Embraer EMB-135KL and Embraer EMB-145LR incident near Chicago, Illinois, August 8, 2011
On August 8, 2011 at about 4:00 pm local time, 2 aircraft, Embraer EMB-135KL (N377SK) and Embraer EMB-145LR (N845HK), were involved in the same incident near Chicago, Illinois (Chicago O'Hare International airport). No one was hurt; 84 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The improper air traffic control takeoff clearance issued by the local controller because of his lack of monitoring and lack of awareness of the conflicting arrival airplane.
The improper air traffic control takeoff clearance issued by the local controller because of his lack of monitoring and lack of awareness of the conflicting arrival airplane.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 8, 2011 · about 4:00 pm local time · cases in 2011
- Place
- Chicago, Illinois · Chicago O'Hare International · cases near this airport · map
- Type
- Incident
- Injuries
- No one was hurt; 84 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft 1
- Embraer EMB-135KL · all EMB-135KLs on the register
- Registration
- N377SK · no longer on the register · serial 145579
- Damage
- Not recorded
- Flight
- Flight · scheduled airline rules (Part 121)
- Aircraft 2
- Embraer EMB-145LR · all EMB-145LRs on the register
- Registration
- N845HK · no longer on the register · serial 14500842
- Damage
- Not recorded
- Flight
- Flight · scheduled airline rules (Part 121)
The NTSB's narrative for the Embraer EMB-135KL final · quoted from the NTSB record
A near-midair collision occurred when an Embraer ERJ-145 regional jet departing from runway 32L passed within close proximity to an Embraer ERJ-135 regional jet on approach to runway 9R. The local controller had cleared the ERJ-145 for takeoff without ensuring that adequate spacing existed between the ERJ-145 and the approaching ERJ-135. The ERJ-135 was instructed to go around, but the two airplanes passed within 125 feet vertically and 350 feet horizontally of each other above runway 32L. When interviewed, the local controller stated that he had overlooked the arriving airplane during his scan, possibly because he was distracted by coordination requirements affecting two other airplanes.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The NTSB's narrative for the Embraer EMB-145LR final · quoted from the NTSB record
A near-midair collision occurred when an Embraer ERJ-145 regional jet departing from runway 32L passed within close proximity to an Embraer ERJ-135 regional jet on approach to runway 9R. The local controller had cleared the ERJ-145 for takeoff without ensuring that adequate spacing existed between the ERJ-145 and the approaching ERJ-135. The ERJ-135 was instructed to go around, but the two airplanes passed within 125 feet vertically and 350 feet horizontally of each other above runway 32L. When interviewed, the local controller stated that he had overlooked the arriving airplane during his scan, possibly because he was distracted by coordination requirements affecting two other airplanes.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record for the Embraer EMB-135KL from the NTSB's investigation tables, in plain English
What happened, in order
- Air traffic event during approach (IFR missed approach) defining event
The NTSB's findings
- cause Personnel issues › Action/decision › Action › Incorrect action selection › ATC personnel
- cause Personnel issues › Action/decision › Info processing/decision › Understanding/comprehension › ATC personnel
The aircraft
- Seats: 37
- Landing gear: fixed
- Engine 1: Rolls-Royc AE 3007A1P (turbojet); 0 hours total
- Engine 2: Rolls-Royc AE 3007A1P (turbojet); 0 hours total
- Operator: Chautauqua Airlines INC
The flight
- Departed from: LSE La Crosse WI
- Destination: ORD Chicago IL
- Flight plan: IFR
- Runway 32L, 9,685 ft by 200 ft
Weather at the time
- Light: daylight
- Wind: from 090° at 5 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 18,000 ft; scat at 3,200 ft
- Temperature: 77°F (25°C), dew point 66°F (19°C)
- Altimeter: 29.77 inHg
- Observation at 3:51 pm from ORD
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Cabi | 1 | |||
| Flight crew | 2 | |||
| Passengers | 36 |
The factual record for the Embraer EMB-145LR from the NTSB's investigation tables, in plain English
What happened, in order
- Air traffic event during takeoff defining event
The NTSB's findings
- cause Personnel issues › Action/decision › Action › Incorrect action selection › ATC personnel
- cause Personnel issues › Action/decision › Info processing/decision › Understanding/comprehension › ATC personnel
The aircraft
- Seats: 55
- Landing gear: fixed
- Engine 1: Rolls-Royc AE3007 SER (turbofan); 0 hours total
- Engine 2: Rolls-Royc AE3007 SER (turbofan); 0 hours total
- Operator: Trans States Airlines LLC
The flight
- Departed from: ORD Chicago IL
- Destination: MLI Moline IL
- Flight plan: IFR
- Runway 32L, 9,685 ft by 200 ft
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Cabi | 1 | |||
| Flight crew | 2 | |||
| Passengers | 42 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The NTSB has not released the docket for this case yet. The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), is usually released when the investigation is nearly complete, and the list here is refreshed when it appears. Check at the NTSB.
Other NTSB records under N377SK the same tail number, which may have belonged to a different aircraft at the time
Connections how this case links to the rest of the register
- N377SK: not on the register today · the record of its deregistration
- Embraer EMB-135 ERJ 135 and Legacy 119 registered today · the model family and its accident history
- Embraer 663 aircraft on the register
- N845HK: not on the register today · the record of its deregistration
- Embraer EMB-145 ERJ 145 313 registered today · the model family and its accident history
- Embraer 663 aircraft on the register
- Engine: Rolls-Royc AE 3007A1P 59 aircraft carry this series today · as the NTSB recorded it
- Engine: Rolls-Royc AE 3007A1P 59 aircraft carry this series today · as the NTSB recorded it
- Chicago O'Hare International · nearest airport
- LA Crosse Regional · departed from
- Quad Cities International · bound for
- Accidents and incidents in Illinois 2,118 since 1982 · 251 in the last ten years
- Illinois 8,069 aircraft registered
- Other NTSB records under N377SK 1 records · the number may have belonged to another aircraft at the time
The whole map of how records connect · these connections as data: /graph/accident/OPS11IA819.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.