B737 flight crew reported temporary loss of aircraft control during approach in turbulence. Flight crew conducted a go around and returned to landing.
Synopsis
B737 flight crew reported temporary loss of aircraft control during approach in turbulence. Flight crew conducted a go around and returned to landing.
Narrative
Cleared for XXR ILS approach into ZZZ with large line of WX approaching. Nearing ZZZZZ +12NM out at 4000 feet ATC advised us due to wind shift to cancel approach clearance and turn right and maintain 4000. We were gear down flaps 15 speed 180kts. FO turned AP (Autopilot)/AT (Auto Throttles) off but never pressed TOGA buttons. As FO was struggling to fly the airplane I was cleaning up the airplane and trying to engage FMC modes to no avail. Busy watching and helping FO fly in very bumpy IMC conditions; talking to ATC and trying to reconfigure AC - I swapped out ILS frequency and cycled FDs (Flight Director). We were able to stabilize the AC at 4000 feet with proper lateral and vertical FMC guidance. At some point we were given a heading back west and speed of 180 kts (reduction from our clean 200-210 speed) I missed FO setting the 180 speed in the window as I was talking to the passengers about the go around. The airplane was clean (flaps up) and we got a right turn and that's when we got one momentary LOW SPEED warning at 172kts at 4000 feet with 180 set in speed window. FO quickly advanced throttles and realizing that were below flaps 1 sped I quickly selected flaps 1 then 5. AC returned to a stable state and we were ready to reattempt the approach.2nd attempt at landing in ZZZ with large thunderstorm cells approaching the field. New runway XXC after a missed of off XXR. FO was flying but due to >100 hour limits for strong gusty winds (30kts) I took the controls. Cleared for the approach and instructed to contact Tower over ZZZZZ1 (FAF) We were 170kts; gear down and flaps 15 at approx. 3500 feet - couple miles outside ZZZZZ1 with choppy; gusty ride inbound and +/-5 kts on speed. AP and AT were engaged and as I took my hand off TLs (thrust levers) to center the heading bug we got a sudden sheer and gained 30kts. We over-sped the flaps momentarily as the speed jumped from 170 to just over 200 kts and AP kicked off. We were in very strong sheer and turbulence as well as in IMC. I struggled to find the TOGA buttons due to the turbulence; but did and called for go-around. We initially climbed straight out to 4000 on runway heading. Very choppy and turbulent climb through the storms blow off. I told the FO to call ATC and advise them of the Go Around. We were still on approach and not switched to tower frequency as we never made it to FAF. As I was struggling to fly and maintain AC control FO was busy with ATC. Approach told him to switch to tower and we did. Tower advised us to climb to 4000 on runway heading. FO advised that we were 4400. 5000 was assigned with subsequent left turn. I was fighting the turbulence and doing my best to maintain speed and altitude and headings. AC was +/- 200-300 feet due to the turbulence and we were advised a couple times to maintain 5000 feet. At no time did we come close to any other aircraft or received TA advisories. Seemed like ATC was unaware of the flight conditions we were experiencing and was task saturating us with constant calls. At one point airspeed was over 250kts in clean configuration and as high as 265 for a couple seconds. Altitude window had 700 feet set from previous approach (touchdown zone) I was fighting to maintain altitude and AC control with extreme weather; up/down drafts constant moderate turbulence in IMC while my probationary FO was dealing with a very high workload from ATC and backing me up. We were able to stabilize the aircraft safely and landed successfully in ZZZ with 30kt gains reported at 3000 feet. Maintenance write up for flap overspend. 3 seconds over 200kts at flaps 15.
Second reporter narrative
After getting established on the ILS at ZZZ we received a vector off the approach and a clearance to climb to 4000. My first reaction as the PF with the A/P (Autopilot) on was to dial the heading and hit hdg (Heading) sel. After the aircraft showed no reaction I realized it was because we were established on the ILS. I was concerned that we were not reacting quickly enough at this point; so I clicking off the A/P and began a shallow climb (we had about 500 feet to climb) and initiated a turn to the right towards the heading. We already had the flaps at 15 because we were partially configured to land; so the first call I made was for the gear up as we became established in the climb. We both had high task saturation as I was flying with no FD (Flight Director) and the PM was trying to get the FD to get unlocked from the ILS. I suggested turning off both FDs and that got us back to a basically useful FD. As we were leveling off I nosed over a little too much and became about 100-200 feet low; so I focused on getting back on altitude. At this same time; the PM brought up the flaps as we were at a safe speed. Immediately following; ATC gave us a 180 knot speed restriction and the PM dialed it in the speed window. The A/T (Auto Throttles) bumped back and along the with turbulence from the storm bearing down on the airport we received a momentary low airspeed warning. I goosed the power up and the PM put out flaps (I believe 5) to give us more buffer. We continued our vectors around to final.After being established on final; tower called a new ATIS with high gusty winds that were above my minimums; so the Captain elected to take the landing. The 900 ER we were flying was heavy; with fuel for a divert to ZZZ1 and we had a very high approach speed. Once on final we experienced a gain of at least 15 knots pushing the aircraft into the caution zone on the airspeed indicator and the captain initiated a G/A. It took at least 10 seconds for me to get a call to ATC due to freq saturation. When I did call; approach swapped me to tower and said to tell them. I had difficulty putting in the freq due to turbulence; and upon calling tower and pireping the wind shear they told us to climb to 4000 but we were already at 4300. They told us to climb to 5000 and gave a heading and another frequency change. We cleaned up and continued climbing; ATC gave us several more frequency changes and headings significantly increasing PM task saturation. This delayed putting an altitude in the window (our MAP altitude was not set because we went around outside 1000 ft). Due to significant turbulence our speeds and altitude fluctuated off our ATC clear and temporarily above 250 knots at one point; but the PF did a great job making corrections to back to clearance.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.