B737-700
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 205
Aircraft Equipment Problem Critical; Inflight Event / Encounter Bird / Animal
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; Flight Crew Landed in Emergency Condition; Flight Crew Landed As Precaution; General Declared Emergency
Aircraft
Hit a small bird at 100 KTS followed by a normal takeoff. After the gear was raised; at approximately 500 FT AGL; three rapid loud 'booms' were felt followed by three more rapid loud 'booms.' Slight aircraft yaw was felt followed by normal flight. Engine instruments were checked and rechecked with NO abnormal indications. An emergency was declared and a return to land was coordinated with ATC asking for the equipment to standby. Flight attendants were informed and told to 'secure' the cabin. The passengers were informed; and Ops was informed and asked to call and inform Dispatch. The decision was made to utilize the Number 2 Engine as normal since we had no adverse readings. Normal landing was made right at max landing weight (128;000 LBS) followed by clearing the runway and having the equipment take a look at the aircraft and the engine. No noticeable damage was observed and the aircraft was taxied back to the gate. The aircraft was taken out of service and the passengers re-accommodated. I gave my apologies to the passengers and asked what they observed. Several sitting on the First Officer's side abeam the Number 2 Engine saw flames coming out of the front and rear of the engine during the 'booms.'Preventative Measures: Not really sure. I'd like to know if the possibility of having too much Glycol (oil based) sprayed into the engines during the overnight deice could have been a contributing factor. Suspected compressor stalls.
[Narrative 2 contained no additional information.]
B737-700 crew felt vibrations and heard loud noises emanating from the Number 2 Engine.