B737-500 crew had a bird strike on takeoff that damaged #1 engine fan blades.

Attributes
ACN	574544
Time
Date	200302
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : ord.airport
State Reference	IL
Altitude	msl single value : 700
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : c90.tracon tower : ord.tower
Operator	common carrier : air carrier
Make Model Name	B737-500
Operating Under FAR Part	Part 121
Flight Phase	climbout : initial climbout : takeoff
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 7000 flight time type : 1581
ASRS Report	574544
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : commercial pilot : instrument
Experience	flight time type : 1846
ASRS Report	574545
Events
Anomaly	aircraft equipment problem : critical inflight encounter : birds
Independent Detector	aircraft equipment other aircraft equipment : eng instruments other flight crewa other flight crewb
Resolutory Action	controller : provided flight assist controller : issued new clearance flight crew : diverted to another airport flight crew : landed as precaution
Consequence	other other other other
Supplementary
Problem Areas	Aircraft Environmental Factor
Primary Problem	Environmental Factor

Narrative:

Aircraft departing runway 22L encountered bird strike on rotation approximately 5000 ft down runway. Flight crew heard loud noise with bird strike. The noise continued, and crew also noticed partial loss of power on left engine (type B737-500). Aircraft yaw was also noticed. Left engine power was lower by approximately 4% N1 and N2. Crew decided that return to airport was safest course of action. After briefing cabin crew, the aircraft was given ATC instructions for a return visual approach runway 27L. Landing was uneventful using normal SOP's. Upon arrival at gate, it became evident that the bird had been ingested partially into the left engine, distorting several fan blades. Dispatch notified. Supplemental information from acn 574545: large bird struck left side of nose just after liftoff. Loud noise begun shortly after, and continued until end of flight -- indicative of engine damage. #1 engine indications were relatively normal, although numbers slightly less than #2's readings (as if at slightly less power). Vibrations normal. Landed as soon as possible runway 27L. Post-landing inspection showed strike left side of radome, bird splatter between aircraft body and #1 engine, and bird impact inside #1 engine wall forward of fan blades. Extensive fan blade damage.

Original NASA ASRS Text

Title: B737-500 CREW HAD A BIRD STRIKE ON TKOF THAT DAMAGED #1 ENG FAN BLADES.

Narrative: ACFT DEPARTING RWY 22L ENCOUNTERED BIRD STRIKE ON ROTATION APPROX 5000 FT DOWN RWY. FLT CREW HEARD LOUD NOISE WITH BIRD STRIKE. THE NOISE CONTINUED, AND CREW ALSO NOTICED PARTIAL LOSS OF PWR ON L ENG (TYPE B737-500). ACFT YAW WAS ALSO NOTICED. L ENG PWR WAS LOWER BY APPROX 4% N1 AND N2. CREW DECIDED THAT RETURN TO ARPT WAS SAFEST COURSE OF ACTION. AFTER BRIEFING CABIN CREW, THE ACFT WAS GIVEN ATC INSTRUCTIONS FOR A RETURN VISUAL APCH RWY 27L. LNDG WAS UNEVENTFUL USING NORMAL SOP'S. UPON ARR AT GATE, IT BECAME EVIDENT THAT THE BIRD HAD BEEN INGESTED PARTIALLY INTO THE L ENG, DISTORTING SEVERAL FAN BLADES. DISPATCH NOTIFIED. SUPPLEMENTAL INFO FROM ACN 574545: LARGE BIRD STRUCK L SIDE OF NOSE JUST AFTER LIFTOFF. LOUD NOISE BEGUN SHORTLY AFTER, AND CONTINUED UNTIL END OF FLT -- INDICATIVE OF ENG DAMAGE. #1 ENG INDICATIONS WERE RELATIVELY NORMAL, ALTHOUGH NUMBERS SLIGHTLY LESS THAN #2'S READINGS (AS IF AT SLIGHTLY LESS PWR). VIBRATIONS NORMAL. LANDED ASAP RWY 27L. POST-LNDG INSPECTION SHOWED STRIKE L SIDE OF RADOME, BIRD SPLATTER BTWN ACFT BODY AND #1 ENG, AND BIRD IMPACT INSIDE #1 ENG WALL FORWARD OF FAN BLADES. EXTENSIVE FAN BLADE DAMAGE.

Data retrieved from NASA's ASRS site as of July 2007 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.