Sikorsky S-76A accident near Chicago, Illinois, September 14, 1983
On September 14, 1983 at about 11:23 pm local time, a Sikorsky S-76A (helicopter), registered N521AC, was destroyed in an accident near Chicago, Illinois. It was an executive or corporate flight under general aviation rules (Part 91). 3 people had minor injuries; 3 others were unhurt. 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 accident. 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
- September 14, 1983 · about 11:23 pm local time
- Place
- Chicago, Illinois · map
- Type
- Accident
- Injuries
- 3 people had minor injuries; 3 others were unhurt.
- Weather
- visual conditions (good weather)
- Aircraft
- Sikorsky S-76A · all S-76As on the register
- Registration
- N521AC · no longer on the register · serial 760159
- Damage
- Destroyed
- Flight
- Executive or corporate flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
WHILE CRUISING AT 2000 FT MSL & 150 KTS, THE CREW HEARD A LOUD NOISE, AND SIMULTANEOUSLY, THE HELICOPTER YAWED APRX 30 TO 40 DEG TO THE RIGHT & PITCHED NOSE DOWN. THE AIRCREW BEGAN AN AUTOROTATION & ACTIVATED THE EMERGENCY FLOATS. THE HELICOPTER CONTINUED IN A RIGHT DESCENDING TURN DURING THE AUTOROTATION. TOUCHDOWN IN THE WATER (LAKE MICHIGAN) OCCURRED WITH A FORWARD SPEED OF ABOUT 40 TO 50 KTS. AFTER CONTACTING THE WATER, THE HELICOPTER TURNED AN ADDITIONAL 180 DEG, THEN LISTED ABOUT 10 DEG TO THE LEFT. THE OCCUPANTS DONNED THEIR LIFE VESTS & EXITED THE HELICOPTER. ABOUT 11 TO 13 MINUTES AFTER LANDING, THE ACFT ROLLED OVER IN THE WATER & EVENTUALLY SUNK. THE OCCUPANTS WERE RESCUED BEFORE THE HELICOPTER SANK. AN INVESTIGATION REVEALED THAT THE LEFT SIDE TAIL ROTOR CABLE. PN 76400-03191-043, HAD FAILED WHERE IT HAD BEEN RUBBING. THE RUBBING WAS ATTRIBUTED TO INCORRECT ROUTING OF THE CABLE.
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, flight instructor
- Ratings: multi-engine land; single-engine land; instructor: airplane single-engine; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 3,730 hours in all; 220 in this make and model; 3,296 as pilot in command
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 631 hours
- Last inspection: 100-hour inspection, September 13, 1983; 1 hours since
- Maximum gross weight: 10,000 lb
- Seats: 7
- Landing gear: fixed
- Engine: Allison 250-C30 (turboshaft); 0 hours total
The flight
- Departed from: CGX Chicago IL
- Destination: GRR Grand Rapids MI
- Flight plan: none
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 360° at 10 knots
- Visibility: 20 statute miles
- Sky: clear
- Temperature: 68°F (20°C), dew point 0°F (-18°C)
- Altimeter: 30.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 | |||
| Passengers | 3 | 1 |
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.