Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Rochester, Minnesota 55901
Thursday, July 8, 2004 12:18 CDT
NTSB Narrative Summary Released at Completion of Accident
A helicopter piloted by a student pilot and a flight instructor was destroyed when it impacted terrain during a landing approach. A witness reported that the helicopter appeared to be making a normal approach toward the helicopter pad. He reported the helicopter was about 100 feet above the ground and going about 30 knots. When he looked at the helicopter again, he saw it "bobble" twice (yawing motion). Within 2-3 seconds, the helicopter rolled, "fell out of the sky" and impacted the ground. The flight instructor reported he could not remember much about the accident. He reported that the student pilot was at the controls and they were flying a right downwind approach to the helicopter pad. He reported that he did not think there was anything mechanically wrong with the helicopter, and did not remember anything being out of the ordinary. The inspection of the helicopter revealed that here were no ground impact marks other than the ground scars immediately below the main wreckage of the helicopter. The helicopter came to rest on its right side in a nose down attitude. The main rotor blades had severed the tailcone. The tail rotor drive shaft was found in one piece about 150 feet from the main wreckage with a 90-degree bend in it. The post accident inspection of the helicopter's airframe and engine revealed no preexisting anomalies that could be associated with a pre-impact condition. The Robinson Helicopter Company issued Safety Notice SN-24 in September 1986 with a revision in June 1994. The safety notice stated the following warning: LOW RPM ROTOR STALL CAN BE FATAL. The safety notice stated, "Rotor stall … can occur at any airspeed and when it does, the rotor stops producing the lift required to support the helicopter and the aircraft literally falls out of the sky." The safety notice explained, "As with the airplane wing, the blade airfoil will stall at a critical angle, resulting in a sudden loss of lift and a large increase in drag. The increased drag on the blades acts like a huge rotor brake causing the rotor RPM to rapidly decrease, further increasing the rotor stall. As the helicopter begins to fall, the upward rushing air continues to increase the angle-of-attack on the slowly rotating blades, making recovery virtually impossible, even with down collective."
NTSB Probable Cause Narrative
The loss of control due to the student pilot's failure to maintain rotor RPM and the flight instructor's inadequate supervision.
Event Information
| Type of Event | Accident |
| Event Date | 7/8/2004 |
| Event Day of the Week | Thursday |
| Time of Event | 1218 |
| Event Time Zone | Central Daylight Time |
| Event City | Rochester |
| Event State | MINNESOTA |
| Event Country | -- |
| Zipcode of the event site | 55901 |
| Event Date Year | 2004 |
| Event Date Month | 7 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 435747N |
| Event Location Longitude | 0922497W |
| 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 | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1233 Central Daylight Time |
| Direction of event from weather observation facility (degrees) | 228 |
| Weather Observation Facility ID | KRST |
| Elevation of weather observation facility | 1317 |
| Distance of event from weather observation facility (units?) | 4 |
| Time Zone of the weather observation | CDT |
| 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) | 22 |
| Dew Point at event time (in degress fahrenheit) | 11 |
| Wind Direction (degrees magnetic) | 50 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 6 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 29.99 |
| Density Altitude (feet) | -- |
| 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 | 1 |
| Injury Total All | 2 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 18411 |
| NTSB Notification Source | FAA |
| NTSB Notification Date | Jul 8 2004 12:00AM |
| NTSB Notification Time | 1406 |
| Fiche Number and/or location -used to find docket information | DMS |
| Date of most recent change to record | Oct 27 2005 6:51AM |
| User who most recently changed record | NTSB\JOHB |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | Minneapolis, Minnesota |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N8118L |
| NTSB Number | CHI04FA177 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | No |
| Damage | Destroyed |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Robinson |
| Aircraft Model | R-22 Beta |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 2409 |
| Certified Max Gross Weight | 1370 |
| 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 | 2 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | 100 Hour |
| Date of Last Inspection | May 1 2004 12:00AM |
| Airframe hours since last inspection | 56 |
| Airframe Hours | 2424 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | Blue Skies, Inc. |
| Aircraft Owner Street Address | 2331 Pinestar Ln. SE |
| Aircraft Owner City | Rochester |
| Aircraft Owner State | MI |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 55904 |
| 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 | AUM |
| Departure City | Austin |
| Departure State | MN |
| Departure Country | USA |
| Departure Time | 1155 |
| Departure Time Zone | CDT |
| Destination Same as Local Flt | -- |
| Destination Airport Code | -- |
| Destination City | Rochester |
| Destination State | MN |
| Destination Country | USA |
| Specific Phase of Flight | Approach |
| Report sent to ICAO? | No |
| Evacuation occurred | No |
| Date of most recent change to record | Jul 26 2005 11:12AM |
| User who most recently changed record | SULP |
| 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 | No |
| Medical Flight | -- |