:
If the Vigil® is set in PRO mode, it will activate at 840 Ft or 256 m above the ground when a falling speed
of 78 mph or 35m/sec is reached. It is well accepted that this minimum activation level must be
guaranteed whatever the position of the skydiver.
If the skydiver is falling in a back to earth position, the reading will reflect the correct pressure, the
sensor is not influenced by a depression, but if the skydiver is falling face to earth, then the sensor
located in the depression zone will read an up to 10mbar lower pressure or an altitude 260 ft or 80 m
superior to the real altitude, and will in this case activate later or 260 ft or 80m lower i.e. at a real
altitude of 580 ft or 176 m above the ground which is too low.
Therefore a compensation of + 260 ft or + 80 m above the nominal activation altitude was integrated.
In PRO mode a programmed activation altitude of 1100 ft or 336 m has been set to guarantee
notwithstanding the position, activation at a minimum altitude of 840ft or 256m (real altitude) above the
ground.

http://www.vigil.aero/files/images/ENGELS___DP_JUN_2010.pdf

I agree with you that AAD doesn't have gyros.

[billvon 2,400]

>I mean this:

"If the skydiver is falling in a back to earth position, the reading will reflect the correct pressure, the sensor is not influenced by a depression, but if the skydiver is falling face to earth, then the sensor located in the depression zone will read an up to 10mbar lower pressure or an altitude 260 ft or 80 m
superior to the real altitude, and will in this case activate later or 260 ft or 80m lower i.e. at a real altitude of 580 ft or 176 m above the ground which is too low. . . . Therefore a compensation of + 260 ft or + 80 m above the nominal activation altitude was integrated."

Agreed - and all modern AAD's do that.

[angryelf 0]

***Update***

Finally got word back from Vigil USA and AAD...

They determined that the AAD fired because it was in Student mode and had a -150ft offset programmed in.

As the Rigger who repacked the reserve and I both turned the Vigil on and off and ensured it was in "PRO" mode (I did it at 8am the morning of the fire)=the only conclusion is that someone at the DZ hates me, programmed my Vigil in Student mode with an altitude adjustment.
OR
The Vigil decided to go into Student mode all by itself-which Vigil USA assures me is impossible.

So-check your AAD before every jump and make sure your buddies haven't set your Vigil to Clown mode as a joke.
I know I'll be checking mine with my reserve pin every time now...

-Harry

"Sometimes you eat the bar,
and well-sometimes the bar eats you..."

[NovaTTT 1]

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As the Rigger who repacked the reserve and I both turned the Vigil on and off and ensured it was in "PRO" mode (I did it at 8am the morning of the fire)

I'm wondering why you both turned it on and off and on? Is it not your practice to just turn it on? At your level of experience one presumes you're familiar with the operation of your AAD and your rigger certainly checked the function of the AAD after the I&R.

Is there anything that comes to mind about that aspect of this situation that might cause you to think the settings changes were made by yourself?

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the only conclusion is that someone at the DZ hates me, programmed my Vigil in Student mode with an altitude adjustment.

It is nearly impossible to believe someone who hates you is going to screw with your AAD, putting it in Student mode with a -150 offset, unless you're screwing someone's wife or daughter. Are you involved in a situation that makes the tampering aspect plausible?

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The Vigil decided to go into Student mode all by itself-which Vigil USA assures me is impossible.

Switched its mode *and* adjusted the firing altitude. That's a pretty significant glitch. I am not aware of any modern AAD having shown such a glitch before and I am ready to be instructed on any such events if they have previously occurred.

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So-check your AAD before every jump and make sure your buddies haven't set your Vigil to Clown mode as a joke.

So, are you saying you believe someone reset your Vigil, including offset? Would it have been noticed that somebody was tampering with your gear?

This Vigil response leaves a lot unanswered:

Are we supposed to suspect the unit was so faulty that it reset the base mode and offset the firing altitude without user input?

Are we to suspect that your own fiddling with the unit was responsible for the settings changes?

Are we supposed to suspect your DZ is rife with assholes of a para-criminal mindset and would put your life at risk as a "joke"? or are we to think it was a revenge tactic for a personal transgression that remains hidden?

It would be helpful to all, I think, if you posted the entire response from Vigil USA (and AAD, if they are different).

ETA: These are real questions, not sarcastic jabs. I think posting the letter(s?) might help frame Vigil/AAD's findings and conclusions. The other questions are best considered and answered by Elf.

"Even in a world where perfection is unattainable, there's still a difference between excellence and mediocrity." Gary73

[tdog 0]

In one of your first posts you said:

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I pulled at 3000 ft following a tandem video jump and had an uneventful canopy descent.

In the last post you said:

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They determined that the AAD fired because it was in Student mode and had a -150ft offset programmed in.

The eye witness posted he was at 1100 feet when he saw your reserve fire a few hundred feet below him.

So, I am confused why it fired. Even in student mode with a -150 offet, pulling at 3000 feet and flying a normal uneventful canopy should not cause a fire, otherwise a lot of AFF students will have two outs too unless there is one more fact filling in the missing link.

What is the missing link Vigil says caused the unit in student mode to fire? Are they saying your canopy (presumably being small and fast) descended faster than the limits for student mode?

[sundevil777 93]

His profile says it is a Katana loaded at 1.6, they have a reputation as being ground hungry, so it would seem that they do indeed have enough of a descent rate to fire in student mode.

People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

[piisfish 135]

Angryelf, would your rig (and Vigil) by any chance, could have served to demonstrate to "people who are novice in Vigil use" the different possibilities and how the Vigil works ? Is it possible that this situation occured, and the demonstrator forgot to put it back to PRO mode, without offset ?

Yes, checking the display on the AAD is part of every prejump/donning check...

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

[angryelf 0]

I turned the rig off and back on early in the morning as the rigger who had done the same did it the night before, the unit turns itself off 14 hours after it is turned on and I did not want it to turn off during the day.

Rdutch was under canopy himself and ESTIMATED I was at 1100 ft. I was in the rig for the fire. The unit activated where it was supposed to for the mode/offset (1150ft), but I did not notice until line stretch of the reserve at around 850ft. (keep in mind the difference between activation and closing loop cutting, factor in burble, Reserve PC hesitation and other factors and the Reserve deployment alt checks out).

I doubt very, very seriously that anyone on the DZ has an axe to grind with me. In 6 years of jumping I have never seen someone mess with someone else's gear, mine included. Furthermore, I hadn't been at the DZ in the 5 months prior to that weekend which kind of rules out any emotionally driven attacks. Lastly, I've been in the same very monogamous relationship for 5 years and haven't been involved in any trysts that would warrant someone trying to sabotage my gear.
I only noted that this was one of Vigil's suggestions as to how the unit in question was put into the wrong mode. As there are 200 rigs or so hanging around the DZ on a normal weekend-some one using my rig as an example for a student is extremely unlikely; but plausible.

As to checking the system before every jump-I had developed the habit of turning the AAD on, watching the unit zero down prior to the first jump of the day, then checking only the reserve pin prior to each jump (Reason being to reduce wear and tear on reserve flap side tuck tabs-V3's reserve pin flap is tight, so I usually only lifted the bottom tab-checked the pin and continued my prejump checks). Call me complacent for this check if you like-but my pre jump gear checks have gotten me this far safely, are much more in depth than those of a lot of folks I've jumped with at over 60 DZ's in 2 different countries and a US territory.

As to there being a lot of unanswered questions-I agree. Candace @ Vigil USA has been very helpful over the phone and in email correspondence. I have never thought at any time that I was being misled by the company and she seemed as puzzled as everyone else as to how the unit wound up in the wrong mode(s).

Even though I am assured that there is no way for the unit to change modes on it's own-I don't know enough about AAD software to completely rule out that the device couldn't have possibly glitched and done it's own thing. Hopefully if this was indeed the case-I will catch it in a gear check in the future and then the unit will go back to AAD for further evaluation. If it does go back into Student mode for some reason and I experience another 2 out malfunction I'm very current on how to deal with it ;).

I will have the unit with a new cutter installed in a few days and intend to put it back in my rig. Make no mistake-I'll be a bit paranoid about it for several hundred jumps, but if Vigil says the unit checks out then I'm going to reinstall it. Obviously I will send it back if I see "S-150" (for STUDENT, MINUS 150ft) show up on the control screen during a gear check for no reason.

If anyone has any further questions-please feel free to PM me.

-Harry

"Sometimes you eat the bar,
and well-sometimes the bar eats you..."

[NovaTTT 1]

Thank you for your reply - comprehensive and to the points.

Do you have letters from AAD and/or Vigil USA? The typical and unhelpful AAD response is "The unit worked as designed" but perhaps you received a different letter? If so are you willing to post it? PM?

Is there a possibility that after the countdown you pressed the button again - and again - and again, etc.? The bootup was normal?

The alteration of mode and altitude offset if unit-induced would represent such a spectacular device failure that I suspect the unit would shut down; the issue seems too great for the system to continue operating normally, if at all.

To my thinking it is much more likely that someone reset the AAD - perhaps another jumper with a very similar rig? Perhaps a student who mistook your rig for a rental or student rig? Maybe you yourself did it without realizing the changes made?

2011 seems to be the Year of the AAD - and that's not a good thing.

"Even in a world where perfection is unattainable, there's still a difference between excellence and mediocrity." Gary73

[swoopgaz 0]

sounds to me like vigil are trying to cover up yet another faulty unit. When are these poorly designed, malfunctioning units going to have their problems dealt with.

[angryelf 0]

I have the graphs that AAD charted for the last two jumps. (actually three as the unit recorded the time between canopy deployment and activation as a new jump). The company was very upfront about their findings and cool about the cost of cutter replacement.

There is zero chance that I accidentally put the unit in Student Mode with an altitude correction.

As I said in the previous post-I will be jumping the unit again soon, may even take it on a skydive in my pocket before I reinstall it in my rig.

Cheers...

"Sometimes you eat the bar,
and well-sometimes the bar eats you..."

[IanHarrop 37]

Why not send it in to Vigil to get checked out?

"Where troubles melt like lemon drops, away above the chimney tops, that's where you'll find me" Dorothy

[angryelf 0]

I did send it in. Which is why I'm waiting for it to get back so I can put it in my rig ;).

"Sometimes you eat the bar,
and well-sometimes the bar eats you..."