N/A Airport
Aircraft Accident/Incident Report

St. Jacob, Illinois 62281
Wednesday, November 20, 2002 14:30 CST

NTSB Narrative Summary Released at Completion of Accident

The helicopter was substantially damaged when the fan shaft failed causing a loss of power to the main and tail rotors. The instructor pilot reported that while in cruise flight the clutch light flickered several times. He stated that he pulled the clutch circuit breaker, "however the noise continued to worsen and [he] suspected the drive belts were loosening." He reset the clutch circuit breaker and the clutch light illuminated steadily. The instructor pilot reported, "Immediately afterward the engine and rotor RPM needles split indicating a drive train failure, and a loud metal to metal grinding noise began." The flight crew (instructor and dual student) immediately initiated an autorotation. At the termination of the autorotation, the helicopter yawed to the left and did not respond to right pedal inputs. A post-accident examination revealed a complete failure of the fan shaft. The portion of the engine cooling fan assembly aft of the fracture point had departed the aircraft. This component was subsequently found approximately 1.2 miles south of the forced landing site. In addition, the tail rotor blade pitch push-pull tube was completely severed at the forward rod end. Extensive scraping and gouging was noted on the rod end fitting. The fan shaft, fan wheel and bearing were sent to the NTSB Materials Laboratory for examination. The examination noted the fan shaft was fractured in a "V"shape from a transition in shaft diameter adjacent to the bearing at the aft end, forward to the attachment bolt holes. Fracture surface features were "indicative of fatigue propagation." According to the dual student, on the delivery flight one of the drive v-belts broke and an emergency landing under partial power was made. The helicopter was repaired by Robinson technicians who replaced the drive belts and clutch actuator. A visual inspection of the fan shaft and lower bearing was completed at that time and no discrepancies were found. The fan shaft and bearing were not disassembled. Therefore, the mating surfaces of the fan shaft and bearing race were not inspected.

NTSB Probable Cause Narrative

Fatigue fracture of the clutch assembly fan shaft and the resulting complete loss of power to the rotor drive system. A contributing factor was the loss of tail rotor authority due to the secondary failure of the control tube assembly.

Event Information

Type of Event Accident
Event Date 11/20/2002
Event Day of the Week Wednesday
Time of Event 1430
Event Time Zone Central Standard Time
Event City St. Jacob
Event State ILLINOIS
Event Country --
Zipcode of the event site 62281
Event Date Year 2002
Event Date Month 11
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 384630N
Event Location Longitude 0894833W
Event Location Airport N/A
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 1453 Central Standard Time
Direction of event from weather observation facility (degrees) 50
Weather Observation Facility ID CPS
Elevation of weather observation facility 413
Distance of event from weather observation facility (units?) 20
Time Zone of the weather observation CST
Lighting Conditions Day
Lowest Ceiling Height --
Lowest Non-Ceiling Height --
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 17
Dew Point at event time (in degress fahrenheit) -1
Wind Direction (degrees magnetic) 290
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 3
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 29.97
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor --
Injury Total None 2
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 15272
NTSB Notification Source FAA
NTSB Notification Date Nov 20 2002 12:00AM
NTSB Notification Time 1841
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Apr 28 2004 3:34PM
User who most recently changed record NTSB\MONR
Basic weather conditions Visual Meteorological Cond
FAA District Office FAA -- St. Louis FSDO

Aircraft Involved

Aircraft #1

Aircraft Registration Number N559DD
NTSB Number CHI03FA025
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? No
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Robinson
Aircraft Model R22
Aircraft Series Identifier --
Aircraft Serial Number 3299
Certified Max Gross Weight 1370
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 Feb 15 2002 12:00AM
Airframe hours since last inspection 65.7
Airframe Hours 72.6
ELT Installed No
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name Helicopter Operation Inc.
Aircraft Owner Street Address 10763 Forest Circle
Aircraft Owner City St. Louis
Aircraft Owner State MO
Aircraft Owner Country USA
Aircraft Owner Zipcode 63128
Operator is an individual? No
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? --
Certified for Part 133 or 137 Operation --
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 No
Departure Airport Code CPS
Departure City Cahokia/St. Lou
Departure State IL
Departure Country USA
Departure Time 1400
Departure Time Zone CST
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? No
Evacuation occurred No
Date of most recent change to record Feb 23 2004 12:09PM
User who most recently changed record SULP
Since inspection or accident Time of Accident
Event Location Runway Number and Location N/A
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --