MH684
1983-DEC-18 · Subang, Selangor, Malaysia

Malaysian Airline System — Flight MH684

Malaysian Airline System Flight 684 crashed 2 kilometers short of the runway at Subang International Airport during a heavy rainstorm. Despite visibility being below company minima, the crew continued a manual descent without the Instrument Landing System (ILS) engaged. The aircraft struck trees and slid into a stream embankment, losing its landing gear and engines. All 247 passengers and crew successfully evacuated the airframe before it was destroyed by a post-crash fire, though 20 occupants sustained injuries.

Aircraft
Airbus A300B4-120
Registration
OY-KAA
Phase
Cause
Souls on Board
247
Fatalities
0
Origin → Dest
Singapore Changi Airport (SIN) → Subang International Airport (SZB)
Report

Investigation Summary

The accident occurred during a flight from Singapore to Kuala Lumpur. The aircraft, an Airbus A300 leased from Scandinavian Airlines System (SAS), featured a cockpit layout that differed from the standard Malaysian Airline System fleet. This discrepancy, combined with a high workload during a stormy night approach, contributed to the crew's failure to engage the Instrument Landing System. According to BAAA-ACRO records, the flight made five failed landing attempts before the final crash occurred on the sixth approach. The Captain took manual control from the First Officer but failed to monitor the descent rate effectively. The aircraft descended below the minimum descent altitude without the crew having the runway in sight. The plane eventually impacted trees 2,000 meters short of the runway threshold, skidding across the ground and over a stream before coming to rest. The successful evacuation of all 247 occupants, with only 20 injuries reported, is often cited as a significant survival success despite the total hull loss.

Final Conclusions

The investigation determined the probable cause was pilot error. The flight crew failed to monitor the aircraft's descent rate while operating in instrument meteorological conditions (IMC). Furthermore, the crew continued the approach below company weather minima without establishing visual contact with the runway environment.

Video Analysis

No video analysis linked for this case file yet.

Airframe & Maintenance

Airframe Hours
3,907
Engines
Pratt & Whitney JT9D-59A

Systems & Failure Modes

i

Instrument Landing System (ILS)

A precision radio navigation system that provides short-range guidance to aircraft to allow them to approach a runway at night or in bad weather. The crew failed to activate this system during the approach.

i

Altimeter Warning

An audio alert designed to warn the crew when the aircraft reaches a pre-set minimum altitude. The warning triggered 30 seconds before impact.

Interesting Facts

  • 01The aircraft was leased from Scandinavian Airlines System (SAS) and had a different cockpit switch configuration than MAS's own A300s.
  • 02Visibility at the time of the accident was 450 meters due to heavy rain, while company policy required 800 meters.
  • 03The aircraft lost both engines and its landing gear during the impact and slide.
  • 04This was the second hull loss of an Airbus A300 since the type entered service.
  • 05The aircraft came to rest 1,200 meters short of the runway threshold.

Safety Actions & Advisories

Crew Resource Management and Standardization

The accident highlighted the dangers of 'cross-cockpit' confusion when operating leased aircraft with different internal configurations, leading to increased emphasis on crew familiarization with specific airframe layouts.

Location

Subang, Selangor, Malaysia · 3.1535, 101.5360

Case File History

  1. CorrectionUpdated event timeline.
  2. CorrectionUpdated investigation summary and event timeline.

Related Cases

Case ID · mas684-1983Last updated · Filed

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