Carb Heat in Piper and Cessna Scandinavia vs UK

[tigermagicjohn]

A friend of mine recently invited me to a flying club in Norway, outside Oslo - where I took check ride on both C172 and PA28 at the local club.
The instructor I flew with, is a SAS pilot flying F50 in Norway - he has been flying for around 30 years now, and mostly Fokker's locally in Norway, so he has great experience in bad weather.

I recently retook my PPL at Stapelford and it was knocked in to our brain to ALWAYS use carb heat, if the RPM was less then 2200 on the PA 28.

However I went to Norway 2 days ago, flying 8 cm snow on the rwy, great experience in short soft field take offs and landings, great fun.

However my instructor, the SAS pilot told me only to use the Carb heat on the Cessna, and NOT on the PA 28.
Actually useing the carb heat could create an engine failure.

Now guess I am very very confused, as this pilot has much greater experience then all the instructors I have worked with at Stapelford.

Now we was flying in Norway on a winter day, had been snow earlier in the day, it was patchy fairly low cloud base, approx. 2200 ft, airfield elevation aroun 650ft.
However air felt fairly dry. Inland climate, few big lakes around.

Now the question has to be, who is right?
Is it the difference in the climate in the UK and Norway that is the reason for this difference in the use of Carb Heat?

SAS pilot in norway said, Cessna always carb heat, PA 28, as long as within green RPM arc, not to use Carb heat.

At Stapelford the carb heat is used as soon as RPM is below 2200 RPM.

Anybody can shed anymore light regarding this?

[P.Pilcher]

In days of yore, Cessna 150's were fitted with Continental (Some built by Rolls Royce in Crewe) engines and Piper Cherokees were fitted with Lycoming engines. In the latter, the inlet manifolds from the carburettor were taken through the oil sump which kept them warm and reduced the chance of icing occurring at low throttle settings. I understand that the carburettor heat control is much more effective in these engines than it is in the old Continental designs. Because of this, only the occasional burst of hot air is required in these engines when, say, descending in the circuit to keep the inlet manifolds and carburettor completely ice free. If , however it is left in hot for the ensuing landing and this is turned into a go-around, the extremely hot air which is then directed into the engine, operating at go-around power can cause damage. With the continental engines, with slightly less efficient hot air systems, it is better to leave hot air to be applied for longer, particularly as the application of full hot air will not damage the engine on a go around - it will merely reduce the amount of power available - which can in itself cause a problem
With Cessna 152s and the later Lycoming engined 172s however the situation is different as these lycoming engined aircraft have a more efficient carburettor heat system, this carb heat should only be selected hot briefly during the approach and then selected cold again.
Please note that what I have said is not based on any reading of a flight manual which is always the final arbiter in the way an aircraft is handled.

P.P.

[tigermagicjohn]

So from this I conclude, in the PA 28 - don;t need to use the Carb Heat?

My friend is very experienced pilot in Norway, real winter snow pilot. Or are the circumstances with humidity in the UK exception for this rule of useing carb heat? (On the PA 28)

[belowradar]

Check out the Piper POH and look at "landing checklist" - carb heat ON is NOT Listed.

[Mark1234]

At the risk of getting shot at, "carb heat on <2200rpm" is in the category of lies-to-children. It's a gross over simplification 'one size fits all' rule that attempts to remove the need for the pilot to think.

Carb heat should be used as appropriate to the conditions, (and by the POH). Tends to be customary to check it on approach 'to be sure' - if the engine coughs and splutters in the circuit, it's less serious than if it does the same when you open up to go around.

Climate wise the damp cold uk climate is more conducive to carb ice; the scandinavian climate is probably colder and drier. It's apparently possible, if the air contains ice particles for carb heat to *cause* carb icing by melting them into water which subsequently re-freezes - that may have a bearing on your friends advice.

As for type differences, scuttlebut is that cessnas are much better at making ice than the warriors. I don't know if that's true, or just an old wives tale (continental engined 150's aside).