Dramatically ramped up North Korean missile testing may pose a risk to passenger jets in the area, officials fear, as Pyongyang does not regularly give notice of its plans as required under international agreements.

On Friday, North Korea tested an intercontinental ballistic missile (ICBM) which it says is capable of hitting the continental United States.

The missile may have posed a much more immediate threat too, flying within miles of the flight path a passenger jet had just completed.

According to a statement from the Japanese military, the missile came down 150 kilometers (93 miles) northwest of Okushiri Island at around 11:27 a.m. ET on July 28.

At that time, according data from FlightAware.com, Air France flight 293 was 100-110 kilometers (62-68 miles) from the splash down site, or around 7 minutes of flight time at its then speed of 914 kilometers per hour (568 mph).

Two airways — fixed routes established for navigation purposes — pass within 10 miles (16 kilometers) of where the missile is believed to have splashed down.

North Korea has been steadily expanding the range of its missile tests away from the country’s east coast into Japanese waters.

The North Korean missile reached a peak altitude of 3,700 kilometers (2,300 miles) before dropping into the sea near Okushiri. Passenger jets fly at around 9,000-12,000 meters (30,000-40,000 feet).

In a statement Wednesday, Air France said “North Korea’s missile test zones don’t interfere in any way” with the company’s flight paths and AF293 completed its flight “without any reported incident.”

“Air France constantly analyzes potentially dangerous flyover zones and adapts its flight plans accordingly,” the statement said.

This is not the first time North Korean missiles have been raised as a potential threat to aviation. After a separate test on July 4, US Defense Department spokesman Jeff Davis warned the “missile flew through busy airspace used by commercial airliners.”

No warnings

While the chance of an unaimed missile striking a plane are “billions to one,” according to CNN aviation safety analyst David Soucie, the ramifications are potentially huge and create a difficult decision for airlines operating in the area.

“Does it start a war? Is it an act of war? The impact of what could happen if that did occur are more than just a cost benefit analysis,” he said.

Under guidelines issued by the International Civil Aviation Organization (ICAO), a United Nations agency tasked with governing air safety and other matters, states have the “responsibility to issue risk advisories regarding any threats to the safety of civilian aircraft operating in their airspace.”

“Said threats may include, but are not limited to, armed conflicts, ash clouds due to volcanic eruptions, (and) missile tests and rocket launches,” the guidelines state.

South Korea has warned since at least 2014 that North Korea fails to regularly issue notices to airmen (NOTAM) when conducting missile launches. Such notices are regularly issued by states to warn pilots and airlines of potential risks during their flights.

In March 2014, Seoul said a passenger jet passed through the trajectory of a North Korean rocket in a “very dangerous” fashion.

North Korea is “clearly breaching international norms” by failing to issue notifications, said Peter Harbison, executive chairman of the Australia-based Center for Aviation.

CNN reached out to North Korean officials for comment on the issue but has yet to receive a response.

Japan’s Ministry of Foreign Affairs said that it issued a warning to all vessels and aircraft operating within the country’s exclusive economic zone 8 minutes after the North Korean missile was launched.

Failure to issue proper guidelines can result in tragedy. During the 2014 conflict in Ukraine, airlines were told to fly above 26,000 feet (7,900 meters), at which level they were believed to safe from ground attack.

However, according to a comprehensive report into the downing of Malaysian Airlines flight 17 by Dutch authorities, the Ukrainians may have failed to take into account the presence of weaponry posing a risk to civil aviation in the conflict zone.

The report concluded the missile — which had a far greater range than other weapons in the area — was what brought down the plane, killing almost 300 people on board. .

Risk assessment

Should a North Korean missile come close to a passenger jet, it’s “probably not something you would be able to detect like you detect another aircraft,” a Hong Kong-based commercial pilot told CNN.

“You wouldn’t even know it was coming,” he said, speaking anonymously as he was not authorized by his employer to discuss sensitive matters.

“The issue is North Korea is firing missiles out of their airspace jurisdiction … it’s quite a big threat.”

A decision to adjust flight paths to compensate for any potential risk from North Korean activity would likely be a costly and difficult one, said CNN’s Soucie.

“The bigger picture is the fact that no one really has the authority to mandate (a no-fly zone),” he said. “It’s up to each airline to make that decision.”

Such a decision could be prohibitively costly for many airlines, as it would require a significant diversion from usual flight paths and airways, potentially racking up large fuel costs for long-haul flights such as those bound from Asia to Western Europe.

The Hong Kong pilot said that it would likely force some flights to carry out “technical stops to land and refuel somewhere” in order to complete their routes.