# NTSB CHI87FA015: Sikorsky S-58ET, N4247S, Becker, MN, November 4, 1986

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: November 4, 1986, 16:45 local (22:45 UTC)
- Place: Becker, MN
- Coordinates: 45.440483, -93.829956 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.4405&lon=-93.8300&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed, report March 7, 1988
- Report: Approved by Office Director
- NTSB case key (mKey): 13619
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI87FA015
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/13619/pdf
- Page: https://openairdocs.org/ntsb/CHI87FA015

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Loss of engine power(total) - nonmechanical, hover
  - planning/decision - improper, pilot in command (cause)
  - fluid,fuel - low level (contributing factor)
  - fluid,fuel - starvation (cause)
  - fuel system - improper use of, pilot in command (cause)
  - aircraft performance,two or more engines - inoperative
- Forced landing, maneuvering - turn to landing area (emergency)
  - autorotation
- In flight collision with object, maneuvering - turn to landing area (emergency)
  - object - building(nonresidential) (contributing factor)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

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.

## Aircraft

- Registration: [N4247S](https://openairdocs.org/deregistered/N4247S-1989-12-15), registration cancelled 1989-12-15, S/N 581493 (OpenAirDocs)
- Reported make and model: SIKORSKY S-58ET
- Registry model: [Sikorsky S-58T](https://openairdocs.org/model/sikorsky-s-58t) (registry code 8141800) (OpenAirDocs)
- Category: Helicopter
- Serial number: 58-1493
- Airframe hours: 4136
- Engines: P&W PT6T-6 970 horsepower turbo shaft
- Damage: Substantial damage
- Fire: On-Ground
- Flight: Other work use, Part 133
- Operator: Helicopter Corp.
- Registered owner: North American Helicopter Inc.
- Airworthiness certificate: Standard, Transport

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 36; commercial; instrument ratings: helicopter; medical: class 2, valid medical--no waivers/lim.; seat: right; toxicology performed; flight hours: 9,961 total, 172 in this make and model, 9,041 as pilot in command, 169 in the last 90 days, 45 in the last 30 days, 7 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 180° at 8 knots
- Visibility: 50 statute miles
- Lowest ceiling: none
- Temperature: 46 °F
- Altimeter: 30.00 inHg

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19861104053349A](https://openairdocs.org/incident/19861104053349A), Nov 4, 1986: Skrsky S58ET, Becker, MN, Substantial damage. Lost power with sling load. Rotor struck conveyor. Ground impact nose down. Fuel contamination and mismanagement.

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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