Date: 201709
Local time of day: 1801-2400
Location: BOI.TRACON, ID
Flight conditions: VMC
Light: Daylight
Aircraft: Small Aircraft; High Wing; 1 Eng; Fixed Gear
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Flight phase: Initial Climb
Airspace: Class C BOI
ATC / advisory: TRACON BOI
Reporter organization: Government
Reporter function: Approach
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Confusion; Human-Machine Interface; Situational Awareness
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance
Contributing factors: ATC Equipment / Nav Facility / Buildings; Airspace Structure; Procedure
Primary problem: Airspace Structure

Narrative: I was working Arrival Sector and had several IFR arrivals on the north downwind for Runway 10L and Runway 10R. Aircraft X; departed Runway 10L and I believed the aircraft to be VFR. The aircraft continued on the upwind for several miles and I queried the pilot about their on course heading. The pilot replied 306 degrees. Believing the aircraft was VFR; I instructed the aircraft to turn left on course. The aircraft entered a 6;500 MVA at 4;700 and climbing. It was not until the aircraft was out of approximately 6;000 in a 5;000 foot MVA did I realize that the aircraft was IFR. The Low Altitude alert did not activate. The aircraft was cleared on course to EMMET intersection and the rest of their IFR flight plan. I did not issue a low altitude alert because I believed the aircraft was VFR.None of the following are excuses; but could have contributed to this incident and changing some of these may prevent this from happening again.1) The TRACON was utilizing only one departure strip printer for both radar sectors. The strip printer for the South Radar position has been out for at least two weeks and all departure strips print on one printer.2) A co-worker made the decision to physically move the printer away from its normal position and place it on the counter between the two radar positions. A small change in the physical layout; but a distraction.3) I never received the departure strip. It was not in the tray and I had to request a flight plan readout on the aircraft. The controller could have taken the strip; thinking the departure was for him; looked at it and since this aircraft is a trainer and normally is VFR; tossed it in the trash.Having a dedicated departure strip printer for each sector is important for situational awareness. My normal scan includes the strip printer to ensure I have the most current strips available. Reaching across the keyboard to retrieve a departure strip took me away from normal routine.The strip printer in tower needs to be fixed immediately.My expectation bias was the main contributor to this incident. I have worked [these] aircraft a thousand times and about 95% of the time; [these] aircraft are VFR. My normal routine is to look at the departure strip and compare it to the data tag. I have no doubt I would have seen the aircraft was IFR if I had a strip. I have consistently used flight strips my entire career and it is how I work.




Synopsis: A TRACON Controller reported they received an IFR departure which they thought was VFR which flew below the Minimum Vectoring Altitude.