Date: 201906
Local time of day: 0601-1200
Location: TEB.Airport, NY
Light: Dawn
Aircraft: Challenger 350
Operator: Corporate
Operating under: Part 91
Mission: Ferry / Re-Positioning
Flight phase: Final Approach
Airspace: Class B N90
ATC / advisory: TRACON N90
Aircraft component: GPS & Other Satellite Navigation
Component problem: Malfunctioning
Reporter organization: Fractional
Reporter function: Captain; Pilot Flying
Human factors: Confusion; Situational Awareness; Human-Machine Interface; Distraction
Second reporter function: Captain; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Unstabilized Approach
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Overcame Equipment Problem; Flight Crew Executed Go Around / Missed Approach
Contributing factors: Aircraft; Equipment / Tooling
Primary problem: Aircraft

Narrative: While on the ILS approach; we did not get the FMS to sequence from magenta needle to green needle in a timely manner. We were unsure why it was taking so long. We thought for a moment that it had something to do with the known GPS issues that the avionics were having in our fleet. We were about 2.3 miles from the Final Approach Fix (FAF) with it yet to sequence. In a hurry; we changed flight modes manually to green needles; but in our haste; the approach became out of parameters quickly and a missed approach was initiated. In our hurried state; we failed to sequence the FMS to the missed approach and soon got off course. This was brought to our attention by Approach. We were given a heading and we returned for an uneventful approach and landing. In hindsight; I should of never allowed the aircraft to get so close to the FAF in this state. It set up some confusion and haste which in my opinion led to our deviation. I initiated the go around later than I should have and would do it much sooner in hindsight.


Second narrative: On ILS 19 to minimums the FMS NAV failed to sequence to approach and green ILS. We manually selected it and the auto pilot kicked off. While trying to manually fly the approach from the right seat it became slightly unstable as we tried to reengage the auto pilot. The Pilot Flying called for a miss and we initiated a go around. Tower said fly publish missed approach. We were unable to get the FMS to sequence the published missed approach in an extremely busy workload environment. While I was communicating to Approach; he issued heading and altitude instructions stating we were no where near the Missed Approach point; and don't climb. As I looked up; I noticed the Pilot Flying having difficulty maintaining altitude by 2 to 300 feet high. I requested the controls and became the Pilot Flying from the left seat. When we landed; ATC asked reason for the miss and we explained the failed sequencing and possible GPS glitch. ATC said everything was fine and we got you covered. Ask for vectors on a missed if your too busy and FMS sequencing not working.


Synopsis: A flight crew reported their FMS failed while conducting an approach; they became unstable and off course and initiated a missed approach.