FAA Regulations

Our flight to Texas this weekend was delayed from 5;25 to 8:30, so George was ready to sleep when we boarded. I was wearing the sling that our friend Melanie made for Sally, so I was looking forward to George snuggling next to me during the flight (and allowing me to catch a few winks myself). I'd just settled in, and George had just fallen asleep, when a humorless flight attendant told me that I would be breaking federal law if George were to remain "harnessed" in the device. In truth, he wasn't so much harnessed as he was nestled peacefully. We reached a compromise by loosening the buckle during take-off and landing.

Looking at Southwest's website, it's not clear that use of the sling would break federal law:

The FAA has banned the use on aircraft of certain types of child restraints that may be harmful to a child in the event of an aviation emergency. These include most booster seats, safety belt extensions (commonly referred to as "belly belts"), and most vest or harness devices that attach to an adult or to the seatbelt of the child's own seat.

The website doesn't offer any way to tell if the sling is among the devices that have been banned by the FAA. Certainly, the sling is neither a belt extension nor a vest. Maybe it could be considered a harness, but it's really just a sheet. I decided to check out the Federal Regs for more detail. Sure enough, Federal Aviation Regulation # 121.311(b)(1) says:

[A] child may . . . be held by an adult who is occupying an approved seat or berth, provided the child has not reached his or her second birthday and the child does not occupy or use any restraining device . . .

I'm surprised by the breadth of this language - "any restraining device." Does that mean you couldn't hold an infant wrapped in the miracle blanket on an airplane? That's certainly a restraining device. How about a plain old blanket used to swaddle? I don't think that is the intent of the regulation, but those items appear to be banned.

I suppose these regulations are aimed at not squashing infants between adults and restraining devices during rapid deceleration, but it seems like they just succeed in (1) creating a potential infant projectile or (2) occupying hands that could otherwise keep you from squashing your baby. Can anyone explain the rationale to me?