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View Full Version : Life expectancy of GA seat belts.


mickjoebill
22nd Aug 2011, 10:20
I recently worked in an helicopter which was built in 1980 and was surprised that the seat belts and buckle appeared to be original. Although not frayed they looked weathered and were very stiff.

How are seat belts determined to be airworthy? Are they replaced on inspection or are they time limited.

I ask as I understand that car seat belts lose their elasticity with age and/or use and I assume the same thing happens with aircraft seat belts?

Dg800
22nd Aug 2011, 10:34
On the gliders I flew the webbing was always time limited to 12 years with the expiration date clearly stamped on each piece of webbing. Metal parts were "on condition" and were to be replaced only if deemed unairworthy upon inspection.
I'm not 100% sure but I do think the 12-year limit was a manufacturer-imposed limit, I don't think there's an actual blanket limit in any regs, that is to say if the manufacturer does not time-limit any belt component part it is then to be understood to be "on condition" only.

mickjoebill
22nd Aug 2011, 11:13
does not time-limit any belt component part it is then to be understood to be "on condition" only.

Thanks DG800,
Ill check for a stamp or tag. I'm concerned that (over 30 years!) they would have lost their elasticity which is an important part of absorbing shock load to the hard point as well as reducing blunt trauma to the passenger.

In this case I don't have faith in "on condition" as it is beyond the means of most to evaluate the elasticity. In general I'm surprised that they have passed master as they look knackered.

As it is a simple lap belt I'll buy my own to solve the problem!

ivor toolbox
22nd Aug 2011, 13:31
Excuse me for jumping in here... in UK you'll need to read
CAAIP (CAP562) leaflet 25-40 Appendix 1; life of the belt is set by the fatigue life of components within the buckle (such as any springs etc)
and is generally set at 10 yrs by the belt manufacturers.

Hope this helps

FlightlessParrot
22nd Aug 2011, 23:03
My understanding is that with car belts, exposure to UV is part of the problem. This is more likely to matter with plastic materials than with stuff that was grown, I'd guess.

mickjoebill
23rd Aug 2011, 00:08
This is more likely to matter with plastic materials than with stuff that was grown, I'd guess.

Stuff that was grown?
The belt is 1908s webbing which I guess is plastic/nylon?



Mickjoebill

ChristiaanJ
23rd Aug 2011, 17:19
The belt is 1908s webbing which I guess is plastic/nylon?LOL re the typo....
If the helo and the belt date from 1908, both should be donated to a museum ASAP.....

As it is a simple lap belt I'll buy my own to solve the problem! Better safe than sorry.... I couldn't agree more.

Makes one wonder about seat-belts in older cars... (I agree, more a subject for JetBlast) I regularly do a pre-flight (err... 'pre-drive') check on the functioning of the inertia reel lock, but of course that tells me nothing about the aging of the belts themselves.

CJ

mickjoebill
24th Aug 2011, 02:59
Ok, the manufacturer says the life of this particular belt is 10 years, so according to the tag, this one is 4 years out of date.
Is it illegal?


In respect to my earlier question about wire insert was answered by the manufacturer.
The latch part (the short end that does not pass over the lap) has wire inserts to make it stiff so that it is easy to find. The wire is designed to break under load so doesn't compromise shock loading.


Mickjoebill

Dg800
24th Aug 2011, 07:30
Ok, the manufacturer says the life of this particular belt is 10 years, so according to the tag, this one is 4 years out of date.
Is it illegal?

Most definitely.

Dg800

matkat
24th Aug 2011, 07:39
The life of the belt is determined by the manufacturer however they shall be changed iaw your approved maintenance program.