National Transportation Safety Board
Aviation Accident Final Report
Location: | MARIETTA, GA | Accident Number: | ATL93MA055 |
Date & Time: | 02/03/1993, 1327 EST | Registration: | N130X |
Aircraft: | LOCKHEED L382E-44K-20 | Aircraft Damage: | Destroyed |
Defining Event: |
| Injuries: | 7 Fatal |
Flight Conducted Under: | Part 91: General Aviation - |
THE ACFT WAS DESIGNED & USED AS THE COMPANY'S ENGINEERING TEST BED. AN EVALUATION OF THE FLY-BY-WIRE RUDDER ACTUATOR & GROUND MINIMUM CONTROL SPEED (VMCG) WAS BEING CONDUCTED. DURING THE FINAL HI-SPEED GROUND TEST RUN, THE ACFT ABRUPTLY VEERED LEFT & BECAME AIRBORNE. IT ENTERED A LEFT TURN, CLIMBED TO ABOUT 250 FT, DEPARTED CONTROLLED FLT & IMPACTED THE GRND. INVESTIGATION REVEALED A DESIGN FEATURE IN THE RUDDER ACTUATOR THAT REMOVES HYD PRESSURE WITHIN THE ACTUATOR IF THE RUDDER POSITION COMMANDED BY THE PILOT EXCEEDED THE ACTUAL RUDDER ACTUATOR POSITION FOR A SPECIFIED TIME, AND THE RUDDER AERODYNAMICALLY TRAILS. THE ACTUATOR PREVIOUSLY DISENGAGED IN FLT. THE COMPANY DID NOT CONDUCT A SYSTEM SAFETY REVIEW OF THE RUDDER BYPASS FEATURE & ITS CONSEQUENCES TO ALL FLT REGIMES, NOR OF THE VMCG TEST. THE FLT TEST PLAN SPECIFIED THAT ENGINE POWER BE RETARDED IF THE RUDDER BECAME INEFFECTIVE. NEITHER PLT HAD RECEIVED TRAINING AS AN EXPERIMENTAL TEST PLT. THE COMPANY ALLOWED EXPERIMENTAL FLT TESTS AT A CONFINED, METROPOLITAN ARPT.
The National Transportation Safety Board determines the probable cause(s) of this accident to be:
DISENGAGEMENT OF THE RUDDER FLY-BY-WIRE FLIGHT CONTROL SYSTEM RESULTING IN A TOTAL LOSS OF RUDDER CONTROL CAPABILITY WHILE CONDUCTING GROUND MINIMUM CONTROL SPEED TESTS. THE DISENGAGEMENT WAS A RESULT OF THE INADEQUATE DESIGN OF THE RUDDER'S INTEGRATED ACTUATOR PACKAGE BY ITS MANUFACTURER; THE OPERATOR'S INSUFFICIENT SYSTEM SAFETY REVIEW FAILED TO CONSIDER THE CONSEQUENCES OF THE INADEQUATE DESIGN TO ALL OPERATING REGIMES. A FACTOR WHICH CONTRIBUTED TO THE ACCIDENT WAS THE FLIGHT CREW'S LACK OF ENGINEERING FLIGHT TEST TRAINING.
Findings |
Occurrence #1: LOSS OF CONTROL - ON GROUND/WATER
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Factual Information
Pilot Information | |||
Certificate: | Airline Transport; Flight Instructor; Flight Engineer | Age: | 42, Male |
Airplane Rating(s): | Multi-engine Land; Single-engine Land | Seat Occupied: | Left |
Other Aircraft Rating(s): | None | Restraint Used: | Seatbelt, Shoulder harness |
Instrument Rating(s): | Airplane | Second Pilot Present: | Yes |
Instructor Rating(s): | Airplane Multi-engine; Instrument Airplane | Toxicology Performed: | Yes |
Medical Certification: | Class 1 Valid Medical--no waivers/lim. | Last FAA Medical Exam: | 07/30/1992 |
Occupational Pilot: |
| Last Flight Review or Equivalent: |
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Flight Time: | 7658 hours (Total, all aircraft), 1260 hours (Total, this make and model), 5276 hours (Pilot In Command, all aircraft), 74 hours (Last 90 days, all aircraft), 16 hours (Last 30 days, all aircraft) |
Aircraft and Owner/Operator Information | |||
Aircraft Make: | LOCKHEED | Registration: | N130X |
Model/Series: | L382E-44K-20 L382E-44K- | Aircraft Category: | Airplane |
Year of Manufacture: |
| Amateur Built: | No |
Airworthiness Certificate: | Experimental | Serial Number: | 4412 |
Landing Gear Type: | Retractable - Tricycle | Seats: | 7 |
Date/Type of Last Inspection: | 03/05/1991, Continuous Airworthiness | Certified Max Gross Wt.: | 155000 lbs |
Time Since Last Inspection: | 29 Hours | Engines: | 4 Turbo Prop |
Airframe Total Time: | 6708 Hours | Engine Manufacturer: | ALLISON |
ELT: | Not installed | Engine Model/Series: | 501-M71K |
Registered Owner: | LOCKHEED AERO. SYSTEMS CO. | Rated Power: | 5250 hp |
Operator: | LOCKHEED AERO. SYSTEMS CO. | Operating Certificate(s) Held: | None |
Meteorological Information and Flight Plan | ||||
Conditions at Accident Site: | Visual Conditions | Condition of Light: | Day | |
Observation Facility, Elevation: | MGE, 1032 ft msl | Distance from Accident Site: | 1 Nautical Miles | |
Observation Time: | 1330 EST | Direction from Accident Site: | 100° | |
Lowest Cloud Condition: | Scattered / 25000 ft agl | Visibility | 7 Miles | |
Lowest Ceiling: | None / 0 ft agl | Visibility (RVR): | 0 ft | |
Wind Speed/Gusts: | 3 knots / | Turbulence Type Forecast/Actual: | / | |
Wind Direction: | 130° | Turbulence Severity Forecast/Actual: | / | |
Altimeter Setting: | 30 inches Hg | Temperature/Dew Point: | 10°C / -12°C | |
Precipitation and Obscuration: |
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Departure Point: | (MGE) | Type of Flight Plan Filed: | Company VFR | |
Destination: | (MGE) | Type of Clearance: | VFR | |
Departure Time: | 1326 EST | Type of Airspace: | Class D; Class E | |
Airport Information | |||
Airport: | DOBBINS AFB (MGE) | Runway Surface Type: | Concrete |
Airport Elevation: | 1032 ft | Runway Surface Condition: | Dry |
Runway Used: | 11 | IFR Approach: | None |
Runway Length/Width: | 10000 ft / 300 ft | VFR Approach/Landing: | None |
Wreckage and Impact Information | |||
Crew Injuries: | 7 Fatal | Aircraft Damage: | Destroyed |
Passenger Injuries: | N/A | Aircraft Fire: | On-Ground |
Ground Injuries: | N/A | Aircraft Explosion: | None |
Total Injuries: | 7 Fatal | Latitude, Longitude: |
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Administrative Information | |||
Investigator In Charge (IIC): | PRESTON E HICKS | Report Date: | 03/18/1994 |
Additional Participating Persons: | ROFF SASSER; ATLANTA, GA CARROLL A SMITH; MIAMI, FL FRANK HILLDRUP; WASHINGTON, DC CHARLES PEREIRA; WASHINGTON, DC | ||
Publish Date: |
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Investigation Docket: | NTSB accident and incident dockets serve as permanent archival information for the NTSB’s investigations. Dockets released prior to June 1, 2009 are publicly available from the NTSB’s Record Management Division at pubinq@ntsb.gov, or at 800-877-6799. Dockets released after this date are available at http://dms.ntsb.gov/pubdms/. |