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SEA89LA177 · Bell 47G

25 Sept 1989 · Corvallis, OR, United States

Bell 47G · Accident: hard landing while maneuvering

From Corvallis Municipal Airport (CVO) to an unrecorded destination

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Event

NTSB case
SEA89LA177
Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
Accident
InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
Completed
API-reported fatalities
0 · all aircraft and ground
Ground fatalities
0
OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
General aviation
WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
Visual Meteorological Cond

Bell 47G

Aircraft type
Bell 47
Category
Helicopter
RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
N47VS
Operator
Unknown
Onboard fatalities
Unknown
Route
From Corvallis Municipal Airport (CVO), Corvallis, ORTo not recorded
Aircraft age
Not recorded
Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
Part 91: General Aviation
Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
Maneuvering · hover
First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
Hard landing
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
Destroyed

Cause areas

  • Dual student › Collective, improper use of
  • Engine assembly, mount › Corroded
  • Engine assembly, mount › Fractured
  • Engine assembly, mount › Previous damage
  • Pilot in command(cfi) › Supervision, inadequate

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

WHILE PRACTICING HOVERING AUTOROTATIONS ON AN ASPHALT TAXIWAY SEVERAL HARD LANDINGS OCCURRED AS A RESULT OF THE STUDENT'S DIFFICULTY LEARNING THE PROPER APPLICATION OF COLLECTIVE PITCH. THE CFI THEN INSTRUCTED THE STUDENT TO MOVE TO A SOD AREA ADJACENT TO THE TAXIWAY FOR THE CUSHIONING EFFECT TO REDUCE IMPACT FORCES ON THE AIRCRAFT. THE CFI SAID HE DID NOT INSPECT THE AIRCRAFT FOR DAMAGE AFTER THE HARD LANDINGS ON THE TAXIWAY. THE STUDENT THEN PERFORMED ONE HOVERING AUTOROTATION ON THE SOD AREA, AND DURING THE SUBSEQUENT HOVER CONTROL WAS LOST. THE AIRCRAFT ROLLED OVER AND IMPACTED THE GROUND. HEAVY SKID IMPACT MARKS WERE FOUND ON THE TAXIWAY. THE ENGINE MOUNT TUBULAR STRUCTURE AT THE BOTTOM MOUNT, AND THE CROSS MEMBER SUPPORT TUBES, WERE FRACTURED. THE WALLS OF THE TUBES WERE OF IRREGULAR THICKNESS, CONTAINED EXTENSIVE CORROSION SCALING, AND IN SOME PLACES COULD BE BENT BY HAND. THE BOTTOM OF THE ENGINE, WHICH IS MOUNTED TO THE TRANSMISSION AND MAIN ROTOR MAST, WAS FREE TO MOVE. LAST ANNUAL INSP. FIVE DAYS BEFORE ACCIDENT.

Probable cause

STUDENT PILOT'S IMPROPER USE OF THE COLLECTIVE CONTROL WHILE PERFORMING HOVERING AUTOROTATIONS, AND THE INSTRUCTOR'S INADEQUATE SUPERVISION OF THE STUDENT'S ACTIONS, WHICH RESULED IN HARD LANDINGS. IN ADDITION, THE ENGINE MOUNT WAS SIGNIFICANTLY WEAKENED STRUCTUALLY AS A RESULT OF CORROSION.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record SEA89LA177
Event ID
20001213X29505
Case number
SEA89LA177
Dataset
historical-pre2008
Source SHA-256
89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
  • Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
  • Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
  • The date is the local date, which is the same as the UTC date the NTSB stores.
  • API snapshot SHA-256: 0e0331a871758ffbd9f9332f7d0fb7e7db0c93c7fa1c5c3b51fe9a5a87885b02; retrieved 2026-09-22T00:01:54.852Z.