Aerospatiale ATR-42-300 N235RM

Summary

On 20 November 1991 at about 19:43 local time, a Aerospatiale ATR-42-300 registered N235RM, operated by Simmons Airlines Inc., was involved in an incident near Chicago, Illinois, United States. 22 people were on board and one had minor injuries. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

20 November 1991 at 19:43

Classification

Incident

Location

Chicago, Illinois, United States

Coordinates

Not recorded

Aircraft

Aerospatiale ATR-42-300

Registration

N235RM

Category

Airplane

Engines

2

Operator

Simmons Airlines Inc.

Operating rule

Part 121: Air Carrier

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

South Bend → Unknown

Aircraft damage

Not recorded

Weather

VMC

Light

Day

NTSB number

CHI92IA030

1 person had minor injuries.

AN INFLIGHT ENCOUNTER WITH WAKE TURBULENCE DURING CRUISE FLIGHT.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

THE INCIDENT AIRPLANE ENCOUNTERED VORTEX TURBULENCE WHILE FOLLOWING RADAR VECTORS FOR LANDING SEQUENCE. THE AIRPLANE WAS NOT DAMAGED. A FLIGHT ATTENDANT SUSTAINED MINOR INJURIES DURING THE ENCOUNTER. THE AIRPLANE WAS OPERATING IN A TERMINAL CONTROL AREA UNDER POSITIVE RADAR CONTROL. FAA RECORDS AND RADAR TRACK DATA SHOW A LIKE CATEGORY AIRPLANE WAS APPROXIMATELY 4 NAUTICAL MILES IN FRONT OF THE INCIDENT AIRPLANE WHEN IT DESCENDED TO AND MAINTAINED THE SAME ALTITUDE AS THE INCIDENT AIRPLANE. THE INCIDENT AIRPLANE WAS PROCEEDING ALONG APPROXIMATELY THE SAME GROUND TRACK AS THE LEAD AIRPLANE AND ENCOUNTERED THE TURBULENCE NEAR THE POINT THE LEAD AIRPLANE LEVELED AT THE SAME ALTITUDE. AT THE TIME OF THE ENCOUNTER THE LATERAL SEPARATION OF THE TWO AIRPLANES WAS 4.6 NAUTICAL MILES. THE MINIMUM ATC SEPARATION IN A RADAR ENVIRONMENT WHEN THE AIRCRAFT ARE WITHIN 40 NAUTICAL MILES OF THE RADAR ANTENNA IS THREE NAUTICAL MILES.

Quoted verbatim from the NTSB record.