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Air carrier flight crew reported experiencing a low speed buffet alert during cruise due to having the aircraft in the incorrect configuration with autothrottles not engaged. Lack of flying was cited as a contributing factor.
| Attributes | |
| ACN | 1744942 |
| Time | |
| Date | 202006 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | ZZZ.ARTCC |
| State Reference | US |
| Aircraft 1 | |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Cruise |
| Flight Plan | IFR |
| Person 1 | |
| Function | Captain |
| Qualification | Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument |
| Person 2 | |
| Function | First Officer |
| Qualification | Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine |
| Events | |
| Anomaly | Deviation - Procedural Published Material / Policy Deviation - Speed All Types |
Narrative:
After departing ZZZ in cruise; I disengaged the autothrottles and autopilot to trim the aircraft. Autopilot was reconnected; but I inadvertently forgot to reconnect the autothrottles. We then encountered continuous light turbulence; I selected .76 in the speed window and manually pulled the throttles back; not realizing that the autothrottles were not on.the speed dropped into the upper yellow band; we got a 'buffet alert' in the FMC. Throttles were manually advanced to continue; but speed recovery was slow so we asked for a descent from FL340 to FL320. Speed recovery was rapid after we started down. In cruise we got a low speed buffet alert. Airspeed was in the lower yellow band. Power levers were manually advanced to continue power; but recovery was not adequate. We asked for a descent from FL340 to FL320. Speed recovered.this was the second leg of my 1st trip back after X months off. I thought after an uneventful 1st leg I thought I was through the danger of being rusty; boy was I wrong. The major cause was my complacency after an uneventful first leg coming back from X months off. I wrongly figured I had knocked the rust off on when the first leg went so well. We don't disconnect the autopilot/ autothrottles in cruise very often; this requires extra vigilance to make sure the aircraft is in the correct configuration.
Original NASA ASRS Text
Title: Air carrier flight crew reported experiencing a low speed buffet alert during cruise due to having the aircraft in the incorrect configuration with autothrottles not engaged. Lack of flying was cited as a contributing factor.
Narrative: After departing ZZZ in cruise; I disengaged the autothrottles and autopilot to trim the aircraft. Autopilot was reconnected; but I inadvertently forgot to reconnect the autothrottles. We then encountered continuous light turbulence; I selected .76 in the speed window and manually pulled the throttles back; not realizing that the autothrottles were not on.The speed dropped into the upper yellow band; we got a 'buffet alert' in the FMC. Throttles were manually advanced to continue; but speed recovery was slow so we asked for a descent from FL340 to FL320. Speed recovery was rapid after we started down. In cruise we got a low speed buffet alert. Airspeed was in the lower yellow band. Power levers were manually advanced to continue power; but recovery was not adequate. We asked for a descent from FL340 to FL320. Speed recovered.This was the second leg of my 1st trip back after X months off. I thought after an uneventful 1st leg I thought I was through the danger of being rusty; boy was I wrong. The major cause was my complacency after an uneventful first leg coming back from X months off. I wrongly figured I had knocked the rust off on when the first leg went so well. We don't disconnect the autopilot/ autothrottles in cruise very often; this requires extra vigilance to make sure the aircraft is in the correct configuration.
Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.