Amateur-built SHD-6 incident near Chicago, Illinois, March 21, 1993
On March 21, 1993 at about 2:06 pm local time, a amateur-built SHD-6, registered N374MQ, was involved in an incident near Chicago, Illinois (O'Hare Int'L Airport). It was a flight of an unrecorded kind under scheduled airline rules (Part 121). No one was hurt; 3 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE LOCAL CONTROLLER'S FAILURE TO MAINTAIN 3 MILES RADAR SEPARATION BETWEEN TWO AIRPLANES. A FACTOR RELATED TO THE INCIDENT WAS THE LOCAL CONTROLLER'S DELAY IN REMEDIAL ACTION.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 21, 1993 · about 2:06 pm local time
- Place
- Chicago, Illinois · O'Hare Int'L Airport
- Type
- Incident
- Injuries
- No one was hurt; 3 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built SHD-6
- Registration
- N374MQ · no longer on the register
- Damage
- Not recorded
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
THE CONTROLLER ISSUED A TAKEOFF CLEARANCE FOR SIMMONS 4085 TO FLY THE RUNWAY HEADING. UNITED 556 WAS NEXT TO TAKEOFF AND WAS ISSUED A CLEARANCE TO FLY A HEADING OF 140 DEGREES AFTER TAKEOFF. THE PILOT DID NOT TURN IMMEDIATELY TO 140 DEGREES AND SEVERAL ATTEMPTS BY THE CONTROLLER TO CONTACT THE FLIGHT WERE TO NO AVAIL. IN AN ATTEMPT TO PREVENT THE UNITED FLIGHT FROM OVERTAKING THE SLOWER SIMMONS FLIGHT, THE CONTROLLER STOPPED UNITED FROM CLIMBING. RADAR SEPARATION OF 3 MILES HAD ALREADY BEEN LOST BY TIME THE UNITED FLIGHT STOPPED ITS CLIMB.
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 from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot, commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 10,000 hours in all
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Last inspection: inspection type not recorded
- Maximum gross weight: 12,500 lb
- Seats: 20
- Landing gear: retractable
- Engine: P&W PT6A (turboprop); 0 hours total
The flight
- Departed from: ORD at 2:02 pm
- Destination: DEC Decatur IL
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 250° at 6 knots
- Visibility: 5 statute miles
- Sky: overcast at 3,700 ft; not recorded at 3,700 ft
- Temperature: 34°F (1°C), dew point 30°F (-1°C)
- Altimeter: 30.00 inHg
- Observation at 1:50 pm from ORD
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 3 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
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 never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.