NEW YORK (BLOOMBERG) - The Boeing 737-800 NG model that crashed in China on Monday (March 21) is considered one of the safest aircraft ever made.
The China Eastern Airlines jetliner carrying 132 people from Kunming in Yunnan province to the manufacturing centre of Guangzhou fell rapidly from cruising altitude, according to Flightradar24.
The 6-year-old single-aisle jet is part of the NG, or Next Generation, era that preceded the 737 Max, which was subjected to a global grounding after two deadly crashes.
The NG has one of the best safety records among all aircraft, with just 11 fatal accidents out of more than 7,000 planes delivered since 1997, according to aviation consultancy Cirium.
"The 737 NG has been in operation for 25 years and has an excellent safety record," said Mr Paul Hayes, director of air safety and insurance at Cirium. "I'm not going to speculate on what happened but if the Flightradar24 logs are accurate, something seems to have happened abruptly and the plane nose dived from cruising altitude."
China Eastern flight MU5735 made a sudden descent from cruising altitude that was interrupted briefly when it actually climbed, according to data posted by Flightradar24.
The plane was headed easterly when at 2.20:59pm it began a sudden plunge, going from level flight to a descent rate of almost 31,000 feet per minute in about five seconds. That type of descent is well outside any kind of normal flight parameter.
But after about 45 seconds, the descent became less steep and for a few moments the jet climbed by more than 1,000 feet. It went from 7,425 feet up to 8,600 feet in a span of about 10 seconds, according to the Flightradar24 data, which is based on transmissions from the plane.
While the earlier dive would have flung items to the ceiling, the rapid rise would have pinned people in their seats.
The climb was short-lived. The jet resumed its dive seconds later, plunging again at about 31,000 feet per minute. The last position recorded on the Flightradar24 track was at 2.22:36pm, about a minute and 35 seconds after it began.
According to Airsafe.com, which tracks aviation safety, NG models had just 0.07 fatal crashes per million flights as of 2019. That puts it among a rare group that includes the Boeing 747-400 and 737's main competitor, the Airbus SE A320 family.
The most recent fatal crash of a 737-800 before Monday came in August 2020, when an Air India Express flight slid off the runway in Kozhikode, India, killing 21 people. An investigation blamed pilot error.
The 737 Max had just been in service for less than two years when it was grounded worldwide in March 2019, after two crashes that killed 346 people. China was the first country to idle the plane and, while it was re-certified there in December following adjustments, the plane hasn't yet been used for commercial flights.
Boeing sent a 737 Max to its new completion and delivery centre in Zhoushan, China, earlier this month.
Investors sent Boeing shares down as much as 5.3 per cent. They fell 4.6 per cent as of 9.32am in New York.
"The NG is a completely different aircraft from the 737 Max, which has just gone through a rigorous recertification process," said aerospace industry analyst John Strickland. "I wouldn't expect today's crash to have any bearing on the Max return to service in China."
"We are aware of the initial media reports and are working to gather more information," Boeing said in an emailed statement.