Lockheed L382E-44K-20 N130X

Summary

On 3 February 1993 at about 18:27 local time, a Lockheed L382E-44K-20 registered N130X, operated by Lockheed Aero. Systems Co., was involved in an accident near Marietta, Georgia, United States. 7 people were on board and 7 died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

3 February 1993 at 18:27

Classification

Accident

Location

Marietta, Georgia, United States

Nearest airport

Dobbins Afb (MGE)

Coordinates

Not recorded

Aircraft

Lockheed L382E-44K-20

Registration

N130X

Category

Airplane

Engines

4

Operator

Lockheed Aero. Systems Co.

Operating rule

Part 91: General Aviation

Purpose of flight

Unknown

Phase of flight

Not recorded

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

ATL93MA055

7 people died.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

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.

Quoted verbatim from the NTSB record.