Date: 201408
Local time of day: 1201-1800
Location: ZZZZ.Airport, FO
Flight conditions: IMC
Weather elements / visibility: Turbulence
Aircraft: B767-300 and 300 ER
Operator: Air Carrier
Operating under: Part 121
Flight phase: Takeoff / Launch
ATC / advisory: TRACON ZZZZ
Aircraft component: Turbine Engine
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness
Second reporter function: Pilot Not Flying; Captain
Anomaly: Aircraft Equipment Problem Critical; Deviation - Altitude Overshoot; Deviation - Speed All Types
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Aircraft Equipment Problem Dissipated; Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Declared Emergency; General Maintenance Action
Contributing factors: Human Factors; Aircraft; Weather
Primary problem: Aircraft

Narrative: I was the pilot flying on this Flight We took-off and were flying the departure. We started to clean-up at 3;000 FT AGL and commenced an approximate 60 degree right hand turn for the SID. We were cleared to 6;000 FT as per the SID. I was hand-flying the aircraft during the departure and throttles were being commanded with auto-throttle. About this same time; the plane entered IMC with choppy ride conditions. During the last part of the turn; as we were rolling out; flaps were retracted to zero. It was at this point; as we were climbing to 6;000; in choppy ride conditions; that we encountered a stick shaker warning. I immediately lowered the nose; power was advanced; and the warning ceased. As power was advanced; it was then that we discovered the right engine RPM had rolled back in an apparent compressor stall. As per the checklist; the right thrust lever was immediately retarded to idle as the left thrust lever was advanced to save airspeed. We tried advancing the right thrust lever after a short wait but encountered a secondary compressor stall after moving the thrust lever only a small amount. Once again; the right thrust lever was retarded back to idle. During the troubleshooting process for the compressor stall and then trying to fly a very heavy; performance limited aircraft on a single engine; our altitude varied slightly between 4;800 FT and 5;300 FT on the SID. We subsequently declared an emergency with Departure Control and elected to remain at 5;000 FT for our return for an overweight landing. Approach Control vectored us around for our arrival and ILS approach. We completed our emergency checklists; dumped a slight amount of fuel (with approval from Approach Control) and conducted an ILS approach. During the vectoring for our arrival; we tried advancing the right thrust lever one more time; and this time; power came back normally. We subsequently landed with both engines working normally. Landing and taxi-in were normal and uneventful. Continue to emphasize engine failures/compressor stalls not only immediately after take-off but also in a turn and in the weather during training. This type of failure is very insidious and potentially dangerous.


Second narrative: While power was being applied to continue to newly assigned altitude the right engine 'hung' around 40-45 percent N1; possibly compressor stalled. We were in the weather with light to mod chop. Aircraft was being cleaned up; turn was just completed; frequency was very congested; aircraft was heavy; and this was a high workload point in the flight. The asymmetric thrust produced a roll; the nose was lowered and wings leveled. While we stabilized the aircraft and diagnosed the problem our altitude varied from about 4;800 to 5;300 and then an emergency was declared.We returned for maintenance. This deviation occurred during that brief period of time where the aircraft was being stabilized; the malfunction was being recognized and an action plan decided upon. Simulator profiles of 'Engine Failure during critical phase of flight' have proven to be quite beneficial and I would recommend their emphasis going forward.


Synopsis: B767 flight crew experiences an engine rollback climbing out of 5;000 FT that result in a large yaw angle and a momentary stick shaker. The thrust lever for the affected engine is brought to idle and attempts to increase thrust are not successful. An emergency is declared; some fuel is dumped and the flight returns to the departure airport. While being vectored for approach the thrust lever is advanced again and the engine responds normally.