Low Altitude - High Speed Pass ???

[WLDMAN 0]

Greetings! I hope this is the best place to start this thread. Here goes...
I was at the "Couch Freaks" Boogie this past weekend (Great Boogie! My 1st time there - yes, that's BEER!) and witnessed the 5 AAD fires/two outs. This Incident is being discussed in that forum but I've read through the entire thread and have not seen a posting as to "How To Properly Make A Successful Low-Altitude - High-Speed Pass Jump"

Can someone please explain (attempt to explain) how to make this type of jump?

From what I understand, the AC speed is increased so that when a jumper exits, at such a low altitude, and deploys the main - the main opens quicker than a Hop-N-Pop (~ 5K ft) subterminal opening exit. Yes, I have made a L.A.H.S.P. jump...from a cessna at about 2.5K. Fun & no issues (but curious to know & understand if I was flirting with disaster).
I just thought a discussion on this topic (by those more experienced than me) would be good for many that might consider making a jump like this in the future.
Thanks!

PS: Those jumpers in the incident mentioned above are already being flamed for lack of Altitude Awareness (and thankfully those injured will eventually recover from their injurys) and making further bad descisions etc. etc. so I don't think that incident necessarily needs to be addressed here. So, one assumption is the jumper is Altitude Aware.
Thanks again!

Anvil Brother #70

"Dance like it hurts. Love like you need money. Work when people are watching." - Dogbert

[billvon 2,997]

>Can someone please explain (attempt to explain) how to make this type of jump?

How I would do it:

I'd use my smaller wingsuit (a Birdman Classic) and my Pilot 150, a very reliable canopy. (No hard openings, no 1000 foot snivels.) I'd get out and track up line of flight for 3-4 seconds, then deploy. This would let me get a little bit above the aircraft (or at least stay on level) while I decelerated, and since terminal for a wingsuit is pretty slow, I'd decelerate relatively quickly.

I would likely _not_ use an AAD since it wouldn't add much safety on such a jump. If I was jumping with other wingsuits I'd request 1 second exit separation.

[WLDMAN 0]

What about WITHOUT wing suit? (since I and many others don't fly one)
Also,
Is tracking down flightline the best/only way to fly or is perpendicular to (or angled just off of) flightline as good? I would guess down the flightline would be "risky" since increase risk of collision with jumpers possibly NOT giving enough seperation.

Anvil Brother #70

"Dance like it hurts. Love like you need money. Work when people are watching." - Dogbert

[matthewcline 0]

How I have done it;

C-130, C-141, C-17, C-5 (140kts), 2000' AGL at around 130kts, poised and deployed as soon as clear of the door facing the line of flight, off the ramp deploy as soon as you drop through the dead spot and the 2nd hard blast of air hits you, AAD was on.

UH-60, Otter, PAC, Porter, 2000' AGL at around 100kts, exit and deployed as above.

CH-47, Skyvan, CASA, C-23B Sherpa, same as above but the exit was a poise off the tail gate.

For all of the jumps the AAD was on and a VISIBLE altimeter was worn and USED.

An Instructors first concern is student safety.
So, start being safe, first!!!

[billvon 2,997]

>I would guess down the flightline would be "risky" . . .

A clear and pull is really nothing like an RW jump. There's just not much time to "go" anywhere. You can bail out with 1 second separation, track in any direction you like for 2 seconds and still be clear of other jumpers. Tracking up line of flight gives you two advantages though:

1) You will slow down your horizontal speed while picking up minimal vertical speed

2) You will see the next jumper exiting. If you both have fast canopies, collision is a potential hazard if he has an off-heading opening; seeing the jumper allows you to avoid him.

[dharma1976 0]

I was told the other day that I apparently got out at 1200 feet when the pilot told us we could exit he was starting his first leg of approach and said anyone want to get out by the time I exited we had gone from 2K to 1200 which I did not realize.... but once I sw the ground I did...

tracked up line of flight dunped in track box and kick kick kick kick...damn line twists...actually it cam e out quick...

then stowed slider while steering with harnerss set up and stil had time for a nice 90 degree turn and decent turf surf...

what I learned...I dont like getting out below 2K

Dave

http://www.skyjunky.com

CSpenceFLY - I can't believe the number of people willing to bet their life on someone else doing the right thing.

[damion75 0]

Quote

Yes, I have made a L.A.H.S.P. jump...from a cessna at about 2.5K. Fun & no issues (but curious to know & understand if I was flirting with disaster).

Perhaps this is just another cultural difference but in the UK AFAIK any jump over 2k is a standard Hop and Pop. The High speed pass is normally only used in demo scenarios with an exit altitude between 1500ft and 2k.

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

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

[phoenixlpr 0]

I had one jump, not in Finland, where exit was about 225-250m and we used RS4/A round canopies.

We were on the ground pretty fast.

[skydived19006 4]

15 or 20 years ago when I was jumping a PD 260, I wouldn't have worried much about getting out at 2k, although I personally wouldn't have wanted the high speed. Currently on a Crossfire, for me I think I would just consider it a reserve ride, whether I dumped, and cut the main first or not, I don't want to be in freefall below 2000' regardless (unless it's between releasing a malfunctioning main and deploying a reserve).

As I understand it, about half the load stayed on the airplane, a second pass was in the plan to begin with. They managed to get quite a bit more altitude for the second pass, so there's no telling exactly how many would have ridden the plane down.

Experience is what you get when you thought you were going to get something else.

AC DZ

[FrogNog 1]

Why would a main canopy open faster with more airspeed? I can see it getting out of the container and bag faster due to more pull force, but it won't finish inflating until the airspeed has dropped enough to stop holding the slider up.

Since drag is related to something like the cube of velocity, I can see the deceleration of a high airspeed deployment being higher, which will feel harsher, but I don't see this necessarily making the canopy finish opening quicker.

-=-=-=-=-
Pull.

[billvon 2,997]

I should also point out that there's an "ideal" speed for a low pass, generally around freefall speeds (120mph.) This gives you a faster opening than an 80mph exit, but does not require you to decelerate to avoid a real slammer.

[WLDMAN 0]

That's way more math than I can handle right now...

I agree (again from what I understand) that process happens faster so there is less loss of altitude.

If I'm incorrect...does that mean that I lose just as much altitude on a "exit & deploy" going 120 mph as I would on a "exit & deploy" going 80 mph?

Anvil Brother #70

"Dance like it hurts. Love like you need money. Work when people are watching." - Dogbert

[freakydiver 0]

U need an alti from 2 grand?

-- (N.DG) "If all else fails – at least try and look under control." --

[matthewcline 0]

Aside from it being a smart safety device, and mandatory for the US Army, no you wouldn't NEED one if the altitude was as planned.

I would think every smart skydiver would want at least a visible altimeter with them. Batteries fail, altitudes may not be high enough to set off alarms, helmets come off, audibles get kicked out of ports or plucked free by risers.

IMO making any jump with out 1 visible altimeter is just asking not a good idea and sets a bad example to our younger impressionable jumpers.

An Instructors first concern is student safety.
So, start being safe, first!!!

[phoenixlpr 0]

Think.

Your canopy opens in a given time from a given speed so it makes some distance.

You have more horizontal speed on high speed pass. Your canopy is opening against the relative wind and because of your bigger horizontal speed you make longer distance in space in the same amount of time than in a low speed pass, so you would get a fully deployed canopy earlier.

[JohnMitchell 16]

Quote

IMO making any jump with out 1 visible altimeter is just asking not a good idea and sets a bad example to our younger impressionable jumpers.

I disagree with you on this one. An experienced jumper should definitely be able to make h/p jumps safely without an alti. When I jm S/L students I don't bother with one. A quick glance at the plane's altimeter (and yes I do the math to convert MSL to AGL) and I'm out the door for a 5 sec delay after I've dropped all my students.

[XXXMAVXXX 0]

I distincly rember from My first jump course back in 96 My instructor saying that all altimiters are back ups and also mechnical devices wich can and offten do fail

3000 jumps later I find that he was very very right having had My altimter both fail and smashed of My wrist from a couple of differant things . I urge you all (and by that I mean anyone who has never tried it ) jump and spend a jump guessing how high you are and really pay attention to how the horizon and ground look at those altitudes (take an altimiter with you and look at it only after guessing what it will say ) you will find you are normally a bit high when you take the time to look around and really pay attention to your suroundings
reguardless of what discapline you practice belly ,headdown, birdman the horizon is visable and that alone is enough referance to tell the differance between 5000 ft and 3000 ft when you really take the time to use your eyes wich are the most reliable altimiter you will ever have . and if they break you really dont have much use for a visual anyhow and I doubt your audible will do much good anyway

as for low altitude highspeed YAAAAAHHHOOO
just make sure you know where you are and how you are going to react to anything that might (or might not ) pop up

Be safe all