Big John wrote

In my thousands of hours I have never experienced a pitot heater
failure. Have you BOb?

Not personally, but it was apparently a problem when I first
started airline flying (1967). Maintenence was constantly
complaining about flightcrews turning it on too soon before
takeoff or not turning it off quickly enough after landing.
After a couple of airline accidents related to pitot heat, a
switch was added to the squat switch to turn the heaters on
regardless of the cockpit switch positions.

I've had insects get in pitot tube and block but that should be
caught on pre-flight.

I've had both pitots blocked on a B-720 (Belize Airways, 1978).
It was not obvious during preflight due to high location of the
pitot tubes and did not manifest itself until about 100kts by
which time it was time to fly. Pitch/Power solved the problem
easily.

If it (heater) were to fail and the pitot tube ice up and become
blocked then you can fly partial panel until you can get to an
altitude where the ice will melt. In fact you can land partial
panel if you have any experience partial panel.
May have used some wrong words so anyone current on systems feel
free to take me to task.

Although technically correct (anything less than full IS partial),
"partial panel" in GA usually refers to loss of gyro instruments.
Pitch/Power would be a better way to describe flying without the
airspeed instrument.

Bob Moore