Refer to this partial NOTAM:

Pella IA [PEA]: Aerodrome WDI OTS

Your initial response might be, "OMG! The WDI is OTS! How will I fly?" Breathe normally. Your flight into Pella Muni (PEA) will be fine provided you know that OTS means "out of service," and WDI means (_____). [Fill in the blank with the best answer.]


WAAS Detection Indicator


Wind Deviation Index


Wind Direction Indicator


Weird Designated Instructor

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