Aircraft Accident/Incident Report

Fond Du Lac, Wisconsin 54935
Thursday, August 8, 1996 9:02 CDT

NTSB Narrative Summary Released at Completion of Accident

The airplane experienced an inflight loss of its propeller assembly. A witness observed the airplane spiraling downward similar to that of a flat spin with smoke coming from it. Examination of the fractured propeller mounting flange revealed a separation of the propeller mounting flange from the remainder of the crankshaft which was the result of fatigue cracking that initiated between the lightening holes in the flange. There is an Airworthiness Directive and Service Bulletin that specifically addressed the subject engine when it is installed on the Piper PA-30 airplane. These inspection requirements arose because of cracking problems generated by bending of the mounting flange under certain aerobatic-type maneuvers, primarily maneuvers that add stresses from gyroscopic action. The weight and balance after the loss of the propeller was 1,531 pounds at 70.09 inches aft. The center of gravity envelope for the N320L is between 60.75 to 66.75 inches aft.

NTSB Probable Cause Narrative

the fatigue in the propeller flange with soft material and oversized lightening holes. A factor was the pilot's inability to maintain control of the aircraft due to the exceeded weight and balance which led to a stall/spin.

Event Information

Type of Event Accident
Event Date 8/8/1996
Event Day of the Week Thursday
Time of Event 902
Event Time Zone Central Daylight Time
Event City FOND DU LAC
Event State WISCONSIN
Event Country --
Zipcode of the event site 54935
Event Date Year 1996
Event Date Month 8
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport
Event Location Nearest Airport ID
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness Not pertinent
Investigator's weather source Weather Observation Facility
Time of the weather observation 853 Central Daylight Time
Direction of event from weather observation facility (degrees) 360
Weather Observation Facility ID FLD
Elevation of weather observation facility 807
Distance of event from weather observation facility (units?) 4
Time Zone of the weather observation CDT
Lighting Conditions Day
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) 10
Air Temperature at event time (in degrees celsius) 22
Dew Point at event time (in degress fahrenheit) 17
Wind Direction (degrees magnetic) 300
Variable Wind Indicator Unknown
Wind Speed (knots) 9
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 30
Density Altitude (feet) 1505
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Fatal
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal 1
Injury Total Minor --
Injury Total None --
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 1722
NTSB Notification Source --
NTSB Notification Date Aug 8 1996 12:00AM
NTSB Notification Time 1050
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 8 2000 10:16AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N320L
NTSB Number CHI96FA278
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 None
Aircraft Explosion None
Aircraft Manufacturer's Full Name LANCAIR
Aircraft Model 320
Aircraft Series Identifier 320
Aircraft Serial Number L 1987
Certified Max Gross Weight 1685
Aircraft Category Airplane
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? Yes
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 Retractable
Aircraft, Type of Last Inspection 100 Hour
Date of Last Inspection May 11 1995 12:00AM
Airframe hours since last inspection 59
Airframe Hours 1502
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name LANCAIR INTERNATIONAL, INC.
Aircraft Owner Street Address 2244 AIRPORT WAY
Aircraft Owner City REDMOND
Aircraft Owner State OR
Aircraft Owner Country
Aircraft Owner Zipcode 97756
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) Personal
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code OSH
Departure City OSHKOSH
Departure State WI
Departure Country
Departure Time 853
Departure Time Zone CDT
Destination Same as Local Flt --
Destination Airport Code ARR
Destination City AURORA
Destination State IL
Destination Country
Specific Phase of Flight Cruise
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 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --