Are there any basic rules for when you should use the “pitot heater”?
Can you wait for suspect air-speed readings or just turn it on all the time?
Thanks in advance, sPK
personnally on the cessna caravan I turn it as soon OAT is equal or below to 4°C, it s what is mentionned on the poh, and checklist, I use this rule on all GA I fly
on airliner always ON cause flight level make it almost always necessary
(ps : this comment come from someone who is just a simmer and never received any flight instruction 
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Also check POH for ground operation of Pitot Heat, it’s limited in minutes, usually right before line up and take off. This prevents damage to the tube and the wing section where it’s attached.
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So if ground OAT is e.g. 10oC there’s no need to turn this on. But what happens when you start to climb and temperature falls? Surely by 3000’ and above even SAT will be below 4oC or less. Do we turn it on then? Do we do that only if we encounter humid or icing conditions with visible moisture? What if the air is dry and temperature falls quicker to minus? Do we turn it on after X feet for good measure? Do we turn it on before landing if we’re unsure about local temperature and perhaps there’s no ATIS?
I’ll search for some answers in When Is It OK To Use Pitot Heat? and https://aviation.stackexchange.com/questions/34557/why-not-have-pitot-heat-always-on
The first site says:
Answer: The activation of pitot heat is predicated on the occurrence of “possible icing conditions.” You mention the temperature was below freezing at altitude and there were clouds forming which indicates moisture, so the potential for icing existed.
Pitot heat, per the Pilot’s Handbook of Aeronautical Knowledge is an anti-icing device, not a deicing, so the prudent thing to do is to activate the pitot heat when in flight and there is the potential for icing to happen. Caveat: the electrically heated pitot tube gets warm very quickly, but the airflow passing over the pitot tube during flight keeps the electrical element from overheating. On the ground, the airflow over the pitot tube is not sufficient to prevent this, therefore the pitot heat should be turned off after landing.
Even so, does any of this have an actual impact in MSFS? I’m pretty sure I’ve forgotten to turn on pitot heat in many of my GA flights, yet I’ve never encountered stuck instruments such as airspeed indicator. Perhaps effects start to kick in only when conditions are really icy?
ps: what I usually do in MSFS (as airliners, and generally anything from private jet and above, is another story because of smarter Pitot Heat controls plus RAT/TAT temperatures coming into play), I turn on pitot heat only when below 8-10oC with potential icing conditions and then only before lining up. If it’s colder (ca. 5 or less) then I may even turn it on during taxiing. Of course with MSFS generally not having persistent states and pitot heat wear and tear (perhaps with a super very few 3rd party exceptions) there’s little incentive to do any of that.You can leave your pitot heat on 24/7 and nothing will break or melt.
Sometimes I’d rather this sim was more of a real sim rather than a Dune sim…
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The C152 JPLogistic (free mod aircraft) simulate pitot blockage, like the comanche 250, probably few other 3rd party aircraft does, Blacksquare have it as failure, not sure if environment may trigger it
about stock aircraft imo this is not incorporated/simulated correctly as I never had such issues
personally I don’t concider presence of moisture, just active it as soon as I see temperature requires it, it s so easy to forgot or not notice icing condition, so better being use to active it than risking a instrument failure… it doesn’t require lot electric load
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You can indeed get a stuck airspeed indicator in icing conditions in MSFS, happened to me a lot in the early days when flying jets. 
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And not just during flight, but they will even block the pitot tube if you forget to add the cover after your flight AND several (2-3) days pass before you load MSFS again. The reasoning being that in the meantime some little insect entered the tube and blocked it.
These guys are amazing. This is how you add incentive to do things properly by the checklist. State saving and little additions here and there. That’s why I keep shouting for so many years now: add state saving everywhere, make everything persistent by default. No EFB needed. Those who don’t like it should be able to turn it off via options and/or reset aircraft state to default via top popup menu.
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Maybe things have changed, but back in the 90’s we turned on the pitot heat immediately, regardless of temperature. Never had any problems doing this in our own airplane, and this was always the procedure in all aircraft that I trained in. We did this even when it was hot. I never knew anybody who did not turn on the pitot heater immediately after engine start.
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Given the damage model isn’t granular to the PT, you could technically turn it on the moment you crank the engine and leave it running.
But that’s why checklists were invented. So you don’t something like this IRL.
Sim the way you want.
What? You mean I don’t have to clear my pitot tube of a wasps nest?. What kind of airfare do I charge them? Do larvae fly free?
Thanks for all the contributions. I feel much better educated about pitot heaters and when I should use them.
It would indeed be nice if they were modelled correctly and we had permanent state saving but I guess it is all one step at a time.
Thanks again, sPK
I lost the airspeed reading a few months ago when I’d forgotten the heater. It was a few moments before I realised, and a few seconds after I switched it on it came back. I think it was the Cirrus before the recent update; the memory plays cruel tricks at my age…
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I so know the feeling, sPK
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IRL…read the the POH. Typically though when OAT is at or below 5 degrees.
Definitely though turn it on before you encounter wrong indications….because you would have to recognize them first to know they are wrong.
And once iced over or blocked you can run into problems if the system is defrosted in flight.
I had one Oldtimer at my airport with a long career as Testpilot for a major manufacturer who said he simply looks at it in flight in his old 176 that he flew to the very end, but most of us will never be as good as John😂
A basic general rule for the sim would be to turn it on when holding short for takeoff and off after clear of runway.
Beyond that consult the checklist that comes with the aircraft or the IRL aircraft POH if you can find a copy.
IRL consult the POH in the aircraft. If the aircraft does not have a POH, don’t fly that plane.
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