300 ft openings

[JerryBaumchen 1,049]

Hi out there in G & R,

I recently received a PM asking about the 300 ft opening req'ment and if that is from PC launch or when the canopy is out of the bag. This caused me to delve into this somewhat and this was my response:

In TSO C23d it says, under Section 2.1.7 FUNCTIONALLY OPEN: Functionally open shall mean a parachute sufficiently deployed to provide a rate of descent equal to or less than the limit specified in 4.3.7.

In TSO C23f it says, under Section 2.1.7: FUNCTUALLY OPEN: Functionally open shall mean a parachute sufficiently deployed and inflated to provide a drag area equal to or greater than 75% of the steady state drag area of the canopy. This condition may be demonstrated by video, film or electronic data of the test in a manner determined by the manufacturer.

In TSO C23d it says under Section 4.3.6 Functional Test: '. . . Alternatively altitude loss instead of time may be measured and the maximum allowable atitude loss may be . . . with a maximum operating weight of 250 lb (113.4 kg) or less is 300 ft (91.5 m) . . . '

In TSO C23f it says under Section 4.3.8 FUNCTIONAL TESTS: ' . . . the maximum allowable opening time or altitude loss shall be determined from either of the following formulas on any drop.

If MOW < 250 lb:

Maximum Allowed Opening Time(s) = (MPOS/150)^2 x 3.00

Maximum Altitude loss (ft) = (MPOS/150)^2 x 300 . . . '

As to your question 'Is that from PC launch or when the canopy is out of the bag? ' :

In TSO C23d under Section 4.3.5 Functional Test it says: ' . . . from the time of pack release.'

In TSO C23f under Section 4.3.7 FUNCTIONAL TESTS is say: ' . . . at the time of pack opening . . . '

Given that, I am of the opinion that there is no req'ment that the parachute open within 300 ft. This 300 ft opening distance is an optional test, not a req'd test.

I hope that this helps in knowing more about this issue.

JerryBaumchen

[pchapman 261]

Since you started a new thread on the subject, I think I'll recycle a post I made recently in another thread.

To get attention, I might have called the thread "reserves are NOT designed to open in 300 ft"!

My post with updates:
==========================
Mark Baur wrote about one of the TSO variants, "manufacturers can choose either 3 seconds or 300 'vertical' feet."

That's the dirty little secret of TSO certification.

Skydivers mostly think that reserves are supposed to open within 300 ft, imagining it to be in vertical freefall, when really the manufacturers can test it from planes flying horizontally -- so there is plenty more distance for the opening, and plenty of time.

The 300 measured feet have to be vertical, not the trajectory of the opening parachute.

Every high speed parachute test video I've seen shows horizontal drops! That's how you get a dummy with a parachute to open at high speed, you drop it out of an aircraft flying fast at low altitude. PD even has a nice video of them doing tests using a B-25.

The regs mention "vertical feet" for checking the 300', and say nothing about vertical drops. The wording is always about "altitude loss" not anything like "opening distance".

And as mentioned for much gear there was a choice between 3 seconds and 300ft; one did not have to satisfy both conditions.


Each TSO is a little different though.

-- C23b/NAS804 requires 3 seconds AND no more than 500 ft in the slow speed test (70 mph "Functional test"). For the high speed strength test, there is no time requirement at all, but presumably the canopy has to be open before it hits the ground from 500 ft max.

-- C23c/AS8015A allows 3 sec for slow and normal speed tests (up to 110 kts) , but has no height or time requirement for the high speed strength tests! The canopy just has to open and not blow apart.

-- C23d/AS8015B requires 3 seconds OR 300 ft.

-- the new C23f / PIA TS-135 v1.4 requires 3 seconds OR 300 ft (With gradually increasing numbers if certified to higher weights or speeds than 250 lbs & 150 kts)

(There are slightly different times in some regs for RSL's, low speed cutaways, etc, but I'm presenting the main requirements.)

Also, in C23c all the distances and times are until the parachute is "fully open" -- it could still be mushing downward with too much speed to land safely for another second or whatever. That made it easy to calculate on video -- just see when the slider hit the links I suppose. Only in C23d does it start to mention "functionally open", with a descent rate less than the max allowed for certification.


So basically reserves are NOT in any way designed to open within 300' of vertical travel!

[JerryBaumchen 1,049]

Hi out there in G & R,

It has been brought to my attention that I have used an outdated version of PIA TS-135. Sorry.

Therefore my post should be changed to read:

In TSO C23f it says, under Section 2.1.7: FUNCTUALLY OPEN: Functionally open shall mean a parachute sufficiently deployed and inflated to provide a rate of descent of not more than 24 ft/s (7.3m/s). This condition may be demonstrated by video, film or electronic data of the test in a manner determined by the manufacturer.

My apologies if I have mislead anyone.

Hey, I never said that I walk on water.

JerryBaumchen

[JerryBaumchen 1,049]

Hi out there in G & R (again),

Thought I would offer some additional info; here are links to TS 135 V 1.4 and the FAA TSO C23f:

http://www.pia.com/piapubs/TSDocuments/TS-135v1.4.pdf

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgTSO.nsf/0/1a8b18fa46db168786257a830054d117/$FILE/TSO-C23f.pdf

One should note that the FAA does take exception to some sections of TS 135 in the TSO. That makes those exceptions absolute.

Have fun reading; it is always worthwhile,

JerryBaumchen

[3mpire 0]

Thanks for sharing, this has been an interesting topic

[councilman24 36]

The short version is it's 3 secs, 4 in certain circumstances. If you can't make that because the airspeed is too slow, i.e. cutaway, then you can use 300'.

I've pointed this out several times when folks quote 300'.

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

[masterrigger1 2]

Quote

The short version is it's 3 secs, 4 in certain circumstances. If you can't make that because the airspeed is too slow, i.e. cutaway, then you can use 300'

If the gear is manufactured under 23f, I would say that is true.
But gear that holds a previous TSO like 23b, etc.. that gear has to meet that previous standard.

Also. if the H/C is manufactured with lets say 23b, then it still needs to meet the standard regardless of what canopies are in it even if the canopies are manufactured under TSO 23F.


On these earlier TSO'd rigs, the three second rule applies regardless.

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com