B737-700
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 248
Situational Awareness; Distraction; Communication Breakdown; Training / Qualification; Workload
Aircraft Equipment Problem Less Severe; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Loss Of Aircraft Control
Flight Crew Regained Aircraft Control; Flight Crew Returned To Clearance
Aircraft; Human Factors
Around FL200; we were told to expedite our climb through FL260 and climb to FL400. We responded no problem as we were in a -700 with only 17 passengers and about 7.5 on the fuel. Out of FL260; I mentioned to the Captain that we were out of FL260. I didn't make any pitch/airspeed adjustments to expedite our climb. I think we were still in VNAV and LNAV. As I was changing approach books and looking down to the right; at FL383; I heard 'Airspeed Low;' and looked at the CDU and saw the message 'Buffet Alert!' I looked at the airspeed and noted it was below 200 KIAS. I looked at the N1s and noted they were at full climb thrust. Either I disconnected the autopilot; or it disconnected. I noticed a very slow descent and then noticed the target Mach displayed at .82. This initially confused me and I mentioned we must be in a severe mountain wave. The Captain said he had spun the speed knob to .82 when he heard the Airspeed Low announcement. I still wasn't sure we weren't in mountain wave; but left the power up and slowly decreased the descent to level flight; and then after considerable time; began to continue the climb to FL400. I think we lost about 300 FT during this episode before we were finally able to continue our climb. I don't recall ever seeing Level Change or anything other than VNAV throughout the climb. Fortunately; we were light and able to reverse the flight path with little altitude loss. I asked to have the FDR downloaded to learn why this incident happened.We could have done a better job monitoring the airspeed in the climb. The Captain was getting ATIS and gate information; and I was filling out upgrade paperwork and changing books during the climb. This is not a real short leg; but getting ahead of the game on shorter legs is crucial. As pilot flying; I need to ensure the airplane is performing as expected before turning my attention to other tasks. The other crew member must always inform the pilot flying when making any inputs to the FMC.
The first thing I looked at was airspeed and noticed it was below 160 KTS. Then; I looked up and saw the airspeed window open so I spun the airspeed to about .82 while the pilot flying disengaged the autopilot and increased the airspeed. I have no idea how the airspeed bled off the way it did with the automation hooked up.
Distracted by ancillary duties while expediting their climb at ATC's request the flight crew of a B737-700 was alerted by an 'airspeed low' warning as they were in the vicinity of FL380.