Useless gauge?
I very timely thread as I am fairly sure I had carb ice ontake-off in a R 22 two weeks ago. It was a training flight with a new student. Half tanks, just after sun up, OAT 14°C and the dew point was 10°C (later noted from a METAR issued an hour before sun rise). All was good in the hover, and the gauge was out of the yellow arc. Immediately after transition while crossing a road and fence the aircraft started vibrating quite badly and the climb became very sluggish. There was an open area after this and I almost opted to put it down there, but as it was not getting worse and there was a little bit of climb performance I kept it going instead. I was using all the power it had and therefore the throttle was wide open. About 20 seconds later the vibration was gone and performance restored.
I then started second guessing myself, thinking that I hadnot chosen the safest option. Yet it seems if I had lowered the collective witha partial carb ice blockage it is possible that the engine could have died froma rich mixture cut out. Our height and speed would have made this a tricky situation at best.
I did some research and found some interesting information especially Richard Mornington-Sanford’s excellent ‘NO ICE, THANK YOU’
http://www.morningtonsanfordaviation.com/pdfs/MSA-No-Ice,-Thank-You.pdf
Most disturbing of all though was Robinson’s own SN 25. Thiswas revised in July 2012. Sure it is on their website but they don’t seem to be shouting it from the rooftops exactly and they certainly did not tell me about it.
In it all reference to the Carb Heat Gauge has been removed. The notice now simply says:
‘When in doubt, assume conditions are conducive to carburetor ice and apply carb heat as required’
So what the hell is the gauge for then?!
Another case of Robinson covering their ass? 
Last edited by Frog Fan; 13th Sep 2012 at 06:36.
Reason: METAR time