Why Lao Airlines flight 301 crashed into the Mekong River
By Ben Wolford
Originally published in Latterly
Before an AirAsia plane plummeted into the sea near Borneo and Malaysia Airlines lost two of its planes, 49 people boarded a routine domestic flight in Southeast Asia’s poorest country. Bound for Pakse from the capital, Vientiane, Lao Airlines flight QV301 became the first in a series of devastating plane wrecks that have focused scrutiny on air travel in this part of the world.
The plane descended into stormy weather on Oct. 16, 2013. In a mess of rain, wind and clouds, the small propeller plane bounced toward the runway. At the last minute, the pilot abandoned the approach. But when he tried to ascend, he instead clipped trees, smashed into the bank of the Mekong River and slammed hard into the water, shattering the plane and killing everyone instantly.
Why the plane wouldn’t climb was a mystery until last month, when the Lao government released its crash report. That report, however, could never have been written except for a team of 11 technicians from a hydroelectric dam who risked their lives to find the black box.
Though Laos put out a call for international support after the crash, no salvage divers came. So, over the following two weeks, the ragtag crew of electricians, welders and mechanics combed the dark, disorienting floor of the river. They could have been trapped and drowned under wreckage or clobbered by debris barreling downstream. But not one was injured. They located the fuselage and the tail, where the black box is held, and they carried up scores of bodies.
Since we published “The men who conquered the Mekong” in the inaugural issue of Latterly magazine, I’ve heard at least one person question why Laos risked the lives of untrained men to recover the wreckage of flight QV301. Aside from returning corpses — mostly Lao, French and Australian — to families, there’s another important kind of closure. A black box may prevent more funerals.
Finding the black box doesn’t guarantee answers, but it is often impossible for crash investigators to determine the cause without it. The bright orange device is actually two devices: One, the flight data recorder, logs numbers like speed and altitude, and another, the cockpit voice recorder, captures cockpit noises. Each was essential in the recommendations from the Lao crash investigators.
At about 3:50 p.m., the captain — Yong Som, a 57-year-old former Cambodian air force pilot — pointed the nose toward the Pakse airport and began the descent into a thunderstorm. His copilot was a 22-year-old Laotian with about 400 flying hours. The cockpit voice recorder revealed they didn’t do too much talking, even as the plane was going down.
At some point prior to the descent, Yong made a grave mistake. Pilots coming into Pakse airport are supposed to program the plane to fly down to 990 feet, at which point they must be able to see the runway — it’s called a “decision height,” and if the runway isn’t visible, pilots need to abort the landing, fly around and try again. Yong or his copilot set the plane to descend to 600 feet during this last descent phase, likely because a navigational chart that day published an inaccurate approach altitude of 645 feet. It’s not clear why the height was incorrect. But it meant that when Yong pulled up on the controls, they were already 390 feet past the “missed approach point,” the last moment a pilot can safely abort a landing.
What followed was a series of incomprehensible, terrifying maneuvers. Yong lifted the plane but not straight ahead and into the sky, as one would expect. Instead, he banked to the right, which caused the plane to drop even more. You always lose some altitude in a turn. They descended to just 60 feet off the ground, which must have been as alarming for the passengers as it was for Yong, who yanked back the controls into a sharp climb. They climbed so steeply that the display known as the flight director (that half brown, half blue dial, which tells pilots where to steer) shut off. Yong took them to 1,750 feet. Then, suddenly, he pointed the nose back down.
In the crash report, the Lao authorities note that Yong may have been experiencing somatogravic illusions. When a climbing plane suddenly levels off, the body can perceive itself to be falling backward, not forward. Experienced pilots, flying in the zero visibility of a thunderstorm, are not immune to the sensation. Meanwhile, the copilot seems to have been mostly concerned with the configuration of the flaps, and not the altitude and attitude of the aircraft. They kept descending until they hit the river. By 3:55 p.m., the plane had disappeared beneath the mud-brown surface.
“The probable cause of this accident were the sudden change of weather condition and the flight crew’s failure to properly execute the published instrument approach,” the investigators wrote. Among their safety recommendations, they suggest more training for pilots on ATR 72-600s, on somatogravic effects and on cockpit communication. It advised airlines to plug gaps leading to erroneous navigation charts.
When Voice of America talked to an aviation consultant named Hugh Ritchie last month about the report, he said he was not optimistic about Asia Pacific air safety standards. “My problem with air safety in this part of the world is that they are growing exponentially,” he said. “They are trying to build systems which are international standards. On the outside it looks like they are doing it but if you go behind the scenes and look at much of the functionality, I don’t think they are achieving these levels.”
