Super King Air 200
Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 99; Flight Crew Total 613; Flight Crew Type 55
Confusion; Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Other / Unknown
Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification
Chart Or Publication; Human Factors
During mission planning for a flight; my Captain and I saw the NOTAM in Foreflight for 'NAVIGATION ILS RUNWAY 31 LOC/DISTANCE MEASURING EQUIPMENT OUT OF SERVICE'. He and I both understood the NOTAM to mean only the DME was not working for the approach. We requested direct FILTA to set up for a straight-in approach to runway 31. Shortly before reaching FILTA we were cleared by the ZMP controller for the approach. When the GPS showed we had reached FILTA; the CDI had not moved off the 'wall'. We immediately advised the ZMP controller the NAVAID was not working and requested vectors for the RNAV 31 approach. He gave us vectors and read us the NOTAM. My Captain and I realized at that time; the NOTAM was for the entire NAVAID being out of service. After landing we checked the DINS NOTAM website; and the verbiage was not much clearer: 'NAV ILS RWY 31 LOC/DME U/S.'The lesson learned for my Captain and I was not to assume anything when reading NOTAMS. A possible solution to future confusion would be to delineate that each component is out of service. Example: 'NAV ILS RWY 31 G/S U/S & LOC/DME U/S.'
BE200 First Officer reported misinterpreting a NOTAM and found more equipment out of service than expected.