[ti:Plane Crash in Tokyo Raises Design Concerns]
[al:As It Is]
[ar:VOA]
[dt:2024-01-05]
[by:www.voase.cn]
[00:00.00]Investigators are studying what went wrong when a Japanese coast guard aircraft and a passenger jet crashed into each other on Tuesday at Haneda Airport in Tokyo.
[00:16.62]Officials want to find out what caused the crash.
[00:21.23]But there are also many questions about the fire that broke out when the planes collided on the runway.
[00:31.02]The body of the passenger jet, an Airbus 350, was made of carbon-composite fibers.
[00:39.98]Passenger aircraft bodies have traditionally been made of aluminum.
[00:45.78]The crash may become an important test of the safety of composite materials for some uses in aircraft.
[00:57.37]Communications from air traffic control at the airport describe some of the events leading to the crash.
[01:07.24]The larger Japan Airlines (JAL) passenger jet was given permission to use the runway where the coast guard plane, a Bombardier Dash-8, was preparing for takeoff.
[01:25.55]When they struck each other, an orange fireball exploded from the aircraft and the passenger jet continued down the runway covered in flames.
[01:38.81]When the plane stopped, crew members and all 379 passengers slid down emergency chutes within 20 minutes. 
[01:51.07]All survived. The captain of the coast guard plane got out, but five members of the crew died in the crash.
[02:03.08]Safety experts are praising the airline's crew and the passengers for escaping the burning plane.
[02:12.32]The crew shouted, warning the passengers to run away from the plane.
[02:19.39]Composite materials have been used for many years inside commercial aircraft.
[02:26.73]But the first commercial plane to have its body, or fuselage, and wings reinforced with carbon fibers was the Boeing 787. 
[02:41.09]It went into service in 2011. About 1,100 of the planes have been produced.
[02:50.69]The Airbus A350 followed in 2018. About 570 have been sold.
[03:02.85]Aircraft designers use composite materials because they strengthen plastics and other materials.
[03:12.70]Boeing says the material can save 20 percent of the weight of aluminum. The reduced weight saves fuel.
[03:24.90]Boeing and the Federal Aviation Administration (FAA) tested the strength of composites to get certification for the 787 jet.
[03:39.05]But concerns remain about gases released from such materials when they burn.
[03:48.04]John Goglia is a former member of the National Transportation Safety Board, which investigates aircraft accidents.
[03:59.90]He said, "There has always been a concern about composites if they catch fire."
[04:08.12]Goglia noted that the gases released when composites burn are dangerous.
[04:15.32]They can even be dangerous after the fire is put out because the fibers might remain in the air.
[04:25.26]The FAA has said for more than 20 years that there are dangers related to composite materials. 
[04:35.06]FAA officials say the main health dangers include sharp pieces of material, dust and poisonous gases caused by burning substances that hold the material together.
[04:53.53]Although the inside of the passenger plane filled with smoke after the explosion, all 379 passengers were able to escape.
[05:05.27]John Cox, a safety expert, noted: "That fuselage protected them from a really horrific fire - it did not burn through for some period of time and let everybody get out."
[05:23.18]Goglia said there is no real evidence whether composite materials or aluminum are better at resisting fire long enough to protect people.
[05:37.40]However, one passenger on the JAL flight said the smoke "stung" very much.
[05:46.74]Todd Curtis, a safety expert and former Boeing engineer, warned that injuries from dangerous smoke could take a long time to show up.
[05:58.93]Passengers involved in accidents usually are in shock and often do not recognize their injuries.
[06:10.57]Another concern, experts noted, was the amount of time it took firefighters to put out the fire. 
[06:20.35]Pictures show the JAL flight's burned wreckage near one of the runways.
[06:28.92]The body was almost completely destroyed by fire.
[06:34.45]In 2013, a fire at London's Heathrow Airport involving an Ethiopian Airlines Boeing 787 was difficult to stop.
[06:48.85]Safety expert Curtis said, "putting out the fire took much more effort that a typical airliner fire."
[06:58.26]Curtis said he worried at the time about composite fuselage fires.
[07:06.08]Those concerns, he said, have not gone away.
[07:11.37]I'm Mario Ritter Jr.