Investigation Summary
The flight, known locally as the Double Six Crash, was transporting high-ranking Sabah government officials from Labuan. As the aircraft approached runway 20 at Kota Kinabalu, the pilot lowered the flaps to 25 degrees. While the aircraft's total weight was within the maximum takeoff limit, it was improperly balanced with 147.4kg of goods in the rear baggage compartment, significantly exceeding the 87.8kg limit for that specific section. This extreme aft center of gravity caused the pilot to run out of forward control column range. The aircraft pitched up, stalled, and entered a spin at approximately 600 feet. It struck the shallow tidal waters of Sembulan at a 60-degree angle, killing everyone on board. The investigation also highlighted that the pilot had exceeded his duty time by 67 minutes and had reported feeling unwell earlier that day. Furthermore, the body of the Chief Minister's son, a trainee pilot, was found in the co-pilot seat, leading to suspicions that he may have been at the controls during the critical phase of flight.
Final Conclusions
The final investigation report, declassified in April 2023, concluded the crash was caused by a combination of aircraft overloading and pilot error. The center of gravity was significantly aft of the approved limit, causing the aircraft to become uncontrollable at low speeds. The pilot's failure to recover from the stall was attributed to fatigue and a history of poor training records. The report also noted that Sabah Air was operating without an approved operations manual at the time of the accident.
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Systems & Failure Modes
Center of Gravity (CoG)
The distribution of weight in the aircraft; an extreme aft CoG reduces longitudinal stability and can make stall recovery impossible.
Flaps
High-lift devices used during landing; their extension on this flight exacerbated the pitch-up tendency caused by the aft loading.
Interesting Facts
- 01The aircraft was carrying 147.4kg of cargo in the rear compartment, exceeding the 87.8kg limit.
- 02The pilot had exceeded his company duty time of 10 hours by 67 minutes.
- 03The aircraft struck the water at a 60-degree angle facing the direction of approach.
- 04The Chief Minister of Sabah, Tun Fuad Stephens, was among the 11 fatalities.
- 05The investigation report remained a state secret under the Official Secrets Act until 2023.
Safety Actions & Advisories
Weight and Balance Documentation
Source ↗The investigation highlighted the need for strict adherence to weight limits, as the Nomad aircraft was found to behave unpredictably at low speeds when not operated within strict limits.
Flight Manual Revisions
Source ↗The investigation revealed that the GAF Nomad's unpredictable behavior at low speeds when improperly loaded was not mentioned in the flight manual at the time of the crash. Subsequent updates to operational documentation were required to address these handling characteristics.
Known Controversies & Unanswered Questions
47-Year Classification
Reference ↗The investigation reports from both Malaysia and Australia were kept classified for nearly five decades, leading to decades of political speculation and conspiracy theories regarding sabotage.
Unauthorized Pilot at Controls
Reference ↗The discovery of the Chief Minister's son, a trainee pilot, in the co-pilot seat led to unresolved questions about whether he was flying the aircraft during the approach.
Political Defamation Lawsuits
Reference ↗The crash led to high-profile defamation lawsuits between former Chief Ministers Harris Salleh and Yong Teck Lee over allegations of 'assassination' and 'blood on hands' related to the flight's passenger list.
Banned Literature
Reference ↗The Malaysian Home Ministry banned the book 'Peter J Mojuntin – The Golden Son of The Kadazan' in 1978 due to its critical description of the crash and the federal government. The ban remains in place as of 2024.