A light drizzle was falling from the low overcast layer.  The Charleston, West Virginia tower was reporting VFR, but it was a day no one really wanted to be out flying.
Our pilot had just flown his Cessna 172 in from Upstate New York and was making a quick fuel stop on his way down to Memphis.  The next leg of his journey was about 4 hours and he was eager to be done for the day.
The air outside was chilly, but certainly well above freezing.  There were no NOTAMS for icing, and the cloud layer seemed thin, stopping at around 5 thousand feet.  The pilot finished his free FBO snack lunch and headed out to the plane.
After a quick walk-around he got in, received his IFR clearance and headed out for takeoff.  The rain had stopped and things were a little more promising.
After takeoff, our pilot was assigned his cruising altitude of 6,000 feet, high enough to clear the reported cloud tops and cruise on-top all the way to Tennessee.  The temperature was getting a little colder so the carburetor heat came on and the climb rate slowed.
At about 3,000 feet he looked out at the wing and noticed a very thin strip of frost forming.  It wasn’t anything he hadn’t seen before and he would be out of the clouds in less than 2 minutes anyway.  The outside temperature had dropped a little and was now around 8° Celsius.
The climb rate was getting slower, just now at 500 feet per minute and barely even that.  It dipped down to 250.  He looked outside at the wing strut and his heart began to pound.  There was a solid strip of ice maybe 1/2″ thick covering everything.  Worse yet, he was at 5,500 feet and there was no sign of any tops.
The climb rate was being significantly slowed by the carb heat.  While it was essential to prevent the engine air intake from freezing, it was also robbing the engine of the power it needed to climb any higher.  Our pilot began to weigh his options.
He could either leave the carburetor heat on, and attempt to climb on top, hoping that the tops would come soon; or he could turn it off, risking engine failure but climbing significantly faster.
He made a quick call to the Center controller and requested 8,000 feet to attempt to climb higher.  It was becoming clear that the plane would not make it that high in its present state.  He reached down and turned off the carburetor heat.
The climb rate jumped but only a few hundred feet per minute, still not enough.  Worse yet, within a minute the engine started getting a little rough.  He quickly turned the heat back on.
At this point the wing, strut, window post were covered in thick ice.  It was either time to get on top, or start diving, hoping to get underneath.  Up or down, nothing looked good.
And then it happened.  A break of sun from above.   Brief, but there was hope.  The engine got rough again…
30 seconds, that’s all he needed, 30 seconds, just a few hundred more feet.
And then it was clear, he was on top.  7,500 feet and not a second too soon.
He breathed a sigh of relief, but the danger was not over.  The engine was still rough, and the wings were still completely iced.  His maximum airspeed was holding steady at about 85 knots.  He was on top, but the airplane didn’t want to be there.
The pilot held out, at least he wasn’t getting any more ice.  A few minutes later he heard a crunch.  It was the first bit of ice breaking off the plane.  A few seconds later it happened again.
10 minutes after level off the engine smoothed, and the ice was gone.  4 hours later his heart rate slowed.
What would you have done?
Would you have even gone at all?
Would you have turned around?  Descended?