Originally Posted by
Clare Prop
It is up to the operator if they want to add things like brakes off to pre-landing checks. It's quite another to ignore the POH and just lazy to adopt a one size fits all instead of reading the POH for different types.
POH for Tomahawk and Warrior state in section 4:
APPROACH AND ANDING
Carburetor heat should not be applied unless there is an indication of carburettor icing, since the use of carburetor heat causes a reduction in power which may be critical in case of a go-around. Full throttle operation with carburettor heat on can cause detonation.
Section 4 of POH for C152 states:
BEFORE LANDING
1. Seats, Belts, Harnesses -- ADJUST and LOCK.
2. Mixture -- RICH.
3. Carburetor Heat -- ON (apply full heat before reducing power).
AFTER LANDING
1. Wing Flaps -- UP.
2. Carburetor Heat -- COLD.
BALKED LANDING
1. Throttle -- FULL OPEN.
2. Carburetor Heat - COLD.
3. Wing Flaps -- RETRACT to 20°.
4. Airspeed -- 55 KIAS.
5. Wing Flaps -- RETRACT (slowly).
So, similar to the "in case of a go-around" reasoning that people give for opening cowl flaps on final, where for example C182 POH says to open them for a baulked landing; it shows that people are just parroting rather than learning.
First of all there is never a go around that requires so much power that the carby heat will be the defining difference. But lets just play this out.
If the POH is written such that we can assume pilots can learn to do things correctly, it SHOULD read like this.
BEFORE LANDING
1. Seats, Belts, Harnesses -- ADJUST and LOCK.
2. Mixture -- LEFT ALONE IN A LOP CRUISE SETTING or at a ROP Cruise position.
3. Carburetor Heat -- ON (apply full heat before reducing power).
AFTER LANDING
1. Wing Flaps -- UP.
2. Carburetor Heat -- COLD.
BALKED LANDING
1. Throttle -- FULL OPEN.
2. Mixture RICH THEN Carburetor Heat - COLD.
3. Wing Flaps -- RETRACT to 20°.
4. Airspeed -- 55 KIAS.
5. Wing Flaps -- RETRACT (slowly).
And yes folks that is how it should be done! Zero harm to engine and airframe, less chance of icing and less than the POH method. Does everything it should and nothing it shouldn't and yes I have generated the data personally.
LAST OF ALL......A MASSIVE OLD WIVES TALE TO KILL OFF.
Please do not start saying the OEM should know........This one is BULL**** of the highest order. I have participated in more detonation testing than anyone on PPRUNE, on the worlds most advanced aero-piston engine dyno. I declare this to be an OWT of the highest order.
Full throttle operation with carburettor heat on can cause detonation.
Simply cannot happen. Not unless you advance timing well out of spec, run on crappy low grade mogas, have oil temps in the 245dF range, CHT's in the 440dF or much higher range (unlikely prior to landing) and you are at 34" MAP with a mixture accurately set at 35-40dF ROP.
If anyone at Piper can explain how a pilot can do that in one of those planes (Chieftain is another matter but still take a bit of effort) and even if they did it would be so mild to begin with the GA and subsequent climb to circuit height would barely clean the cylinders let alone damage anything.
So......any more OWT's need busting?
