B737 air carrier crew reported an unstable approach resulting in a terrain warning and flap overspeeds due to windshear on final approach. The crew performed a go-around; and returned for another approach and landed safely.
Synopsis
B737 air carrier crew reported an unstable approach resulting in a terrain warning and flap overspeeds due to windshear on final approach. The crew performed a go-around; and returned for another approach and landed safely.
Narrative
Strong gusty winds on final. Due to gusts; flaps blew up. 'Too Low Terrain' callout. Go Around. Flaps stuck Between 30 and 25. Flap disagree. Flight was uneventful until approach began. Once approach began; ATIS stated wind was 160 18G46. I was PF (Pilot Flying) and began the ILS Z XXR. On the final approach segment when calling tower at the FAF; tower advised gains and losses of 13 kts and cleared us to land. On glidepath inside 1000 ft RA we hit a gain shear speeding us up to 175 + KTS with the power in idle. This resulted in the flaps to blowing up from 30 to 25 along with the LE (Leading Edge) Flaps Transit light illuminated and the flaps stopped in between Flaps 30 and 25. Speed slowed and the flaps went down. Another gust resulted in the flaps blowing up again. Around 200 ft RA we received a 'Too Low Terrain' callout. I initiated a go-around. During the go-around procedure; the flaps did not retract when the flap handle was placed at 15 or flaps 5 on cleanup. Because the gear was retracted per the missed approach procedure and flaps remained between 30 and 25 degrees; we began receiving the gear handle horn. We agreed to put the gear handle down to alleviate the horn. Fuel was 4.6k lbs. Due to the fuel state; extending vectors to contact Dispatch along with additional communication was determined to be inappropriate. The fuel state also precluded diversion to other airports. The PM (Pilot Monitoring) Captain elected to discontinue efforts to contact dispatch and promptly advised ATC with Approach due to the non-normal checklists being accomplished as well as the low fuel state and the weather conditions. On the missed approach; the flaps were over sped several times on the climb to 13000 ft. due to the turbulent and windy conditions. In addition; due to the gusty and turbulent conditions; the too low annunciation was activated 2 times. The captain completed trailing edge flap disagree non-normal checklist and assumed PF duties. On final approach for the visual to XXR the fuel was 4.0k lbs. The flaps were over sped several more times; between 170-195 KIAS during the visual approach. Due to the wind conditions; airspeed fluctuated greatly between gains and losses though ZZZ Tower was only calling gains and losses of 10 kts from previous aircraft. Landing was uneventful. During taxi back to the gate; cabin called regarding a passenger medical. The passenger had stood up and laid down in the aisle. Medical assistance was requested and met at the gate. EMS took the passenger off the airplane. Unfortunately; these wind conditions were not forecast and not in any of our WX (Weather) documents.
Second reporter narrative
Flap malfunction and overspeed due to major gains and losses in windshear. FO (First Officer) flying the approach ILS Z XXR. On final approach; at FAF; ZZZ tower advised gains and losses of 13 kts and cleared us to land. On glidepath around 1000 ft. RA we hit a gain shear speeding us up to 175 kias; which caused the flaps to blowup from 30 to 25. In the process; the yellow LE (Leading Edge) Flaps Transit light illuminated and the flaps stopped in between Flaps 30 and 25. Below 500 ft. RA we received a Too Low Terrain; the FO initiated a go-around. Upon go around; the flaps never retracted despite the flap handle being actioned to the 15 position. After gear retraction we began receiving the gear handle horn due to trailing edge flap disagreement and the gear handle being up. The FO and Captain agreed the best course of action was to put the gear handle back down to alleviate the horn. Fuel was noticed to be at 4.6k lbs; while dispatch was attempted to be contacted; unfortunately; time was critical. No other feasible airports were available despite the severe wind conditions at ZZZ. The Captain elected to discontinue efforts to contact dispatch and promptly advise Approach due to the non normal checklists being actioned as well as the low fuel state and the weather conditions. On the missed approach; the flaps were oversped several more times on the way up to 13000 ft due to the turbulent and windy conditions. In addition; due to the extremely turbulent conditions; the too low airspeed annunciation was activated several times. The Captain after finishing the non normal checklist for trailing edge flap disagree assumed the controls. On final approach for the visual to XXR the fuel was noted to be 4.0k lbs. the flaps were oversped several more times between 170-195 kias with the airspeed fluctuating greatly between gains and losses. At the time; ZZZ Tower advised gains and losses of 10 kts. Landing was uneventful and taxied back to the gate. Separately; once on the ground; a passenger stood up and laid down in the aisle. Medical assistance was requested and met at the gate. EMS took the passenger off the airplane.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.