Robinson Helicopter Company apparently has had something of an epiphany and has released the following:

Safety Notice SN-40

Issued: Jul 2006

POSTCRASH FIRES

There have been a number of cases where helicopter and light plane occupants have survived an accident only to be severely burned by fire following the accident.  To reduce the risk of injury in a postcrash fire, it is strongly recommended that a fire-retardant Nomex flight suit, gloves and hood and helmet be worn by all occupants.

Well, I certainly can’t argue with the concept of this bit of CYA, but the reality is that virtually no civilians are likely to wear a Nomex flight suit, let alone a hood and helmet. However, you can still take a big step for safety by avoiding the common low-temperature melting point man-made fabrics such as nylon, polyester and the like which MELT in a fire, causing much worse injuries than you might otherwise sustain.

Anytime you fly, whether in a general aviation aircraft or by the airlines, always wear natural fabrics that will not melt.  Many natural fabrics and materials, such as silk, wool, and leather, also have some natural fire resistance.

For colder weather, you can now get Nomex fleece clothing, both as underwear and as jackets and the like. The down sides are that it’s not readily available and it’s expensive. While it isn’t microfiber or fleece, I find that SmartWool makes excellent products that many find very comfortable. This is not your father’s scratchy wool underwear. Wool also has relatively high fire-resistance and it will also provide good insulation even if wet, unlike most synthetics.