Thursday, January 4, 2024

Plane Crash In Tokyo: The Fuzzy Logic Of Fleeing For Your Life

One thing that stands out about both this evacuation and the Air France incident in Toronto where 309 people were able to escape is that multiple exits were rendered unavailable by fire or crash damage but the flight attendants and passengers were able to improvise on the fly and do the 90-second miracle thing. Just amazing.

From the Wall Street Journal, January 3:

Inside a Flaming Jet, 367 Passengers Had Minutes to Flee. Here’s How They Did It.
Vacationer on Japan Airlines plane in Tokyo airport collision recalls a ‘big boom’ and a dash for survival

It was 18 minutes of terror, confusion and determination to get out alive.

A blaze was spreading in the back of the plane and smoke was filling the cabin. The realization began to dawn on the 367 passengers: They had only minutes to save themselves from a fiery death. A child cried out, “Please, open the door!”

Joseph Hayashi, 28, was in seat 27B, returning from a ski vacation in northern Japan.

“People were trying to get away from the jet engines because they were worried that the jets would explode,” said Hayashi, who is from Dallas and works in finance in Tokyo. “I’m not a scientist, but I know that fire and jet fuel aren’t a good recipe. Everyone is trying to push to the front.”

In tests, aircraft manufacturers must show they can evacuate a plane in 90 seconds. Real life is usually harder.

In those 18 minutes between 5:47 p.m. and 6:05 p.m. Tuesday at Tokyo’s Haneda Airport, some things went wrong. It took several minutes to get the Japan Airlines plane’s doors open. The PA system didn’t work. Most of the evacuation chutes weren’t available.

But a lot went right too. Once the doors were open, passengers calmed down and followed directions. The airline said it was prepared to stop people who tried to bring along bulky carry-on luggage—a vexing human instinct that has bedeviled previous evacuations—and wasn’t aware of anyone who did it. Although the rear of the

A350 was aflame, the fire didn’t spread into the aircraft’s interior until minutes later.

Those minutes were lifesavers. The 367 passengers, as well as 12 crew, all made it to safety, with no major injuries beyond some sprains and bruises.

Japan Airlines spokesman Yasuo Numahata said of the successful evacuation, “We believe it was the result of the provision of training and knowledge brush-ups every year.” ....
....JL516 was burning on the outside—but, crucially, not yet on the inside. It was 5:47 p.m., according to the airline. The race for survival was on.

To operate around the world, aircraft manufacturers must prove to regulators that passengers can evacuate a plane in 90 seconds. They conduct tests under conditions meant to simulate real life. A typical demonstration is conducted with people of various ages and sizes playing passengers, plus life-size dolls simulating infants. Half the exits are blocked, and blankets, pillows and bags are strewn in the aisles to create obstructions.

The tests often fall short of replicating real accident conditions, said Ed Galea, a professor at University of Greenwich in the U.K. who specializes in fire safety and analyzes evacuations. As one example, he observed that the planes in tests are level to the ground, while the Japan Airlines plane’s nose was angled down, making it harder for passengers to get to exits and use the slides.

Very few evacuations match testing conditions and can wrap up in 90 seconds, said Galea. “That’s indicative of the fact that it’s just nonsense.”

Still, the Federal Aviation Administration in the U.S. has said overall evacuation safety is high, crediting developments such as better emergency lighting and less flammable materials used in aircraft interiors.

Airlines and safety specialists have studied past evacuations to improve the chances of survival. One conclusion: The instinct of people to try to grab their bags from the overhead bin can be lethal.

The Japan Airlines plane rolled down the runway for some distance before coming to a stop. The main lights went out.

“Everyone was screaming from the initial impact and then everything got eerily quiet because everyone was confused,” Hayashi said. The passenger next to him appeared to know about emergency procedures. “She started yelling, ‘Put your head down, keep your seat belts on, stay in your seat,’ ” he said.

Hayashi estimated it took about three to five minutes for the doors to open.

Japan Airlines said it took some time to get the doors open because flight attendants first needed the pilot’s confirmation that the airplane had come to a complete stop and they needed to check whether it was safe to evacuate.

Ultimately, the airline said, only three of the eight slides were used because fire was burning outside the other doors and it wouldn’t have been safe to open them. Flight attendants opened the two front doors—one each on the right and left sides of the plane—after communicating with the pilot.

An additional door in the left rear was opened by a flight attendant acting without the pilot’s authorization because a communications system breakdown made it impossible to check, the airline said.....


And our 2015 post "The Fuzzy Logic of Fleeing for Your Life" which I used as a jumping-off point to the Toronto near-disaster:

From IEEE Spectrum:
On 31 December 2014, approximately 300,000 people packed Chen Yi Square on the riverfront of the Bund in Shanghai to watch the New Year’s Eve light show. The popular, bedazzling event took a tragic turn when observers on a stairway to the waterfront mistook a sudden shift in crowd traffic for something more sinister. Panic and confusion caused a chaotic stampede, resulting in 36 dead and about 50 injured.

Jian Ma, a researcher at Southwest Jiaotong University, in China, is trying to better understand the events of the Shanghai stampede. “Right now, we do not have enough insight into why people choose their escape in such an irrational way,” he says.

Civil engineers have been modeling evacuations during these kinds of emergencies and disasters for decades, but they haven’t been able to completely capture the way a hammering heart or a body zinging with adrenaline can alter a person’s behavior during a crisis. A new approach that integrates the concept of “fuzzy logic” can make computerized crowds behave more like hysterical humans.
Typically, computers answer questions with an absolute truth (either yes or no, 0 or 1). Fuzzy logic, on the other hand, understands truth on a sliding scale, where the answer can be “maybe.” When applied to a model of pedestrian traffic, it can account for emotions like fear, panic, and anxiety, and it can show how each variable influences how fast a crowd evacuates. These fuzzy models can more accurately reflect pedestrian behavior like that seen during the stampede in Shanghai, according to Ma....
....One of the more interesting examples of people actually doing the right thing was the crash of Air France Flight 358 in Toronto. Attempting to land in really lousy weather the plane went too far down the runway and into a ravine. There were 309 people on board.

From the Aviation Investigation Report
Runway Overrun and Fire:

...1.15  Survival Aspects

1.15.1  General
The passenger load comprised 297 passengers: 168 adult males; 118 adult females; 8 children; and 3 infants. Adult passengers included: three wheelchair passengers and one blind passenger.

Three non-revenue passengers were seated in crew seats: one in the third occupant seat of the flight deck, and two in the flight crew rest area.

The dynamic loads generated in this occurrence were within range of human tolerance. However, given the number of serious impact injuries incurred by passengers and crew located in the flight deck and forward cabin, it is apparent that significant forces were experienced in those areas of the aircraft.

1.15.2  Runway Excursion
From the time the aircraft left the runway until it came to a stop in the ravine, it bounced violently and repeatedly, and there were a minimum of three distinct impacts. On each impact, cabin occupants were propelled upward from their seats, their arms and legs flailing. It is estimated that approximately 15 to 20 seconds elapsed between the time the aircraft departed the runway hard surface and it came to a stop in the ravine. The following events occurred during the impact sequence:

  • a number of overhead baggage compartment doors opened, uncommanded, allowing carry-on baggage to fall into the cabin;
  • the L2 passenger door opened while the aircraft was moving, sometime after it left the end of the runway;
  • a portable serving table stowed/secured in the forward galley dislodged and fell in the cross-aisle between the L2 and the R2 exit doors;
  • the fire started on the aircraft exterior before the aircraft came to a stop; and
  • smoke entered the cabin through the opened evacuation doors before the evacuation was complete....
  • ...
When the plane came to a stop it was discovered that 4 of the 8 exits were unusable:....