Pitot Heat & Static Ports
Pitot heat probes and static inlet ports are primary safety devices in instrument conditions where moisture is present. Sometimes we get into a “temperature” mode when turning on these items but what we really need to focus on is moisture.
We must remember that heat applied to the pitot/static system needs to be done in flight or just before we begin the takeoff roll. These items should not be turned on without cooling air flowing over them. We do need to check them on the ground. So how do we do that?
Alternate Static Source
First, not all planes have a heated static inlet port. Usually if the plane does not have a anti ice static port the alternative would be to use another source. Some aircraft such as single engine aircraft have an alternate static port that is activated by pulling a knob that is marked “alternate static source”. This puts the alternate static into the cockpit which creates a “higher than you are” on the altimeter.
If you do not have an alternate static source, your alternate static source in an emergency becomes the vertical speed indicator. In instrument conditions with a frozen static inlet port you would break the vertical speed indicator glass. Now again you are reading the air inside the aircraft which again will show a higher altitude number than you actually are. There has been positive and negative as to this approach but the breaking of the glass on the vertical speed indicator will give you a “cabin atmosphere” reading which is going to be a lower pressure than outside pressure. THEREFORE, THE ALTITUDE WILL READ HIGHER THAN YOU ARE.
Also, trust your GPS to give you an altitude. This is your “new” type of backup.
Quick Check Alternative
Finally, if you want to make a quick check of anything that creates heat in your airplane to determine if it is operating buy an inexpensive “heat” thermometer that reads the temp on the built-in gauge. These units cost very little money and you shoot the beam of light at the heated unit and it tells you the temp. Then you immediately turn off the system that is on. This is good for pitot static systems, heated windshields even the air coming out of your vents.
Fly educated is flying safely.