Date: 201908
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Night
Aircraft: Medium Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach; Initial Approach; Landing
Airspace: Class C ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Autopilot
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human factors: Confusion; Situational Awareness; Time Pressure; Workload; Distraction
Anomaly: ATC Issue All Types; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach; Inflight Event / Encounter CFTT / CFIT
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem; Flight Crew Became Reoriented; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Regained Aircraft Control; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Procedure; Aircraft
Primary problem: Ambiguous

Narrative: Two separate events occurred on this flight that are of concern to me. My recollection of positions; altitudes; and airspeeds are approximations and are not to be taken as fact without review of the associated data. 1) Our arrival into the ZZZ terminal area was not idea to begin with. Center kept us unusually high and we agreed that this could develop into a problem. We were well in excess of 10;000 ft. AGL at 30nm away from the airfield; and upon seeing the rotating beacon and airport lighting at approximately 15 nm away; I became concerned that we wouldn't arrive on final approach to Runway XX at an appropriate altitude to conduct a stabilized approach. I voiced this to the Captain and after brief discussion we elected to continue with the goal of seeing how it ended up looking on final. Approach Control noticed the problem and asked if we could make it; I responded that we were going to continue. We were cleared to ZZZZZ intersection (the final approach fix on the ILS Runway XX) and nearing that waypoint; we conceded to the fact that we were far too high for a stable approach to result. I estimate our altitude at this point to be well in excess of 3;000 ft. MSL. We joined the localizer fully configured with Approach mode selected on the FCP and LOC/ ALTS on the FMA (Flight Mode Annunciator) (with GS armed); but quickly elected to discontinue the approach due to our height. I communicated this with the Tower Controller and he instructed us to simply 'make left traffic.' Although we didn't discuss it; I am confident that we both silently agreed that this wouldn't be considered a go around situation due to our altitude; and proceeded as if we were just making our own vectors for a visual in a manner resembling a traffic pattern thus neglecting pushing the TOGA (Takeoff/ Go-Around) buttons or performing the go around checklist. However; we did begin to reconfigure the aircraft by retracting flaps and gear. On the midfield upwind leg; I estimate our altitude to be approximately 2;000 ft. MSL when the aircraft suddenly pitched up and airspeed began decaying; this happened quickly twice and I called out 'Check speed.' Autopilot was engaged and this un-commanded pitch startled the both of us as we thought we were in ALTS (as aircraft control was suddenly our primary concern; we didn't notice any changes to the FMA). The Captain disconnected the autopilot and corrected the attitude before a stall was indicated and we continued on our upwind climbing back up to an altitude more like 3;000 ft. MSL. Once things settled down; I realized that GS had become active and the aircraft was probably pitching to seek a high glide slope reflection. This pitching event and subsequent decay in airspeed made a somewhat stressful situation even worse; and likely distracted us from complete attention on task management. 2) On a midfield downwind; we began to reconfigure for landing; and the Captain began a gradual descent towards 2;000 ft. MSL; the FAF (Final Approach Fix) altitude. In this this descent; at an altitude I recall to be approximately 2;200 ft. MSL; a GPWS (Ground Proximity Warning System) 'obstacle' aural alert sounded; followed quickly by a 'pull up' command. At this point; the Captain leveled off and began pitching up for a climb and; with my free hand; I advanced the thrust levers. Moments later we were clear from whatever obstacle was detected and continued on our base and final leg for a normal landing. Our reaction as a crew to the GPWS command could definitely have been more swift and assertive; and this may have been because we were still in a state of disbelief caused by the un-commanded pitching on the upwind leg not long ago. Later; after thorough review of the approach plate; and the accompanying obstacle imagery; we were still unsure what could have caused this GPWS alert.1) Any time an approach is discontinued; regardless of altitude; it is a go around. As such; go around procedures must be followed. If this decision ismade at sufficient altitude in VMC; then a climb may not be necessary; but the TOGA buttons should definitely be pushed in order to reset the FMA. The un-commanded pitching we experienced on upwind was a direct result of our failure to do so. Also; I should have been more assertive with my concern that the arrival was going to result in us being excessively high when I noticed minutes ago and miles away from the airfield. An easy fix that would have prevented this is just to request vectors off course or even a 360 degree turn to lose altitude. I am still a relatively new First Officer and I feel that it isn't normally appropriate for me to tell a Captain how to conduct their arrival; but I will definitely be way more vocal when I sense an undesired situation developing. 2) When a GPWS aural sounds; it must be addressed immediately. We did follow the command; but it could've definitely been done more expeditiously. There's no time to doubt these warnings or even look for an obstacle. If the GPWS sounds; you're too low for your position and it must be corrected swiftly. Although the Captain was busy levelling off then seeking a climb attitude; I shouldn't have hesitated to jam the thrust levers into the MAX POWER detent as I did. This entire procedure should be much more sudden and no confusion can be tolerated. Also; I will not hesitate to take control of the airplane to initiate a full power climb if I am unfortunate enough to experience another one in the future; regardless of who's flying the aircraft.




Synopsis: First Officer reported ATC held the fight too high creating an unstable approach situation. There was an accompanying malfunction with the autopilot system.