Carb heat

or at least tell him not to teach stuff that Mr. Piper and Mr. Cessna don’t write in theit manuals

that doesn’t work either, there’s a lot of essential stuff not in the POH. For example, the POH doesn’t say how to fly an ILS, yet I still went to my FI/FTO to be taught how to do it.

Procedures and manuals are usually written so that mediocre people do an acceptable job. As Bosco wrote, to do a good job, you need good people. As an FI/FTO customer, I definitely prefer Bosco’s approach.

tomjnx, the manual wouldn’t tell you to apply carb heat before a climb. :)

For what it’s worth, I also despair at additional nonsense. My particular bug bear being the 47 checks that plots choose to complete prior to landing – in most SEPs a BUMPFFH will suffice. That said, show me one instructor who elaborates and I’ll show you ten pilots who are equally inventive. Perhaps the clearest example I’ve seen was a pilot who would switch his engine off (Rotax, it stopped instantaneously) at the commencement of the flare to ‘reduce his landing distance’. Or there are always the chaps who add a few knots ‘here and there’.

Finally, a quick look at accident statistics points towards medium/high hour PPLs and not instructors.

As an instructor I will gladly accept the suggestion that instructors are superior pilots and so have better accident statistics. But I am afraid the truth is that instruction is not very risky. For one thing, you could take weather out of the equation. Is it foggy, low ceilings or windy? Lesson cancelled. In most lessons we stay in the local area so whatever problem turns up – weather or malfunctioning equipment – just go the familiar short trip back to the familiar airport. And the goal of the flying is flying itself – not “getting there” – external pressures are also out of the equation. Any risk factor that turns up is an opportunity to learn and make judgements, not a distraction. So the low risk of instruction is probably more in the mission than in the PIC in the right seat.

Sorry, I digressed, even further away from carb ice.

How many accidents are caused directly by not using carb heat?

It has long been a firmly held belief among many pilots that lots of forced landings, and therefore a proportion of fatal crashes, are the result of carb icing.

Then the ice melts, leaving no evidence.

Is that really true?

On a related point, it is notable how little “carb heat” discussion there has been on EuroGA over the years, with just a couple of very old threads (now merged), while the subject tends to fill the pages of most aviation magazines, reliably year after year

huv wrote:

As an instructor I will gladly accept the suggestion that instructors are superior pilots and so have better accident statistics. But I am afraid the truth is that instruction is not very risky.

Sorry to drift the carb heat thread, but I cannot agree with either of these statements.

I agree that in general instructors are more frequent pilots, and that does improve and maintain skill in certain repeated tasks, but I know many frequent flying private pilots who maintain skills with unusual airplane types, and different operations to which an instructor would likely never be exposed. Frequently when I have flown in the company of an instructor – who was sent to “check me out” as I test flew a club aircraft, I have observed that instructor to demonstrate skills and judgement which were “canned”. They appeared to conform to the required standard, but didn’t go much further than that. I have flown with low time PPLs who were obviously current, but deeply lacking in precision of basic skills – who trained these pilots? I can’t teach the next skills to a pilot who cannot master the basic skills! The instructors I have flown with who really impressed me were part time instructors, who flew lots either recreationally as well, or flew “something else” for a living. I have learned that a pilot telling me that they are an instructor means I can expect to fly with a pilot who is competent on the types they instruct on.

As for risk, the only accident I was ever involved with was while I was giving instruction – to a competent PPL owner who made an error I could not correct in time. The scares I can think of during more than 40 years of flying have often been while I was giving training or a check out. A factor in this is that while instructing it is necessary to allow a deviation from ideal flying so the candidate learns what “not so good” looks like, and how to recover it. When you’re flying on your own, even as a modest skill PPL, you’re less likely to deliberately let the plane deviate from a “normal” path and increase risk. I did four hours of test flying a few weeks back on a Cessna T206H, quite a lot of it flying slow flight, slow approaches, and short landings. I hadn’t flown a 206 in years. All the flying was accomplished with adequate safety (I did not scare myself, nor the avionics tech riding with me). Now, the 3000+ hour owner pilot of the aircraft would like me to train him in advanced techniques, ‘cause it seems I had the plane safely doing things he has not mastered. The thought of the testing and set up didn’t worry me, the thought of being an instructor for advanced techniques (though still within the POH procedures) with the owner/pilot does!

Sorry for the thread drift Peter, if you need to move this post, feel free….

Peter wrote:

Then the ice melts, leaving no evidence.

Is that really true?

I don’t know, but based on a sample of one, probably not.

The one time I ended up in a field with the engine stopped was very nice day with a 15 degree spread, and while in theory carb ice was a possibility, if it happened that easily PA28s would be falling out of the sky like flies. I also turned carb heat OFF as part of the failure drills (which included also mixture, exercising the throttle, mags & tank switch) so am as sure as I can be that carb heat was on.

Yet, a lots of people still say “must have been carb icing”.

I can’t rule it out, of course – that was a pretty intense minute [it happened on base with less than 1000ft height], but I consider it unlikely.

I’ve read only your first post, not the comments, so apologize is this has been already commented on and explored in depth.
Your tachometer could be reading incorrectly. I recently replaced mine after discovering my old tach was reading 200 RPM too low at higher settings. That partially explains why I had such a fast Rallye.

I expect this is a very aircraft specific matter.

Flying a PA28-181 I can say that in 950+ hours, 90% VFR, I have never experienced carb icing. Obviously
a wide range of RH. Mostly cruise 65% power, various altitudes not above FL55

Three years ago I had an EDM830 fitted with carb and OAT temps etc. So I have a
staggering amount of data (every two seconds). At taxi at 14C OAT the carb temp is 16C so at the hold I
only need to check if carb heat causes an increase to make sure the gauge is working.
In the cruise for an outside temp of 10C, carb temp is -4C for example. But regular applications of
carb heat have not shown RPM increases. When applying carb heat in the cruise I wait till the carb temp
hits max say at 13C, OAT as above.
The landing phase as follows, use carb heat descending from circuit OAT 12C carb temp 10C @ 1800rpm
but carb heat off say 300’ carb temp 7C and as power is reduced for landing so carb temp increases.

A good thing about having carb temp is if one forgets to use it early in the descent one can always
apply it later and take comfort in the increase even in low power settings for a PA28-181

There is a lot more to learn about ones flying and ones engine from an engine monitor.

Peter wrote:

it is notable how little “carb heat” discussion there has been on EuroGA over the years

Because most here fly behind fuel injected engines ? Just a thought.