AvWeb report into Whyalla - Labelled as 'Popycock'
For what its worth in these discussions on flow meters and EGT gauges. Few months ago I flew a Seneca 2 (normally aspirated) and found out that the EGT indicator (one gauge with a switch over knob) was inoperative. Previous pilots knew this but chose not to report the defect nor enter it into the MR.
I then leaned both mixtures to top of the fuel flow arc at the 68% section. Within two minutes we lost 20 knots IAS. Placing both mixtures to full rich caused a noticeable increase in engine noise and power and we soon picked up the lost IAS. Did this several times because I couldn't believe what I had seen.
Same results again.
Entered defect in MR only to have an engineer write off the defect as "Ground run -serviceable - suggest pilot leaned mixture too much". How does that grab you for an expert reply. Gives you lots of confidence in LAME's opinions?
If we had leaned the mixtures to 55% on the fuel flow gauges I have no doubt we would have lost both engines.
Emailed Lycoming re the problem. They replied that only the EGT should be used for leaning and that if the owner could not afford to repair the EGT gauge maybe there are other things to worry about on his aircraft. Lycoming then added that Piper made the decision to install fuel flow gauges - not the engine manufacturer.
Previously I accepted the accuracy of fuel flow gauges on GA types. Now I am very sceptical of them along with single probe EGT gauges. I remain more sceptical of owners who penny pinch on maintenance and leave the pilot to cop it sweet. Worse are the pilots who deliberately choose not to report defects in the MR leaving the next pilot to risk his neck.
I then leaned both mixtures to top of the fuel flow arc at the 68% section. Within two minutes we lost 20 knots IAS. Placing both mixtures to full rich caused a noticeable increase in engine noise and power and we soon picked up the lost IAS. Did this several times because I couldn't believe what I had seen.
Same results again.
Entered defect in MR only to have an engineer write off the defect as "Ground run -serviceable - suggest pilot leaned mixture too much". How does that grab you for an expert reply. Gives you lots of confidence in LAME's opinions?
If we had leaned the mixtures to 55% on the fuel flow gauges I have no doubt we would have lost both engines.
Emailed Lycoming re the problem. They replied that only the EGT should be used for leaning and that if the owner could not afford to repair the EGT gauge maybe there are other things to worry about on his aircraft. Lycoming then added that Piper made the decision to install fuel flow gauges - not the engine manufacturer.
Previously I accepted the accuracy of fuel flow gauges on GA types. Now I am very sceptical of them along with single probe EGT gauges. I remain more sceptical of owners who penny pinch on maintenance and leave the pilot to cop it sweet. Worse are the pilots who deliberately choose not to report defects in the MR leaving the next pilot to risk his neck.
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Hey Gaunty, if he was a real old roundy engineer, he would've said "oil".
But the principle is exactly the same
Centaurus, while the gauges might not have worked, and I agree that that is not acceptable, the engineer is in fact correct. To get the engine to lose power like that, you did lean them too far......... But of course, how are you supposed to know that............ with no accurate gauges. Doesn't the seneca 1 have lycomings?, 2 onwards Conti's?(turbocharged)
But the principle is exactly the same Centaurus, while the gauges might not have worked, and I agree that that is not acceptable, the engineer is in fact correct. To get the engine to lose power like that, you did lean them too far......... But of course, how are you supposed to know that............ with no accurate gauges. Doesn't the seneca 1 have lycomings?, 2 onwards Conti's?(turbocharged)
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MarkD,
I searched without quotation marks, and the last link on the first page is to the work of Petr S Berdonosov for 'lead (II) oxybromide' - the link goes to a list of his publications, the third of which repeats the compound name with the same chemical formula assumed by Deakin - Pb3 O2 Br2.
Cheers
I searched without quotation marks, and the last link on the first page is to the work of Petr S Berdonosov for 'lead (II) oxybromide' - the link goes to a list of his publications, the third of which repeats the compound name with the same chemical formula assumed by Deakin - Pb3 O2 Br2.
Cheers
I think Ovation has a point re the pilot's decisions.
Reading from the ATSB report, at 1847 the aircraft diverges right and groundspeed reduces. At this point the aircraft was overhead the middle of the Yorke Peninsula.
1856 was top of descent and the Mayday call was at 1901, overhead Spencer Gulf.
If one engine failed at about 1847 as suggested in the report why did the pilot not make any calls to ATS to advise them?
This single issue has as much bearing on the event as why the engines failed.
Had he made a Pan call, traffic may have been available to escort the aircraft but more importantly, closer airfields may have been suggested by ATS.
The alternative is that the divergence from track and groundspeed reduction were not connected with an engine failure (?) and that both engines failed almost simultaneously followed quickly by the Mayday call.
Reading from the ATSB report, at 1847 the aircraft diverges right and groundspeed reduces. At this point the aircraft was overhead the middle of the Yorke Peninsula.
1856 was top of descent and the Mayday call was at 1901, overhead Spencer Gulf.
If one engine failed at about 1847 as suggested in the report why did the pilot not make any calls to ATS to advise them?
This single issue has as much bearing on the event as why the engines failed.
Had he made a Pan call, traffic may have been available to escort the aircraft but more importantly, closer airfields may have been suggested by ATS.
The alternative is that the divergence from track and groundspeed reduction were not connected with an engine failure (?) and that both engines failed almost simultaneously followed quickly by the Mayday call.
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Centaurus,
If you lean the mixture controls to 68% fuel flow on the flow gauges then I would suggest that prior to leaning you should have consulted the AFM to determine the correct power setting for your pressure altitude and temperature. In other words the correct MP/RPM for 68% power.
Sounds to me like you had a higher power setting than 68% selected on the MP/RPM! If you had say, 75% set, simply leaning the mixtures to 68% will result in running the engine on the lean side of peak with just the symptoms you describe. Leaning to 55% would definitely result in total power loss with higher power set on throttles/RPM. Not good for the engines old boy!
If you lean the mixture controls to 68% fuel flow on the flow gauges then I would suggest that prior to leaning you should have consulted the AFM to determine the correct power setting for your pressure altitude and temperature. In other words the correct MP/RPM for 68% power.
Sounds to me like you had a higher power setting than 68% selected on the MP/RPM! If you had say, 75% set, simply leaning the mixtures to 68% will result in running the engine on the lean side of peak with just the symptoms you describe. Leaning to 55% would definitely result in total power loss with higher power set on throttles/RPM. Not good for the engines old boy!
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Interesting Reading
Go here for ATSB response to AvWeb article:
http://www.atsb.gov.au/atsb/media/whyalla_report.cfm
Hepi reading olgetta.
http://www.atsb.gov.au/atsb/media/whyalla_report.cfm
Hepi reading olgetta.
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Isn't it so wonderful to have these brilliant minds in our ATSB which get involved in such things as X-ray powder diffraction, analytical chemistry and raman spectroscopy yet there still hasn't been any mention of any connection between the left engine in MZK and the engines which were recalled by Lycoming for crankshaft replacement. The engine which was installed in MZK was a factory reman and somehow its serial number is 'in between' those which were recalled.
Would you smell a rat?
I wonder if the Bureau will re open its investigation and find out more from Lycoming re this crankshaft problem and whether there was any connection with these engines and MZK's.
Methinks they haven't got the guts, as this would open one hell of a litigation case against John Anderson and their mates at CASA for closing the airline down.
Get ready for yet another 'ticket tax'.
Would you smell a rat?
I wonder if the Bureau will re open its investigation and find out more from Lycoming re this crankshaft problem and whether there was any connection with these engines and MZK's.
Methinks they haven't got the guts, as this would open one hell of a litigation case against John Anderson and their mates at CASA for closing the airline down.
Get ready for yet another 'ticket tax'.
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Engine operation manual - Part of certification. Does not apply to the engine /airframe installation but will give you true data on how to "operate" the engine. Can be a rarely seen document in Australia. Interesting also is how much data in the POH is not "approved" i.e. manufacturers data could be read as advertising propaganda or similar.
BIK. Good points - and thanks. Can't quite trace where I read it, but I believe one purpose of the fuel flow gauge is to set the fuel flow needles at the density altitude for takeoff indicated in small figures at the edge of the gauge. I presume this means that for take off at say 8000 ft DA (typical PNG highlands on a hot day) you go to full throttle them lean until the fuel flow needle is opposite the DA figure. This then gives you correct take off power for the ambient conditions. Obviously if you failed to lean under these conditions the power loss is significant.
If that is the reason for the various altitude figures listed on the take off area of the fuel flow gauge, then that would suggest that the fuel flow gauge is certified to a certain accuracy. If it is found not to be accurate, then presumably the defect would be picked up by an alert LAME during the 100 hourly who would, if diligent, re-calibrate the fuel flow gauge. Normally one leans to an EGT figure for cruise, and to fuel flow when setting the mixtures for take off at high airport density altitudes?
If that is the reason for the various altitude figures listed on the take off area of the fuel flow gauge, then that would suggest that the fuel flow gauge is certified to a certain accuracy. If it is found not to be accurate, then presumably the defect would be picked up by an alert LAME during the 100 hourly who would, if diligent, re-calibrate the fuel flow gauge. Normally one leans to an EGT figure for cruise, and to fuel flow when setting the mixtures for take off at high airport density altitudes?
Blue Hauler. Before leaning we consulted the power setting tables from the POH performance section. There were several RPM versus MP combinations listed. There were three witnesses aboard to testify that the power settings were dead accurate.
That's what stumped me when we then carefully leaned to 68% and saw the IAS gradually bleed off. Never seen that before.
That's what stumped me when we then carefully leaned to 68% and saw the IAS gradually bleed off. Never seen that before.
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Centaurus
You can't argue with the book - check out the following extract from Avco Lycoming Operators Manual O-320 & IO-320 Series.
Fuel Mixture Leaning Procedure.
Improper fuel / air mixture during flight is responsible for many engine problems, particularly during take-off and climb power settings. The procedures described in this manual provide proper fuel / air mixture when leaning Avco Lycoming engines; they have proven to be both economical and practical by eliminating excessive fuel consumption and reducing damaged parts replacement. It is therefore recommended that operators, of all Avco Lycoming aircraft power-plants, utilize the instructions in this publication any time the fuel / air mixture is adjusted during flight.
Manual leaning may be monitored by exhaust gas temperature indication, fuel flow indication, and by observation of engine speed and / or airspeed. However, whatever instruments are used in monitoring the mixture, the following general rules should be observed by the operator of Avco Lycoming aircraft engines.
GENERAL RULES
For maximum service life, cylinder head temperatures should be maintained below 435 F, (224 C) during high performance cruise operation and below 400 F (205 C) for economy cruise powers.
Maintain mixture control in ‘Full Rich’ position for rated take-off, climb and maximum cruise powers (above approximately 75%). However, during take-off from high elevation airports or during climb, roughness or loss of power may result from over-richness. In such a case adjust mixture control only enough to obtain smooth operation – not for economy. Observe instruments for temperature rise. Rough operation due to over-rich fuel / air mixture is most likely to be encountered in carbureted engines at altitude above 5,000 feet.
Always return the mixture to full rich before increasing power settings.
Operate the engine at maximum power mixture for performance cruise powers and at best economy mixture for economy cruise power; unless otherwise specified in the airplane owner’s manual.
During led-down flight operations it may be necessary to manually lean uncompensated carbureted or fuel injected engines to obtain smooth operation.
Leaning to Exhaust Gas Temperature Gage.
a. Normally aspirated engines with fuel injectors or uncompensated carburetors.
(1) Maximum Power Cruise (approximately 75% power). Never lean beyond 150 F on rich side of peak EGT unless aircraft operator’s manual shows otherwise. Monitor cylinder head temperatures.
(2) Best Economy Cruise (approximately 75% power and below) - Operate at peak EGT, or if desired, drop 50 F on rich side of peak EGT.
Leaning to Flowmeter
Lean to applicable fuel-flow tables or lean to indicator marked for correct fuel-flow for each power setting…Power drops rapidly when the engine is leaned beyond peak exhaust gas temperature; also best power is attained on the rich side of peak exhaust gas temperature.
You can't argue with the book - check out the following extract from Avco Lycoming Operators Manual O-320 & IO-320 Series.
Fuel Mixture Leaning Procedure.
Improper fuel / air mixture during flight is responsible for many engine problems, particularly during take-off and climb power settings. The procedures described in this manual provide proper fuel / air mixture when leaning Avco Lycoming engines; they have proven to be both economical and practical by eliminating excessive fuel consumption and reducing damaged parts replacement. It is therefore recommended that operators, of all Avco Lycoming aircraft power-plants, utilize the instructions in this publication any time the fuel / air mixture is adjusted during flight.
Manual leaning may be monitored by exhaust gas temperature indication, fuel flow indication, and by observation of engine speed and / or airspeed. However, whatever instruments are used in monitoring the mixture, the following general rules should be observed by the operator of Avco Lycoming aircraft engines.
GENERAL RULES
For maximum service life, cylinder head temperatures should be maintained below 435 F, (224 C) during high performance cruise operation and below 400 F (205 C) for economy cruise powers.
Maintain mixture control in ‘Full Rich’ position for rated take-off, climb and maximum cruise powers (above approximately 75%). However, during take-off from high elevation airports or during climb, roughness or loss of power may result from over-richness. In such a case adjust mixture control only enough to obtain smooth operation – not for economy. Observe instruments for temperature rise. Rough operation due to over-rich fuel / air mixture is most likely to be encountered in carbureted engines at altitude above 5,000 feet.
Always return the mixture to full rich before increasing power settings.
Operate the engine at maximum power mixture for performance cruise powers and at best economy mixture for economy cruise power; unless otherwise specified in the airplane owner’s manual.
During led-down flight operations it may be necessary to manually lean uncompensated carbureted or fuel injected engines to obtain smooth operation.
Leaning to Exhaust Gas Temperature Gage.
a. Normally aspirated engines with fuel injectors or uncompensated carburetors.
(1) Maximum Power Cruise (approximately 75% power). Never lean beyond 150 F on rich side of peak EGT unless aircraft operator’s manual shows otherwise. Monitor cylinder head temperatures.
(2) Best Economy Cruise (approximately 75% power and below) - Operate at peak EGT, or if desired, drop 50 F on rich side of peak EGT.
Leaning to Flowmeter
Lean to applicable fuel-flow tables or lean to indicator marked for correct fuel-flow for each power setting…Power drops rapidly when the engine is leaned beyond peak exhaust gas temperature; also best power is attained on the rich side of peak exhaust gas temperature.
Last edited by Blue Hauler; 12th Jul 2002 at 14:05.
