Originally Posted by
lomapaseo
I would have gone a step farther. The bioscide problem is generic or not? but if it is generic to the fuel for most jets, then any engine with fancy hydro metering would be susceptible.. The idea behind the AD is not to point at an inadequate standard of engine or aircraft standard, but is necessary as a stop gap control on the environment external to the engine/aircraft design
Loma, having worked many different engines from all three major manufacturers, there is little consistency in how the various engine controls react to different types of contamination (I know the biocide isn't technically a contaminate since it's there intentionally, but you get the idea).
For example, high sulfur content created deposits in the PW2000 fuel control that caused operational problems, but didn't seem to bother Rolls engines that were operated in the exact same environment. We had a number of "thrust instability" events on CFM56-7 that were traced to the buildup of residue on high time fuel controls - yet the CF6-80C2 fuel control that the CFM control was derived from never had that problem
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I'm sure there are some pretty smart people looking at this issue with this biocide, and why it seems to be an issue with GE controls while apparently not bothering those from the other guys.
BTW, a little unfair to say this is a MAX problem, given the LEAP engine is also on the A320NEO...