Date: 201809
Local time of day: 0001-0600
Location: DEN.Airport, CO
Flight conditions: VMC
Weather elements / visibility: Windshear; Turbulence
Aircraft: Large Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class B DEN
ATC / advisory: TRACON D01
Reporter organization: Air Carrier
Reporter function: Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Human factors: Distraction; Confusion; Communication Breakdown; Situational Awareness; Workload; Human-Machine Interface; Fatigue
Anomaly: Deviation - Speed All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Executed Go Around / Missed Approach; Flight Crew Became Reoriented; General Flight Cancelled / Delayed
Contributing factors: Weather; Human Factors; Procedure; Environment - Non Weather Related
Primary problem: Weather

Narrative: While being vectored for Runway 16L; DEN Approach gave us direct KIKME. As the Pilot Flying; I slowed the aircraft to 180 knots and called for flaps 2. DEN Approach advised Windshear Alert for 16L with windshear +35 knots. The Pilot Monitoring inquired about 16R and started loading 16R into our box. DEN Approach advised windshear alerts for 16R also. The Pilot Monitoring advised we would take 17R and started loading the box with 17R. I felt comfortable with the change to 17R because I had a visual on the airport and we had time to load 17R. I believed with [our] current position; visual conditions and our speed; the Pilot Monitoring would be able to brief the appropriate items after loading the box. I did slow the aircraft even further to 165-170 knots and selected a more squared off heading for the 17R LOC to allow more time for the runway change. Although early; the Pilot Monitoring asked if I wanted gear down. I knew that would help us slow even faster and reduce workload; so I called gear down and flaps 3.We started experiencing increasing turbulence and my scan alternated from inside to outside. Our airspeed was fluctuating from the turbulence/windshear. As I transitioned from inside to outside focus; I realized we were overshooting the LOC for 17R. I disconnected the autopilot and started hand-flying to make the correction for the LOC. We were still outside (approximately 5 miles) of JOSEE and we were at an appropriate glideslope intercept for 17R. The Pilot Monitoring was verifying the box and talking to ATC. The turbulence/windshear increased. I scanned the PFD to verify the LOC and GS and realized we were shedding airspeed rapidly. At the same time; the Pilot Monitoring stated '... watch your speed.' We were closing in on Vls. I increased the throttle because I believed the airspeed was due to increasing windshear/turbulence. I then realized the autothrust was off and I stated the autothrust was off and I lowered the nose of the aircraft to assist/stop the airspeed decay and increased the thrust levers. The airspeed increase away from Vls. I heard the Pilot Monitoring say; 'I turned the autothrust off...' and; '...I am redirecting us to JOSEE.'As my assessment of the situation became clear with an unexpected autothrust disconnection; windshear/turbulence and below the glideslope; I felt a go-around was warranted and the safest course of action even though we were still high enough not to violate our stabilized approach criteria. I called go-around and pushed the thrust levers to TOGA and pulled the thrust levers back in an effort not to overspeed. Simultaneously; the turbulence/windshear increased even more. Although trying to apply smooth thrust inputs; the airspeed was abnormally erratic and unpredictable. The turbulence/windshear was affecting our climb rate and stability. The airspeed exceeded the flap setting limitations. I reduced the thrust levers further and continued a climb to reduce the speed. I called for the Pilot Monitoring to set an altitude. I cannot remember if I called for a specific altitude or not; but my intention was for the Pilot Monitoring to communicate with DEN for an altitude. We were passing 8;500 MSL when I called for an altitude and was getting the airspeed back to a normal condition. As the airspeed was normalizing; I called for the autothrust to be re-engaged. The Pilot Monitoring stated he had controls and stated he wanted 10;000 MSL. I advised DEN we were climbing to 10;000 MSL. DEN advised to stop climb at 9;000 MSL and state intentions. I advised we wanted vectors to assess the weather situation. The original Pilot Monitoring leveled us at 9;000 and stated; you have controls and I resumed Pilot Flying duties. We took delayed vectors while we reviewed our fuel status and pulled weather for COS.I asked the Pilot Monitoring what happened with the autothrust and he stated he saw our airspeed increasing before he could activate the approach so he disconnected the autothrust and pulled the thrust lever to approximately 50%. The Pilot Monitoring stated he announced his actions when he disconnected the autothrust by saying; '...autothrust disconnected - you have the thrust levers.' As I was hand flying the aircraft onto the LOC while experiencing increasing turbulence/windshear; I did not hear the Pilot Monitoring state the autothrust was disconnected. Admittedly; I was very focused on hand flying the aircraft; monitoring the ATC communication regarding windshear; our present position and the increasing turbulence/windshear while mentally preparing for a potential go-around that I missed the Pilot Monitoring state he turned the autothrust off. I was not expecting the autothrust to be disconnected. I was performing increasing instrument scans; but dismissed the initial airspeed trend indicator and contributed it to the turbulence/windshear instead of the autothrust being disconnected by the Pilot Monitoring.After delayed vectors; the wind event moving across DEN subsided and we were assigned 16L and vectored to the approach. As the Pilot Flying; a landing to 16L occurred without further abnormal events. A logbook entry was made for Flap Overspeed and Severe Turbulence due to the large; abrupt changes in altitude and large variations in airspeed from turbulence/windshear.After landing and discussing the event; the Pilot Monitoring and I agreed we lost proper pilot-to-pilot communication. I failed to hear and verbalize the autothrust was disconnected. He failed to hear me acknowledge the autothrust was disconnected. Also; the Pilot Monitoring thought I called for him to take control when I actually called for an altitude during the go-around. The turbulence/windshear was a significant factor in our miscommunication; combined with workload and possible fatigue from a second night of double red-eye flights. Small errors were being trapped on our descent into DEN. We both agreed a better course of action would have been to ask for delayed vectors when we were told the second runway was experiencing a Windshear Alert.




Synopsis: Air Carrier pilot reported miscommunication between flight crew while initiating a go-around due to windshear and turbulence.