Changing activation altitude on Cypre 2

[normiss 774]

Courtesy. Kindness. Consideration. Mercy.

[ChrisD 0]

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Here's one I can imagine.. let's say you have an open main canopy with a malfunction and your "hard deck" is 1500 ft. You cutaway, potentially slightly lower then 1500ft (No RSL or malfunctioning RSL) and have issues opening your reserve. It is plausible that you will not speed up and reach the activation requirements (78 mph?) by 880ft, at which point you are hooped unless you can get that reserve out on your own as it will no longer activate at all from the AAD. Just a new jumper thinking about it though....

You nailed it. You cutaway at some altitude that puts you reaching 78 mph at 850' AGL. But because you lied to your CYPRES and told it that the DZ was 750' higher than where you took off from, the CYPRES now believes that you're only at 100' AGL. The manual tells us that below (approximately) 130' AGL, the CYPRES won't fire, since it wouldn't make a difference anyway.

If, however, you use the activation altitude adjustment (rather than the DZ offset), the CYPRES still "knows" where the ground really is, and the 130' critical altitude is still at 130'.

Ken

I think "Normiss" in spot on when he says this subject may (should) get its own whole section considering the amount of talk, both here and at local safety day events, this subject has been getting. Additionally the implications for those of us, say for example start off at pendelton north and land at 400, (i.e. Aircraft emergencies, turn back, etc,...) this is huge considering many rigs require the rig be removed in flight to shut it off...

In fact the whole subject of all of the issues involving offsets needs to be fully understood by the user considering an aircraft emergency at 2000 agl from the starting port esp if your dialed in a 3000 foot offset???

As it stands: The new, (2013) cypres allows a user selectable activation altitude change, but the most recent purchaser has to wait in que???? for their service visit to enable this feature...(the static electricity excuse, it may not work anyways thing...)

The vigil user is not able to change the activation altitude.

All this talk of using offsets, and I find NO MENTION in either manual, cypres/vigil of the what cypres calls the: "AGL opening is no longer useful" feature is no doubt going to cause some user's to actually want to raise their activation altitude consideiring the recent press, by entering an offset!

The AGL opening is no longer useful thing is very troublesome to me? The Cypres Expert says it shuts off at 130 feet, the vigil says it shuts off at 150 feet? Has anyone actually confirmed with the manuf that this is in fact how both of these devices operate? During offset opeeration? If so consideering the local hub bub about raising the whole activation altitude USPA thing,...both of these manufacturers have been and I mean in a creepy way, very silent considering the operating parameters and the information thay publish in their manuals.

Similar to vigil takes the time in its aad manual to explain the depression bubble, but cypress does not???? Does this mean that for flat flyers the cypres is actually calibrated at a higher altitude in order to garantee its published activation altitude, I'd imagine they both operate in a similar fashion and if there is pressure sensors in both companies units they would be both susceptiable to the same air pressure samples??? Considering the manuf rehtoric you could look at it this way: (I'm going to spin this a little to make this point) if lets say your are back/ freeflyers in freefall and totally loose altitude awarness your cypress is going to operate correctly at 750 foot activation altitude. BUT if your belly flying and totally loose altitude awarness, and considering the (vigil) depression bubble of 260 feet your cypres (750 - 260 = ) your cypres is going to open at 490 feet. (is this too low)

Does anyone know what vigils plans are considering the fact that the USPA/ BSR's question of raising opening altitudes are still on the table? Considering that by not openly stating that their unit (vigil) can not change its activation altitude they are in fact, (by being silent) implying something that their unit isn't capeable of doing???

And while I'm at it I'm very disapointed with the quality of the english manuals of both of these companies. Considering the United States keeps them in buisness they could at least keep their primary customers better served by better writing!
Both manuals suffer from shitty language issues, and these issues translate into safety issues! (Right William M.?) For gripes sake it's as if I wrote their manuals,....

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

[f94sbu 0]

Talk to a local instructor if you are genuinely interested in knowing how your lifesaving gear works. (No offense meant, it is not uncommon that layers and journalists register accounts here to get a ammunition for their own agendas )
The internet is way to blunt as a tool to get understand completely how your gear works. I have been teaching 100s of students over the years and I have have never had any trouble using the AAD manuals as a basis explaining how the device works. However to be able to explain all the nuances of how things work, no manual will be able to accurately explain all followup questions.

As for your 130AGL question, the logic is pretty simple. To avoid releasing your reserve in the event of a water landing, the unit will not react below 130 feet AGL. The difference between a Cypres and Vigil is most likely how the two manufacturers build in margins for any errors in the measurements.

[jurgencamps 0]

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Similar to vigil takes the time in its aad manual to explain the depression bubble, but cypress does not???? Does this mean that for flat flyers the cypres is actually calibrated at a higher altitude in order to garantee its published activation altitude, I'd imagine they both operate in a similar fashion and if there is pressure sensors in both companies units they would be both susceptiable to the same air pressure samples??? Considering the manuf rehtoric you could look at it this way: (I'm going to spin this a little to make this point) if lets say your are back/ freeflyers in freefall and totally loose altitude awarness your cypress is going to operate correctly at 750 foot activation altitude. BUT if your belly flying and totally loose altitude awarness, and considering the (vigil) depression bubble of 260 feet your cypres (750 - 260 = ) your cypres is going to open at 490 feet. (is this too low)

Pffffft Cypres, Vigil ... are all using the same physical laws. The burble is "there" when a skydiver is falling flat and must be compensated for. Some explain it in their manual others not.
Your Cypres is not going to open at 490 ft, it is supposed to fire at 750 ft if you fall on your belly, otherwise it will fire higher.
History has proven this enough. More than one Cypres has already fired around 1000 ft during the snivel of the canopy or when a free flyer was still in a sit or ...

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Does anyone know what vigils plans are considering the fact that the USPA/ BSR's question of raising opening altitudes are still on the table? Considering that by not openly stating that their unit (vigil) can not change its activation altitude they are in fact, (by being silent) implying something that their unit isn't capeable of doing???

And while I'm at it I'm very disapointed with the quality of the english manuals of both of these companies. Considering the United States keeps them in buisness they could at least keep their primary customers better served by better writing!
Both manuals suffer from shitty language issues, and these issues translate into safety issues! (Right William M.?) For gripes sake it's as if I wrote their manuals,....

With a cypres you have to set the offset before each jump again. With a vigil you have to clear the offset, even switching it off and on will not delete the offset.

Euh, how many skydivers read the manuals?

[ChrisD 0]

I'm much more conceerned with the number of individuals that are contemplating "raising" their activation altitudes by using the offset feature.

The manuals of both units make no reference whatsoever that the "off" 150/130 altitude raises as the offset raises??? This I think is a question that needs a written answer!

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

[the_raven 0]

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I'm much more conceerned with the number of individuals that are contemplating "raising" their activation altitudes by using the offset feature.

The manuals of both units make no reference whatsoever that the "off" 150/130 altitude raises as the offset raises??? This I think is a question that needs a written answer!

Keep in mind the purpose of the offset function. It is for designed for scenarios where your landing area is at a different altitude then take off or where you gear up, in which case you are telling it what the correct altitude is for landing. The 130ft no action altitude is still going to be 130ft AGL, that doesn't change if the feature is used properly. The issue being discussed is lying to the AAD and giving it an offset just to change the activation altitude. This is not an intended feature and would not be in the manual imo.

[demon4o7 0]

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, the CYPRES now believes that you're only at 100' AGL. The manual tells us that below (approximately) 130' AGL, the CYPRES won't fire, since it wouldn't make a difference anyway.
Ken

I was always wondering about rationale behind this, why would they even bother to set up this 'no fire' altitude. Surelyi it cant make things worse if it fires below 130 agl, are they trying to save a cutter for the estate of the unlucky skydiver? Can anyone explain?

I thought in the manual, it said do not fire below 130' was in place for water landings. When the rig is submerged it created pressure differences that were enough to make the cypres fire. That's all iirc of course.

[ksaylor1 0]

similar thread going on right now - AAD hidden functions. the water landing thing makes a lot of sense to me - submerging the unit just a little bit will appear to the cypres as a very rapid drop in altitude. if that was truly a design consideration, i just wish airtec would publish that rather than the "it wouldn't matter anyway" storyline that they put in the manual. it's pretty plausible, but i don't know if it's just a happy coincidence, or if they planned it that way.

ken

ETA: from page 11 of the CYPRES manual. Don't know why Chris D insists that it's not in the manual. Haven't looked for the water explanation, but here's the "party line" in black and white. It says "For this reason....." not "for this reason AND A COUPLE OF OTHERS....."

2.1 Expert CYPRES
The Expert CYPRES can be recognized by the red
button on the control unit.
It activates the release unit when it detects a rate
of descent higher than approx. 78 mph (35 m/sec)
at an altitude of approx. 750 feet (approx. 225
meters) above ground level (AGL). In the event of
a cutaway CYPRES will operate down to approx.
130 feet AGL. Below approx. 130 feet (approx.
40 meters) AGL opening is no longer useful. For
this reason, CYPRES ceases operation below approximately 130 feet AGL.