Piper PA-42-720 and Mcdonnell Douglas DC-10 incident near Chicago, Illinois, May 11, 1988
On May 11, 1988 at about 8:18 pm local time, 2 aircraft, Piper PA-42-720 (N900MP) and Mcdonnell Douglas DC-10 (DADSO), were involved in the same incident near Chicago, Illinois (Chicago O'Hare Intl airport). No one was hurt; 274 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The NTSB has not yet published a probable cause for this incident. Investigations usually take one to two years; this page updates when the final report is released.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 11, 1988 · about 8:18 pm local time
- Place
- Chicago, Illinois · Chicago O'Hare Intl · map
- Type
- Incident
- Injuries
- No one was hurt; 274 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft 1
- Piper PA-42-720 · all PA-42-720s on the register
- Registration
- N900MP · registry record · serial 42-5501014
- Damage
- Not recorded
- Flight
- Business flight · general aviation rules (Part 91)
- Aircraft 2
- Mcdonnell Douglas DC-10 · all DC-10s on the register
- Registration
- DADSO · no longer on the register
- Damage
- Not recorded
- Flight
- Flight of an unrecorded kind · foreign airline rules (Part 129)
The NTSB's narrative for the Piper PA-42-720 final · quoted from the NTSB record
CONDOR FLT 610 (MCDONNELL DOUGLAS DC-10, GERMAN REGISTRATION: DADSO) WAS APRX 2 HRS LATE AS THE FLT CREW MEMBERS WERE PREPARING TO TAKEOFF. SUBSEQUENTLY, FLT 610 WAS CLRD FOR TAKEOFF WITH INSTRUCTIONS TO CROSS THE 5 DME (ON THE STANDARD INSTRUMENT DEPARTURE/SID) AT OR ABOVE 3000 FT. THE TAKEOFF CLNC WAS THEN CANCELED, BUT WAS REISSUED ABOUT 1 MIN LATER WITH THE SAME RESTRICTIONS. AT ABT THAT TIME, THE FLT WAS EXACTLY 2 HRS OVERDUE & THE COMPUTER DROPPED THE FLT PLAN DATATAG & BLOCK (AS PROGRAMMED TO HANDLE OVERDUE/UNUSED FLT PLANS). AFTER TAKEOFF, FLT 610 CONTACTED DEPARTURE CTL. THE CTLR NOTED ONLY A PRIMARY TRANSPONDER TARGET & OBSERVED NO ALT DATA. MEANWHILE, PIPER PA-42, N900MP, WAS ON AN IFR ARRIVAL FOR A VISUAL APCH TO PAL-WAUKEE ARPT AT 2800 FT. SUBSEQUENTLY, THE TWO ACFT CONVERGED & PASSED WITH ABOUT 2 MI (HORIZONTAL) & 200 FT (VERTICAL) SEPN. INTERVIEWS WITH THE CTLRS REVEALED THEY HAD INTENDED FLT 610 TO CLIMB TO 5000 FT AS PROVIDED BY THE SID. THE ERROR WAS NOT NOTED (WITH THE DATA TAG DROPPED FROM THE COMPUTER).
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 Mcdonnell Douglas DC-10 final · quoted from the NTSB record
CONDOR FLT 610 (MCDONNELL DOUGLAS DC-10, GERMAN REGISTRATION: DADSO) WAS APRX 2 HRS LATE AS THE FLT CREW MEMBERS WERE PREPARING TO TAKEOFF. SUBSEQUENTLY, FLT 610 WAS CLRD FOR TAKEOFF WITH INSTRUCTIONS TO CROSS THE 5 DME (ON THE STANDARD INSTRUMENT DEPARTURE/SID) AT OR ABOVE 3000 FT. THE TAKEOFF CLNC WAS THEN CANCELED, BUT WAS REISSUED ABOUT 1 MIN LATER WITH THE SAME RESTRICTIONS. AT ABT THAT TIME, THE FLT WAS EXACTLY 2 HRS OVERDUE & THE COMPUTER DROPPED THE FLT PLAN DATATAG & BLOCK (AS PROGRAMMED TO HANDLE OVERDUE/UNUSED FLT PLANS). AFTER TAKEOFF, FLT 610 CONTACTED DEPARTURE CTL. THE CTLR NOTED ONLY A PRIMARY TRANSPONDER TARGET & OBSERVED NO ALT DATA. MEANWHILE, PIPER PA-42, N900MP, WAS ON AN IFR ARRIVAL FOR A VISUAL APCH TO PAL-WAUKEE ARPT AT 2800 FT. SUBSEQUENTLY, THE TWO ACFT CONVERGED & PASSED WITH ABOUT 2 MI (HORIZONTAL) & 200 FT (VERTICAL) SEPN. INTERVIEWS WITH THE CTLRS REVEALED THEY HAD INTENDED FLT 610 TO CLIMB TO 5000 FT AS PROVIDED BY THE SID. THE ERROR WAS NOT NOTED (WITH THE DATA TAG DROPPED FROM THE COMPUTER).
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 Piper PA-42-720 from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot, flight instructor
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 8,000 hours in all; 5,000 in this make and model
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Last inspection: inspection type not recorded
- Maximum gross weight: 11,200 lb
- Seats: 11
- Landing gear: retractable
- Engine: P&W PT6A-61 (turboprop); 0 hours total
The flight
- Departed from: BNA Nashville TN at 7:00 pm
- Destination: PWK Chicago IL
- Flight plan: IFR
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 160° at 5 knots
- Visibility: 7 statute miles
- Sky: broken clouds at 25,000 ft; not recorded
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
- Altimeter: 30.00 inHg
- Observation at 8:23 pm from ORD, 7 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 | |||
| Passengers | 1 |
The factual record for the Mcdonnell Douglas DC-10 from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; instrument: airplane
- Flight time: 12,000 hours in all; 1,088 in this make and model
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Last inspection: inspection type not recorded
- Maximum gross weight: 572,000 lb
- Seats: 297
- Landing gear: retractable
- Engine: Ge CF6 (turbofan); 0 hours total
The flight
- Departed from: ORD Chicago IL at 8:14 pm
- Destination: Frnkfrt,Germany OF
- Flight plan: IFR
- Runway 32R, 10,003 ft by 150 ft
- A second pilot was aboard
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 12 | |||
| Passengers | 259 |
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.