What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(.4)Flight 146, an ATR-42 was approximately 18 miles from the airport on the ILS 09R approach when it encountered wake turbulence from a flight 554, a Boeing 737-300, which was vectored onto the approach from the north in front of flight 146. Radar data showed flight 554 intercepted the localizer approximately 17.5 miles from the airport while descending from 5,200 feet to 4,800 feet. Flight 146 was at an altitude of about 4,900 feet when the wake turbulence encounter occurred. Separation of the two airplanes when the encounter occurred was approximately 4.8 miles. Vertical acceleration of flight 146 varied from 2.3679 g's to .5542 g's during the encounter. (-23) on September 17, 1998, at 1954 central daylight time (CDT), an ATR-42, operated by American eagle (sima), as flight #4146, encountered moderate wake turbulence from a Boeing 737. The flight was 20 miles out on approach to o'Hare international airport. The aircraft was not damaged. No passengers received any injuries. The flight attendant received a fractured ankle. Two cockpit crewmembers were not injured.
As the FAA filed it
(.4)FLIGHT 146, AN ATR-42 WAS APPROXIMATELY 18 MILES FROM THE AIRPORT ON THE ILS 09R APPROACH WHEN IT ENCOUNTERED WAKE TURBULENCE FROM A FLIGHT 554, A BOEING 737-300, WHICH WAS VECTORED ONTO THE APPROACH FROM THE NORTH IN FRONT OF FLIGHT 146. RADAR DATA SHOWED FLIGHT 554 INTERCEPTED THE LOCALIZER APPROXIMATELY 17.5 MILES FROM THE AIRPORT WHILE DESCENDING FROM 5,200 FEET TO 4,800 FEET. FLIGHT 146 WAS AT AN ALTITUDE OF ABOUT 4,900 FEET WHEN THE WAKE TURBULENCE ENCOUNTER OCCURRED. SEPARATION OF THE TWO AIRPLANES WHEN THE ENCOUNTER OCCURRED WAS APPROXIMATELY 4.8 MILES. VERTICAL ACCELERATION OF FLIGHT 146 VARIED FROM 2.3679 G'S TO .5542 G'S DURING THE ENCOUNTER. (-23) ON SEPTEMBER 17, 1998, AT 1954 CENTRAL DAYLIGHT TIME (CDT), AN ATR-42, OPERATED BY AMERICAN EAGLE (SIMA), AS FLIGHT #4146, ENCOUNTERED MODERATE WAKE TURBULENCE FROM A BOEING 737. THE FLIGHT WAS 20 MILES OUT ON APPROACH TO O'HARE INTERNATIONAL AIRPORT. THE AIRCRAFT WAS NOT DAMAGED. NO PASSENGERS RECEIVED ANY INJURIES. THE FLIGHT ATTENDANT RECEIVED A FRACTURED ANKLE. TWO COCKPIT CREWMEMBERS WERE NOT INJURED.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.