Err... Just SLF here, but bow? Double bow ? On all my flights over the last five years, both within Europe and half way accross the world, all the lifejackets which I have seen demonstrated have plastic clips to fasten the lifejacket, which you attach, then pull the excess strap to tighten... No mention of tying bows
I thought I was paying attention...
Hi Maxbert...
Indeed, you were paying attention and are correct. The minimum performance standards for the design of life preservers approved for use on board aircraft in North America (and many other parts of the world that have adopted a similar standard, such as EASA) requires the following:
4.1.11 Life Preserver Retention and Donning Characteristics. The means of retaining the life preserver on the wearer, excluding infant-small child wearers, must require that the wearer secure no more than one attachment and make no more than one adjustment for fit. It must be demonstrated, in accordance with the donning tests specified in paragraph 5.9, that at least 75% of the total number of test subjects and at least 60% of the test subjects in each age group specified in paragraph 5.9 can don the life preserver within 25 seconds unassisted, starting with the life preserver in its storage package.
TSO-C13f, LIFE PRESERVERS
ETSO-C13f, LIFE PRESERVERS
Typically, in order to meet this performance standard (one attachment and one adjustment), a plastic clip is used by the manufacturers. You can see a typical example of this type of life preserver and attachment at the following links:
Eastern Aero Marine EAM XF-35
Eastern Aero Marine EAM UXF-35 - photograph
Switlik AV-35H - photograph