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A uav at FL230 lost communications with its operator for two minutes because of an unscheduled system reset. During that period the uav entered a non approved pre-programmed ATC flight pattern because the correct lost link flight profile had not been previously entered in the aircraft's system. An altitude and track deviation resulted.
| Attributes | |
| ACN | 892296 |
| Time | |
| Date | 201006 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | Other |
| Operating Under FAR Part | Part 91 |
| Flight Phase | Cruise |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Air/Ground Communication |
| Person 1 | |
| Function | Single Pilot Pilot Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor Flight Crew Multiengine |
| Experience | Flight Crew Last 90 Days 20 Flight Crew Total 7000 Flight Crew Type 200 |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Published Material / Policy Deviation - Procedural Clearance Deviation - Track / Heading All Types |
Narrative:
Due to the inadvertent spma (system processor modem assembly) reset during a pldl (back up communications) power up; the uav experienced a lost link situation not lasting more than two minutes. The uav was cruising at FL230 to avoid weather when the lost link occurred. The pilot failed to update the lost link profile to reflect the ATC clearance which caused the aircraft to turn towards the closest lost link entry point and initiate a descent to FL190 which was the previous lost link profile. The pilot immediately called the ATC center watch desk and notified the center and that link should be regained within two minutes. Once the spma reset link was reestablished and the aircraft climbed to its previous altitude hold of 23;000 ft. HUD display showed the aircraft climbing from approximately 22;500 ft when link was established. No additional information was requested by center after communications were regained and the flight continued without further incident. A software change request is being researched for added protection from inadvertent spma resets.
Original NASA ASRS Text
Title: A UAV at FL230 lost communications with its operator for two minutes because of an unscheduled system reset. During that period the UAV entered a non approved pre-programmed ATC flight pattern because the correct lost link flight profile had not been previously entered in the aircraft's system. An altitude and track deviation resulted.
Narrative: Due to the inadvertent SPMA (System Processor Modem Assembly) reset during a PLDL (back up communications) power up; the UAV experienced a lost link situation not lasting more than two minutes. The UAV was cruising at FL230 to avoid weather when the lost link occurred. The pilot failed to update the lost link profile to reflect the ATC clearance which caused the aircraft to turn towards the closest lost link entry point and initiate a descent to FL190 which was the previous lost link profile. The pilot immediately called the ATC Center watch desk and notified the Center and that link should be regained within two minutes. Once the SPMA reset link was reestablished and the aircraft climbed to its previous altitude hold of 23;000 FT. HUD display showed the aircraft climbing from approximately 22;500 FT when link was established. No additional information was requested by Center after communications were regained and the flight continued without further incident. A software change request is being researched for added protection from inadvertent SPMA resets.
Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.