One of the nastier emanations....
....of this nasty bit of kit came when they were trialling it on the Nimrod. On the day, the route nav had runny nose and after some time airborne asked the trial supervisor if he could take the AR5 off and clean up.
"No", was the firm response," that will invalidate the trial and we'll have to do the whole thing again".
When they finally landed and got off the a/c the nav bent down at the bottom of the steps and pulled the helmet off - cue disgusting mess and one of the trials team having to have a quick retch.
The Ancient Mariner