Aircraft Accident/Incident Report

Thornton, Colorado 80229
Saturday, September 19, 1998 13:14 MDT

NTSB Narrative Summary Released at Completion of Accident

While in cruise flight at 1,200 feet agl, on a banner tow flight, 21.6 inches of one of the two bladed 38-inch propeller blades separated from the aircraft. The engine separated from three of the four engine mounts and swung around against the right side of the aircraft. The remaining propeller blade penetrated the cockpit but did not strike the pilot. The aircraft became uncontrollable and impacted in a field after striking trees in the back yard of a home. The propeller blade failed due to fatigue from corrosion pitting. The pilot received serious injuries.

NTSB Probable Cause Narrative

The separation of a propeller blade due to corrosion initiated fatigue, followed by the separation of several of the engine's mounts, and the subsequent inability of the pilot to control the aircraft. A contributing factor was the trees.

Event Information

Type of Event Accident
Event Date 9/19/1998
Event Day of the Week Saturday
Time of Event 1314
Event Time Zone Mountain Daylight Time
Event City THORNTON
Event State COLORADO
Event Country --
Zipcode of the event site 80229
Event Date Year 1998
Event Date Month 9
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 Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 1245 Mountain Daylight Time
Direction of event from weather observation facility (degrees) 270
Weather Observation Facility ID BJC
Elevation of weather observation facility 5671
Distance of event from weather observation facility (units?) 15
Time Zone of the weather observation MDT
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 11000
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 80
Air Temperature at event time (in degrees celsius) 27
Dew Point at event time (in degress fahrenheit) 4
Wind Direction (degrees magnetic) 80
Variable Wind Indicator Unknown
Wind Speed (knots) 10
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) 7500
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Serious
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor --
Injury Total None --
Injury Total Serious 1
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 1541
NTSB Notification Source --
NTSB Notification Date Sep 19 1998 12:00AM
NTSB Notification Time 1300
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 11 2000 11:46AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N6028D
NTSB Number FTW98FA392
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 Piper
Aircraft Model PA-20-180
Aircraft Series Identifier PA-20-180
Aircraft Serial Number 22-4681
Certified Max Gross Weight 2000
Aircraft Category Airplane
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 Nov 1 1997 12:00AM
Airframe hours since last inspection 80
Airframe Hours 1600
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name MICHAEL P. MALONEY
Aircraft Owner Street Address 10187 CRESTVIEW DRIVE
Aircraft Owner City MORRISON
Aircraft Owner State CO
Aircraft Owner Country
Aircraft Owner Zipcode 80465
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 No
Departure Airport Code O1V
Departure City AURORA
Departure State CO
Departure Country
Departure Time 1300
Departure Time Zone MDT
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 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 --