2023년 12월 군산 바다에 추락한 미공군 F-16의 추락 원인은 악천후시 항법장치 고장

[위종민]

작년 12월 11일 미공군 F-16이 군산공군기지 이륙 후 서해 바다로 추락하는 사고가 있었는데, 조사 결과 GPS와 연동된 항법장치의 고장 때문이었다고 합니다. EGI의 고장 원인은 불명이나 동력 손실로 뻗은 것으로 추정되네요. 

오전 8시 23분 이륙 직후 항공기가 짙은 구름에 휩싸인 계기 기상조건에 돌입했는데, 때마침 EGI가 고장났고 백업인 대기자세표시기(SAI) 역시 고장나 잘못된 피치 / 뱅크 데이터를 표시해 방향감각을 상실하고 군산 서쪽 81해리 떨어진 서해상에 추락했다고 합니다. 

2024년 1월 발생한 추락사고는 여전히 조사중입니다. 

An 8th Fighter Wing F-16 takes off at Kunsan Air Base, Republic of Korea. Tech. Sgt. Kristin High

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F-16 Navigation System Failure in Bad Weather Led to Crash off Korea: New Report

Sept. 27, 2024 | By Unshin Lee Harpley

A critical failure of an F-16’s navigation system and its backup, coupled with poor weather conditions, led to a crash off the coast of South Korea last December, destroying the $28 million fighter, according to an Air Force Accident Investigation Board release Sept. 26.

The F-16 was flying from Kunsan Air Base, South Korea, for a training mission on Dec. 11, 2023. The pilot, who ejected safely, sustained no serious injuries and was returned to full flight duties a few weeks later.

The investigation found the crash was primarily due to a failure in the aircraft’s embedded global positioning and inertial navigation system known as EGI. The EGI combines GPS and inertial navigation that tracks movement using onboard sensors. When the EGI fails, the pilot loses access to critical navigation and must rely on backup instruments.  

But in this case, the backup also failed the pilot; investigators faulted a malfunctioning backup Standby Attitude Indicator (SAI) and poor weather conditions with limited visibility as causes of the pilot’s disorientation that contributed to the crash. The SAI shows the jet’s orientation—whether it’s level, climbing, or turning.

Although the exact cause of the EGI failure remains unclear due to the loss of the black box, a power outage is suspected to have triggered the malfunction, as seen in similar past incidents.

“Based on the data available, I could not determine why the EGI malfunctioned,” Col. Philip Lancaster, the board president, wrote in the report. “The ‘most likely’ cause of failure is a loss of power which may or may not be visible to the pilot.”

The incident began shortly after the 8:23 a.m. takeoff of a four-ship formation of F-16s from Kunsan during a routine exercise. The pilot involved in the mishap encountered dense cloud cover, forcing him to rely fully on the aircraft’s navigation system to fly, a state known as instrument meteorological conditions (IMC).

About 15 minutes into the flight, the jet’s EGI system malfunctioned, wiping out the pilot’s critical navigation and attitude displays that are essential for keeping the plane level or on course.

“The absence of the EGI failure while in IMC may have prevented this mishap,” the report stated.

With the EGI down, the pilot tried to rely on the backup SAI, which had already shown some faulty pitch and bank data earlier in the flight. Hoping for clear skies, the pilot then started a descent through the clouds.

The system kept giving conflicting readings, showing a climb while airspeed and altitude instruments indicated a descent. This mismatch of data with the cloudy conditions led to the pilot experiencing spatial disorientation—a condition where the pilot could not accurately interpret the aircraft’s position relative to the horizon.

“After transitioning to the SAI, the Mishap Pilot had difficulty maintaining level flight and overall spatial orientation due to the weather conditions and a poorly performing SAI, so the [pilot] prioritized a descend below the forecasted ceiling (believed to be 3,500 ft) where clear sky was expected,” the report stated.

The pilot told one of his wingmen to follow closely, about 500 feet behind, while relaying altitude and airspeed information during the descent. However, the report noted that radar data alone from the other F-16 wasn’t enough to resolve the mishap pilot’s spatial awareness. When the other pilot’s radar showed the mishap plane slightly climbing, the mishap aircraft’s SAI still indicated a nose-up position with continued altitude loss.

“When unable to find airspace free of clouds at 3,000 feet, the Mishap Pilot attempted to level off, causing further disorientation,” the report read.

At around 8:42 a.m., the pilot attempted to eject, though without the black box data, the exact timing and aircraft position at ejection remain uncertain. Shortly after, the F-16 crashed into the Yellow Sea, approximately 81 nautical miles west of Kunsan. The jet, belonging to the 8th Fighter Wing, was completely destroyed, with a valued loss of $28,259,045. The pilot was rescued by a Republic of Korea Navy ship and treated for hypothermia.

Since last year, Kunsan has experienced three F-16 crashes, occurring in May and December of 2023, and January of this year. No personnel have been injured in any of the crashes, and the Air Force has stated that the incidents do not appear to be related.

“The Air Force is working to limit the impacts of temporary power fluctuations on flight instrument systems in the F-16,” the service said in a statement following the release of the report.

The investigation report for the third F-16 crash in January this year is still being conducted and its results will be published “as soon as they are available,” the statement added.

[백선호]

구름 속에서 계기가 맛이 가버리니 내가 상승하는지 하강하는지도 알 수 없고... ㅠ.ㅠ

[위종민]

FS-X 베타판에서 대낮 바다에서 첫 비행하는데, 분명 자세지시계는 "너 지금 꼬라박고 있어!"라고 말해주고 있는데도 멀쩡한 하늘 놔두고 바다에 경착륙한 뒤엔 비행은 타고 난 사람만 하는 거구나 생각하고 있습니다.