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A B767 flight crew had a low airspeed condition during initial climb when VNAV is selected shortly after the autopilot is engaged. The autopilot engagement had caused the aircraft to pitch up to maintain V2 and VNAV had caused a power reduction at the same time. Autopilot was overridden to regain airspeed.
| Attributes | |
| ACN | 1008393 |
| Time | |
| Date | 201204 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | EDDF.Airport |
| State Reference | FO |
| Aircraft 1 | |
| Make Model Name | B767-300 and 300 ER |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Initial Climb |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Autopilot |
| Person 1 | |
| Function | Captain Pilot Not Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Person 2 | |
| Function | Pilot Flying First Officer |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Deviation - Speed All Types |
Narrative:
We were performing the BIBTI3G RNAV departure from eddf. The first officer was flying the aircraft and the captain was monitoring. We had programmed the VNAV climb to maintain V2+20 (approximately 180 KTS) to 1;500 ft AGL. A normal reduced power takeoff was performed and at 400 ft AGL RNAV was selected and at 500 ft AGL the right autopilot was engaged. At that time the airspeed was a few knots above V2. The autopilot pulled the nose up to maintain V2 and shortly afterwards VNAV was engaged which selected climb power. At that point I observed the airspeed bleeding down and I told the first officer to watch the airspeed and he immediately pushed the yoke forward overriding the autopilot and the airspeed began increasing. The rest of the departure went normally. I think the airspeed went down to approximately 160 KTS. We did not get down to stick shaker speed. I am writing this narrative to alert other 767/757 pilots to this situation. I have learned that this is not something new to the 767/757 fleet. Be careful and alert when engaging the autopilot near the time of selecting climb power.
Original NASA ASRS Text
Title: A B767 flight crew had a low airspeed condition during initial climb when VNAV is selected shortly after the autopilot is engaged. The autopilot engagement had caused the aircraft to pitch up to maintain V2 and VNAV had caused a power reduction at the same time. Autopilot was overridden to regain airspeed.
Narrative: We were performing the BIBTI3G RNAV departure from EDDF. The FO was flying the aircraft and the Captain was monitoring. We had programmed the VNAV climb to maintain V2+20 (approximately 180 KTS) to 1;500 FT AGL. A normal reduced power takeoff was performed and at 400 FT AGL RNAV was selected and at 500 FT AGL the right autopilot was engaged. At that time the airspeed was a few knots above V2. The autopilot pulled the nose up to maintain V2 and shortly afterwards VNAV was engaged which selected climb power. At that point I observed the airspeed bleeding down and I told the FO to watch the airspeed and he immediately pushed the yoke forward overriding the autopilot and the airspeed began increasing. The rest of the departure went normally. I think the airspeed went down to approximately 160 KTS. We did not get down to stick shaker speed. I am writing this narrative to alert other 767/757 pilots to this situation. I have learned that this is not something new to the 767/757 fleet. Be careful and alert when engaging the autopilot near the time of selecting climb power.
Data retrieved from NASA's ASRS site as of July 2013 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.