Casualties unknown

Wake Turbulence Encounter During ILS Approach (N233RM)

Chicago, IL, US

On September 18, 1998, an Aerospatiale ATR-42-300 (registration N233RM) operated by American Eagle, Inc. was involved in an aviation accident near Chicago, IL. Investigators recorded the probable cause as: the wake turbulence encountered by Flight 146. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-06-10Data APIEditorial standards

Flight 146, an ATR-42, experienced wake turbulence from a preceding Boeing 737-300 during an ILS 09R approach, 18 miles from the airport.

Incident Overview

During an ILS approach to Runway 09R, Flight 146, an ATR-42, encountered wake turbulence from Flight 554, a Boeing 737-300. The incident occurred approximately 18 nautical miles from the airport when Flight 146 was at an altitude of about 4,900 feet.

Flight Path Details

Radar data indicated that Flight 554 was vectored onto the approach from the north and intercepted the localizer approximately 17.5 nautical miles from the airport while descending from 5,200 feet to 4,800 feet. At the time of the encounter, the separation between the two aircraft was approximately 4.8 nautical miles.

Aircraft Response

During the wake turbulence encounter, the vertical acceleration of Flight 146 varied from 2.3679 g's to 0.5542 g's, indicating significant turbulence.

Conclusion

No other details regarding injuries or damage were provided in the source.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X11023. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.