Malaysian Airline System Flight 653 (MH653) was a scheduled domestic flight from Penang to Kuala Lumpur in Malaysia, operated by Malaysian Airline System (MAS). On the evening of 4 December 1977, the Boeing 737-200 aircraft flying the service crashed at Tanjung Kupang, Johor, Malaysia, while purportedly being diverted by hijackers to Singapore. It was the first fatal air crash for Malaysia Airlines (as the airline is now known), with all 93 passengers and 7 crew killed. The flight was apparently hijacked as soon as it reached cruise altitude. The circumstances in which the hijacking and subsequent crash occurred remain unsolved.
At approximately 19:54, while at an altitude of 4,000 feet (1,200 m) over Batu Arang and descending toward Runway 33 at Subang Airport, the crew reported to Subang Tower that an "unidentified hijacker" was on board. The tower immediately notified the authorities, who made emergency preparations at the airport.
A few minutes later, the crew radioed: "We're now proceeding to Singapore. Good night." Investigators heard a series of gunshots in the last few minutes of the cockpit voice recorder, concluding that both the pilot and co-pilot were fatally shot by the hijacker, which left the plane "professionally uncontrolled". At 20:15, all communication with the aircraft was lost. At 20:36, the residents of Kampong Ladang, Tanjung Kupang in Johor reported hearing explosions and seeing burning wreckage in a swamp. The wreckage was later identified as the aircraft; it had hit the ground at a near-vertical angle at a very high speed. There were no survivors discovered on the site.
The full circumstances of the hijacking and crash were never solved. However, airport officials at Kuala Lumpur claimed pilots had radioed that members of the Japanese Red Army had hijacked the plane. In 1996, CNN reporters wrote that the hijackers were in fact identified as Red Army members, but this has not been confirmed. All recovered remains were x-rayed in an attempt to discover evidence of a projectile or weapon, but no such evidence was ever found. The remains of the victims were interred in a mass burial.
^The aircraft was a Boeing 737-200 model; Boeing assigns a unique customer code for each company that buys one of its aircraft, which is applied as a suffix to the model number at the time the aircraft is built. The code for Malaysian Airline System (now Malaysia Airlines) is "H6", hence "737-2H6".
^"Ethiopia mourns crash victims". CNN. 25 November 1996. Archived from the original on 23 December 2004. Retrieved 22 July 2014. "The deadliest previous hijacking took place in 1977, when terrorists identified as the Japanese Red Army took over a Malaysian airlines jet traveling to Kuala Lumpur."
^"Mass burial planned for unidentified victims". New Straits Times. 18 September 1995. p. 7.