Individually Owned: 151,845
Corporate Owned: 143,699
Unmanned Vehicles Intl Airport
Aircraft Accident/Incident Report
Whetstone, Arizona 85635
Wednesday, September 24, 2008 8:41 PDT
NTSB Narrative Summary Released at Completion of Accident
Note: This case was reclassified from an accident to an incident as a result of applicable revisions to 49 Code of Federal Regulations Part 830.2, as amended at 75 FR 51955, Aug. 24, 2010. The case was previously identified under accident number DEN08FA160.
An unmanned aerial system (UAS) was flying a pre-programmed flight profile to test a mapping camera and telemetry package when it lost engine power. During the subsequent attempt to force land the aircraft on the runway, the UAS entered a commanded right banking turn and the aircraft descended,impacted desert terrain, and was destroyed. The aircraft had flown for approximately 39 minutes. During approximately 30 minutes of the flight, the aircraft's engine was operated at a high constant power setting of 5,300 RPM. An examination of the engine showed that one of the pistons overheated, expanded and rubbed against the cylinder wall, stopping the engine. The needle valves on the carburetor were set at a very lean fuel mixture which would contribute to the damaged piston. An examination of the autopilot software showed that during the attempt to put the vehicle into automatic landing mode, an improper command was sent by the operators.
NTSB Probable Cause Narrative
A total off of engine power resulting from an overheated piston, and the pilot's subsequent failure to send a proper command to the UAS. Contributing to the accident was the operation of the engine at high power for an extended period with a lean fuel setting.
Event Information
| Type of Event | Incident |
| Event Date | 9/24/2008 |
| Event Day of the Week | Wednesday |
| Time of Event | 841 |
| Event Time Zone | Pacific Daylight Time |
| Event City | Whetstone |
| Event State | ARIZONA |
| Event Country | -- |
| Zipcode of the event site | 85635 |
| Event Date Year | 2008 |
| Event Date Month | 9 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 314212N |
| Event Location Longitude | 1101453W |
| Event Location Airport | Unmanned Vehicles Intl |
| Event Location Nearest Airport ID | -- |
| 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 | 4200 |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 755 Pacific Daylight Time |
| Direction of event from weather observation facility (degrees) | 170 |
| Weather Observation Facility ID | KFHU |
| Elevation of weather observation facility | 4719 |
| Distance of event from weather observation facility (units?) | 10 |
| Time Zone of the weather observation | PDT |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | -- |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 70 |
| Air Temperature at event time (in degrees celsius) | 21 |
| Dew Point at event time (in degress fahrenheit) | 5 |
| Wind Direction (degrees magnetic) | -- |
| Variable Wind Indicator | Variable |
| Wind Speed (knots) | 1 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 30.21 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | -- |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | -- |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | -- |
| NTSB Docket Number (internal use) | 25906 |
| NTSB Notification Source | NTSB Central Region |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Jan 7 2011 12:38PM |
| User who most recently changed record | broda |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N602RN |
| NTSB Number | DEN08IA160 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | -- |
| Damage | Destroyed |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | RAYTHEON |
| Aircraft Model | COBRA |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 002 |
| Certified Max Gross Weight | 110 |
| Aircraft Category | -- |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | -- |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Conditional |
| Date of Last Inspection | Jan 31 2008 12:00AM |
| Airframe hours since last inspection | 16 |
| Airframe Hours | 26 |
| ELT Installed | No |
| ELT Activated | Unknown |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | Raytheon Company |
| Aircraft Owner Street Address | P.O. Box 11337 |
| Aircraft Owner City | Tucson |
| Aircraft Owner State | AZ |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 85734 |
| Operator is an individual? | No |
| Operator Name | Raytheon Company |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | P.O. Box 11337 |
| Operator City | Tucson |
| Operator State | AZ |
| Operator Country | USA |
| Operator Zip code | 85734 |
| Operator Code | -- |
| Owner has at least one certificate | None |
| 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) | Flight Test |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | Yes |
| Departure Airport Code | -- |
| Departure City | Whetstone |
| Departure State | AZ |
| Departure Country | USA |
| Departure Time | 809 |
| Departure Time Zone | PDT |
| Destination Same as Local Flt | crash at destination city |
| Destination Airport Code | -- |
| Destination City | Whetstone |
| Destination State | AZ |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Jul 1 2014 9:20AM |
| User who most recently changed record | broda |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | 17 |
| Runway Length | 2500 |
| Runway Width | 50 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |