Individually Owned: 151,845
Corporate Owned: 143,699
Washoe Medical Center Heliport Airport
Aircraft Accident/Incident Report
Reno, Nevada 89502
Sunday, January 17, 2010 12:50 PST
NTSB Narrative Summary Released at Completion of Accident
The pilot reported that he lifted the single-engine helicopter from the helicopter pad for the emergency medical service positioning flight to pick up a patient. The pilot maneuvered the helicopter into a 25-foot hover and, just as he was beginning the transition to forward flight, he heard a loud bang. The helicopter experienced a power loss and the pilot lowered the collective slightly, resulting in a hard landing on the pad. A surveillance camera that captured the accident sequence indicated that after the helicopter lifted into a hover over the pad, the nose abruptly rotated right 90 degrees and the helicopter descended vertically in a slight nose-down attitude, landing hard on the helipad.
The postaccident airframe examination revealed that the nuts that attach the engine-to-main gear box flex coupling were not present on their respective bolts. The nuts and associated washers were located loose and clumped together just forward of the gimbal ring in the transmission input housing. An examination of the bolts and flex coupling by the Safety Board Materials Laboratory concluded that the nuts most likely had been hand tightened and that cotter pins had not been installed on the bolts. The improper installation lead to the failure of the flex coupling and resulted in a loss of power to the rotor system.
Maintenance records showed that 59 flight hours before the accident the engine had been removed, the helicopter painted, and then the engine was reinstalled. The time between the engine removal and the reinstallation was 88 days. The mechanic who removed the engine stated that he removed the bolts to the engine-to-main gear box flex coupling, and then partially reassembled the flex coupling bolts. This action was not in accordance with the AS350 maintenance manual engine removal procedure. The mechanic who installed the engine 88 days later stated that he did not check the flex coupling bolts because the removal of those bolts is not specified in the maintenance manual as part of the engine removal or replacement procedure. The overall maintenance activity involved a 100-hour inspection, which included a visual inspection of the engine-to-main gear box flex coupling. Although a visual inspection of the engine-to-main gear box flex coupling is a required action, the Quality Assurance inspector signed off the maintenance without performing the visual inspection of the flex coupling.
NTSB Probable Cause Narrative
The improper installation of the engine-to-main gear box flex coupling, which resulted in the failure of the flex coupling and a loss of power to the rotor system during takeoff. Contributing to the accident was the mechanic who removed the engine's failure to follow the operator’s maintenance procedures. Also contributing was the Quality Assurance inspector's failure to follow the operator’s post-maintenance inspection requirements.
Event Information
| Type of Event | Accident |
| Event Date | 1/17/2010 |
| Event Day of the Week | Sunday |
| Time of Event | 1250 |
| Event Time Zone | Pacific Standard Time |
| Event City | Reno |
| Event State | NEVADA |
| Event Country | -- |
| Zipcode of the event site | 89502 |
| Event Date Year | 2010 |
| Event Date Month | 1 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 393134N |
| Event Location Longitude | 1194746W |
| Event Location Airport | Washoe Medical Center Heliport |
| Event Location Nearest Airport ID | NV57 |
| 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 | -- |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1255 Pacific Standard Time |
| Direction of event from weather observation facility (degrees) | -- |
| Weather Observation Facility ID | KRNO |
| Elevation of weather observation facility | 4415 |
| Distance of event from weather observation facility (units?) | 2 |
| Time Zone of the weather observation | PST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 9000 |
| Lowest Non-Ceiling Height | 6000 |
| Sky/Lowest/Cloud Conditions | Scattered |
| Sky Condition for Lowest Ceiling | Broken |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | 11 |
| Dew Point at event time (in degress fahrenheit) | -1 |
| Wind Direction (degrees magnetic) | 170 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 13 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Gusting |
| Wind Gust (knots) | 18 |
| Altimeter Setting at event time (in. Hg) | 29.72 |
| 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 | 3 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 27623 |
| NTSB Notification Source | FAA Operations Center |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Dec 13 2010 3:26PM |
| User who most recently changed record | kelz |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N904CF |
| NTSB Number | WPR10FA112 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | Company VFR |
| Flight plan Was Activated? | Yes |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | EUROCOPTER |
| Aircraft Model | AS350 B3 |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 3676 |
| Certified Max Gross Weight | -- |
| Aircraft Category | Helicopter |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | 1 |
| Cabin Crew Seats | -- |
| Passenger Seats | 3 |
| Total number of seats on the aircraft | 4 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | AAIP |
| Date of Last Inspection | Jan 17 2010 12:00AM |
| Airframe hours since last inspection | 0 |
| Airframe Hours | 3940 |
| ELT Installed | Yes |
| ELT Activated | Yes |
| ELT Aided Location of Event Site | No |
| ELT Type | C126 |
| Aircraft Owner Name | ZIONS CREDIT CORP |
| Aircraft Owner Street Address | PO BOX 3954 |
| Aircraft Owner City | SALT LAKE CITY |
| Aircraft Owner State | UT |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 84110-3954 |
| Operator is an individual? | No |
| Operator Name | Air Methods |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | 7301 South Peoria |
| Operator City | Englewood |
| Operator State | CO |
| Operator Country | USA |
| Operator Zip code | 80112 |
| Operator Code | -- |
| Owner has at least one certificate | Yes - certificate holder |
| Other Operator of large aircraft? | No |
| 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) | Positioning |
| Second Pilot on Board | No |
| Departure Point Same as Event | No |
| Departure Airport Code | NV57 |
| Departure City | Reno |
| Departure State | NV |
| Departure Country | USA |
| Departure Time | 1250 |
| Departure Time Zone | PST |
| Destination Same as Local Flt | -- |
| Destination Airport Code | -- |
| Destination City | Winnemucca |
| Destination State | NV |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Oct 26 2010 5:20PM |
| User who most recently changed record | coos |
| 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 | Yes |
| Medical Flight | Discretionary |