Carburetor IceCarburetor Ice

The Insidious KillerPresented by:

Aerospace Services International, Inc.

Navy Flying Club Managers Workshop, 1999

AgendaAgenda

• The Killer

• How does it happen?

• Observations

• Detecting Ice

• Carb Heat on Takeoff?

• Just be SAFE!!

The Killer!The Killer!

• Carburetor ice is an insidious killer that appears without warning, often when least expected.

• Because it can form and “ambush” a pilot unexpectedly, we must exercise prudence when dealing with “Carburetor Ice”.

How Does it Happen?How Does it Happen?

• Carburetor creates a fuel/air mixture.

• Air is forced through a narrow opening in the intake, called a venturi.

• Air and fuel are mixed and a volatile mixture is created.

• Side effect of this reduction in pressure is a concurrent reduction in temperature.

• Moisture + below freezing temperature =

• Carburetor Ice (The Killer)

Carb. Icing Probability Chart Carb. Icing Probability Chart

ObservationsObservations

• Weird Stuff

• Cessna 150/172 Skyhawks

• Piper Cherokee

• Beechcraft

• Carburetor Heat– Meant to prevent the formation of ice, not to

remove it.

Detecting IceDetecting Ice

• Is there anything we can do or is it a fact of life we have to live with?– Carburetor Air Temperature Gauge– Iceman Probe

Two Instruments AvailableTwo Instruments Available

• Carburetor Air Temperature Gauge.– Operates by placing a

probe in the venturi and measuring the temperature at that point in the intake.

– (This is where ice will form if it going to.)

• Iceman Probe.– Unlike the Carb. Temp

Gauge, the Iceman Probe is said to alert the pilot to the actual formation of ice itself. It is designed to actually detect ice as it begins to form in the venturi tube of the carburetor.

Carb HeatCarb Heat

• The only thing that can “reduce or prevent” carb ice, is the application of carb heat early and often. If your Aircraft is not equipped with detection instruments, apply carb heat if you have the slightest suspicion that conditions may be conducive to ice forming in the carburetor.

Carb Heat on Takeoff?Carb Heat on Takeoff?

• Students are told not to do so.– Unless a pilot is required to get out of a short

strip with an obstacle at the end of the runway, a slight loss of power won’t substantially detract from the aircraft’s ability to take off and climb. Leaning the mixture will compensate for the slight loss of power.

Just be Safe!!Just be Safe!!

• No matter what your experience level, always be aware of the possibility of Carburetor Ice. Students and Instructors should make sure carb heat is applied when simulating a forced landing due to engine failure.

ConclusionConclusion

• Proper pre-flight planning can keep you from experiencing carb ice.

• Use the chart and you won’t be surprised.

• FLY SAFE!FLY SAFE!