Multi-Engine runups
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Also, don't forget to be extra careful at NIGHT during the runups - whether you believe 'on the run' or 'stationary' is the most prudent.
The lack of peripheral visual cues at night when you are checking the integrity of the systems might have you taxiing at a ridiculous speed inadvertently, or worse, moving off your stationary position - GPU in tow
The lack of peripheral visual cues at night when you are checking the integrity of the systems might have you taxiing at a ridiculous speed inadvertently, or worse, moving off your stationary position - GPU in tow
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Yeah Jarsie, ive heard of something similar...except they weren't lucky enough to continue rotating up their own @rse, it was more like off the runway on to the grass somewhere
PS I am in no way inferring that has happened to yours truly; but there but for the grace of God go I........TTYS
PS I am in no way inferring that has happened to yours truly; but there but for the grace of God go I........TTYS
Grandpa Aerotart
Pinky raises an interesting point.
Why the difference?
Because some clever fella at Cessna or Piper just thought it was a 'reasonable' number....it is really that simple.
There is absolutely no real difference between the engine in a Chieftain and a C402...the numbers are arbitrary.
Doing a mag check at say 2300 rpm actually shows you nothing much that you wouldn't learn at 1500 rpm...or idle for that matter. In the big radial engines the mag checks are done at 'field barometric' which is 29.5 inches MP at MSL ISA. At that power setting you do actually learn something, for instance if RPM at that MP was not a certain value the engine was not producing it's proper power.
That is full power in a modern piston engine and no one is suggesting you should do full power mag checks on the ground I hope...whether in the runup bay or not.
In a typical piston twin if you run the engines up to approximately 1500 RPM, carry out a quick mag check and then gently cycle the props through to feather (ONCE is enough 99% of the time) and back out before the RPMs drop below 1000 rpm you have tested the ignition/prop systems as well as you would sitting in the runup bay with the engines roaring at 2300 rpm...except you haven't heated them up excessively before asking them to produce max power on takeoff...and you haven't risked damaging the props...and you haven't risked flinging stones at whatever/whoever is behind you.
There is nothing magical about the number 1500 either except the prop may not feather cleanly at much lower rpm...if you push them up and they settle at 1550,1600 or 1700 who cares?
Every minute running on the ground your engine is heating up...after a long taxi and a typical 'run up' as taught by most 'instructors' your engine will quite likely be approaching temps in the range of 370-400F which while it may be 60-90F below the published redline is still approaching the temp where long term damage starts to be inflicted.
If you want to really test your ignition system do it in cruise...select to left or right and leave it there for a goodly time and listen to your engine. If it runs smoothly with only a slight drop in power the system is fine...a live mag check at idle before you select cut off on the mixtures and you have done as much as you need to do. This check carried out in cruise LOP with an all cylinder monitor is even better.
In the days when I flew piston twins for a living we NEVER went out to the aircraft before the pax arrived and went through all the rigamarole espoused here...a daily inspection is a walk around not 'get in a flog the engines sitting still'...a efficient engine prop check carried out parked or while taxiing depending on circumstances and you were off....if something was not working you weren't...but lets face it people the chances of a regularly flown aeroplane's prop not cycling into feather and out cleanly is rare indeed...as is a 'live mag' that wasn't picked up on the previous flight and 'just broke' while the aeroplane was sitting undisturbed
Why the difference?
Because some clever fella at Cessna or Piper just thought it was a 'reasonable' number....it is really that simple.
There is absolutely no real difference between the engine in a Chieftain and a C402...the numbers are arbitrary.
Doing a mag check at say 2300 rpm actually shows you nothing much that you wouldn't learn at 1500 rpm...or idle for that matter. In the big radial engines the mag checks are done at 'field barometric' which is 29.5 inches MP at MSL ISA. At that power setting you do actually learn something, for instance if RPM at that MP was not a certain value the engine was not producing it's proper power.
That is full power in a modern piston engine and no one is suggesting you should do full power mag checks on the ground I hope...whether in the runup bay or not.
In a typical piston twin if you run the engines up to approximately 1500 RPM, carry out a quick mag check and then gently cycle the props through to feather (ONCE is enough 99% of the time) and back out before the RPMs drop below 1000 rpm you have tested the ignition/prop systems as well as you would sitting in the runup bay with the engines roaring at 2300 rpm...except you haven't heated them up excessively before asking them to produce max power on takeoff...and you haven't risked damaging the props...and you haven't risked flinging stones at whatever/whoever is behind you.
There is nothing magical about the number 1500 either except the prop may not feather cleanly at much lower rpm...if you push them up and they settle at 1550,1600 or 1700 who cares?
Every minute running on the ground your engine is heating up...after a long taxi and a typical 'run up' as taught by most 'instructors' your engine will quite likely be approaching temps in the range of 370-400F which while it may be 60-90F below the published redline is still approaching the temp where long term damage starts to be inflicted.
If you want to really test your ignition system do it in cruise...select to left or right and leave it there for a goodly time and listen to your engine. If it runs smoothly with only a slight drop in power the system is fine...a live mag check at idle before you select cut off on the mixtures and you have done as much as you need to do. This check carried out in cruise LOP with an all cylinder monitor is even better.
In the days when I flew piston twins for a living we NEVER went out to the aircraft before the pax arrived and went through all the rigamarole espoused here...a daily inspection is a walk around not 'get in a flog the engines sitting still'...a efficient engine prop check carried out parked or while taxiing depending on circumstances and you were off....if something was not working you weren't...but lets face it people the chances of a regularly flown aeroplane's prop not cycling into feather and out cleanly is rare indeed...as is a 'live mag' that wasn't picked up on the previous flight and 'just broke' while the aeroplane was sitting undisturbed
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Snap feather is just a term a few old engineers used to use to emphasise not leaving the pitch lever in feather long enough to drop below 1000RPM hence just snap it in and then straight out of feather. I don't care how many thousands of hours you have in piston twins, why does everyone feel it necessary to put their resumes in their posts?
When you read some of the crap written in here at times its hard to believe the authors have done anymore than a TIF.
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Overdone??
Chimbu is quite correct, as always.
Engines and propellors are subjected to all sorts of abuse during runups on the ground. It's often more showmanship than airmanship. Most air cooled engine have "pressure cooling", and on the ground the pressure is not there, so the cooling system is not working well. If we read the makers manuals we find the advice that a few minutes is usually adequate. The longer we run it on the ground, the more likely we are to have fouled plugs.
When temps are very low (that's around zero in most of Australia) the best way to warm it up is to run it for long enought to heat the exhaust system, which will the warm the oil and the rest of the nengine after it is shut down.
(starter motors have limits too)
Mostly a thorough DI and short runup before first flight followed by simple checks during the days flying, done on the move if you are on a gravel surface in a piston engined aircraft, is an appropriate way to operate.
We have to adjust to the environment we operate in.
POH's and flight manuals are important sources of information, and those silly old buggers who have been flying them since Adam was a cowboy often have useful information too.
Engines and propellors are subjected to all sorts of abuse during runups on the ground. It's often more showmanship than airmanship. Most air cooled engine have "pressure cooling", and on the ground the pressure is not there, so the cooling system is not working well. If we read the makers manuals we find the advice that a few minutes is usually adequate. The longer we run it on the ground, the more likely we are to have fouled plugs.
When temps are very low (that's around zero in most of Australia) the best way to warm it up is to run it for long enought to heat the exhaust system, which will the warm the oil and the rest of the nengine after it is shut down.
(starter motors have limits too)
Mostly a thorough DI and short runup before first flight followed by simple checks during the days flying, done on the move if you are on a gravel surface in a piston engined aircraft, is an appropriate way to operate.
We have to adjust to the environment we operate in.
POH's and flight manuals are important sources of information, and those silly old buggers who have been flying them since Adam was a cowboy often have useful information too.
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Hey CC, next time I take off in the Chieftain and only get 29.5 inches of MAP, I'll remember that that is supposed to be normal, shall I? At 2300, if you do your run up, you'll get something like 29 inches of MAP. Same as "the big radial" If you only get 29.5 max, then you aren't going anywhere fast......
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CC, not really mate. You said that was full power in a modern piston engine. It isn't. I know you generalised, but hey, there are differences. What's the difference in the type of info i'd get from the Chieftain at 29/2300 versus the "big Radial" at 29/2300 or whatever? From a pilot's perspective I mean, not an engineers? If you want to know if the L/TIO 540 in the plane is producing the power it should, then wouldn't you set your 2300 see what MAP you get and fuel flow? Just like the big ones you talked of? If you don't see it, you ain't getting it I would have thought.
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Conducting runups with pax on might be fine in some of oz's cooler climates, but in the middle of the wet season in a piston twin? 
Well, you won't have to worry about repeat business!
Best to do them before the pax turn up, in addition to the points already raised.
Well, you won't have to worry about repeat business!
Best to do them before the pax turn up, in addition to the points already raised.
Grandpa Aerotart
Do you have any info about what rpm you should see for 29in in the Chieftain?
Not flown one but many hours in 402s and there was never a figure given for the TSIO520. I don't remember ever hearing it suggested there was one for the TSIO540 in Aerostars, not was it ever mentioned for the GTSIO engines in the the 404 or Queenairs...all of which I used to fly and train on.
It might very well be that 29/2300 is a perfectly reasonable relationship but I don't have any solid factual information to base that on...do you?
Yes I made a generalisation with the full power comment...my mistake...but if that is all you were able to take from the entire post then you obviously have little left to learn...and as such it was not aimed at you but to pilots who might just like to maintain an open mind about possibly better ways to treat the machinery their lives and income depend on.
I have not instructed in nor even flown piston twins in over 12 years...but I still fly and own a piston single and am constantly learning.
The bottom line is you're learning NOTHING sitting at 2300 rpm in your Chieftain fiddling with the magnetos and pondering a small drop in rpm between left, right and both that you wouldn't learn at 1500 rpm. As long as you get some drop and the engine doesn't stop that is as much as you'll gleen at 2300 rpm, 1500 rpm or anywhere in between when all you have to look at is a tacho.
Between a regulator who lacks any interest in GA and marginally profitable charter operations not interested in spending money most piston twins in Australia used on commercial operations lack the one piece of technology that would allow, with a modicum of training, truly diagnostic engine checking...a modern digital all cylinder engine monitor...and what is really funny? They cost about as much as 3 engine cylinders
Then you could sit back at cruise power in flight and check the performance of your individual spark plugs, injectors and valves...if you know what you're looking at.
Recently in the US a chap enroute in his Bonanza got enough warning from his engine monitor to divert and land normally when one of his cylinders developed a crack so bad the head was about to depart the engine. At the other end of the spectrum we see the Spencer Gulf crash and loss of life. Long accepted Chieftain 'SOPs' and piston 'Lore' were at least partly responsible for that crash...not the young bloke flying it but the 'senior' and 'experienced' pilots who taught him to operate the engines in a manner that gauranteed long term damage that surfaced when, after a probably pre existing fault, the crankshaft, stopped one engine, he asked more of other one to get him home. That is what happens when you abuse high powered engines over an extended period through ignorance.
Not flown one but many hours in 402s and there was never a figure given for the TSIO520. I don't remember ever hearing it suggested there was one for the TSIO540 in Aerostars, not was it ever mentioned for the GTSIO engines in the the 404 or Queenairs...all of which I used to fly and train on.
It might very well be that 29/2300 is a perfectly reasonable relationship but I don't have any solid factual information to base that on...do you?
Yes I made a generalisation with the full power comment...my mistake...but if that is all you were able to take from the entire post then you obviously have little left to learn...and as such it was not aimed at you but to pilots who might just like to maintain an open mind about possibly better ways to treat the machinery their lives and income depend on.
I have not instructed in nor even flown piston twins in over 12 years...but I still fly and own a piston single and am constantly learning.
The bottom line is you're learning NOTHING sitting at 2300 rpm in your Chieftain fiddling with the magnetos and pondering a small drop in rpm between left, right and both that you wouldn't learn at 1500 rpm. As long as you get some drop and the engine doesn't stop that is as much as you'll gleen at 2300 rpm, 1500 rpm or anywhere in between when all you have to look at is a tacho.
Between a regulator who lacks any interest in GA and marginally profitable charter operations not interested in spending money most piston twins in Australia used on commercial operations lack the one piece of technology that would allow, with a modicum of training, truly diagnostic engine checking...a modern digital all cylinder engine monitor...and what is really funny? They cost about as much as 3 engine cylinders
Then you could sit back at cruise power in flight and check the performance of your individual spark plugs, injectors and valves...if you know what you're looking at.
Recently in the US a chap enroute in his Bonanza got enough warning from his engine monitor to divert and land normally when one of his cylinders developed a crack so bad the head was about to depart the engine. At the other end of the spectrum we see the Spencer Gulf crash and loss of life. Long accepted Chieftain 'SOPs' and piston 'Lore' were at least partly responsible for that crash...not the young bloke flying it but the 'senior' and 'experienced' pilots who taught him to operate the engines in a manner that gauranteed long term damage that surfaced when, after a probably pre existing fault, the crankshaft, stopped one engine, he asked more of other one to get him home. That is what happens when you abuse high powered engines over an extended period through ignorance.
Man Bilong Balus long PNG
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A couple of eloquently argued posts from Chuckles & Bushy.
I have my copy of the Chieftain Pilot's Information Manual open in front of me and on page 6-3 in the warm-up and ground check section it states,
It goes on to say,
Like others here I have often wondered at the difference between the Chieftain (Lycoming) and the 402 (Continental) regarding the mag checks but in general, questioning LAMES, Chief Pilots etc mostly only drew the response along the lines of "Do as the manual says; The manufacturer knows what they are talking about" etc etc.
Anyone have any info as to what Lycoming and Continental themselves actually recommend?
Mungrel; Can't remember for sure but in last Chieftain I flew, mag check at 2300rpm gave MP about 31''. I may be wrong.
I have my copy of the Chieftain Pilot's Information Manual open in front of me and on page 6-3 in the warm-up and ground check section it states,
Feathering is checked with the throttles set at 1500rpm. No more than 500rpm drop should be allowed in this check.
The magnetos are checked with the propellors in low pitch and the throttles set at 2300rpm. The drop should not exceed 175rpm, and the difference in drop between both magnetos should not exceed 50rpm.
Anyone have any info as to what Lycoming and Continental themselves actually recommend?
Mungrel; Can't remember for sure but in last Chieftain I flew, mag check at 2300rpm gave MP about 31''. I may be wrong.
They are probably trying to avoid/check for this: From sacskyranch.com
Does anyone want to hazard a guess why Pa31 mags are pressurised and why they should be checked at the higher RPM now?
Pinky, which report number is that POH you've got? 2046?
Different POH's (report numbers) for the Pa31 will outline differing procedures for what amount to similar aircraft. It is preferable (from a CP's point of view) that aircrew stick with what is in the manual for many reasons, not the least of which are insurance, owner and contractual (hire) requirements.
Of interest: www.ramaircraft.com/Aircraft-Parts/Magnetos/Magnetos.htm
2200RPM or above for the mag check? Possibly because Piper/Lycoming knows something about one way a prop or its governor might fail giving 2100rpm max and around 30-32"Hg. Better to be finding that out without the pax on board me thinks.
Much like the reasoning behind letting turbo brgs cool down so they wont coke up, but then again what would I know... Of further interest to those who claimed I was wrong before (check point six): Save-A-Turbo
Have a lovely day.
Severe example of Carbon Arc Tracking damage to magneto.
When the pilot did the magneto check on run-up, what did this magneto do?
Answer: Magneto exhibited normal rpm drop during the engine magneto check prior to takeoff.
However, magneto misfired with a resultant loss of engine power at full power.
As power increases the voltage required to jump the spark plug gap increases. In this example the spark plug would fire at lower engine power settings but at higher power settings the voltage arc'd within the magneto causing the destruction you see on the left.
When the pilot did the magneto check on run-up, what did this magneto do?
Answer: Magneto exhibited normal rpm drop during the engine magneto check prior to takeoff.
However, magneto misfired with a resultant loss of engine power at full power.
As power increases the voltage required to jump the spark plug gap increases. In this example the spark plug would fire at lower engine power settings but at higher power settings the voltage arc'd within the magneto causing the destruction you see on the left.
Pinky, which report number is that POH you've got? 2046?
Different POH's (report numbers) for the Pa31 will outline differing procedures for what amount to similar aircraft. It is preferable (from a CP's point of view) that aircrew stick with what is in the manual for many reasons, not the least of which are insurance, owner and contractual (hire) requirements.
Of interest: www.ramaircraft.com/Aircraft-Parts/Magnetos/Magnetos.htm
2200RPM or above for the mag check? Possibly because Piper/Lycoming knows something about one way a prop or its governor might fail giving 2100rpm max and around 30-32"Hg. Better to be finding that out without the pax on board me thinks.
Much like the reasoning behind letting turbo brgs cool down so they wont coke up, but then again what would I know... Of further interest to those who claimed I was wrong before (check point six): Save-A-Turbo
Have a lovely day.
2200RPM or above for the mag check? Possibly because Piper/Lycoming knows something about one way a prop or its governor might fail giving 2100rpm max and around 30-32"Hg. Better to be finding that out without the pax on board me thinks.
. Last Thursday, when a particular Chieftain engine failed to increase the engine RPM past 2,100Rpm.Whilst I do agree with most of what you say Chuckles, I tend to agree more with what Lycoming and Piper say about conducting mag checks at 2,300Rpm. I've found more problems at that Rpm in the Chieftain, than I have at 1,700Rpm. Sounds silly I know, but that's purely from my own experience.
And besides, since my Chief is having some input into the thread, best I be good and not suggest things outside his ops manual,
.morno
Grandpa Aerotart
That sounds reasonable
But it's checking the prop governor rather than the ignition system.
As shown by opsnormal even a magneto problem didn't show up during a runup presumably carried out at 2300 rpm(?). I wonder if an engine monitor would have shown it..probably not if it was functioning normally at the lower rpm...it would have as the maggy self destructed.
But it's checking the prop governor rather than the ignition system.
As shown by opsnormal even a magneto problem didn't show up during a runup presumably carried out at 2300 rpm(?). I wonder if an engine monitor would have shown it..probably not if it was functioning normally at the lower rpm...it would have as the maggy self destructed.
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CC ..pinky makes a good point....how far should one go in checking "reasonable parameters" with ones aircraft.....I use my AC manual all the time,listen to my mates(with the same A/C)..talk to the LAME,s...and like a womem ..try to fly her like she likes to be flown.....thats certainly something no one teaches you....
....like most,I will adhere to the normal operating procedures that the manufacturer recommends,and the operaters manual is just that....outside of that, ..its the RENO AIR-RACES!!!....
I would speculate CC that you are very well endowed and proficient with A/C engines .....that by your postings is very evident,and personally have taken some of your recommendations......in saying that ,would you not agree that the manufacturers specs are for reason and are there for "persons" of less capability than yours ...for reasons of liability etc etc.....
...if one is to take the advice given here,there are no disclaimers....for those of us who own A/C ......there is always something to know and learn,.......
I believe all of us will agree.."Good operating practices" are in the eye of the beholder.....if there is a starting point,it lies with the operaters manual and the pilots that fly these animals....PB
....like most,I will adhere to the normal operating procedures that the manufacturer recommends,and the operaters manual is just that....outside of that, ..its the RENO AIR-RACES!!!....
I would speculate CC that you are very well endowed and proficient with A/C engines .....that by your postings is very evident,and personally have taken some of your recommendations......in saying that ,would you not agree that the manufacturers specs are for reason and are there for "persons" of less capability than yours ...for reasons of liability etc etc.....
...if one is to take the advice given here,there are no disclaimers....for those of us who own A/C ......there is always something to know and learn,.......
I believe all of us will agree.."Good operating practices" are in the eye of the beholder.....if there is a starting point,it lies with the operaters manual and the pilots that fly these animals....PB
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Chuck,
firstly, let me state that I have the highest regard for your usually very informative,
thought provoking, and practical discussions, both on Pprune and via PM's.
However, I do need to set the record straight with a few other bits of information (possibly facts?).
With regard to the Whyalla VH-MZK PA31 accident,
the investigation and report was bound to be flawed due to the unprecedent level of political and media interest.
Laurie Brereton, minister for signs, a former CASA director, and many others all wanted to be involved and all had something to say.
a very good analysis of the ATSB report was made by John Deakin, "Pelican's Perch",
he is of similar vintage and experience to yourself, and like you,
is very much into LoP ops with a properly instrumented aircraft.
However, he correctly labelled the ATSB report as "Junk Science".
http://www.warmkessel.com/jr/flying/td/jd/57.jsp
The particular operator usually managed 30% extensions to TBO by their operating methods,
a rather contradictory expectation, if how they operated was detrimental to engine life.
In hindsight, and with the passage of time,
it is now known that the failure was due to a known manufacturing defect in a batch of Lycoming crankshafts. Continental IO-520s also went through a similar fault phase prior to Lycoming.
(you do acknowledge that fact, and perhaps the post crankshaft failure ops could have been better.)
The ATSB report emotively described the POH method of leaning as "Aggressive Leaning".
I have had a broken crankshaft in a BE58, (Continental IO-520), it's no fun, but you can get home or to a suitable alternate.
I have operated both C402's and PA31's and yes, the Piper POH does require higher mag test rpm than Cessna / Continental.
Always go by the book, even though ATSB may sometimes deem it aggressive.
Chuck, thanks for the excellent articles you contribute, please continue, and I'm sorry to query you on this one.
firstly, let me state that I have the highest regard for your usually very informative,
thought provoking, and practical discussions, both on Pprune and via PM's.
However, I do need to set the record straight with a few other bits of information (possibly facts?).
With regard to the Whyalla VH-MZK PA31 accident,
the investigation and report was bound to be flawed due to the unprecedent level of political and media interest.
Laurie Brereton, minister for signs, a former CASA director, and many others all wanted to be involved and all had something to say.
a very good analysis of the ATSB report was made by John Deakin, "Pelican's Perch",
he is of similar vintage and experience to yourself, and like you,
is very much into LoP ops with a properly instrumented aircraft.
However, he correctly labelled the ATSB report as "Junk Science".
http://www.warmkessel.com/jr/flying/td/jd/57.jsp
The particular operator usually managed 30% extensions to TBO by their operating methods,
a rather contradictory expectation, if how they operated was detrimental to engine life.
In hindsight, and with the passage of time,
it is now known that the failure was due to a known manufacturing defect in a batch of Lycoming crankshafts. Continental IO-520s also went through a similar fault phase prior to Lycoming.
(you do acknowledge that fact, and perhaps the post crankshaft failure ops could have been better.)
At the other end of the spectrum we see the Spencer Gulf crash and loss of life.
Long accepted Chieftain 'SOPs' and piston 'Lore' were at least partly responsible for that crash...
not the young bloke flying it but the 'senior' and 'experienced' pilots who taught him to operate the engines
in a manner that gauranteed long term damage that surfaced when, after a probably pre existing fault,
the crankshaft, stopped one engine, he asked more of other one to get him home.
That is what happens when you abuse high powered engines over an extended period through ignorance.
Long accepted Chieftain 'SOPs' and piston 'Lore' were at least partly responsible for that crash...
not the young bloke flying it but the 'senior' and 'experienced' pilots who taught him to operate the engines
in a manner that gauranteed long term damage that surfaced when, after a probably pre existing fault,
the crankshaft, stopped one engine, he asked more of other one to get him home.
That is what happens when you abuse high powered engines over an extended period through ignorance.
I have had a broken crankshaft in a BE58, (Continental IO-520), it's no fun, but you can get home or to a suitable alternate.
I have operated both C402's and PA31's and yes, the Piper POH does require higher mag test rpm than Cessna / Continental.
Always go by the book, even though ATSB may sometimes deem it aggressive.
Chuck, thanks for the excellent articles you contribute, please continue, and I'm sorry to query you on this one.
Last edited by Mainframe; 21st Jan 2007 at 05:32. Reason: fix some typo's
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Mainframe,
Perhaps your comparing John Deakin with CC is flattering for one and a bit of a come down for the other, John Deakin has reportedly some 33,000 hours, including 33 years with Japan Air Lines, for the most part as an 747 skipper. His breadth of experience covers a much wider spectrum of internal combustion engines than anyone of such tender years as CC could possibly have amassed, even in the wilds of PNG.
John Deakins assertion that allowing operators to continue using the steam age instrumentation for high power piston engines used in public transport is bordering on criminal negligence should certainly have gained a lot more credence than it has been given. But it costs so it wont.
Looks like I missed a few thousand hours on Mr Deakins total, apologies, what an incredible record.
Perhaps your comparing John Deakin with CC is flattering for one and a bit of a come down for the other, John Deakin has reportedly some 33,000 hours, including 33 years with Japan Air Lines, for the most part as an 747 skipper. His breadth of experience covers a much wider spectrum of internal combustion engines than anyone of such tender years as CC could possibly have amassed, even in the wilds of PNG.
John Deakins assertion that allowing operators to continue using the steam age instrumentation for high power piston engines used in public transport is bordering on criminal negligence should certainly have gained a lot more credence than it has been given. But it costs so it wont.
Looks like I missed a few thousand hours on Mr Deakins total, apologies, what an incredible record.
Last edited by prospector; 21st Jan 2007 at 07:53. Reason: mistake???
Grandpa Aerotart
No need to appologise at all...I am not infallible...I think we are in complete agreement on Whyalla
My memory of reading Deakins article on Whyalla (Junk Science) was that leaning on climb probably contributed to a hole in a piston on the 'good' engine and when asked for all it could give after the crankshaft let go in the other engine that hole got real big real quick...leading to the outcome that night...not the young pilots fault, he was as much a victim as his passengers.
That is what I mean about PA31 'Lore'. Leaning on climb in similar engines has been espoused by many who should know better over the years..the fella who owned the PA60-700p I used to fly insisted on it so when he was on board I did and when he wasn't I climbed full rich and then leaned no leaner than 100 ROP in cruise..he insisted on 50F ROP and sometimes peak EGT for better economy ...and that was early 90s long before I ever heard of LOP or engine monitors.
The simple act of fitting an engine monitor to an engine replaces lore with fact, or it should. I have shown massively experienced lifetime GA pilots what is really going on inside my IO550 in flight and they shook their heads in amazement and then go off and ignored the insight completely.
Clearly there is a 'good' reason, apparently, to use higher power for run ups in a PA31...but would not the same end be achieved by doing the run ups in a more mechanically sympathetic way and then checking you're getting full rated power on takeoff?
I postulate this not to encourage pilots to ignore their CP but to suggest perhaps the CPs have a think and way up one set of circumstances against another.
On the one hand high powered run ups (often longwinded due innexperienced pilots checking everything twice while reading a checklist) are clearly damaging to an engine, any engine, and on the other we have a justification for those high power settings to detect a possible prop fault.
Are we not belting the engine everytime we do this to detect a possible failure mode that is very rare and would be picked up anyway in the first 30m of takeoff run?
It's one of a CP's jobs to think about these things...blindly following a POH is just plan silly when you realise these things were written 35 years ago.
My POH for EZU was written in 1969 and expressly forbids LOP operation.
At CASA's insistance a few years ago I ordered a new one and the ammendment service that fullfilled CASA's requirements.
Guess what?
The ONLY difference between the new POH and the original is the cover...Ratheon just said "what ammendment service?"
It's has never been ammended.
LOP operation is a no brainer in terms of being 'good' all the way around yet if I just accept as gospel everything in the POH I wouldn't be doing it. The boss of CASA airworthiness said to me years ago "all engines should be operated this way" after they had been to the US and witnessed GAMi's TSIO540 on the test stand after Deakin stuck it up ATSB over Whyalla. They went to the US at the invitation of George Braily after ringing him and whinging long and loud about Deakin and left the US with a completely different opinion.
I just want people to think and ask "why?"
Edit: Yup comparing me to Deakin is just dumb... we seem to be similar personality types based on our conversations in the past and emails and certainly share a love of old aeroplanes and piston engines. We share a bushflying early career...but he has 38000 hrs and is a truly clever fella..he's also 20 years older than me...he and I email each other from time to time...I am certainly flattered by the comparison but I don't think it is justified.
His variety of aviation experience is breathtaking.
My memory of reading Deakins article on Whyalla (Junk Science) was that leaning on climb probably contributed to a hole in a piston on the 'good' engine and when asked for all it could give after the crankshaft let go in the other engine that hole got real big real quick...leading to the outcome that night...not the young pilots fault, he was as much a victim as his passengers.
That is what I mean about PA31 'Lore'. Leaning on climb in similar engines has been espoused by many who should know better over the years..the fella who owned the PA60-700p I used to fly insisted on it so when he was on board I did and when he wasn't I climbed full rich and then leaned no leaner than 100 ROP in cruise..he insisted on 50F ROP and sometimes peak EGT for better economy
...and that was early 90s long before I ever heard of LOP or engine monitors.The simple act of fitting an engine monitor to an engine replaces lore with fact, or it should. I have shown massively experienced lifetime GA pilots what is really going on inside my IO550 in flight and they shook their heads in amazement and then go off and ignored the insight completely.
Clearly there is a 'good' reason, apparently, to use higher power for run ups in a PA31...but would not the same end be achieved by doing the run ups in a more mechanically sympathetic way and then checking you're getting full rated power on takeoff?
I postulate this not to encourage pilots to ignore their CP but to suggest perhaps the CPs have a think and way up one set of circumstances against another.
On the one hand high powered run ups (often longwinded due innexperienced pilots checking everything twice while reading a checklist) are clearly damaging to an engine, any engine, and on the other we have a justification for those high power settings to detect a possible prop fault.
Are we not belting the engine everytime we do this to detect a possible failure mode that is very rare and would be picked up anyway in the first 30m of takeoff run?
It's one of a CP's jobs to think about these things...blindly following a POH is just plan silly when you realise these things were written 35 years ago.
My POH for EZU was written in 1969 and expressly forbids LOP operation.
At CASA's insistance a few years ago I ordered a new one and the ammendment service that fullfilled CASA's requirements.
Guess what?
The ONLY difference between the new POH and the original is the cover...Ratheon just said "what ammendment service?"
It's has never been ammended.
LOP operation is a no brainer in terms of being 'good' all the way around yet if I just accept as gospel everything in the POH I wouldn't be doing it. The boss of CASA airworthiness said to me years ago "all engines should be operated this way" after they had been to the US and witnessed GAMi's TSIO540 on the test stand after Deakin stuck it up ATSB over Whyalla. They went to the US at the invitation of George Braily after ringing him and whinging long and loud about Deakin and left the US with a completely different opinion.
I just want people to think and ask "why?"
Edit: Yup comparing me to Deakin is just dumb... we seem to be similar personality types based on our conversations in the past and emails and certainly share a love of old aeroplanes and piston engines. We share a bushflying early career...but he has 38000 hrs and is a truly clever fella..he's also 20 years older than me...he and I email each other from time to time...I am certainly flattered by the comparison but I don't think it is justified.
His variety of aviation experience is breathtaking.
Last edited by Chimbu chuckles; 21st Jan 2007 at 07:43.