B767 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Type 2017
Situational Awareness
Deviation - Speed All Types; Inflight Event / Encounter Weather / Turbulence
Flight Crew Became Reoriented; Flight Crew FLC Overrode Automation
Environment - Non Weather Related; Human Factors
Departing 4L; flaps 15; full power 1.57 EPR; Gusty winds out of 030 at 19 kts gusting 31 kts. Moderate rain and wet runway. Captain flying; I was the pilot monitoring. A B747 departed prior. There was adequate separation for our departure. We [experienced] a normal takeoff roll and liftoff. After positive rate; Captain called it out and asked gear up and then heading select. I did as such; turning commenced at about 500 feet AGL. Our climb rate was significant. Through 800 feet and closer to 1000 feet captain called VNAV; brief pause; flaps 5. I selected VNAV; the power reduced. Our positive speed trend reduced and our airspeed was reducing. The climb became greater and through about 2500 feet the IRO called out VNAV; VNAV disengaged. I saw ALT CAP as the FMA and called it as such. The command bars displayed an even further pitch up attitude and the airspeed degraded even further and is now entering the yellow band (Low Speed Va). The speed trend was still degrading further; I callout 'AIRSPEED AIRSPEED!' The Captain and I pushed the nose forward to break the negative speed trend. The aircraft accelerated; and we continued normal ops.
B767 First Officer reported airspeed degraded during their initial climb when the autopilot aggressively pitched up.