Jay

Dan Wilson, I am not referring to the vertical reference switches. I am referring to the ADI select switch (ADI, SKE Range, SKE positions) I posed this question in the first place because I can't find a logical answer on my own. Let me clear up some confusion. Here is the inverter check verbatim from the T.O. itself *15. Inverter Checked a. Place ADI SEL switches to NORM. b. Place the voltage and frequency selector switch to the INV position. c. Check the AC Inst and Engine Fuel Control inverter by placing the phase selector switch to C phase and reading the voltage and frequency. d. Turn AC Inst and Engine Fuel Control switch to the ESS AC/ESS AV position. The AC INV caution light should not illuminate. The frequency and voltage cannot be read from this position. Check TIT indicators for power indications. e. On AF95-1001 and up, place the AC Inst and Engine Fuel Control Switch to the DC position. I really hope this can clarify confusion so that there are no assumptions as to what I am asking.

NATOPS1, Thank you for the reply. I think I should have been more specific about the model. This is for an H3 that doesn't have a Co-pilot's inverter and is equipped with EFI's (Electronic Flight Instruments, glass ADI/HSI). Again, this is for the AC Instrument and Engine Fuel Control Inverter check. Your response has been the instinctual response I've received from other engineers. But, after a bit of clarification, I can't seem to get a clear cut answer.

Okay gentleman. I've got two questions. On the H-3 -1 preflight, the expanded portion of the AC inst. & eng. fuel control inverter check says to put the ADI sel switch in norm. Why? Second question. I was reading through the -6, and for an overspeed of the ramp and door (150+KIAS), an inspection of the elevator and rudder surfaces and trim tabs are required. Why?

I noticed that same thing when I was going through H3 differences training. Then an instructor pointed out our FCB, which states that the fuel contam check will be done at high power settings for both models (E/H3) we fly.