The U.S. aircraft register, updated daily · Carbon Free Flight by 2050
Accidents · NTSB SEA91FA143 · Final report

Sikorsky S-64E accident near Index, Washington, June 27, 1991

On June 27, 1991 at about 9:05 pm local time, a Sikorsky S-64E (helicopter), registered N6959R, was destroyed in an accident near Index, Washington. It was an other work-use flight under external-load helicopter rules (Part 133). 2 people were seriously injured. The weather was visual conditions (good weather).

Preview. This page is not yet listed for search engines.

The NTSB's probable cause their words, unchanged

THE CONTROL INTERFERENCE BY THE MECHANIC WHEN HE INADVERTENTLY RAISED THE COLLECTIVE PITCH AND THE COPILOT'S FAILURE TO ATTEND THE FLIGHT CONTROLS. FACTORS RELATING TO THE ACCIDENT WERE THE MOTION SICKNESS OF THE MECHANIC, INADEQUATE COLLECTIVE PITCH CONTROL LOCKING MECHANISM UTILIZED BY THE COMPANY, AND ADMINISTRATIVE TASKS THAT DIVERTED THE CO-PILOT'S ATTENTION FROM ATTENDING THE FLIGHT CONTROLS.

Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.

What the record shows

Date
June 27, 1991 · about 9:05 pm local time
Place
Index, Washington · map
Type
Accident
Injuries
2 people were seriously injured.
Weather
visual conditions (good weather)
Aircraft
Sikorsky S-64E · all S-64Es on the register
Registration
N6959R · no longer on the register · serial 64002
Damage
Destroyed
Flight
Other work-use flight · external-load helicopter rules (Part 133)

The NTSB's narrative final · quoted from the NTSB record

THE ACFT WAS ON AN EXTERNAL LOAD LOGGING OPN AND THE PIC HAD LANDED AT A FIELD SITE TO REFUEL. THE PIC EXITED, WITH THE ACFT RUNNING AT FULL RPM WHILE IT WAS BEING REFUELED, AND THE COPILOT REMAINED IN THE RIGHT SEAT COMPLETING LOAD REPORTS. THE ACFT CONTROLS WERE UNATTENDED. THE CREW CHIEF WAS SEATED IN THE AFT FACING HOIST OPR STATION, WHICH HAD THE COLLECTIVE PITCH STICK INSTALLED BESIDE THE SEAT. HE HAD BECOME AIR SICK DURING THE FLT, AND REMAINED SEATED AFTER THE PIC EXITED. WHEN HE ATTEMPTED TO EXIT, WHICH REQUIRED THAT HE STAND, TURN AROUND AND STEP UP OUT OF THE SEAT WELL, THE ACFT TOOK OFF TO A HOVER AND ROTATED TO THE LEFT. THE TAIL ROTOR STRUCK A ROTOR BLADE BOX ON TOP OF A SUPPORT TRAILER PARKED BY THE REFUELING SITE, FRACTURING THE AFT TAIL BOOM, PYLON AND TAIL ROTOR FROM THE ACFT. THE ACFT PITCHED NOSE DOWN, ROLLED OVER AND IMPACTED THE GROUND.

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: multi-engine land; single-engine land; instrument: airplane; rotorcraft: glider; rotorcraft: helicopter
  • Flight time: 17,000 hours in all; 9,000 in this make and model; 110 in the last 90 days; 48 in the last 30 days; 15,000 as pilot in command
  • Medical certificate: Class 1 (valid medical--no waivers/lim.)
  • Seat: unk

The aircraft

  • Last inspection: inspection type not recorded; 0 hours since
  • Maximum gross weight: 42,000 lb
  • Seats: 3
  • Landing gear: fixed
  • Engine: P&W JFTD12A4A (turboshaft); 0 hours total
  • Fire on the ground
  • Operator: Erickson Air Crane CO.

The flight

  • Departed from: NONE Index WA at 8:15 pm
  • Flight plan: none
  • Runway 0
  • A second pilot was aboard

Weather at the time

  • Light: daylight
  • Wind: from 340° at 13 knots
  • Visibility: 35 statute miles
  • Sky: scat at 2,500 ft
  • Temperature: 70°F (21°C), dew point 52°F (11°C)
  • Altimeter: 29.00 inHg
  • Observation at 8:52 pm from PAE, 38 miles away

Injuries

FatalSeriousMinorNone
Crew2

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.

About this page

Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number SEA91FA143.