B737-700
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Overcame Equipment Problem; Flight Crew FLC Overrode Automation
Aircraft; Human Factors
During climbout; approaching the flight levels the autopilot pitched down rather quickly to maintain the climb speed schedule with VNAV engaged. To make the flight more comfortable the Captain elected to use V/S to continue the climb to FL390. Approaching the low FL300s I began looking in my publications and took my eyes off the instruments. Shortly thereafter the Captain gasped and I looked away from the EFB and noticed our airspeed had deteriorated significantly since I last looked moments earlier. The aircraft was at a speed just shy of the amber header. Meanwhile the Captain lowered the nose to gain speed. Altitude loss was minimal and this occurred around FL370. ATC never queried us and we continued our climb to FL390 once the aircraft returned to a normal energy state. The Captain noted the MCP window had a flashing A. No other buffet alerts or stall indications were activated.
[Report narrative contained no additional information.]
B737 flight crew reported that during climb the autopilot pitched over to regain airspeed.