Flight Crew Air Transport Pilot (ATP)
Flight Crew Total 14400
Aircraft Equipment Problem Critical; Inflight Event / Encounter Weather / Turbulence
Aircraft Equipment Problem Dissipated; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Exited Penetrated Airspace
Aircraft; Weather
The First Officer was the Pilot Flying with the 'B' autopilot engaged. We had been in cruise flight for approximately one hour at FL370; at night and IMC with intermittent to continuous light turbulence; OAT approximately -54 when the Captain's airspeed indication began to decrease followed by multiple failure warnings including: Captain's 'A/S DISAGREE;' Captain's 'ALT DISAGREE;' Thrust levers increased; Master Caution: and the six pack annunciated 'ENG.' Both EEC's annunciated 'ALTN' and VNAV disengaged. The thrust levers moved to firewall and the upper center DU annunciated 'A/T LIMIT.' We completed immediate action items and determined we had unreliable Captain's airspeed and altimeter indications. We then completed the appropriate QRH checklists. We were now unable RVSM; so advised ATC; and were cleared to descend to FL270. As we descended through FL290; all the Captain's instruments returned to normal and remained normal for the duration of the flight. All probe heat indicators remained normal. A Maintenance review the next day indicated they had replaced the Captain's pitot probe; TAT; and the left ADIRU.
A B737-800 flight crew was confronted with numerous Captain's pitot/static system anomalies and warnings at FL370. During the subsequent descent to exit RVSM all systems returned to normal. Maintenance replaced the Captain's pitot probe; TAT and the left ADIRU.