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 -

Analysis

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.

Probable Cause and Findings

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
Phase of Operation: OTHER

Findings
1. (C) FLT CONTROL SYST,RUDDER CONTROL - INADEQUATE
2. (F) ACFT/EQUIP,INADEQUATE DESIGN - MANUFACTURER
3. (C) INADEQUATE SUBSTANTIATION PROCESS,INSUFF REVIEW - COMPANY/OPERATOR MGMT
4. (C) FLT CONTROL SYST,RUDDER - DISENGAGED
5. (C) DIRECTIONAL CONTROL - NOT POSSIBLE - PILOT IN COMMAND
6. PROCEDURES/DIRECTIVES - NOT FOLLOWED - PILOT IN COMMAND
7. (F) INADEQUATE TRAINING - COMPANY/OPERATOR MANAGEMENT
----------

Occurrence #2: LOSS OF CONTROL - IN FLIGHT
Phase of Operation: TAKEOFF - INITIAL CLIMB

Findings
8. LIFT-OFF - PERFORMED - PILOT IN COMMAND
9. (C) AIRCRAFT CONTROL - NOT POSSIBLE - PILOT IN COMMAND
10. STALL/SPIN - INADVERTENT - PILOT IN COMMAND
----------

Occurrence #3: IN FLIGHT COLLISION WITH TERRAIN/WATER
Phase of Operation: TAKEOFF - INITIAL CLIMB

 

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:

 

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:

 

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:

 

 


 


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:

 

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/.