Lifespan of a parachute canopy?

Martyn Johnson wrote:
Does anyone know when our 17 year old emergency parachute
canopy will pass its use-by date? Indeed, is there
a definite lifespan, or is it down to the discretion
of the packer?

Some of the posts on this subject got me wondering about my 26 year old
Strong parachute, even though it's been repacked every year, including
at Strong in '97. So, I checked with Strong, National, and
Para-phernalia, the major manufacturers.

Strong: they are quite clear that they don't have a life limitation,
saying on their website they will repack and certify their parachutes
based on inspection, even 30 year old parachutes. They recommend having
them repack it at least once every 5 years, so it can be inspected and
any modifications done. They also say leaving it in the aircraft is not
a problem, as long as the parachute is protected from the sun.

Para-Phernalia (Softie Parachutes): Dan told me they don't have a
service life, but "they get picky" about the condition of the parachute
after 20 years. They will repack their parachutes (Softies) that are
more than 20 years old, but not other brands. Leaving it in the glider
in the trailer is not a problem; however, if the parachute temperature
will exceed 130 degrees F, he urged it be stored some place cooler.

National: I talked to a rigger there, who told me they have a 20 year
service life. He did not think it was a good idea to leave the parachute
in glider (even in a trailer) during the summer, because high
temperatures (100+ degrees F or so) could damage the rubber bands they
use to sequence the opening. Winter temperatures could also be a
problem, as the rubber bands could become brittle in sub-zero (F)
temperatures, and be damaged if the parachute was moved.

Based on the above, I'm going to have Strong repack my parachute before
the season, even though I'm still considering a new parachute. I've
eliminated the National because I don't like the idea of the rubber
bands, so it's down to the Para-Phernalia Softie. The Micro-Softie seems
the most attractive of their line, and I'm thinking one with the
"thread-thru" adapters instead of snaps on the leg straps would be the
most comfortable.

Does anyone have experience with the thread-thru adapters?

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Eric Greenwell
Washington State
USA