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Accidents · NTSB ANC84LA034 · Preliminary: the investigation is not finished

Helio H-250 accident near Iliamna, Alaska, February 1, 1984

On February 1, 1984 at about 8:25 pm local time, a Helio H-250, registered N5966X, was substantially damaged in an accident near Iliamna, Alaska (Iliamna airport). It was a personal flight under general aviation rules (Part 91). 1 person was seriously injured. 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 12, 2026. Docket and reports at the NTSB.

What the record shows

Date
February 1, 1984 · about 8:25 pm local time · cases in 1984
Place
Iliamna, Alaska · Iliamna · cases near this airport · map
Type
Accident
Injuries
1 person was seriously injured.
Weather
visual conditions (good weather)
Aircraft
Helio H-250 · all H-250s on the register
Registration
N5966X · no longer on the register · serial 2529
Damage
Substantial damage
Flight
Personal flight · general aviation rules (Part 91)

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

ACCORDING TO WITNESSES, THE SKI EQUIPPED ACFT TOOK OFF TOWARD THE NORTH. THEY REPORTED THAT AFTER TAKING OFF, THE ACFT MADE A TIGHT LEFT TURN, THEN SPIRALED TO THE GROUND. THEY ESTIMATED THAT THE MAXIMUM ALT WAS APRX 150 FT. ALSO, THEY REPORTED THAT THE ENG WAS DEVELOPING FULL POWER UNTIL THE TIME OF IMPACT. THE 1229 ADT WINDS WERE FROM 010 DEG AT 19 GUSTING 27 KTS.

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: private
  • Ratings: single-engine land
  • Medical certificate: Class 2 (expired)
  • Seat: left

The aircraft

  • Last inspection: inspection type not recorded
  • Maximum gross weight: 3,400 lb
  • Seats: 6
  • Landing gear: fixed
  • Engine: Lycoming O-540-A1A5 (piston); 0 hours total

The flight

  • Destination: 5NN Nondalton AK
  • Flight plan: none
  • Runway 35, 4,800 ft by 150 ft

Weather at the time

  • Light: daylight
  • Wind: from 010° at 19 knots, gusting 27
  • Visibility: 25 statute miles
  • Sky: overcast at 3,000 ft; not recorded at 3,000 ft
  • Temperature: 0°F (-18°C), dew point 0°F (-18°C)
  • Altimeter: 29.00 inHg
  • Observation at 9:29 pm from ILI

Injuries

FatalSeriousMinorNone
Crew1

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.

Connections how this case links to the rest of the register

Aircraft
Place
Analytics

The whole map of how records connect · these connections as data: /graph/accident/ANC84LA034.json.

The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.

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 does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.