Setting Cypres at a DZ with hills around

[pchapman 279]

Just food for thought:
A DZ I jump at just moved to a location where the land around the DZ is 200' higher in some directions, particularly towards the most common exit spot.

The DZO is suggesting Cypres' be set for a landing offset of 200', but is leaving it at the jumpers' discretion. (Student reserve FXC's will be set to 1200' rather than 1000' as before.)

Just curious what other DZ's have done, that have similar or even higher terrain near the DZ. There are obvious arguments both ways. (Plus some less obvious ones about altitude offsets that require careful understanding of one's AAD manual.)

With 200' difference, realistically I expect most jumpers won't bother to set an offset. (It's a piston Cessna DZ too, so we don't have as much altitude to play with to begin with.)

[hookitt 1]

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Student reserve FXC's will be set to 1200' rather than 1000' as before.

The firing range of an FXC pin puller is not very precise. Placing one on a reserve is a pretty scary thing to do.

As for setting a CYPRES, Adventure center in Hollister has a landing zone field elevation of about 350 feet higher than the runway. The hills around it are up to about 300 feet higher as well. They tend to set the CYPRES for 460 and 490 up.

My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

[tbrown 26]

Sounds like offsetting may be warranted in your situation, especially if your DZO is recommending it. Popping a Cypres at 550 ft over surrounding hills is a dodgy proposition, especially if you take the +/- 200 ft tolerance into account. If you're 950 ft over the runway, that's still not bad, you shouldn't be that low anyway. The final decision is yours of course.

BUT if you do offset, I believe you have to do it before EVERY jump, it's not a blanket all day deal. Get out your Cypres Owner's Manual and read and re-read the section on offsetting VERY carefully. Mark the section up with a hi-liter, so you can share the info with your friends. We had a fatality last year at Perris involving a jumper who did not correctly understand how to use a Cypres - the Cypres worked as programmed, just not in time to save her life. These things don't think - they only do what you tell them.

Also, if anyone lands out in them thar hills, they will be coming back down to the dropzone from a 200 ft elevation and that will screw the calibration of the unit. Anyone who lands in the hills should turn their Cypres off and then restart it back at the dropzone.

This is a very specific set of issues that your dropzone should post some kind of an info display. It's also a really great topic for Safety Day, which is when, next weekend ?

Your humble servant.....Professor Gravity !

[hookitt 1]

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BUT if you do offset, I believe you have to do it before EVERY jump

That is correct.

My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

[nate_1979 9]

Most of my jumps are at a DZ which is surrounded by some pretty big hills... If I had a cypress fire on some of those jumps I doubt it would be a great day, but I have never seen anyone offset their cypress and I definately would never see myself setting a cypress offset before every jump I do.. It's just one of the things we accept, especially if you go on a jump which takes you into the higher ground

We did however have a slightly higher average for pulling altitudes than I've seen at some other DZs.. Only a couple times I've seen people suck it down to 2500 feet. If a visitor said they were going to pull low sometimes you'd hear the locals tell them that mabey they should re-consider when at that DZ..

FGF #???
I miss the sky...
There are 10 types of people in the world... those who understand binary and those who don't.

[jsaxton 0]

We set 420 up, probably a little high for our higher landing area but we go to 15K on almost every load so the common thinking is:'Y'all got no business in the basement anyway!'

[billvon 2,991]

We have mountains surrounding Otay, heights from 500' to 2000'. Near a not-uncommon spot we see 200-300' increases in elevation. There's no practical way for us to change AAD heights to accommodate for that, primarily because we never know what the spot is going to be - and the risk of a premature fire during a snivel goes up along with the firing height.

Fortunately the people who jump down there are pretty familiar with the increases in elevation. The biggest risk is a cloudy day, a bad spot and a low pull; that could quickly lead to finding some rocks in a cloud. Hence best to avoid all parts of that scenario.

[councilman24 37]

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The firing range of an FXC pin puller is not very precise. Placing one on a reserve is a pretty scary thing to do.

FXC12000's have been used on student equipment reserves widely for years, still are used by DZ's, and were used by experienced jumpers who wanted an AAD before Cypres came on the market. On the low side they are pretty good. If anything tended to fire high. Minimum set altitidue is 1000'. So for experienced jumpers with pack opening at 2000' (d license minimum) they were somewhat iffy. For students pulling at 3500' they work very well. For student low pulls they sometimes fired, just as cypres' do. They have save lots of lives. Factory maintenance is required every 2 years IIRC. IMHO, placing them on student reserves is not scary at all.

Routine function tests of FXC12000's were a common part of rigging. I haven't done any in a while because I didn't maintain the student gear. Still have the rubber bumper for testing in my rigging kit. It was a "What is this" out at Dave's course for a couple of the instructors. I also have a barrel I can pull vacuum on and vent to test while installed on a rig, as well as a smaller vacuum chamber for function testing out of the rig. One convenient feature was that you could test it and reset it with no expense. Can't function test a loop cutter. At least not without spending a lot of money. Often thought about a test light to replace the field replacable cutter so that we could function test a cypres. With one batteries not a big deal if at the end of battery life. For II's not so convenient.

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

[riggerrob 643]

FXC sells a test light so that you can run their ASTRA AADs through a test chamber.
You just remove the cutter and plug the test light into the same socket.

[riggerrob 643]

When I jumped at Hemet, California, our landing field was 300 feet higher than the airport and was surrounded by hills considerably higher.
We just left tandem Cypres at the factory setting, but used to reset student AADs 300 feet higher. FXCs - on student rigs - would hold that setting all day, unless a major weather system blew through.

It was a nuisance to reset Student Cypres (up 300 feet) before every jump, but we accepted that as part of the cost of doing business.

[sundevil777 102]

If common to be over them, I think I would be offsetting the AAD to the 300 ft nearby hills.

I think I would also inlcude my visual alti to be offset. I haven't seen anyone mention it, but wouldn't that be the consistent thing to do?

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

[billvon 2,991]

>but wouldn't that be the consistent thing to do?

Might cause some problems with instructions like "be in the pattern by 1000 feet, no turns below 200 feet.)

[azureriders 0]

For a while we were jumping about 30 miles north and +400' from where we were taking off. We would set our visualls for the offset. However, the landing area there is flat and flat all around with no hills, just 400' above take off, so it caused no problems with the pattern.

[ZigZagMarquis 9]

I was going to say... but, CMan24's post pretty much beat me to it...

... if I may add my 2 cents though, back when I was an active SL Jumpmaster, we'd set the FXCs on the student rigs to 1500' and no lower. Given the +/- range that an FXC will fire in, IMO this was a prudent setting based on student pulls up at or above 3500' and that we put SL's out at 3500-4000' and I agree wiht CMan's statement that FXCs on student gear are fine... proper maintenance, checks, etc. being done, of course. Of course, Cypres (and I'd expect the Vigil) are now being seen more and more (maybe most) on student rigs.


Anyway... back to the original topic... setting a Cypres 200' "up" where the landing area is about 200' up from the hangar. Well... if you didn't and you were over that +200' dirt... that would mean your Cypres would go off at about 550' AGL rather then 750'... that might make a difference between living and not if you need it... but I can see the "hastle factor" of setting it over and over again on jump after jump which is what I think you'd need to do?

At Cal City... sometimes we jump into the Silver Saddle, which is about 500' higher in elevation then the airport / DZ where we're usually at. That's definitly enough of a difference to go through resetting your Cypres IMO.

[nate_1979 9]

I can definately see changing the cypress if the landing area is significantly different altitude to the takeoff area, ... But I cant imagion doing it because the land AROUND the landing area is higher..

FGF #???
I miss the sky...
There are 10 types of people in the world... those who understand binary and those who don't.

[kelpdiver 2]

So there isn't full consensus at Hollister on the offset to use. Since we have to go to the effort of changing the cypress every jump anyhow, many opt to use 420 or 450. Others argue that it's silly and use the exact (I believe it's 310) - so maybe that means 330. Jump run usually is right over the valley and most of the time I open over it rather than the ridges. But not always.

AFAIK, everyone sets their altimeter for the LZ, ignoring the hills.

Cypress 2 is definitely much nicer than the 1 with its rapid POST.