static line

[margo81 0]

i was wondering why is a static line done from 3000 ft or so (at least the first few jumps)... isn't it logical that in case u need to cutaway woudn't it be nicer if u were a bit higher just to give u a bit more reaction time??

[mnealtx 0]

You're doing a low speed deployment (vertical velocity-wise), so you actually would have MORE time from a 3k static deployment than an AFF jump to do emergency procedures.

From terminal at 3k, you're about 15 seconds from impact.

Leaving the plane at 3k, you're about 20 seconds from impact.

*note: The above assumes 10 seconds from exit to terminal (first thousand feet) and 5-6 seconds per 1000 feet at terminal velocity, per the SIM (Section 4, para 3).

Mike
I love you, Shannon and Jim.
POPS 9708 , SCR 14706

[jakee 1,566]

  Quote

Leaving the plane at 3k, you're 30-32 seconds from impact.

*note: The above assumes 10 seconds from exit to terminal (first thousand feet) and 5-6 seconds per 1000 feet at terminal velocity, per the SIM (Section 4, para 3).

Using those numbers you've got 20 seconds, not thirty. 10 secs to 2k, 15 secs to 1k, 20 secs to impact.

Edit: Of course going through SL you're almost certain to have something out and slowing you down.

Do you want to have an ideagasm?

[mnealtx 0]

SIM states 5.5 sec/thousand for an "average" skydiver, and round down to 5 for safety reasons, which I certainly don't disagree with.

I wrote the numbers before going to the SIM and didn't change them after putting the reference in...my bad.

Lil' bits will be a bit slower, anvils like me a bit faster...

Mike
I love you, Shannon and Jim.
POPS 9708 , SCR 14706

[CornishChris 5]

  Quote

From terminal at 3k, you're 15-18 seconds from impact.

Leaving the plane at 3k, you're 30-32 seconds from impact.

This is wrong. Well the second part anyway. If you assume timings of 10 secs for the first 1k then 5 secs per k thereafter; whatever height you pick you will have roughly 5 secs longer if you exit from that height than if you pass that height at terminal. So c. 20 secs from 3k.

To answer the first posters question you have to weigh up amount of time given by an exit altitude against other factors like canopy time, climb time etc. Doing static lines from 10k wouldn't make a huge amount of sense as whilst it would give you some more seconds to deal with a problem you would probably lose half your students in their 20 minute descent under canopy and you open them up to other risks.

Incidentally it used to be lower for statics (2k) and many military static line jumps are sub 1000 feet.

CJP

Gods don't kill people. People with Gods kill people

[Orange1 0]

  Quote

i was wondering why is a static line done from 3000 ft or so (at least the first few jumps)... isn't it logical that in case u need to cutaway woudn't it be nicer if u were a bit higher just to give u a bit more reaction time??

Presumably this is also why SL training teaches you that if you don't have a good canopy over your head by 5000 (on the count) you need to do something about it...iow the "window" of your reaction time is in the training.

Skydiving: wasting fossil fuels just for fun.

[mnealtx 0]

Corrected my boo-boo...thanks, y'all, for pointing that out for me

Mike
I love you, Shannon and Jim.
POPS 9708 , SCR 14706

[JohnMitchell 16]

It used ot be USPA doctrine to drop SL jumpers from 2800. Most DZ's I worked at just rounded up to 3000. Some DZ's use 3500. The higher you go, the more it costs and the harder it is to spot for the winds (longer canopy time means more drift.) The lower you go the less time there is for emergency procedues. Like everything in life, it's a compromise.

There's plenty of time to do your EP's from 3000 feet, especially with modern gear. For those who fail to do so in a timely fashion, I doubt if the extra time would often help. Frozen with fear is frozen with fear.

[damion75 0]

  Quote

You're doing a low speed deployment (vertical velocity-wise), so you actually would have MORE time from a 3k static deployment than an AFF jump to do emergency procedures.

From terminal at 3k, you're about 15 seconds from impact.

Leaving the plane at 3k, you're about 20 seconds from impact.

*note: The above assumes 10 seconds from exit to terminal (first thousand feet) and 5-6 seconds per 1000 feet at terminal velocity, per the SIM (Section 4, para 3).

This could be why on AFF jumps the student opens significantly higher than 3k! I seem to remember pulling at about 5k? I am sure that an AFFI will correct me if I am wrong...

***************

Not one shred of evidence supports the theory that life is serious - look at the platypus.

[TrickyDicky 0]

In the UK the rules are:
Students on squares must have full deployment by 3000ft
Experienced and rounds (students) must have full deployments by 2000ft (1500ft for demos)

This means S/Ls are usually done above 3200 to get full inflation (and rounds were done at 2200ft!)

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