Sport Pilot Talk

drseti wrote: If you check the POH of a Cessna or Piper product (except for the PiperSport), you'll see you are advised to pull on full carb heat when downwind, every time.

The POH for my Piper Warrior say to use carb heat when icing is suspected. There is no mention of using it for every landing. That being said I teach my students to apply it for a few seconds on downwind while making their radio call.

On the flip side some of the Cessna 182's are so prone to carb ice that they have carb temp gauges installed. You use carb heat as needed to keep the temp in a safe range during all phases of flight.

3Dreaming wrote:

MrMorden wrote:The most common Rotax 912 carb ice scenario, from what I have read, is about 60-65°F OAT and higher than average humidity.

Best policy, if the engine is running normally and gets suddenly boggy, rough, or loses RPM, add the heat and keep it in! Usually if I have feelings that "these are good carb ice conditions" I will just put in the carb heat and leave it on until landing. In my airplane I don't even see a noticeable RPM drop using it, so why not?

I was taught temps in the mid 50's, and visible moisture.

Potato, potahto...my conditions were based on a lot of reading from various sources, yours are just as valid. I think the take away is that carb ice in Rotax engines seems to occur most frequently at moderate temperatures and moist conditions.

MrMorden wrote: Best policy, if the engine is running normally and gets suddenly boggy, rough, or loses RPM, add the heat and keep it in!

Agreed, but what's the best policy if the plane isn't equipped with carb heat?

==================================
EMERGENCY CHECKLIST:
->Rough engine during descent
--->Carb icing
------>Establish glide
------>Look for most suitable crash site
------>Bow head
------>"Our Father, which art in heaven,...."

Half Fast wrote: what's the best policy if the plane isn't equipped with carb heat?

Don't fly in conditions where carb icing is a possibility. Better yet, take up another hobby.

Several Tecnams Rotax combinations do not have carb heat.

drseti wrote:
Don't fly in conditions where carb icing is a possibility. Better yet, take up another hobby.

Skydiving comes to mind....

drseti wrote:

Half Fast wrote: what's the best policy if the plane isn't equipped with carb heat?

Don't fly in conditions where carb icing is a possibility. Better yet, take up another hobby.

I hope you know he was joking.

In any plane you should know and understand what carb ice is and how it presents. In the airplane without carb heat you need to be aware of the conditions for which it might be a problem and avoid them if possible. Beyond that be well prepared and practiced in emergency procedures including landings.

In almost 10,000 hours of flight time I have only had carb ice once that I know of. That was flying in a J3, the day I bought the airplane flying it home. I was strapped in, fat, dumb, and happy. It was my first flight in the airplane, and first time flying a J3. I was cruising along, and had made a couple adjustments to power because the RPM had dropped a little. I thought it was just the throttle creeping a little. Then all of a sudden the engine gave out a big cough, that brought me to my senses. Then I realized that when I'm strapped into the back seat I couldn't reach the carb heat knob. I used the side of my shoe the pull on the carb heat, and the engine ran rough for a few seconds, then cleared up. When all was said and done my RPM was about 100 higher than when I started. When all this was going on the outside temperature was in the 30"s with snow showers in the area.

I hope you know he was joking.

Yeah, I sorta figured that out from it being blindingly obvious.

But this discussion started from my mentioning the hot conditions we fly in here in FL and Paul (correctly) pointing out that mere hot weather doesn't preclude icing. It can still occur at certain levels of humidity, though it's a smaller probability than the wintry conditions you described.

I had a customer who had an engine failure at cruising altitude (7500-8500 feet) in a CT 2 or 3 years ago returning from the July 4th weekend. He wound up landing in a corn field. He and his wife sustained minor injuries, and the airplane was totaled. The FAA attributed the accident to carb ice.

3Dreaming wrote: The FAA attributed the accident to carb ice.

Sometimes I think they say that when they can't figure out anything else. Hard to disprove, since the ice will be gone long before any investigation happens.

I think the term NTSB uses is "probable cause".

Half Fast wrote:

MrMorden wrote: Best policy, if the engine is running normally and gets suddenly boggy, rough, or loses RPM, add the heat and keep it in!

Agreed, but what's the best policy if the plane isn't equipped with carb heat?

In your situation, nothing. The airplane has full time carb heat, so don't worry about it.

1) My Sky Arrow does have carb heat, selectable from the cockpit, drawing warm air from around an exhaust pipe. My air intake is a single oiled mesh type but very close to the cowling opening, so I suspect the air going into it is close to ambient, or maybe a tiny bit warmer due to radiated engine heat.

2) Don't routinely use it, and have not had a problem to date in about 9 years and 440 hours.

3) I, also, have had carb icing only once, also in a Cub. Kept thinking the throttle was creeping out. When full throttle was not producing anywhere near full power, I put the carb heat on and the engine died momentarily before coming back up. On landing, the carb had frost all over the outside of it, this on a relatively warm S FL day.

Do the Tecnam's have something like Skydrive full-time carb heat system?

dstclair wrote:Do the Tecnam's have something like Skydrive full-time carb heat system?

It's available, I believe, but not standard.