Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Estes Park, Colorado 80517
Tuesady, July 30, 2002 18:43 MDT
NTSB Narrative Summary Released at Completion of Accident
The helicopter was engaged in fire suppression activities. As the pilot made an approach for a water drop, witnesses said the engine made a "high-pitch whine," there was "a loud pop," they saw the rotor blades "slowing down," and heard the blades making a "thump, thump, thump" sound. The pilot was heard to say he was "going down." Witnesses reported seeing purple or blue flames shooting 2 to 3 feet from the exhaust stack. After the helicopter struck the ground and rolled over, witnesses heard the engine spooling down and saw flames coming from the engine "like a blowtorch." A post-impact ground fire, confined to the cockpit area, was quickly extinguished. An examination of the helicopter engine revealed evidence of heat distress aft of the labyrinth seal. The turbine section had a "corn cob" appearance. The first and second stage nozzles showed heat damage. The third stage nozzle was totally destroyed. According to the engine manufacturer, the turbine blades were exposed to "around 1,000 degrees C., about 400 degrees C. beyond the normal operating temperature over a short period of time." According to "Helicopter Aerodynamics," if the rate of descent exceeds 1/4 of the hover induced velocity, the flow conditions are such that the air is going both up and down through and around the rotor in a disorganized and unsteady manner. This is called vortex ring state. It exists until the helicopter is descending at about twice the hover-induced velocity. In the vortex ring state, the helicopter pilot may find himself in the unusual situation where pulling up the collective pitch does not slow the rate of descent. This is known as settling with power. The pilot has entered "a flight condition where the required power is more than the available power." According to the Artouste IIIB Training Manual, engine rotation (nominal) speed is 33,500 rpm, plus or minus 200 rpm. The fuel control unit maintains this speed. If a load is placed on the engine, the fuel-metering valve opens, fuel flow increases, and engine torque increases. Variation from this speed must not exceed 1,000 rpm. The time it takes to return from a speed variation to the nominal engine rotation speed is less than 4 seconds.
NTSB Probable Cause Narrative
the pilot's abrupt collective input during water application to a forest fire. Contributing factors were encountering a vortex ring state, the inadvertent settling with power, the low altitude, and the mountainous terrain.
Event Information
| Type of Event | Accident |
| Event Date | 7/30/2002 |
| Event Day of the Week | Tuesday |
| Time of Event | 1843 |
| Event Time Zone | Mountain Daylight Time |
| Event City | Estes Park |
| Event State | COLORADO |
| Event Country | -- |
| Zipcode of the event site | 80517 |
| Event Date Year | 2002 |
| Event Date Month | 7 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 401759N |
| Event Location Longitude | 1052656W |
| 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 | 1746 Mountain Daylight Time |
| Direction of event from weather observation facility (degrees) | 130 |
| Weather Observation Facility ID | BJC |
| Elevation of weather observation facility | 5670 |
| Distance of event from weather observation facility (units?) | 45 |
| Time Zone of the weather observation | MDT |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 12000 |
| 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) | 40 |
| Air Temperature at event time (in degrees celsius) | 33 |
| Dew Point at event time (in degress fahrenheit) | 8 |
| Wind Direction (degrees magnetic) | 160 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 17 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 30.07 |
| Density Altitude (feet) | 8746 |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | Fatal |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| 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) | 15092 |
| NTSB Notification Source | FAA COMM CTR |
| NTSB Notification Date | Jul 30 2002 12:00AM |
| NTSB Notification Time | 1900 |
| Fiche Number and/or location -used to find docket information | DMS |
| Date of most recent change to record | Mar 30 2004 8:14AM |
| User who most recently changed record | NTSB\MONR |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | Denver, Colorado |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N3978Y |
| NTSB Number | DEN02GA085 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Public Use |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | No |
| Damage | Destroyed |
| Aircraft Fire | Ground |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Aerospatiale |
| Aircraft Model | SA315B |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 2520 |
| Certified Max Gross Weight | 5070 |
| 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 | 5 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | AAIP |
| Date of Last Inspection | May 10 2002 12:00AM |
| Airframe hours since last inspection | 202 |
| Airframe Hours | 3709 |
| ELT Installed | Yes |
| ELT Activated | Yes |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | Roberts Aircraft Co. |
| Aircraft Owner Street Address | P.O. Box 1 |
| Aircraft Owner City | Granite Canyon |
| Aircraft Owner State | WY |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 82059 |
| Operator is an individual? | No |
| Operator Name | Geo-Seis Helicopters, Inc. |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | 116 N. Raquette Dr. |
| Operator City | Fort Collins |
| Operator State | CO |
| Operator Country | USA |
| Operator Zip code | 805242757 |
| Operator Code | EKKL |
| Owner has at least one certificate | -- |
| Other Operator of large aircraft? | -- |
| Certified for Part 133 or 137 Operation | External Load |
| 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) | Public Use |
| Second Pilot on Board | No |
| Departure Point Same as Event | No |
| Departure Airport Code | NONE |
| Departure City | Estes Park |
| Departure State | CO |
| Departure Country | USA |
| Departure Time | 1840 |
| Departure Time Zone | MDT |
| Destination Same as Local Flt | -- |
| Destination Airport Code | 1V5 |
| Destination City | Boulder |
| Destination State | CO |
| Destination Country | USA |
| Specific Phase of Flight | Maneuvering |
| Report sent to ICAO? | No |
| Evacuation occurred | No |
| Date of most recent change to record | Jan 16 2004 2:20PM |
| User who most recently changed record | MCBM |
| Since inspection or accident | Last Inspection |
| Event Location Runway Number and Location | -- |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |