Flagstaff Pullium Airport
Aircraft Accident/Incident Report

Flagstaff, Arizona 86001
Monday, November 4, 1996 8:23 MST

NTSB Narrative Summary Released at Completion of Accident

The test pilot made a successful preplanned autorotation to a runway in the test helicopter for certification purposes. The aircraft was operated at a designed maximum gross weight to establish a height velocity curve for future operations in high density altitudes. During the ground slide, the main rotor blades contacted and severed the tail boom. Various combinations of engineering design and the 'blowback' phenomena allowed the retreating main rotor blades to tilt downward and contact the tail boom.

NTSB Probable Cause Narrative

An uncommanded main rotor blade to tail boom contact due to a 'blowback' phenomena after a successful preplanned autorotation by the pilot to a high density altitude airport with a test aircraft designed at a maximum gross weight.

Event Information

Type of Event Accident
Event Date 11/4/1996
Event Day of the Week Monday
Time of Event 823
Event Time Zone Mountain Standard Time
Event City FLAGSTAFF
Event State ARIZONA
Event Country --
Zipcode of the event site 86001
Event Date Year 1996
Event Date Month 11
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport FLAGSTAFF PULLIUM
Event Location Nearest Airport ID FLG
Indicates whether the acc/inc occurred off or on an airport On Airport
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation 7011
Weather Briefing Completeness Not pertinent
Investigator's weather source Pilot
Time of the weather observation 0
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID
Elevation of weather observation facility 0
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation
Lighting Conditions Dawn
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 25
Air Temperature at event time (in degrees celsius) 0
Dew Point at event time (in degress fahrenheit) -2
Wind Direction (degrees magnetic) 210
Variable Wind Indicator Unknown
Wind Speed (knots) 2
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) 6800
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor --
Injury Total None 1
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 1795
NTSB Notification Source --
NTSB Notification Date Nov 4 1996 12:00AM
NTSB Notification Time 825
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 8 2000 10:27AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N630N
NTSB Number LAX97LA034
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name McDonnell Douglas
Aircraft Model MD-600
Aircraft Series Identifier MD-600
Aircraft Serial Number 0004F
Certified Max Gross Weight 4100
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 2
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Apr 26 1996 12:00AM
Airframe hours since last inspection 63
Airframe Hours 1961
ELT Installed No
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name MCDONNELL DOUGLAS
Aircraft Owner Street Address 5000 E MCDOWELL RD,BLD 560-G23
Aircraft Owner City MESA
Aircraft Owner State AZ
Aircraft Owner Country
Aircraft Owner Zipcode 85215
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
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) Unknown
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code FLG
Departure City
Departure State
Departure Country
Departure Time 740
Departure Time Zone MST
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 Landing
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:34AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 21
Runway Length 7999
Runway Width 150
Sight Seeing flight No
Air Medical Flight No
Medical Flight --