Flipping belts?

[californiagirl]

OK, so we always flip over the seatbelt when we're installing the carseat in an airplane, but I get a pang of guilt every time. I have a friend who's a search and rescue pilot, the kind of guy who does incident command seminars for the fire department, has his emergency medical certificate, knows way too much about safety, and he freaks about twisted seatbelts. "They're not crash-worthy if they're twisted! Studies show that it concentrates forces and weakens the belt! And it'll weaken the belt even in everyday force situations, so it may fail in a crash even if it's flat if you let it be twisted all the time!" In his car, it doesn't start until your seatbelt is on FLAT.

Does anybody know any reassuring reason why it's really OK to twist the airplane seatbelt?

[Joolsplus2]

Here's what www.carseat.org under "technical" and "twisted seatbelt" says:
Vehicle belt webbing is extremely strong and can withstand pull tests of over 6000 lb. This is 3 to 4 times the strength needed to restrain a 60-lb child in a severe crash. Laboratory tests conducted by IMMI Child Restraints in 1998-99 found that the average strength of vehicle belt webbing, pulled until failure, gradually reduced depending on the number of full twists: 1=6%, 2=11%, 3=20%, 6=40%. Some of the webbing had been soaked in apple juice or cola, which resulted in slightly more degradation than untreated webbing. When other samples were twisted and later untwisted, the webbing returned to its normal strength. These data indicate that up to three full twists in belt webbing will not reduce its strength enough to risk failure when restraining a child."

There's more to it, but that's the most technical part. Ask him if he knows of any recorded instances of belts actually snapping in crashes... I'd love to see some evidence of that... I'm not saying he's wrong, of course, belts should be flat as much as possible, but still, it'd be interesting to see.

:)
Julie CPS Tech and mom to 2 in seats
http://www.cpsafety.com/articles/RFAlbum/SarahMA.aspx

[californiagirl]

I feel much better now. Thank you!

[cgdmom]

I don't know anything about it weakening the belt, and this doesn't apply to your situation (twisting the belt that holds a carseat in place), but I can't stress enough that in a belt positioning booster or when an adult or older child is restrained by the seatbelt, it is critical to make sure the belt is flat to spread the crash forces evenly. Same goes for the harness straps on a carseat. Otherwise there is a risk of (potentally fatal) internal injuries because of the added crash forces on your body at the location of the twist. So your friend is right to insist that your belt be flat before the car goes.