OTD in 2002, PK-GWA, a Garuda Indonesia Boeing 737-3Q8, under Flight 421, suffered a dual engine flameout during heavy rain and hail while going on its way to Selaparang Airport, Ampenan. The aircraft ditched in the Bengawan Solo River in Java, Indonesia, killing a flight attendant. 59 survived.

As the Boeing 737-300 aircraft was on approach to its destination, the pilots were confronted with substantial thunderstorm activity visible ahead and on their onboard weather radar. They attempted to fly between two intense weather cells visible on their radar. They later entered a thunderstorm containing heavy rain and hail. About 90 seconds later, as the aircraft was descending through 19,000 ft (5,800 m), both CFM International CFM56 engines experienced a flameout, which resulted in the loss of all generated electrical power. Both engines were set at their flight-idle power setting before flameout occurred.

The crew tried unsuccessfully to restart the engines two or three times. They then tried but failed to start the auxiliary power unit (APU), at which time total electrical power loss occurred. (During the later investigation, the NiCd battery was found to have been in poor condition due to inadequate maintenance procedures.)

First Officer Gunawan attempted to transmit a Mayday call, but was unable to. As the aircraft descended through the lower layer of clouds at approximately 8,000 ft (2,400 m), the pilots saw the Bengawan Solo River and decided to attempt to ditch in the river with the flaps and gear retracted. The ditch procedure was successful, leaving the aircraft settled down on its belly in the shallow water, with the fuselage, wings and control surfaces largely intact. There was no fire.

There was severe damage to the submerged aircraft belly, especially near the tail, leading to the inference that it landed nose high with tail impacting the shallow river bed, which ripped away the cabin floor together with the two flight attendants seated there. Both were found with severe injuries in the river behind the aircraft, and one did not survive.

Twelve passengers suffered injuries, while the flight crew and other two flight attendants were injured. The aircraft was written off as a total loss, making the accident the 11th hull loss and eighth fatal accident involving the Boeing 737-300.