B737-700 flight crew reported a safe landing following the failure of the Captain's airspeed indicator.
Synopsis
B737-700 flight crew reported a safe landing following the failure of the Captain's airspeed indicator.
Narrative
We pre-diverted to ZZZ before leaving ZZZ2 because ZZZ1 weather was below minimums to dispatch. At the top of descent; Captain flying; the Captain's airspeed started to roll back and the auto throttles started to move forward as the aircraft started down. We subsequently received 'IAS disagree' annunciations. Captain performed the memory items for airspeed unreliable and we leveled out. As a crew we determined that the FO (First Officer) and standby airspeed were matched; and asked ATC to confirm our ground speed because the wind readout seemed erroneous. We maintained our filed route. We advised ATC; maintained our filed route and continued to ZZZ. ZZZ1 was not an option with the 1/16 mile reported fog. We did not feel comfortable returning to ZZZ2 with the severity of the situation; not knowing if the FO's side would possibly fail. We had to manage the QRH; start down; [and] change the approach from the RNP to the LDA as we would have 1 FD for the approach. While continuing the descent the Captain's airspeed bled to 45 kts. and the airplane cycled through its aural warnings but we never received the stick shaker. While on the arrival and approach the weather was fluctuating from 10SM to 1 3/4 due to a fog bank. The rapidly changing weather conditions were not helpful but we prepared for a possible go around by briefing the go around pitch and power settings. We were able to pick up the field about 6 miles out and landed uneventfully with the FO flying.We have practiced this scenario in the simulator [which] provided valuable experience to deal with the scenario in real life.
Second reporter narrative
We experienced a failure of the Captain's airspeed indicator. We had begun our descent; with the Captain flying; when we both got 'Unreliable Airspeed' annunciations. We complied with the memory items of the QRC but did not set a pitch power setting as we knew the aircraft was at a safe altitude and airspeed. We quickly determined that the FO (First Officer) and standby airspeed indicators were matched up; and confirmed that our ground speed matched what ATC was reading. I would say the training in this very scenario in the simulator was very helpful to practice for the rare chance that it happens in real life.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.