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O540 - Piper Dakota
Carburetored
D3000 Mag, 350hr since IRAN
During a routine run up today, with a leaned out mag check the engine would lose all power when selecting the LEFT mag with the all EGTs and CHTs and RPM dropping quickly, although I didn't let it shutdown entirely. The behavior is repeatable.
On selecting the RIGHT mag, there was no mag RPM drop, which would make sense if that is the only mag that is running, but with a normalized engine analysis display there is a large relative jump in the Cyl #2 EGT. On reviewing the tracing, it is obvious that EGT #2 is not only moving paradoxically, but is also running quite a bit cooler than typical. The immediately previous capture is a good comparator.
I am puzzled as to why there should be a difference between BOTH & RIGHT positions, if the only issue were a failed LEFT mag.
Perhaps I don't understand this correctly, but if the LEFT mag alone sparks the engine start with the D3000's common Magneto spring, how can it not be producing a spark after it starts up. Does the D3000 use both coils to start up the engine? Or, perhaps the engine start created the mechanical fault.
I have a Horizon tach, and there were no error lights when the mag switch was on BOTH.
Is this an issue with the switch or Mag, and do I have a co-incidental bad plug on Cyl #2?
Will be calling my shop tomorrow, but throw it out here for discussion.
* Orest
Flight with the problem ...
https://www.savvyanalysis.com/flight/3195896/f4141dcf-5f79-4489-8e74-cc47f7c3f0a1
Previous flight, with normal Mag check ...
https://www.savvyanalysis.com/flight/3195895/1085704a-2b08-40fc-a6e9-2a1e2d9cb6e3
Carburetored
D3000 Mag, 350hr since IRAN
During a routine run up today, with a leaned out mag check the engine would lose all power when selecting the LEFT mag with the all EGTs and CHTs and RPM dropping quickly, although I didn't let it shutdown entirely. The behavior is repeatable.
On selecting the RIGHT mag, there was no mag RPM drop, which would make sense if that is the only mag that is running, but with a normalized engine analysis display there is a large relative jump in the Cyl #2 EGT. On reviewing the tracing, it is obvious that EGT #2 is not only moving paradoxically, but is also running quite a bit cooler than typical. The immediately previous capture is a good comparator.
I am puzzled as to why there should be a difference between BOTH & RIGHT positions, if the only issue were a failed LEFT mag.
Perhaps I don't understand this correctly, but if the LEFT mag alone sparks the engine start with the D3000's common Magneto spring, how can it not be producing a spark after it starts up. Does the D3000 use both coils to start up the engine? Or, perhaps the engine start created the mechanical fault.
I have a Horizon tach, and there were no error lights when the mag switch was on BOTH.
Is this an issue with the switch or Mag, and do I have a co-incidental bad plug on Cyl #2?
Will be calling my shop tomorrow, but throw it out here for discussion.
* Orest
Flight with the problem ...
https://www.savvyanalysis.com/flight/3195896/f4141dcf-5f79-4489-8e74-cc47f7c3f0a1
Previous flight, with normal Mag check ...
https://www.savvyanalysis.com/flight/3195895/1085704a-2b08-40fc-a6e9-2a1e2d9cb6e3
Last edited:
