Old AAD's

[fcajump 153]

Ok, need some help here... I recall several discussions with older jumpers who were discussing the early AAD's they had on student rigs.

Specifically AAD's that required the jumper to disarm them after the main opened as their only firing parameter was altitude.

One jumper even described a reserve fire while descending under a fully open main because he forgot to disarm it.

While I will be going back to some of these older jumper/acquaintances of mine, I was looking for the wisdom of the group here to see if anyone recalls these older AAD's.

JW

Always remember that some clouds are harder than others...

[piisfish 135]

KaP-3
I saw one once

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

[nt8us 0]

yes ,the original Sentinal by steve Snyder

[airtwardo 6]

Quote

yes ,the original Sentinal by steve Snyder

You had to 'disarm' the sentinel?

~ If you choke a Smurf, what color does it turn? ~

[Skybear 0]

KAP-3, Sentinel and FXC 12000 are for sure the most popular early AADs. Hard to believe in times of modern electronic AADs, but the FXC 12000 is still in production and used at many dropzones. I saw them last at a spanish dropzone which is run by the brits.

All of the early AADs had their specifics which could easily trap the skydivers. They needed adjustment before every jump. some had saftey pins which had to be pulled out before the exit and they were at least partially mounted outside on the rig. Sometimes saftey pins were accidentally pulled when entering the aircraft, and the ticking sound raised the question: Whose reserve is gonne open in a few seconds? If you forgot to pull the pin the AAD was not able to work at all. The design of the Sentinel often trapped people in pulling on a cable which was mounted on the reserve container, instead of pulling the reserve handle.

Maintenance was scheduled every 6 months and you never knew what it would cost. Sometimes it would have cheaper to replace the AAD by a new one than doing the maintenance.

That 's only a short summary of my incomplete knowledge about that era. Anybody here who can tell us first-hand storys?

One more thing to be said: Thank you, Helmut Cloth, for giving us the first modern AAD in 1991!

[fcajump 153]

Sometimes I wish the new jumpers had a better understanding of how far we've come... I was there for the birth of the new era...

When I bought my first rig, I had to seriously decide whether or not to get:
Sentinal / FXC / Cypres / none
Round / Square reserve
Dytter / Paralert

Chose the Cypres / Square / Dytter, but there were those who really thought I was too far out on the leading edge with these newer things... (even though it was 1991!)

JW

Always remember that some clouds are harder than others...

[377 20]

I wonder why the Sentinel MK 2000 wasnt more highly regarded? I thought it was a pretty good design. I guess without a microcontroller and software, you can't deal with all the pressure transients presented in freeflying, tumbling, swooping etc.

The MK 2000 was dirt simple, 2 AA cells, an altitude switch and a rate switch in series to fire a pin puller if both switches closed. If you were low and descending fast, it fired. No software, not one "bit".

The MK 2000 saved a lot of lives, but I've read stories about misfires in freefall. I've not read about any failures to fire, but as with all AADs they dont work perfectly 100% of the time.

When I was a static line student in 1968 (Livermore CA, Cal Club DZ) they used the original Sentinels which you had to arm in the plane above the fire altitude and disarm under canopy above the fire altitude as I recall. MANY students forgot to disarm them after opening resulting in an expensive refit of the explosive driven pin puller cartridge and a reserve repack. I was a college student and dint have the bucks to pay for that so I was very careful about disarming.

377

2018 marks half a century as a skydiver. Trained by the late Perry Stevens D-51 in 1968.

[airtwardo 6]

the explosive driven pin puller

You mean 'Slide Hammer' doncha?

~ If you choke a Smurf, what color does it turn? ~

[vanair 0]

Had a novice friend that around 1980 had a sentinal fire under her main, 2 out hard landing broke back. Sued Steve Snyder and or his Co. Don't know how much but she won a fair amount of money. There were probably others. Sometime late 70's C182 my father climbed out at 7500 my brother started to climb out, I was 3'rd heard a pop his sentinal fired I saw his chest mounted reserve going out. He was half out the door. I started to reach with my right hand to grab it. thank God it had no pilot chute. In the split second realizing that that was a mistake. I pushed him as hard as I could with my left hand. I think this was right after I graduated USMC boot camp so I was pretty strong. His reserve started to open as he was almost all the way out, He slammed into the door frame on the way out, with my right hand between him and the door frame. My brothers reserve went under the tail, lucky no pilot chute. So he had a long ride under a 28' round. My father said he was out there and all of a sudden the strut jerked back and hit his chest, He looked at me like WTF. I pointed back at my brother. He realized, so we just did a 2 way. Picked up my brother, he was fine, the plane was fine. My hand was fine, other than being swollen to twice it's normal size for a week. Sentinal must have gotten confused in the door burble or something. I never used one and thats the day my brother stopped using them. And that was the end of it. we didn't look for some deep pocket. For what? my sore hand. Plus according to the disclaimer it's only a paper weight. And we are old school.

[airtwardo 6]

Wasn't there something in a manual about using a pilot-chute with the sentinel?

I use to have an old Mk 2000 with the manual and a box of squibs that somebody gave me, haven't seen it in years...

~ If you choke a Smurf, what color does it turn? ~

[nt8us 0]

the idea of using a pilotchute with a sentinel came about after a fatality t snyders dropzone of a first jump student(she pushed off the strut,went onto her back and as the pilotchute wasdeploying between her feet she trapped it.continued to fall back to earth ,sentinal fired but without a pilotchute, it did not start deploying until about 200 ft,(too low for sure). the next weekend snyder and elek puskas sat down with all thier instructor/jm's and had an all day discussion about it.the concensus was that a student who was "out of it" likely would not be throwing a reserve if they didnt pull it either.so pilotchutes became the norm on all his student reserves and a recommendation was put in the manual as well.

[pchapman 261]

Quote

I wonder why the Sentinel MK 2000 wasnt more highly regarded? I thought it was a pretty good design. I guess without a microcontroller and software, you can't deal with all the pressure transients presented in freeflying, tumbling, swooping etc.

The pin puller on the 2000 was a neat little device. Not in the same class as a loop cutter, but actually practical for experienced jumpers, unlike the massive mess of hardware for the traditional Sentinel on the reserve flap.

Wasn't there a problem getting service on them, since they were supposed to be sent in for service every couple years?

After Steve Snyder died in '99 that was the beginning of the end for SSE. For a while someone still serviced Sentinels (in Texas??), but I got the impression it didn't last too long.

Why exactly did Sentinels not get supported more? I don't know when SSE actually disappeared or Alti-2 took over the altimeter line.

At one DZ I was at, Sentinel 2000s were moderately popular in the mid to late 1990s.

(A good selling point was a 4-way went low. All lived, but the one person with an AAD, a Sentinel, wasn't the lowest person open on the load. On the other hand, in later years, there was at least one misfire above normal firing altitude.)

But when it wasn't possible to get proper, legal servicing on the Sentinels, they went out of use. All the Student gear with regular Sentinels got replaced in 2000 with gear with FXC's.

Otherwise they might have kept going in use for a few more years as reasonably priced AAD for experienced jumpers, before the Cypres (1991+) slowly took over.

[377 20]

Vanair wrote:

Quote

And that was the end of it. we didn't look for some deep pocket. For what? my sore hand. Plus according to the disclaimer it's only a paper weight. And we are old school.

Good for you. I am a lawyer, but not the type that makes money off accidents. I view things a lot like you do.


Your brother is lucky to be alive. VERRRY close call. Really quick thinking on your part to eject him. Another few milliseconds and it would have been his body trying to enlarge the door frame of the 182 and take it all the way back to the tail. I'm sure you've seen the pictures of shredded Cessna fuselages where this happened.

I often wonder if these MK 2000 burble fiires could have been prevented with some simple RC (resistor capacitor) integrators or timers in loop. I spoke with a guy from SSK who was very knowledgeable about the Cypres archetecture. He said there is no reliable way to immunize a simple switch fired device like the MK 2000 from burble fires. He said you need to look at historical data and trends and make a lot of 'if-then" logic decsions, and that means software. The Cypres knows you can't get from 14,000 ft to 700 ft in three seconds, but the MK 2000 system architecture can't figure that out.

We are lucky ANYBODY wants to make AADs. I am sure they get sued all the time, even if the AAD didnt malfunction, and the market is really tiny.

I like AADs. Nothing else is gonaa save you if you become incpacitated during freefall. It's an ironic tragedy when a malfunctioning AAD kills a jumper, but they have saved far more than they have harmed.

377

2018 marks half a century as a skydiver. Trained by the late Perry Stevens D-51 in 1968.

[JerryBaumchen 1,048]

Hi Jim,

They were fairly common when I started in the mid-60's. As Jim Twardo says, they were a slide hammer. This 'hammer' was a piston in a cylinder with a cable protruding out of it with two ripcord pins. At the end of the cylinder was the firing cartridge. As mentioned, you armed them ~2500 ft and if you did not turn them off, at 1,000 ft', then 'OOPSIE.'

Some trivia: Snyder just started making them; I 'think' he was a graduate of George Tech so he had some good engineering education under his belt. He never did anything in the way of FAA-approval on them. Then in late 68 when Strong was TSO testing his StyleMaster rig, they included the Sentinal ripcord on some of the tests. This then allowed Snyder to get a FAA PMA approval on them.

I had some correspondence with him about the time that he sold and he said that he was fed up with getting sued so many times. By then his interest was on his airpark and his collection of aircraft.

They were a good device; heck, it was them or nothing. They were fairly reliable; I never saw or heard of any misfire of any type with a Sentinel. The early ones used a 20,000 ft altimeter & then he designed the one that just had an On/Off switch and it mounted in the stopwatch hole of chest pack instrument panel.

Howard White might find a few photos in his collection of old PARACHUTIST magazine.

JerryBaumchen

PS) As you know, I like a challenging project. Back in the mid-60's Snyder & I were discussing the concept of a Sentinel for a piggyback rig; one of thos wild-hair ideas of mine. He had done some work on one but felt that the piggyback rig was just never going to catch on & that there would not be a market for them. That got me going ( remember 'challenging project' ) & in the winter of '66-'67 I designed, built & tested a AAD for a piggyback rig. I jumped it for about a year & it worked good, but an 'incident' caused me to remove it and to never jump it again. To this day, I think that 'one-off' that I designed & built was the first ever AAD for a piggyback rig. It was large & crude but it did work. I wish I still had it or a photo or two of it. I was in engineering school at the time & a classmate was a machinist on the night shift. I designed and he did the machining & welding.

[jackwallace 3]

I don't remember if it was a Sentinal or not. But a guy I jumped with was given the ultimatum by the wife, no AAD no jumpin. So he got one. You had to turn them on, on the ground and off before you got to 1000 ft or they fired. First jump on the thing I see him in a ball under 2K and open under a grand. Second jump same thing. "So what the hell where you doing we ask him?" "Turning off the AAD so it didn't fire, before I pulled my main." \
We took the firing cartridge out of it. So his wife couldn't tell it didn't work and he could jump it and not go in.
We had fun in those days!!!!

U only make 2 jumps: the first one for some weird reason and the last one that you lived through. The rest are just filler.
scr 316

[ciscobird 0]

Quote

I don't remember if it was a Sentinal or not. But a guy I jumped with was given the ultimatum by the wife, no AAD no jumpin. So he got one. You had to turn them on, on the ground and off before you got to 1000 ft or they fired. First jump on the thing I see him in a ball under 2K and open under a grand. Second jump same thing. "So what the hell where you doing we ask him?" "Turning off the AAD so it didn't fire, before I pulled my main." \
We took the firing cartridge out of it. So his wife couldn't tell it didn't work and he could jump it and not go in.
We had fun in those days!!!!

A cheapo!

But on a serious note, if he had turned it off and went in his wife would have a strong case.

[patmoore 14]

Never one to be content to just ride a canopy down, I discovered that pulling down on one of the front risers of my newly acquired StratoStar would cause it to dive forward and begin spinning rapidly. It would race downward so fast that I could actually see the horizon above the canopy. Recovering from this spiral was simple – just let go of the riser. My reserve chute was equipped with a Sentinel that was designed to deploy if I passed through 1000 feet elevation at speeds greater than ½ terminal velocity. Apparently my earthward spins triggered the sensor and the reserve (remember it was hanging on my left side) suddenly burst open inflating the 26’ canopy. I realized instantly what had happened and then thought, “No problem, I’ll just ride both chutes down”. That would have been fine under a round parachute but no one had ever deployed a reserve with a square before. The forward speed of the main chute was so powerful that it continued going forward, fighting the drag of the reserve. It got level with me in front and then dove toward the ground collapsing and floating back up at me. Since it could entangle with my reserve, I immediately popped the canopy releases to jettison it. Just as I did I had the horrible realization that I was only connected to one side of my reserve! I had installed an extra D ring low on the left main lift web and would connect the right butterfly of my reserve to it after opening to give me better visibility for accuracy approaches.

Fortunately, when I built my rig I had sewn in a connecting strap between the reserve’s two butterflies that attached to the canopy. The strap was a meter long so that I was only attached at my left hip to the right side of my reserve. The left side of the reserve was a full meter higher secured by the strap. The reserve started a slow spin with me hanging below it powerless to steer it. I crashed into a tree and slammed into the ground twisting my ankle. In retrospect I guess I was lucky. The Darwin Awards hadn’t been created in 1976 but I came close to being an early contender.

A few years later I ran into Steve Snyder at an air show in New Hampshire where he was flying his Super Pinto and I told him about my experience. He seemed surprised that a reserve could have that effect on a ram air canopy but the more he thought about it he could see it happening.

DZGone.com
B-4600, C-3615, D-1814, Gold Wings #326, Diamond Wings #152.

If you're not living on the edge, you're taking up too much room!

[Andy9o8 0]

At my first DZ back in the mid-70s, I can recall a 1:1:1 record with the MK2000 Sentinel.
- 1 guy got killed freefalling into a reserve dumped by a premature Sentinel fire.
- 1 girl either froze or totaled and was saved by her Sentinel. (Another girl, who was her friend, did a very low pull around the same time, so they were dubbed "Low Pull and No Pull".)
- 1 guy whose Sentinel fired properly, but sadly went in anyway when his reserve fouled on his malfunctioned main which he neglected to cut-away.

Few experienced jumpers there jumped an "AOD", and some wouldn't do RW with anyone jumping one; and that was possibly reinforced by Incident #1. But, they were considered good for students doing solos in case they no-pulled or froze with a mal.

[nt8us 0]

when i worked for SSE/ParaFlite, there was an incident exactly like you described in inccident#1. investigation turned up witnessesthat saw the jumper calibrate his unit IN the aircraft instead of on the ground.

[baign32 0]

I went through AFF in Antioch, CA in 1985 and my student rig was equipped with an FXC12000. On my 3rd level AFF jump the manafest lady checked to make sure I put on my gear correctly before being turned over to the instructors. She set the FXC by just turning it to the opening altitude. On the jump the thing fired at 9,000ft giving me a long canopy ride. I was told on the ground that the correct way that the FXC should have been set was: 1) to zero it and then 2) set it to the desired opening height.

[377 20]

RAF surplus, just two wires come out from switch contacts. Part of an AAD? Ejection seat stuff?

It has a moveable trigger altitude 500 ft to 15,000 ft and has a baro calibration scale in millibars. no active electronics inside, just an aneroid and a switch.

377

2018 marks half a century as a skydiver. Trained by the late Perry Stevens D-51 in 1968.

[377 20]

Finally found out what this gizmo is (see photo link in prior post) It's the world's first swoop audbile altimeter, so to speak.

It was used in RAF WW 2 planes to sound a horn during a dive bombing run when the plane had reached a preset pullup atitude. They were installed in Sea Fury aircraft.

377

2018 marks half a century as a skydiver. Trained by the late Perry Stevens D-51 in 1968.

[jackwallace 3]

So what did they have to do? Set it to bottom or top altitude then push go button when they started the dive?

U only make 2 jumps: the first one for some weird reason and the last one that you lived through. The rest are just filler.
scr 316

[377 20]

The pilot just turned it on when flying above the pull out setting and left it on. When they dove down to that warning altitude, a horn wasw activated. When they pulled out and climbed above it, the switch opened and the horn stopped sounding. I guess after youd done all your bombing youd want to turn it off for a landing.

377

2018 marks half a century as a skydiver. Trained by the late Perry Stevens D-51 in 1968.

[feuergnom 22]

Quote

We are lucky ANYBODY wants to make AADs.

just some weeks ago I had the chance to meet helmuth cloth, inventor of the Cypres at the Cypres Aniversary Boogie in CZ - thre he told the audience about his early attempts of finding a manufacturer and presenting his idea on PIA Symposium.
long story short: Big companies turned his idea down ("to impractical, standards to high, impossible to make etc...). and when presenting his idea at PIA everbody thaught that his invention was great but - according to his story - he got the advice to leave it more than once.
moral of the story. Thanks to his dedication and his funding (he paid most if not all of the R&D out of his own pocket!) skydivers have a reliable backup-device if the brain decides to take a rest

The universal aptitude for ineptitude makes any human accomplishment an incredible miracle

dudeist skydiver # 666