Corvallis Airport
Aircraft Accident/Incident Report

Corvallis, Oregon 97330
Monday, September 25, 1989 10:10 PDT

NTSB Narrative Summary Released at Completion of Accident

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.

NTSB Probable Cause Narrative

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.

Event Information

Type of Event Accident
Event Date 9/25/1989
Event Day of the Week Monday
Time of Event 1010
Event Time Zone Pacific Daylight Time
Event City CORVALLIS
Event State OREGON
Event Country --
Zipcode of the event site 97330
Event Date Year 1989
Event Date Month 9
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport CORVALLIS
Event Location Nearest Airport ID CVD
Indicates whether the acc/inc occurred off or on an airport On Airport
Distance from airport in statute miles 0
Degrees magnetic from airport 0
Airport Elevation 245
Weather Briefing Completeness Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 1000 Pacific Daylight Time
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID CVO
Elevation of weather observation facility 245
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation PDT
Lighting Conditions Day
Lowest Ceiling Height 4000
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Unknown
Sky Condition for Lowest Ceiling Overcast
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 21
Dew Point at event time (in degress fahrenheit) 13
Wind Direction (degrees magnetic) 0
Variable Wind Indicator Unknown
Wind Speed (knots) 0
Wind Velocity Indicator Calm
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) 995
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor 1
Injury Total None 1
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 2020
NTSB Notification Source --
NTSB Notification Date Sep 25 1989 12:00AM
NTSB Notification Time 1030
Fiche Number and/or location -used to find docket information 41216
Date of most recent change to record Dec 13 2000 1:04PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N47VS
NTSB Number SEA89LA177
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Destroyed
Aircraft Fire Ground
Aircraft Explosion None
Aircraft Manufacturer's Full Name BELL
Aircraft Model 47G
Aircraft Series Identifier 47G
Aircraft Serial Number 1394
Certified Max Gross Weight 2350
Aircraft Category Helicopter
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 3
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Sep 20 1989 12:00AM
Airframe hours since last inspection 1
Airframe Hours 8148
ELT Installed No
ELT Activated No
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name ALI A. BROWN
Aircraft Owner Street Address 2857 NW AUDENI
Aircraft Owner City CORVALLIS
Aircraft Owner State OR
Aircraft Owner Country
Aircraft Owner Zipcode 97330
Operator is an individual? --
Operator Name
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address
Operator City
Operator State
Operator Country
Operator Zip code
Operator Code 06
Owner has at least one certificate None
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Instructional
Second Pilot on Board Yes
Departure Point Same as Event Yes
Departure Airport Code CVO
Departure City CORVALLIS
Departure State OR
Departure Country
Departure Time 925
Departure Time Zone PDT
Destination Same as Local Flt dest & departure same, accident can occur anywhere
Destination Airport Code
Destination City
Destination State
Destination Country
Specific Phase of Flight Other
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:30AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --