AvWeb report into Whyalla - Labelled as 'Popycock'
Join Date: Apr 2002
Location: Qld. Aus.
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
My first encounter with PA31's I was taught to lean on th EGT.
The next time around I was taught to set a fuel flow and just monitor EGT's below max.
The latter is quicker but I feel happier doing the former.
What is the normal procedure out there?
The next time around I was taught to set a fuel flow and just monitor EGT's below max.
The latter is quicker but I feel happier doing the former.
What is the normal procedure out there?
Grandpa Aerotart
Not an expert but having read almost all the articles written by Deacon on Avweb and having flown many hours between turbo piston engines I am prepared to make the following observations.
1/. Deacon is a VERY knowledgeable and VERY VERY experienced bloke and his contacts within the engine business are more so. The list of experienced CAF (Confederate Air Force) IPs with whom he works/has flown with would make your head spin.
2/. Over 1000 hours between C404, C402 and Aerostar 700p and I never leaned on climb. None of my peers did either and we got good life from the engines. This includes C402As at Talair where they were overhauled 'in house' over and over.
3/. I would be willing to bet Deacon has more knowledge and direct experience of big turbo piston engine operation than any 20 ATSB flunkeys or any 10 posters on this site. Added to that is a keenly enquiring mind when it comes to this sort of thing...not something your average pilot posseses.
Chuck.
1/. Deacon is a VERY knowledgeable and VERY VERY experienced bloke and his contacts within the engine business are more so. The list of experienced CAF (Confederate Air Force) IPs with whom he works/has flown with would make your head spin.
2/. Over 1000 hours between C404, C402 and Aerostar 700p and I never leaned on climb. None of my peers did either and we got good life from the engines. This includes C402As at Talair where they were overhauled 'in house' over and over.
3/. I would be willing to bet Deacon has more knowledge and direct experience of big turbo piston engine operation than any 20 ATSB flunkeys or any 10 posters on this site. Added to that is a keenly enquiring mind when it comes to this sort of thing...not something your average pilot posseses.
Chuck.
Join Date: Sep 2000
Location: Adelaide, South Australia
Posts: 394
Likes: 0
Received 0 Likes
on
0 Posts
There has been far too much focus on the engines and very little on the way the pilot handled the emergency. What no-one has really alluded to (perhaps in deference to the late pilot and his family) is the unwillingness of the pilot to land the aircraft while he had the opportunity. The first engine failed well before he was over water, and there were a couple of airstrips along the path that would have been suitable for an emergency landing (Kadina for one). The terrain on a reciprocal path is flat farmland that would be the least worst alternative if an off-airfield landing at night were required. A Duchess carrying out night Navaid train experienced CFIT not far from Kadina about 10-12 months ago and both instructor and pupil survived with severe embarrassment.
I feel the pilot may have "chanced his arm" on getting a crippled airplane back to the home base, but the second engine failure intervened to cause the tragic outcome. It would have been interesting to see this hypothesis considered.
I feel the pilot may have "chanced his arm" on getting a crippled airplane back to the home base, but the second engine failure intervened to cause the tragic outcome. It would have been interesting to see this hypothesis considered.
Join Date: Nov 2001
Location: Bagot Community
Posts: 181
Likes: 0
Received 0 Likes
on
0 Posts
The normal way might NOT be the correct way (in the eyes of CASA).
In the POH it says to lean the mixtures by reference to the EGT and so I believe this the correct way to do it.
Use fuel flow only as a means to crosscheck the mixture set by EGT.
However with accurate instruments (EGT, Fuel Flow) and accurately set MP and RPM, the leaned mixture will always be at the same EGT and same fuel flow (eg. 1450 EGT, 72litres/hour) on a particular aeroplane. I suppose there would be nothing wrong in this case once you know the particular aeroplane well to lean the mixture using Fuel flow and then crossheck the EGT.
Just be careful as the peak EGT varies from aeroplane to aeroplane ( I have seen ranges from 1450 to 1625).
In the POH it says to lean the mixtures by reference to the EGT and so I believe this the correct way to do it.
Use fuel flow only as a means to crosscheck the mixture set by EGT.
However with accurate instruments (EGT, Fuel Flow) and accurately set MP and RPM, the leaned mixture will always be at the same EGT and same fuel flow (eg. 1450 EGT, 72litres/hour) on a particular aeroplane. I suppose there would be nothing wrong in this case once you know the particular aeroplane well to lean the mixture using Fuel flow and then crossheck the EGT.
Just be careful as the peak EGT varies from aeroplane to aeroplane ( I have seen ranges from 1450 to 1625).
Join Date: May 1999
Location: Australia
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Not a good idea using fuel flows as different aircraft have different readings due to instrument inacuracies.
EGT the only way but fuel flow can be used as a back up if the setting for each aircraft is recorded or placarded.
EGT the only way but fuel flow can be used as a back up if the setting for each aircraft is recorded or placarded.
Join Date: May 2002
Location: Permanently lost
Posts: 1,785
Likes: 0
Received 0 Likes
on
0 Posts
Ovation
I'm not sure that you are correct when you state that the first engine failed before the aircraft was over water and I don't have either Mr Deacon's article or the ATSB report in front of me at the moment.
I understand that one engine may have had a developing problem that caused the engine to fail when the pilot carried out the Phase 1 actions after the other engine had a catastrophic failure. The developing problem may not have been detectable during the flight, and don't forget that Mr Deacon is speculating when he suggests that the pilot had a vibration and operated the engine(s) at a reduced power setting.
On a more general note, it should be remembered that a lot of what Mr Deacon recommends, regarding the operation of large capacity piston engines at lean of peak, is based on having an aircraft equipped with very accurate EGT gauges and, in the case of his own aircraft, a set of fuel injectors that are calibrated for the specific aircraft. He is not recommending that we all go out and aggressively lean based on some of the standard aircraft gauges.
I certainly agree with some of the commentators that there is a need to resolve the issues raised by this crash. There are still a lot of large capacity piston engined aircraft in Australia, ageing rapidly, and a better understanding of how these aircraft should be managed might go a long way to assuring those of us who fly them that they are not going to go quiet on us.
I'm not sure that you are correct when you state that the first engine failed before the aircraft was over water and I don't have either Mr Deacon's article or the ATSB report in front of me at the moment.
I understand that one engine may have had a developing problem that caused the engine to fail when the pilot carried out the Phase 1 actions after the other engine had a catastrophic failure. The developing problem may not have been detectable during the flight, and don't forget that Mr Deacon is speculating when he suggests that the pilot had a vibration and operated the engine(s) at a reduced power setting.
On a more general note, it should be remembered that a lot of what Mr Deacon recommends, regarding the operation of large capacity piston engines at lean of peak, is based on having an aircraft equipped with very accurate EGT gauges and, in the case of his own aircraft, a set of fuel injectors that are calibrated for the specific aircraft. He is not recommending that we all go out and aggressively lean based on some of the standard aircraft gauges.
I certainly agree with some of the commentators that there is a need to resolve the issues raised by this crash. There are still a lot of large capacity piston engined aircraft in Australia, ageing rapidly, and a better understanding of how these aircraft should be managed might go a long way to assuring those of us who fly them that they are not going to go quiet on us.
Don Quixote Impersonator
Join Date: Jul 1999
Location: Australia
Age: 77
Posts: 3,403
Likes: 0
Received 0 Likes
on
0 Posts
Dear oh dear.
1. Anyone who believes anything they see on on the fuel gauges of a 20 year old aircraft with bladder tanks as being anything other than a rough estimation and especially the Heath Robinson fuel system of the PA31 is, one day, going to get a surprise.
2. EGT probes whether they indicate some "mythical" temperature are calibrated or not, old or new can only indicate THE AVERAGE of the exhaust temps from all of the cylinders.
I gaurantee you that the actuals at each exhaust port will be different and can be some miles apart.
Unless of course you have an exhaust temp analyser for each, which again is only interesting as you usually have to cycle through each to find out whats going on and who has the time for that on T/O.
So the only indication that actually means anything is "the peak" and which side of it you are, given that the individual cylinders do not have a seriously deviant one amongst them.
Where is the hot one and there will one or more that are causing you to run richer than you might?
And whilst I am on that subject I have seen more than a few engines with no less than 3 different size injector nozzles on them. When was the last time your fuel distribution system was on the test bench?
Given the instrument inaccuracies, age and calibration status of the probes and having regard to the fact that it is an average, peak is the only measurement for any particular condition that is absolute.
Fuel flow gauges by the nature of their design can be reasonably accurate but in any event event aren't nor should the primary means setting FF, it comes back to the EGT, where the peak is and how rich of peak you mean to operate. Lean of peak may be fine for an engine system in and kept in absolutely tip top condition and constantly monitored in flight for changes in engine and ambient temperatures.
The fuel flow will then be whatever it becomes.
Which brings us to the nub of the problem.
If the operator has to operate the engines to six decimal places of fuel flow to make a profit or just break even, then he shouldn't be there.
The 5, 6 or even 10 litres ph = maybe $10,000 he thinks he may save, over the life of the engine, say $3,000 per year is, if I recall correctly, less than one cylinder overhaul and if you don't do it that way there will be many more than one.
Everybody chases the EGT end, how many chase the fuel distribution system? The EGT end only tells you what's already happened.?
I guess what I'm trying to say is it's never one thing on it's own and I am not at all comfortable with the recieved wisdon from the ATSB on this Whyalla thing, it's much too neat.
1. Anyone who believes anything they see on on the fuel gauges of a 20 year old aircraft with bladder tanks as being anything other than a rough estimation and especially the Heath Robinson fuel system of the PA31 is, one day, going to get a surprise.
2. EGT probes whether they indicate some "mythical" temperature are calibrated or not, old or new can only indicate THE AVERAGE of the exhaust temps from all of the cylinders.
I gaurantee you that the actuals at each exhaust port will be different and can be some miles apart.
Unless of course you have an exhaust temp analyser for each, which again is only interesting as you usually have to cycle through each to find out whats going on and who has the time for that on T/O.
So the only indication that actually means anything is "the peak" and which side of it you are, given that the individual cylinders do not have a seriously deviant one amongst them.
Where is the hot one and there will one or more that are causing you to run richer than you might?
And whilst I am on that subject I have seen more than a few engines with no less than 3 different size injector nozzles on them. When was the last time your fuel distribution system was on the test bench?
Given the instrument inaccuracies, age and calibration status of the probes and having regard to the fact that it is an average, peak is the only measurement for any particular condition that is absolute.
Fuel flow gauges by the nature of their design can be reasonably accurate but in any event event aren't nor should the primary means setting FF, it comes back to the EGT, where the peak is and how rich of peak you mean to operate. Lean of peak may be fine for an engine system in and kept in absolutely tip top condition and constantly monitored in flight for changes in engine and ambient temperatures.
The fuel flow will then be whatever it becomes.
Which brings us to the nub of the problem.
If the operator has to operate the engines to six decimal places of fuel flow to make a profit or just break even, then he shouldn't be there.
The 5, 6 or even 10 litres ph = maybe $10,000 he thinks he may save, over the life of the engine, say $3,000 per year is, if I recall correctly, less than one cylinder overhaul and if you don't do it that way there will be many more than one.
Everybody chases the EGT end, how many chase the fuel distribution system? The EGT end only tells you what's already happened.?
I guess what I'm trying to say is it's never one thing on it's own and I am not at all comfortable with the recieved wisdon from the ATSB on this Whyalla thing, it's much too neat.
Join Date: Mar 2000
Location: North son, I say go North..........
Posts: 599
Likes: 0
Received 0 Likes
on
0 Posts
Gaunty,
Out of curiosity what is your opinion of the accuracy of the Shadin fuel flow meter?
One thing I have noticed is that the PA31 book states certain EGT limits. This is all well and good if your EGT's are calibrated - if there not then???
I must say I use both instruments to check each other, you have your power setting your EGT and your fuel flow and you know what indications you should be getting if x is set... not that hard really. With time you get to learn each aircraft as they are all different, well the 4 different ones I've flown have been.
HA
Out of curiosity what is your opinion of the accuracy of the Shadin fuel flow meter?
One thing I have noticed is that the PA31 book states certain EGT limits. This is all well and good if your EGT's are calibrated - if there not then???
I must say I use both instruments to check each other, you have your power setting your EGT and your fuel flow and you know what indications you should be getting if x is set... not that hard really. With time you get to learn each aircraft as they are all different, well the 4 different ones I've flown have been.
HA
Join Date: Mar 2000
Location: North son, I say go North..........
Posts: 599
Likes: 0
Received 0 Likes
on
0 Posts
DD,
Agreed totally. INST 9's though are not due all that often, I like to get the calibrated every 100 hours. If you jump into a new machine you cannot be sure wether or not the EGT's are correctly calibrated.
Infact I can say that the last 2 I have jumped in it has been this way. So does that say the EGT's go out of calibration easily or does it mean that they haven't been calibrated correctly???
HA
Agreed totally. INST 9's though are not due all that often, I like to get the calibrated every 100 hours. If you jump into a new machine you cannot be sure wether or not the EGT's are correctly calibrated.
Infact I can say that the last 2 I have jumped in it has been this way. So does that say the EGT's go out of calibration easily or does it mean that they haven't been calibrated correctly???
HA
Don Quixote Impersonator
Join Date: Jul 1999
Location: Australia
Age: 77
Posts: 3,403
Likes: 0
Received 0 Likes
on
0 Posts
HA
From memory the Shadin was a pretty accurate piece of gear.
But regardless, the old fuel in, gases out the exhausts (hopefully) fuel in check, is still the only way to verify for each flight.
As you say check, x check, double check and use every means at your disposal to monitor the health of those engines.
I have always said that pilots really should belong to the Engine drivers, Fettlers and Firemans Union .. EFFU....
Coz thats what they really get paid for.
From memory the Shadin was a pretty accurate piece of gear.
But regardless, the old fuel in, gases out the exhausts (hopefully) fuel in check, is still the only way to verify for each flight.
As you say check, x check, double check and use every means at your disposal to monitor the health of those engines.
I have always said that pilots really should belong to the Engine drivers, Fettlers and Firemans Union .. EFFU....
Coz thats what they really get paid for.
Join Date: Sep 1999
Location: Brisbane
Posts: 41
Likes: 0
Received 0 Likes
on
0 Posts
It's interesting that Deakin says he couldn't find any info on lead oxybromide, and implies that it is an imaginative renaming of another (assumed) molecule; I've just done a Google search and there's a reference on the first page.
Cheers
Cheers
Everyone seems to be scared stiff of what they perceive is "shock cooling". There are all sorts of fancy power settings that various pilots are taught (perpetuation of aviation myths) for the descent including the one inch MP per 1000 ft of descent and variations thereof. People are even apprehensive of reducing power in the circuit beyond a certain figure.
It is sometimes difficult to sort out fact from myth when it comes to engine handling on aircraft such as the Chieftain/Navajo genre.
There is some interesting reading in www.avweb.com by some pretty experienced engineers. Navigate your way to Pelican's Perch which are articles by a well respected pilot called John Deakin. He has recently written a damning article on the ATSB accident report on the Whyalla accident.
These are a few selected extracts from Avweb articles on shock cooling.
From Kas Thomas - aeronautical engineer who wrote in March 1966 issue of TBO Advisor: "Shock cooling - Myth or Reality". His article examined the physics and metallurgy of shock cooling and concluded that, contrary to the conventional wisdom, it is not a major contributor to cylinder head cracking"
He added that there is no scientic proof that cooling plays a significant role in cylinder damage in aviation. He says that to his knowledge that Bob Hoover has not experienced any problem with cylinder-head cracking on his Shrike, despite his rather odd predisposition to feather bothengines while in a redline dive.
Kas Thomas continues: Every pilot flies through rain occasionally and rain should make a very effective coolant) more so than mere air, certainly) - yet no one ascribes cylinder damage to flying through too much rain. If shock cooling were a definate hazard your engine should fall apart when you bring the mixture into idle ciut-off at the end of a flight. CHT's fall off at a rate of 100 degrees F per minute or more in the first few seconds of shutdown - triple the rate that starts the typical "shock cooling" annunciator blinking. The why are we worried about pulling the throttle back?
There are many opinions on engine handling for Chieftains and Navajos. Everyone from LAME's to pilots have favourite set- in- stone theories which they swear will save engine wear and tear. Most of them are just that - theories and not established measured facts.
I suggest that you research the engine manufacturer's websites and trawl through the various first class articles on engine handling in Avweb and the Lycoming Flyer magazine.
It is sometimes difficult to sort out fact from myth when it comes to engine handling on aircraft such as the Chieftain/Navajo genre.
There is some interesting reading in www.avweb.com by some pretty experienced engineers. Navigate your way to Pelican's Perch which are articles by a well respected pilot called John Deakin. He has recently written a damning article on the ATSB accident report on the Whyalla accident.
These are a few selected extracts from Avweb articles on shock cooling.
From Kas Thomas - aeronautical engineer who wrote in March 1966 issue of TBO Advisor: "Shock cooling - Myth or Reality". His article examined the physics and metallurgy of shock cooling and concluded that, contrary to the conventional wisdom, it is not a major contributor to cylinder head cracking"
He added that there is no scientic proof that cooling plays a significant role in cylinder damage in aviation. He says that to his knowledge that Bob Hoover has not experienced any problem with cylinder-head cracking on his Shrike, despite his rather odd predisposition to feather bothengines while in a redline dive.
Kas Thomas continues: Every pilot flies through rain occasionally and rain should make a very effective coolant) more so than mere air, certainly) - yet no one ascribes cylinder damage to flying through too much rain. If shock cooling were a definate hazard your engine should fall apart when you bring the mixture into idle ciut-off at the end of a flight. CHT's fall off at a rate of 100 degrees F per minute or more in the first few seconds of shutdown - triple the rate that starts the typical "shock cooling" annunciator blinking. The why are we worried about pulling the throttle back?
There are many opinions on engine handling for Chieftains and Navajos. Everyone from LAME's to pilots have favourite set- in- stone theories which they swear will save engine wear and tear. Most of them are just that - theories and not established measured facts.
I suggest that you research the engine manufacturer's websites and trawl through the various first class articles on engine handling in Avweb and the Lycoming Flyer magazine.
Join Date: Sep 2001
Location: Melbourne, Australia
Posts: 343
Likes: 0
Received 0 Likes
on
0 Posts
Not that I am necessarily predisposed towards the theory of shock cooling, I think that to compare the temp drop immediately after shutdown does not compare to the temp drop when the cylinder is at operating temp. Maybe 400 deg or more. The cylinder is much more highly stressed at this temp than it ever will be at 200 deg and losing 100 deg in 30 seconds. Still, we use a simple system of cooling, works well for planning and the flight and is theoretically gentle in cooling. We get good cylinder life, so who really knows.......
Rebel PPRuNer
Join Date: Aug 2000
Location: Toronto, Canada (formerly EICK)
Age: 51
Posts: 2,834
Likes: 0
Received 0 Likes
on
0 Posts
google
32bits
did you search for
lead oxybromide
or
"lead oxybromide" - i.e. the lead and oxybromide are a phrase.
Google does return results for the former, but where it refers to lead in one part of the document and an different form of oxybromide - like calcium oxybromide.
If you specify the phrase, only the ATSB and Aus papers quoting same return hits. Same with Copernic.
did you search for
lead oxybromide
or
"lead oxybromide" - i.e. the lead and oxybromide are a phrase.
Google does return results for the former, but where it refers to lead in one part of the document and an different form of oxybromide - like calcium oxybromide.
If you specify the phrase, only the ATSB and Aus papers quoting same return hits. Same with Copernic.
The problem would be eliminated completely with a FADEC contolled engin that had liquid cooled cylinders. Don't believe they exist....have a look at this site;
www.liquidcooledairpower.com
No fuel wasted cooling the cylinders for takeoff
Cylinder head temps stay at 195 deg F + or - 3 deg F no matter where the throttle or IAS is.
With Gammi injectors, precise fuel metering and much improved cost of operation.
oh and 3,000 hr TBO
Have a look at new V8 from the US
www.americanengine.com
www.liquidcooledairpower.com
No fuel wasted cooling the cylinders for takeoff
Cylinder head temps stay at 195 deg F + or - 3 deg F no matter where the throttle or IAS is.
With Gammi injectors, precise fuel metering and much improved cost of operation.
oh and 3,000 hr TBO
Have a look at new V8 from the US
www.americanengine.com
Last edited by Ozgrade3; 6th Jul 2002 at 04:16.
Join Date: Sep 2001
Location: Melbourne, Australia
Posts: 343
Likes: 0
Received 0 Likes
on
0 Posts
Great idea, but for 30 odd grand US I get a set of cylinders and fittings, untried on a L/TIO 540. And according to the website untested as yet even on a o-540. Hmmm, oh. the lack of an STC or PMA MIGHT be a problem here too. Like I said, great idea, but for 30 grand US, I can buy a set of cylinders for each engine between overhauls and stilll have money to spend on running them slightly rich anyway............. Oh for the day of real technology.........BTW the TBO in OZ will still be 1800/2000hrs for a L/TIO 540, as the bottom end will be the limiting factor..........
Don Quixote Impersonator
Join Date: Jul 1999
Location: Australia
Age: 77
Posts: 3,403
Likes: 0
Received 0 Likes
on
0 Posts
Seems to me from all of the above that the wise old engineer brought up on big pistons who said;
"The cheapest thing that you can put in an engine is fuel" sorta knew what he was on about.
"The cheapest thing that you can put in an engine is fuel" sorta knew what he was on about.
Join Date: May 2001
Location: Aust.
Posts: 84
Likes: 0
Received 0 Likes
on
0 Posts
A large part of the problem is the fact we operate engines and ancillary systems designed in the 1940s and the FARs have not allowed real developement to take place, Porches attempt to adapt their flat 6 with Mooney a prime example of regulatory impediments to what should have been a great marriage of airframe/engine.
Creampuff will be waiting a long time for engineers to make definative statements as nobody has done any long term research on aircraft in active sevice with multi life cylinders etc,
all that information comes from the operators themselves, each with their own ideas as written here and it's all anecdotal.
In the meantime we'll continue to baby our flats,rounds and PT6s
with lots of fuel and reduced power takeoffs (in complete contradiction to latest Flightsafety propaganda I notice) or as otherwise directed by the employer/owner at the time.
PS: Bring on the Orendas' .
Creampuff will be waiting a long time for engineers to make definative statements as nobody has done any long term research on aircraft in active sevice with multi life cylinders etc,
all that information comes from the operators themselves, each with their own ideas as written here and it's all anecdotal.
In the meantime we'll continue to baby our flats,rounds and PT6s
with lots of fuel and reduced power takeoffs (in complete contradiction to latest Flightsafety propaganda I notice) or as otherwise directed by the employer/owner at the time.
PS: Bring on the Orendas' .