B737-700
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 207
Aircraft Equipment Problem Critical; Inflight Event / Encounter Weather / Turbulence
Aircraft Aircraft Damaged; Flight Crew Inflight Shutdown; General Declared Emergency
Aircraft; Weather
While being vectored for an ILS approach we experienced a moderate airframe vibration accompanied by a loud popping similar to a compressor stall. With no adverse indications on the engine instruments; I disconnected the autopilot and autothrottles. At that point; thrust was still symmetrical and no indications on the engine instruments; but high airframe vibration; especially in the elevators. Within a few seconds; the Number 2 Engine N1 began to decay rapidly but with no increase in EGT. I closed the Number 2 Thrust Lever to determine if this was just a compressor stall or something worse. With the thrust lever closed; the high airframe vibration continued along with the loud rapid popping sound.At this point we determined this was a severe damage situation. The flight crew performed memory and QRH Checklist for Engine Fire/Severe Damage/Separation/Seizure. There was never any indication of increased EGT or fire and the vibration gauge never went above 0.1. We declared an emergency with ATC and requested ARFF equipment. Because the flight was full; Company Captain was on the cockpit jumpseat and was a great resource; handling all communications with the cabin by making PAs to the passengers and relaying commands to the flight attendants to prepare the cabin.After landing I stopped the aircraft on the runway; made a PA to the cabin; and established communications with the ARFF crew who advised no fire or smoke from the Number 2 Engine and then followed us into gate. Post-flight inspection revealed no visible damage to the fan; however; the fan was locked and would not rotate.
N1 below flight idle; no abnormal VIB; EGT; overheat; or fire indications. ENG anti-ice was on; wing anti-ice had been selected for a short period prior to the event (nine degrees C TAT).
A B737-NG flight crew; while being vectored for approach and landing in IMC; performed an inflight shutdown of the right engine due to aggravated compressor stalls; declared an emergency and landed safely. Postflight inspection determined the compressor fan was jammed and could not be rotated.