Agree with Rob2701, freezing rain is mainly associated with warm fronts – SCLD encounters in VMC are typically found in the summer in the mid levels and associated with flying too close to CB. The next stage is new ventilation due to hail.
Most precipitation (at least the sort that we’re discussing) starts in the ice phase (snow, graupel etc.) and melts on its way down to form raindrops. To form freezing rain you need an inversion, a warm layer through which the precip falls, and a cold layer below that.
Peter started this thread by saying:
In some cases it is obvious e.g. a cloudbase of 5000ft, 0C level of 4000ft, and it’s raining. There has to be freezing rain between 4000ft and some level above that which will obviously be inside the cloud. In that situation I would never depart on an IFR flight.
In fact, that doesn’t produce freezing rain in most circumstances. The layer between 4000 and 5000 ft will normally be snow (or an icy mix), not rain.
Robert – Jason’s point was that even in the warm front scenario, the droplets must be supercooled momentarily before hitting the airframe. Otherwise they would either just run off the airframe as liquid water, or would turn to ice/hail before reaching the airframe, and not accumulate.
Peter, I agree you need fuel or something else with heat capacity but this could still lead to ice accumulation, if not at the leading edge?
In the warm front we do not get SCLD, unless there is embedded convective activity. The freezing rain, typically from large stable nimbostratus, falls as rain into freezing conditions. The aircraft is cold soaked and the rain freezes on contact, usually producing mixed icing. SCLD produces clear icing.
Icing comes in many shapes and sizes, and sometimes it’s a salad of all types at once – fortunately the days of commercial ops in piston twins has long gone, and this generation of commercial pilots enjoy much better equipment.
Remember though that the frost you get on cold fuel after landing is just that, frost. Same as taking a frozen water bottle out of the freezer. It causes the local air layer to drop below the dew point so frost appears through deposition.
Found this article which seems quite a comprehensive study on FZRA and FZDZ. What am trying to see if typical warm front FZRA is of the large droplet type, and Jason I think is correct.
Jan apologies for not expanding SCLD, it is also sometimes described as SLD, and means supercooled large droplets, although large is only 50 microns plus.
I got freezing rain yesterday. Quite heavy rain in almost IMC and -1C showing on both OAT instruments.
But nothing stuck.
How can that be explained?
I did an immediate descent from FL110 to FL100 anyway, but that takes time.
Normally the airframe reflects the OAT instantly (seconds at most).
I would assume the water droplets were not supercooled and the surface not quite cold enough to freeze on impact. So not really freezing rain, rain when it is cold.
Few days ago when I departed from LQSA in heavy rain at 9 degrees I was thinking about this topic 
Sub-zero level started at 8000 ft with rain and IMC from 7000 ft and VMC again at FL120. I turned on TKS on departure and nothing sticked on. So I’m asking myself would’ve I picked up some ice if I hadn’t turn on TKS? However, the worst rain was overhead the airport while in direction of flight was much less precipitation.
I continued climb to two more cloud layers up to FL180 and clear sky with TKS off but these layers were thin and temperature gradually went to -18 and not ice formed. While descending towards LDZA I left TKS off and picked some ice in cloud layer between 8000 and 6000 ft.
