Individually Owned: 151,845
Corporate Owned: 143,699
Porter Memorial Hospital Airport
Aircraft Accident/Incident Report
Valparaiso, Indiana 46383
Thursday, July 14, 2005 16:04 CDT
NTSB Narrative Summary Released at Completion of Accident
The helicopter was substantially damaged when it struck the helipad during an uncommanded yaw encountered during the initial hover after liftoff from a roof-top hospital heliport. The pilot reported that he picked up into a 4 to 6-foot hover and initiated a right pedal turn. He stated that as the helicopter reached a west heading "the aircraft would not turn any more" despite his continued application of right pedal. He stated: "As I continued to apply right pedal the aircraft then went into [a] sudden and uncommanded yaw to the left. I was unable to stop the yaw." The helicopter subsequently impacted the helipad and roof structure. It came to rest at the east edge of the helipad oriented on a southeast heading. A post accident inspection revealed that the Fenestron (tail rotor) drive shaft had failed approximately 6 inches aft of the main gearbox. The failure occurred at the point where the drive shaft entered a tunnel formed by the left and right engine firewalls. The firewalls and drive shaft segments in the vicinity of the point of failure exhibited scrape marks. Examination of the forward section of the drive shaft revealed features characteristic of an overload failure. The main gearbox output shaft assembly and rear transmission coupling connected the tail rotor drive shaft to the gearbox. Further examination revealed that the coupling flange could be moved laterally relative to the pinion approximately 3/32 (0.094) inch. Allowable lateral play in the drive flange was 1 millimeter (0.039 inch). Disassembly of the transmission coupling determined that the nut which secured the drive flange to the output assembly pinion gear was improperly installed. Wear patterns indicated that the locking tangs on the cup washer did not engage the corresponding slots on the shaft allowing the nut to loosen over time. In addition, the condition of the locking tangs indicated that they were folded over during installation causing them to separate from the cup. The resulting wear had removed material to such an extent that the contact face was no longer perpendicular to the longitudinal axis of the shaft. This allowed excessive radial play in the transmission coupling, which permitted contact between the tail rotor drive shaft and the firewalls. The FAA Rotorcraft Flying Handbook, FAA-H-8083-21, provided information related to failure of the anti-torque system on a helicopter. The handbook stated: "The loss of antitorque normally results in an immediate yawing of the helicopter's nose. The helicopter yaws to the right in a counter-clockwise rotor system and to the left in a clockwise system. . . . The severity of the yaw is proportionate to the amount of power being used and the airspeed. An antitorque failure with a high power setting at a low airspeed results in a severe yawing." The main rotor system of the accident helicopter rotated clockwise as viewed from above.
NTSB Probable Cause Narrative
The loose tail rotor drive shaft coupling due to its improper installation by the operator's maintenance personnel, which resulted in the failure of the tail rotor drive shaft. An additional cause was the inability of the pilot to maintain control of the helicopter in the hover following the drive shaft failure.
Event Information
| Type of Event | Accident |
| Event Date | 7/14/2005 |
| Event Day of the Week | Thursday |
| Time of Event | 1604 |
| Event Time Zone | Central Daylight Time |
| Event City | Valparaiso |
| Event State | INDIANA |
| Event Country | -- |
| Zipcode of the event site | 46383 |
| Event Date Year | 2005 |
| Event Date Month | 7 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 412800N |
| Event Location Longitude | 0870302W |
| Event Location Airport | Porter Memorial Hospital |
| Event Location Nearest Airport ID | 46II |
| Indicates whether the acc/inc occurred off or on an airport | On Airport |
| Distance from airport in statute miles | 0 |
| Degrees magnetic from airport | -- |
| Airport Elevation | 864 |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1553 Central Daylight Time |
| Direction of event from weather observation facility (degrees) | 90 |
| Weather Observation Facility ID | VPZ |
| Elevation of weather observation facility | 771 |
| Distance of event from weather observation facility (units?) | 2 |
| Time Zone of the weather observation | CDT |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | 900 |
| Sky/Lowest/Cloud Conditions | Few |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 7 |
| Air Temperature at event time (in degrees celsius) | 28 |
| Dew Point at event time (in degress fahrenheit) | 23 |
| Wind Direction (degrees magnetic) | 360 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 11 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Gusting |
| Wind Gust (knots) | 0 |
| Altimeter Setting at event time (in. Hg) | 29.91 |
| 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 | 4 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 20947 |
| NTSB Notification Source | FAA |
| NTSB Notification Date | Jul 14 2005 12:00AM |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | DMS |
| Date of most recent change to record | Feb 26 2007 11:14AM |
| User who most recently changed record | NTSB\lema |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | FAA-South Bend FSDO |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N365S |
| NTSB Number | CHI05FA192 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 135: Air Taxi & Commuter |
| Type of Flight Plan filed | VFR |
| Flight plan Was Activated? | No |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Aerospatiale |
| Aircraft Model | AS365N |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 6036 |
| Certified Max Gross Weight | 8818 |
| Aircraft Category | Helicopter |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 4 |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | AAIP |
| Date of Last Inspection | Feb 1 2005 12:00AM |
| Airframe hours since last inspection | 13.8 |
| Airframe Hours | 6268.9 |
| ELT Installed | Yes |
| ELT Activated | Yes |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | Chase Equipment Leasing Inc. |
| Aircraft Owner Street Address | 1111 Polaris Pkwy |
| Aircraft Owner City | Columbus |
| Aircraft Owner State | OH |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 43240 |
| Operator is an individual? | No |
| Operator Name | CJ Systems Aviation Group |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | 57 Allegheny County Airport |
| Operator City | West Mifflin |
| Operator State | PA |
| Operator Country | USA |
| Operator Zip code | 15122 |
| Operator Code | BAQA |
| Owner has at least one certificate | -- |
| 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 | Non-scheduled |
| Indicates Domestic or International Flight | Domestic |
| Operator carrying Pax/Cargo/Mail | Passenger Only |
| Type of Flying (Per_Bus / Primary) | -- |
| Second Pilot on Board | No |
| Departure Point Same as Event | Yes |
| Departure Airport Code | 46II |
| Departure City | Valparaiso |
| Departure State | IN |
| Departure Country | USA |
| Departure Time | 1603 |
| Departure Time Zone | CDT |
| Destination Same as Local Flt | -- |
| Destination Airport Code | 4IS3 |
| Destination City | Chicago |
| Destination State | IL |
| Destination Country | USA |
| Specific Phase of Flight | Takeoff |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Dec 5 2006 1:29PM |
| User who most recently changed record | DINC |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | NA |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | Yes |
| Medical Flight | Medical Emergency |