Originally Posted by
Lead Balloon
How will you know the cylinder is running ROP if the EGT probe has failed?
Think about what Jabba said. All your EGT probes are working. You set a mixture that results in all the cylinders being LOP. You have a known MP, RPM, density altitude, IAS fuel flow and CHT for each cylinder.
You then snip the connections to all the EGT probes. What changes in the engine? Nothing.
You then do a touch and go, and climb at full rich (not the most efficient way to get there, but let's not complicate things) and max RPM, and then level off at the same density altitude as before and set the same RPM and fuel flow as before. The MP is the same as before, and you note the IAS is the same as before and the CHT for each cylinder is the same as before.
It's very (very) probable that all the cylinders are at the same or nearly the same point LOP as they were before. And anything that would change that outcome would mean you couldn't be sure you were ROP and "compliant".
So in that situation we would revert back to old school using the TIT probe and lean the engine to peak egt and then richen by 125 degrees at say 65% power. Does a jpi monitor qualify for original aircraft certification? Not sure, still I wouldn't remove the TIT probe hence its still there as backup.
I am just trying to get a picture of how we would advise casa we could comply in the case of a engine monitor or probe failure, and what goes in the Ops manual. Obviously we can't always cruise at the same level or power setting due maybe traffic or a crossing time requirement etc, understanding casa only has to accept your method not approve it.