B737 flight crew reported a go-around caused by turbulence resulting in airspeed fluctuations. On approach to the reciprocal runways; both PFDs failed with The Captain able to see the runway and continue to land.
Synopsis
B737 flight crew reported a go-around caused by turbulence resulting in airspeed fluctuations. On approach to the reciprocal runways; both PFDs failed with The Captain able to see the runway and continue to land.
Narrative
Was on approach into ZZZ at about midnight after about an hour delay getting out of ZZZ1. The approach had been through layers of icing and precipitation ranging from light to heavy. We were given a heading to intercept and cleared ILS [Runway] XXL at 2;500 feet. ATIS winds were 110/10. The CA (Captain) configured as normal and spun the speed back to target of 150 kts. (145 + 5). We were in heavy winds and rain at this point with no forward visibility. Tower reported winds at ~20020G35. The jet was now fully configured; all anti ice on; on glide slope and the automation was attempting to keep the speed at 150. I was just saying how we needed to add 10 knots when the jet bounced and the stick shaker went off. I did not note the speed but the CA pushed the throttles up and I spun the speed to 160. No upset call was made but the quick throttle advancement corrected the speed. It was about this time that the CA said he no longer had an ILS and his FD (Flight Director) was gone. I still had one at the time but it then went out. He announced a Go-Around and we climbed up to 5;000 feet. The automation was reestablished and we talked about the winds and divert. We figured we had 16 minutes before heading to ZZZ2. ZZZ decided to change runways to XYR and we were given short vectors back around. We agreed we were ready and made the approach. On the approach the same thing happened where the CA FD dropped and the jet went into CWS (Control Wheel Steering) at about 2;000 feet. Mine was still available and the CA transferred the aircraft to me. About that time mine was lost as well. The visibility was better on the XYR approach despite the heavy rain and winds. We could make out the runway so the CA took back the jet and made the approach visually. During the visual I recycled the FD which eventually brought back the FD and ILS before touchdown.
Second reporter narrative
Intercepting the glide path on ILS final to Rwy (Runway) XXL at ZZZ; I responded to a momentary stick shaker with pitch and power; without an SOP compliant 'Upset' call and without first disconnecting the autopilot. Regaining airspeed; the CWS (Control Wheel Steering) Pitch and Roll annunciations alerted me to my error and I disconnected the autopilot. Anticipating continuing the approach; I asked the PNF (Pilot not Flying) to add appropriate airspeed to my target speed. Looking to my PFD (Primary Flight Display); my command bars and ILS guidance were out of view. I stated; 'I have lost the ILS on my PFD' and that we will have to take this one around. I announced 'Going around' and we executed a go around from approximately 1;700 feet AGL. Leveling at 5;000 feet MSL; we were vectored east and south of the airport for an approach to the reciprocal runway as the winds now favored the XYs. Again; after intercepting ILS course and glide-slope to XYR; Flight Director Guidance disappeared on my PFD. Cross checking; the FO (First Officer) had FD (Flight Director) command bars; I announced that I had lost my FD and directed the FO take control of the airplane. Almost immediately; his command bars disappears from view. As I had the field in sight; I retook control of the airplane and conducted the remainder of the approach visually to landing.Conditions upon our late arrival to ZZZ were rapidly changing. Light rain and light steady winds on ATIS during our descent brief had turned to heavy rain along final approach and the wind at the surface was reported to be 20020G35. While adjusting our target speed from 150 KIAS for the new tower reported winds; the momentary stick shaker occurred. Prior to the warning; we were stable with autopilot; auto-throttle; wing anti-ice and engine anti-ice on. The loss of ILS display prompted the go around as we did not yet have the field in sight. The same FD anomaly happened on our second approach; this time however; the field was in sight and a safe visual approach was conducted. The PNF cycled the FDs and was successful in returning FD ILS guidance inside of approximately 1;200 feet AGL. I suspect the weather front rapidly encroaching from the west created wind shear that lead to an approach to stall. As well; wing anti-ice use increased the stick shaker sensitivity. Fatigue; the late hour;(the entire sequence occurred between XA:45 and XB:15);the startle factor; and a continuation bias likely contributed to the improperly executed upset recovery procedure.
More incidents for this aircraft family →
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.