# NTSB DCA93MA037: Mcdonnell Douglas MD-11, Shemya, AK, April 6, 1993

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Class 1 · Major · Final report
- Date: April 6, 1993, 02:30 local (06:30 UTC)
- Place: Shemya, AK
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal, 60 serious, 96 minor, 97 uninjured
- Status: Completed, report December 27, 1994
- Report: Approved by Office Director
- Investigation class: Class 1
- NTSB office: Major Investigations Division
- Safety recommendations: Yes
- NTSB case key (mKey): 10974
- NTSB case page: https://www.ntsb.gov/investigations/Pages/DCA93MA037.aspx
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/10974/pdf
- Board report AAR9307 (PDF): https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR9307.pdf
- Page: https://openairdocs.org/ntsb/DCA93MA037

## Probable cause

THE NATIONAL TRANSPORTATION SAFETY BOARD DETERMINES THAT THE PROBABLE CAUSE OF THIS ACCIDENT WAS THE INADEQUATE DESIGN OF THE FLAP/SLAT ACTUATION HANDLE BY THE DOUGLAS AIRCRAFT COMPANY THAT ALLOWED THE HANDLE TO BE EASILY AND INADVERTENTLY DISLODGED FROM THE UP/RET POSITION, THEREBY CAUSING EXTENSION OF THE LEADING EDGE SLATS DURING CRUISE FLIGHT.  THE CAPTAIN'S ATTEMPT TO RECOVER FROM THE SLAT EXTENSION, GIVEN THE REDUCED LONGITUDINAL STABILITY AND THE ASSOCIATED LIGHT CONTROL FORCE CHARACTERISTICS OF THE MD-11 IN CRUISE FLIGHT, LED TO SEVERAL VIOLENT PITCH OSCILLATIONS.  CONTRIBUTING TO THE VIOLENCE OF THE PITCH OSCILLATIONS WAS THE LACK OF SPECIFIC MD-11 PILOT TRAINING IN RECOVERY FROM HIGH ALTITUDE UPSETS, AND THE INFLUENCE OF THE STALL WARNING SYSTEM ON THE CAPTAIN'S CONTROL RESPONSES. CONTRIBUTING TO THE SEVERITY OF THE INJURIES WAS THE LACK OF SEAT RESTRAINT USAGE BY THE OCCUPANTS.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, cruise - normal
  - flt control syst,wing flap control - inadequate (cause)
  - acft/equip,inadequate design, manufacturer (cause)
  - flight control,slat - deployed inadvertently
- Abrupt maneuver, cruise - normal
  - aircraft handling - improper, pilot in command (cause)
  - inadequate training, pilot in command (contributing factor)
  - seat belt - not used, passenger (contributing factor)
- Altitude deviation,uncontrolled, cruise - normal

## Analysis

FLIGHT 583 WAS LEVEL AT 33,000 FEET WHEN THE LEADING EDGE SLATS DEPLOYED INADVERTENTLY.  THE AUTOPILOT DISCONNECTED AND THE CAPTAIN WAS MANUALLY CONTROLLING THE AIRPLANE WHEN IT PROGRESSED THROUGH SEVERAL VIOLENT PITCH OSCILLATIONS AND LOST 5,000 FEET.  THE SAFETY BOARD DETERMINED THAT THE INADVERTENT DEPLOYMENT OF THE SLATS WAS THE RESULT OD AN INADEQUATELY DESIGNED FLAP/SLAT HANDLE THAT ALLOWED THE HANDLED TO BE EASILY AND INADVERTENLY DISLODGED FROM THE UP/RET POSITION, THEREBY CAUSING SLAT EXTENSION.

## Factual narrative

SEE NTSB BLUE COVER FACTUAL ACCIDENT REPORT - NTSB/AAR- 93/07

## Aircraft

- Registration: B2171 (not matched to a registry record)
- Reported make and model: MCDONNELL DOUGLAS MD-11
- Category: Airplane
- Engines: GE CF6 61500 lbs thrust turbo fan
- Damage: Minor damage
- Flight: Part 129
- Operator: China Eastern Airlines
- Registered owner: China Eastern Airlines
- Airworthiness certificate: Standard, Transport
- Departed: SHANGHAI,CHINA, OF
- Destination: LAX, LOS ANGELES, CA
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 42; foreign; airplane ratings: multi-engine land; instrument ratings: airplane; medical: unknown, unknown; seat: right; flight hours: 8,535 total, 1,341 in this make and model

## Weather

- Conditions: Visual (VMC), Night/dark

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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