Date: 202001
Local time of day: 0601-1200
Weather elements / visibility: Windshear
Aircraft: Q400
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class B ZZZ
ATC / advisory: TRACON ZZZ
Second aircraft: B737 Undifferentiated or Other Model
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Anomaly: Deviation - Speed All Types; Inflight Event / Encounter Wake Vortex Encounter; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Executed Go Around / Missed Approach; Flight Crew Regained Aircraft Control
Contributing factors: Airport; Weather
Primary problem: Weather

Narrative: During the arrival from the south we encountered continuous light turbulence. We heard a B737 report moderate turbulence below 4;000 feet. We were vectored onto the ILS for Runway XX. Below 4;500 feet. we encountered continuous moderate turbulence along with wind shear. We also encountered what we perceived as wake from the B737. We delayed flap selections several times during the descent for wildly fluctuating air speeds. We had ref speeds increased due to icing conditions during the descent. We were fully configured at around 1;500 feet AGL. We heard the B737 go-around. Somewhere between 1;500 and 1;000 feet we encountered a wind shear; maybe two; maybe several that caused instant fluctuations in airspeed from stick shaker to flap 35 max speed exceedance in less than 1 second. Then another. I saw the acceleration cue plus 30; then minimum speed cue; all in under a second.The auto pilot disconnected on its own and the First Officer decided to go around. I was in agreement and said so. It was a very busy missed approach; even though it was begun above 1;000 ft. During the vectoring and climb portion; it became evident that [two other air carriers] and ourselves had all executed missed approaches and were being resequenced for second approaches.All 3 of those approaches were successful; including others. We did encounter another abrupt; but instant stick shaker about 400 ft. AGL. I had already added a generous amount of power prior so that event was about as long as an eye blink. We continued the approach to a successful landing. We had a short discussion about our fit to fly condition for the following flight. We both agreed that we had enough time to properly detune and de-amplify from our previous arrival. The duty officer asked us the same question a short time later. Good on them for doing so.Little did we know that our arrival into [our next destination] an hour later was going to be a repeat of earlier that day. We had; again; easily comparable one of the most challenging wind shear and moderate turbulence events in my career. Had we known...If someone told us we had to go repeat what we had just been through; surely we would have declined.The wind shear detection equipment [at destination] has been out of service for several weeks now. The timing seems inappropriate. The reports from other aircraft were timely. We have to remind those who are unaware that 15 to 20 kt oscillations from another aircraft can equal 25 to 30 in the Q400; its airspeed tape fluctuates wildly compared with other 121 aircraft.On the second attempt the First Officer said he was okay with a second attempt; but subsequently decided it would be better for me to make the second attempt. This short discussion was paramount. I believe it did some good to shake off the jitters from the previous approach and missed approach and helped in the success of the second attempt. Equally so if it were the Captain relinquishing Pilot Flying duties to the Pilot Monitoring in this situation.




Synopsis: Q400 Captain reported encountering wind shear and wake turbulence on approach that resulted in a go-around.