10 little things
Join Date: Jun 2001
Location: England
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Big Pistons,
Whats a runup mixture check? Is that one of them high altitude things?
I am pretty sure we don't do them in the UK and other than to stop the engine at the end of the flight thats it for the mixture
(except of course when it is mistaken for carb heat on base).(insert appropriate smiley).
Whats a runup mixture check? Is that one of them high altitude things?
I am pretty sure we don't do them in the UK and other than to stop the engine at the end of the flight thats it for the mixture
(except of course when it is mistaken for carb heat on base).(insert appropriate smiley).
This is what I teach my students to check with respect to the mixture control during the runup. ( for this example I am refering to your typical C150/152/172 1700 RPM runup,not at high altitude airport )
1) Push the mixture knob in. This ensures you are starting from full rich. The knob should stay fully in. If it pops out a little bit it means the mixture cable is too long and is kinking in the sleeve which will result in premature failure. This fault should be snagged.
2) Slowly pull mixture knob out while watching tach. The RPM should initially increase 25 to 50 RPM then slowly decrease. Stop leaning when the RPM has decreased by about 50 to 100 hundred RPM and the engine just starts to stumble. Observe for a rise in EGT indication (if fitted). If the engine does not have an initial rise in EGT then the carb is set too lean or if there is a large RPM rise then the carb is set too rich, and again the fault should be snagged. Obviuosly if the EGT does not rise it should not be used for any inflight leaning. Finally if there is no smooth reduction in RPM and the engine just quits as it is leaned ( As happened to me once ) then the airplane has some serious carb and or mixture control problems and should not be flown.
3) Push mixture control back in and ensure the mixture control moves freely and does not hang up. The mixture knob should return to the full in position and the RPM return to the pre check value.
In practice this procedure takes about 10 seconds and will give you a good indication that the carb is properly set up, The mixture control assembly is in good working order and is in fact selecting full rich and the EGT instrumentation is working.
1) Push the mixture knob in. This ensures you are starting from full rich. The knob should stay fully in. If it pops out a little bit it means the mixture cable is too long and is kinking in the sleeve which will result in premature failure. This fault should be snagged.
2) Slowly pull mixture knob out while watching tach. The RPM should initially increase 25 to 50 RPM then slowly decrease. Stop leaning when the RPM has decreased by about 50 to 100 hundred RPM and the engine just starts to stumble. Observe for a rise in EGT indication (if fitted). If the engine does not have an initial rise in EGT then the carb is set too lean or if there is a large RPM rise then the carb is set too rich, and again the fault should be snagged. Obviuosly if the EGT does not rise it should not be used for any inflight leaning. Finally if there is no smooth reduction in RPM and the engine just quits as it is leaned ( As happened to me once ) then the airplane has some serious carb and or mixture control problems and should not be flown.
3) Push mixture control back in and ensure the mixture control moves freely and does not hang up. The mixture knob should return to the full in position and the RPM return to the pre check value.
In practice this procedure takes about 10 seconds and will give you a good indication that the carb is properly set up, The mixture control assembly is in good working order and is in fact selecting full rich and the EGT instrumentation is working.
Join Date: Jul 2004
Location: uk
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Instructed on the west coast and in the uk. Just remembered about the mixture check on the run up eh. It's a Canadian thing but probably a good idea! Lots of little differences on both sides but better scenery over there, no doubt eh!!
But back to the important issues.... what about the heavy breathers? Please remember its a mouthpiece not a nosepeice.
But back to the important issues.... what about the heavy breathers? Please remember its a mouthpiece not a nosepeice.
Join Date: Oct 2001
Location: Vancouver Island
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jaarrgh :
With all due respect I must disagree with your comment about the signifigance of the mixture check proceedure that Big Pistons has described.
There is zero difference between any location on the planet when it comes to understanding the mechanical workings of an engine.
I would suggest that knowing how the mixture control works and how the engine should respond to the mixture control is very important.
If it is a Canadian thing then maybe landing on the nose wheel and collapsing same is a British thing?
I ask this based on the AIIB accident / incident reports, and feel that it is fair comment.
Chuck E.
With all due respect I must disagree with your comment about the signifigance of the mixture check proceedure that Big Pistons has described.
There is zero difference between any location on the planet when it comes to understanding the mechanical workings of an engine.
I would suggest that knowing how the mixture control works and how the engine should respond to the mixture control is very important.
If it is a Canadian thing then maybe landing on the nose wheel and collapsing same is a British thing?
I ask this based on the AIIB accident / incident reports, and feel that it is fair comment.
Chuck E.
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No, the British thing is using the rudder pedals as footrests and nothing else, and landing at anything other than the correct speeds, which could actually lead to your observation.
Join Date: Jun 2002
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ACW,
I beg to differ...
...but some of the circuits flown by Tomahawks at my home base are certainly bigger than the Hercules circuits I've witnessed whilst flying overhead Lynham (under a zone transit of course).
They go bombing (not literally) downwind at 800' QFE, overflying a medium sized town that is positioned just after I would turn base. Then they proceed to the centre of the town before turning onto a right base. Definately not able to glide clear and that is if they are at circuit height. Then they start descending on base down to 500' to final where they have to drag it in with lots of power. If they have any engine failure at all past the point where I and indeed most sensible pilots would, well they are either going into the town OR into the Bristol Channel's lovely muddy water.
The Tornado's at local St Athan are making MUCH MUCH tighter circuits than the Tomhawks / Warriors / etc at Cardiff. In fact you could probably fit two of their circuits in ours.
Grrr... always makes me cringe.
Best wishes,
Charlie Zulu.
I beg to differ...
...but some of the circuits flown by Tomahawks at my home base are certainly bigger than the Hercules circuits I've witnessed whilst flying overhead Lynham (under a zone transit of course).
They go bombing (not literally) downwind at 800' QFE, overflying a medium sized town that is positioned just after I would turn base. Then they proceed to the centre of the town before turning onto a right base. Definately not able to glide clear and that is if they are at circuit height. Then they start descending on base down to 500' to final where they have to drag it in with lots of power. If they have any engine failure at all past the point where I and indeed most sensible pilots would, well they are either going into the town OR into the Bristol Channel's lovely muddy water.
The Tornado's at local St Athan are making MUCH MUCH tighter circuits than the Tomhawks / Warriors / etc at Cardiff. In fact you could probably fit two of their circuits in ours.
Grrr... always makes me cringe.
Best wishes,
Charlie Zulu.
Join Date: Jan 2003
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A couple of points.....
Using a feature as a turning point rather than reference to a runway - it cuts the workload for both the instructor and the low-hours student. Saying 'turn base over the lakes' is lot easier than saying 'look over your shoulder and when the runway is at 45 degrees etc etc' when the student is struggling to fly S&L. That sort of finesse can wait until the student is more aware of whats happening.
Obviously, the turning points have to be chosen to give the correct runway reference, there is no point in saying 'turn over the blindingly obvious lake' which is 5 miles from the runway when there might be a smaller, but less obvious feature in exactly the right place.
Bomber circuits; I try now to keep my circuits as tight as possible, but thats also helped by the STOL characteristics of the aircraft I fly. Thinking back to the time when I first started circuit training, personally, I sometimes wished that the downwind leg was twice as long as it was.
By the time I'd lifted off, climbed to 600', turned x-wind, climbed to 1000', turned downwind (over the gasometers!), levelled off, let the speed build, throttled back, let the aircraft settle down and trimmed it, it was time to call 'downwind' .
Then it was time to do the downwind checks, (if I could remember them), correct the height, watch the heading, corect the height and speed and hell we are over the lakes turn right, head for the inlet on the river, carb heat reduce the power keep the nose up looking for 65 lower the flaps and lower the nose trim for 65 is there any other traffic watch the speed do I call the tower? turn base ignore the PAPIs watch your attitude getting low getting slow etc etc etc.
So yes, I certainly needed all the airspace I could get and It didn't get any easier for another good few hours. Add in another 3-4 aircraft all flying circuits and the necessity for a large well-defined circuit becomes apparent.
If I visit the airfield where I trained, then I will use those same landmarks, not because I want to, but because that is local practice and procedure and I don't want to turn inside someone in the circuit, just because I can.
So the circuit size has to accomodate the least experienced pilot, who will need the most airspace and that circuit gets fixed by convention. And we haven't factored in noise abatement.
And yes, I do get a bit miffed, following a Cessna/PA28etc downwind at homebase,getting to my turning point, only to see him sailing off on a long downwind leg when I know that I'm going to have to follow him.
I also think that its human nature for us less experienced pilots, when visiting an unfamiliar airfield, to fly a slightly larger circuit than normal, just to get the feel of the place.
Using a feature as a turning point rather than reference to a runway - it cuts the workload for both the instructor and the low-hours student. Saying 'turn base over the lakes' is lot easier than saying 'look over your shoulder and when the runway is at 45 degrees etc etc' when the student is struggling to fly S&L. That sort of finesse can wait until the student is more aware of whats happening.
Obviously, the turning points have to be chosen to give the correct runway reference, there is no point in saying 'turn over the blindingly obvious lake' which is 5 miles from the runway when there might be a smaller, but less obvious feature in exactly the right place.
Bomber circuits; I try now to keep my circuits as tight as possible, but thats also helped by the STOL characteristics of the aircraft I fly. Thinking back to the time when I first started circuit training, personally, I sometimes wished that the downwind leg was twice as long as it was.
By the time I'd lifted off, climbed to 600', turned x-wind, climbed to 1000', turned downwind (over the gasometers!), levelled off, let the speed build, throttled back, let the aircraft settle down and trimmed it, it was time to call 'downwind' .
Then it was time to do the downwind checks, (if I could remember them), correct the height, watch the heading, corect the height and speed and hell we are over the lakes turn right, head for the inlet on the river, carb heat reduce the power keep the nose up looking for 65 lower the flaps and lower the nose trim for 65 is there any other traffic watch the speed do I call the tower? turn base ignore the PAPIs watch your attitude getting low getting slow etc etc etc.
So yes, I certainly needed all the airspace I could get and It didn't get any easier for another good few hours. Add in another 3-4 aircraft all flying circuits and the necessity for a large well-defined circuit becomes apparent.
If I visit the airfield where I trained, then I will use those same landmarks, not because I want to, but because that is local practice and procedure and I don't want to turn inside someone in the circuit, just because I can.
So the circuit size has to accomodate the least experienced pilot, who will need the most airspace and that circuit gets fixed by convention. And we haven't factored in noise abatement.
And yes, I do get a bit miffed, following a Cessna/PA28etc downwind at homebase,getting to my turning point, only to see him sailing off on a long downwind leg when I know that I'm going to have to follow him.
I also think that its human nature for us less experienced pilots, when visiting an unfamiliar airfield, to fly a slightly larger circuit than normal, just to get the feel of the place.
Join Date: Jul 2004
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Chuck, relax,
Dear me. Perhaps if you were to read my post properly you will find that I suggest a mixture control check on the run up does indeed seem to be a good idea. I go on to say that it is a Canadian thing in that we don't really do that here.
Really, Chuck, your post doesn't seem to reflect the easy going and generous spirit found on the Island.
As an aside what is the 'ALTP' you mention under licence on your profile? If it says that on yours then you should have checked it before you down loaded it!
Dear me. Perhaps if you were to read my post properly you will find that I suggest a mixture control check on the run up does indeed seem to be a good idea. I go on to say that it is a Canadian thing in that we don't really do that here.
Really, Chuck, your post doesn't seem to reflect the easy going and generous spirit found on the Island.
As an aside what is the 'ALTP' you mention under licence on your profile? If it says that on yours then you should have checked it before you down loaded it!
Join Date: Oct 2001
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Jaarrgh..
Thank you for pointing out the error in mt pilot license description, I was not paying attention and described it based on what it was called over forty years ago when I received it. We referred to it as an airline Transport Pilot License and used that acronym.
So I will correct it and list the licenses that I hold.
ATPL Canadian........fixed wing all aircraft single and multi engine land and Sea.
Commercial Pilot Helicopter...........Canadian.
Commercial Pilot.................Airplane single and Multi Engine land and sea........ U.S.A.
Commercial Pilot Helicopter............. U.S.A.
Commercial Pilot Gyroplanes........... USA
Temporary Air Display Authorisation The Netherlands...( expired on Sept. 05/04 )
Trust that clarifies my mistake?
Chuck E.
Thank you for pointing out the error in mt pilot license description, I was not paying attention and described it based on what it was called over forty years ago when I received it. We referred to it as an airline Transport Pilot License and used that acronym.
So I will correct it and list the licenses that I hold.
ATPL Canadian........fixed wing all aircraft single and multi engine land and Sea.
Commercial Pilot Helicopter...........Canadian.
Commercial Pilot.................Airplane single and Multi Engine land and sea........ U.S.A.
Commercial Pilot Helicopter............. U.S.A.
Commercial Pilot Gyroplanes........... USA
Temporary Air Display Authorisation The Netherlands...( expired on Sept. 05/04 )
Trust that clarifies my mistake?
Chuck E.
