Sikorsky S-58ET accident near Becker, Minnesota, November 4, 1986
On November 4, 1986 at about 10:45 pm local time, a Sikorsky S-58ET (helicopter), registered N4247S, was substantially damaged in an accident near Becker, Minnesota. It was an other work-use flight under external-load helicopter rules (Part 133). 1 person was killed. 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
- November 4, 1986 · about 10:45 pm local time
- Place
- Becker, Minnesota · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Sikorsky S-58ET · all S-58ETs on the register
- Registration
- N4247S · registry record · serial 58-1493
- Damage
- Substantial damage
- Flight
- Other work-use flight · external-load helicopter rules (Part 133)
The NTSB's narrative final · quoted from the NTSB record
THE HELICOPTER (HEL) WAS BEING USED ON AN EXTERNAL LOAD OPN TO PSN A 2500 LB VENTILATOR TO THE ROOF OF A BLDG. ON THE NEXT TO LAST LOAD, THE PLT RADIOED THAT HE NOTED A MOMENTARY ILLUMINATION OF THE FUEL BYPASS ADVISORY LIGHT. HE ELECTED TO CONT THE OPN & RETURNED TO THE STAGING AREA TO PICK UP THE 2500 LB LOAD. WHEN THE LOAD WAS APRX 8' FM THE ROOF TOP, WITNESSES NOTED THE LOAD (& HEL) BGN TO SETTLE. THE PLT RLSD THE LOAD AS THE ROTOR RPM BGN DECREASING & MNVRD AWAY FM THE ROOF. THE HEL HOVERED MOMENTARILY OVR AN ELEVATED CONVEYOR, THEN THERE WAS AN ADNL LOSS OF RPM. AS THE HEL DSCNDD, THE MAIN & TAIL ROTORS HIT THE CONVEYOR & THE HEL FELL APRX 150' & CRASHED IN A NOSE DOWN ATTITUDE. THE FWD FUEL BLADDERSPLIT OPEN DRG IMPACT. THE AFT FUEL BLADDER CONTAINED A USABLE, BUT UNDETERMINED, AMOUNT OF FUEL. DIRT WAS FND IN THE FUEL BLADDERS & FUEL FILTERS, BUT NO FUEL BLOCKAGE WAS NOTED. FUEL X-FEED SELECTOR & VLV WERE FND IN THE OPEN PSN. THE FLT MANUAL LIMITS THE USE OF X-FEED FOR EMERGENCY & CRUISE FLT ONLY; BOOST PUMP MUST BE ON WHEN UNUSED TANK IS EMPTY.
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: commercial pilot
- Ratings: instrument: helicopter; rotorcraft: helicopter
- Flight time: 9,961 hours in all; 172 in this make and model; 169 in the last 90 days; 45 in the last 30 days; 9,041 as pilot in command
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 4,136 hours
- Last inspection: approved inspection programme; 50 hours since
- Maximum gross weight: 13,000 lb
- Seats: 7
- Landing gear: fixed
- Engine: P&W PT6T-6 (turboshaft); 0 hours total
- Fire on the ground
- Operator: Helicopter CORP.
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 180° at 8 knots
- Visibility: 50 statute miles
- Sky: clear
- Temperature: 46°F (8°C), dew point 0°F (-18°C)
- Altimeter: 30.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 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.