WRT the noise canceling headsets, I remember MH saying there is also a certification issue being dreamt up by the paper pushers in CAD. If I remember correctly they insist the headset is part of the aircrafts avionics fit, therefore must be certified in the aircraft type by the manufacturer (read; screeds of paperwork and piles of money!). Rather than part of the removable pilots equipment, as most authorities see it.
Imagine the frustration of getting most of the way through the certification process, only to discover the proposed headset is no longer in production and have to start again!
When flying the freighter I prefer to leave the ANR's on for the whole flight as well, although that obviously needs to be a crew decision, and I have seen a few of the older guys take exception to it.
