New 912 MML Airbox Temp. Check Procedure

Hi Roger,

I think you must have "put the frighteners " into RW & RO😈

I don't understand why they want to do this now after many decades without doing it and the tens of thousands of planes worldwide with millions of engine hours. 

Surely the factory must have a reason. I'd like to be educated on it. What about the many thousands of planes that don't have an airbox to do this test. Why is it important?

Hi Roger,

My guess is that the reason for the check is something to do with the issues discussed in SB-912-079. (Which applies only to 912S/ULS engines and thus so far had not been applicable to my aircraft with a 912A)

Aircraft without an airbox are actually addressed, but you need to look very hard to find it: In the MML procedure, there is a reference under the heading "Values" on page 19 referring you to the Installation Manual. If you look in Chapter 72-60-00 of the 912 IM (Ed.3, Rev.1) at the bottom of page 8 you'll see a note that says: "Air intake Heat up = Air temperature measured in the airbox - Ambient temperature. Without airbox measure the air temperature on the outside of the air filter."

I'm more concerned with why they specifically require using the air temp sensor from the iS engines and then don't provide enough information to allow you to actually use it. If we're going to have to use that specific sensor, it would be nice to know such basic things as how it attaches to the airbox, how the wires attach to it, and some kind of method or equipment to get a temperature reading from it. At the moment, all I know about the sensor is what it looks like in the 912iS IPC and that in that document it is listed as a "TEMPERATURE SENSOR."

The fact that, from what little I can see, it appears to be impossible to install that sensor into my airbox in the prescribed location is a secondary problem which only really affects me (and the owners of the other 150-odd Skyfox aircraft produced with the same airbox design)

It seems that the airbox temp will be greatly affected by the outside air temp. If I'm in Arizona on a 105F day then the air temp running or not will be different than a test at 32F in the winter.

I'd still like to know the why is it needed now and it never has been.

Waiting, with great anticipation, to hear from RO & RW, on this topic 😈