[News Terms] The '90-Second Rule' Gaining Attention After Japanese Passenger Plane Accident

'Golden Hour' Before Gas Is Engulfed in Flames
'Informal Speech and Shouting' Orders, Evacuation Time Reduced to '71 Seconds'
AP News: "Advanced Materials Burn Slowly, Buying Time"

The '90-Second Rule' is a regulation related to aircraft manufacturing standards designed to prepare for aircraft accidents. It is a concept that requires aircraft to be designed so that passengers can evacuate within 90 seconds using no more than half (50%) of the emergency exits in the event of a collision or fire.

Established through experiments by the U.S. Federal Aviation Administration (FAA) in 1965, the original standard was 120 seconds. However, after the FAA revised and presented the rule as 90 seconds on September 20, 1967, all commercial aircraft must be designed according to this standard. If the location and structure of the aircraft’s fuel tanks, interior lighting, seat arrangement, etc., do not comply with the '90-Second Rule,' the aircraft cannot obtain FAA type certification.

An aircraft belonging to Japan Airlines (JAL) completely burned on the runway at Haneda Airport in Japan.
[Photo by Kyodo/Yonhap News]

Golden Hour: 1 Hour for Maritime Accidents, 72 Hours for Burial/Collapse

For maritime accidents, the golden hour is typically 1 hour, and for burial or collapse accidents caused by earthquakes, it is generally 72 hours. In contrast, the golden hour for aircraft accidents is uniquely short at 90 seconds. This is because a slowly burning fire reaches a 'flashover' phenomenon at 90 seconds, where the cabin suddenly becomes engulfed in flames due to oxygen supply. This means that an aircraft on fire after a crash or collision can only withstand 90 seconds.

To increase survival chances, aisles must be kept clear at all times in preparation for emergencies. Passengers should abandon all carry-on items during evacuation, follow the order when using emergency evacuation slides, and if wearing a life jacket, they should not inflate it inside the cabin.

Following the instructions of trained crew members thoroughly in any situation is the best way to maximize survival chances. Crew members are trained to repeatedly shout commands like "Duck down!" and "Stay low!" during emergencies, in accordance with International Civil Aviation Organization regulations and airline cabin operation manuals.

On the afternoon of the 2nd, firefighters at Haneda Airport runway in Tokyo, Japan, are examining a burnt part of a Japan Coast Guard aircraft.
[Photo by Tokyo AP/Kyodo/Yonhap News]

Polite Evacuation Commands Take 104 Seconds, Casual/Shouting Commands Reduce It to 71 Seconds

This refers to giving commands in a casual tone or shouting. While it may feel uncomfortable for Koreans accustomed to polite speech, experiments show that casual speech is more efficient. A 2016 experiment by a broadcasting company found that evacuation took 104 seconds when instructions were given politely, but only 71 seconds when commands were given casually.

The most dangerous times during a flight are the first 3 minutes after takeoff and the last 8 minutes before landing, collectively called the 'deadly 11 minutes.' The Japan Airlines (JAL) passenger plane accident on June 2 at Tokyo Haneda Airport, where a fire broke out after a collision with a Japan Coast Guard aircraft, also occurred during landing.

On June 4, Asahi Shimbun reported that foreign media praised the safe evacuation of all 379 passengers as a miracle of the '90-Second Rule.' The newspaper noted that the accident occurred at 5:47 p.m., and evacuation was completed by 6:05 p.m., meaning it actually took about 18 minutes.

Nihon Keizai Shimbun reported that it seemed to take 5 to 15 minutes for the emergency exits to open after landing, and that some crew members used megaphones because the announcement system was not working. Hiroshi Sugie, a former JAL captain and aviation critic, commented, "Although the detailed circumstances of the accident are not yet clear, it seems the evacuation took a long time."

Tokyo Shimbun reported that a man in his 20s who was on the accident flight said some passengers did not hear the crew’s voices or were gathering their belongings, describing the evacuation as feeling like a chaotic rush once the emergency exits opened. Yomiuri Shimbun reported that while all passengers survived, pets in the cargo hold were not rescued.

Regarding this accident, opinions differ between those who believe the passengers were safely rescued because it was a Japanese aircraft and those who think the same would have happened if it had been a Korean aircraft.

Flight attendants of a domestic airline are conducting emergency evacuation slide safety training.
[Photo by Asia Economy DB]

Advanced Materials: 'Positive' vs. Lack of Precise Physical Evidence

On June 3 (local time), the Associated Press (AP) reported an interesting analysis. The AP diagnosed that the reason all 379 passengers survived was because the aircraft’s material, carbon fiber-reinforced plastic, delayed ignition. The advanced aircraft material burned slowly over a certain period instead of igniting rapidly, giving people time to evacuate.

The JAL aircraft involved in the accident was an Airbus A330-300, a two-year-old plane made with carbon fiber-reinforced composite materials. This model has been produced since 2018 with 570 units sold, while competitor Boeing has produced 1,100 units of aircraft such as the Boeing 787 using the same materials since 2011, according to AP.

Safety consultant John Cox said, "It is a positive sign that the aircraft material may have saved people from a terrifying fire." On the other hand, John Goglia, accident investigation director at the U.S. National Transportation Safety Board (NTSB), drew a line, stating, "There is no precise physical evidence yet on how much more fire-resistant or heat-resistant these composite materials are compared to past aluminum, or whether they provide enough time for passengers to evacuate safely."

The AP reported that while aircraft manufacturers claim passengers can evacuate within 90 seconds even if half of the exits are blocked, skeptics question the accuracy of government-conducted inspections.