NTSB: 2019 fatal mid-air collision near Ketchikan could have been avoided
Board urges use of alert technology to enhance safety
ANCHORAGE, Alaska (KTUU) - The National Transportation Safety Board discussed Tuesday morning the final report and recommendations about the plane crash on May 13, 2019, involving two flightseeing planes that collided mid-air near Ketchikan. The crash resulted in the death of six individuals and injured 10 others.
During the meeting, the safety board revealed technology existed and was installed that could have helped the pilots avoid each other, but the alert functions on the day of the flights had limitations.
“Had these limitations not existed, aural and visual traffic alerts in each airplane would have occurred early enough for the pilots to taken actions to prevent the collision,” the board said Tuesday during a live stream of its meeting.
The planes, operated by Mountain Air Services and Taquan Air, collided in a scenic area above the Misty Fjords National Monument.
Pilots use a principle called “see and avoid,” which calls upon them to visually scan for potential hazards and take action to avoid those hazards. Limitations include blind spots in the field of vision created by the frame of the aircraft — cockpit visibility — and other duties pilots attend to during flight. The board called for the use of avoidance alert technology to be installed and functional.
The board found that the “see and avoid” visibility for each pilot would have been obscured by the frame of the aircraft they were in or their passengers, preventing them from seeing each other.
During the board meeting, NTSB investigators presented several animations showing how visible the planes were to each other, and with how much time prior to impact, from a view outside the planes, as well as from inside the cockpits.
The planes were traveling toward convergence, with the Taquan Otter in a slight descent, while the Mountain Air Services Beaver was climbing. The board said the Taquan aircraft broke up in flight after impact, while the Mountain Air Services craft made a nearly 180 degree turn, crash landing in the waters of George Inlet.
A photographic image captured by one of the passengers in the Beaver shows the Otter as it approached just prior to the collision.
Additionally, had the electronic alert systems worked to their full potential, the NTSB found that the Mountain Air plane would have received an alert 1 minute and 44 seconds before the collision, and that the Taquan Air plane would have received an alert 37.4 seconds before the collision, the board said.
According to the FAA, it takes at least 12.5 seconds for a pilot to avoid a collision from the time they observe a hazard.
Investigators found that some aspects of the Taquan aircraft’s alert system had been turned off during maintenance performed two weeks prior to the crash and that the pilot was unaware those systems were not turned on. The board mentioned it is not unusual for avionic systems to be turned off during maintenance.
The board also acknowledged a 2015 equipment change on the Taquan plane that was meant to upgrade the plane’s avionics. However, the change actually eliminated a type of outbound data transmission that could have alerted the Mountain Air plane to the Taquan plane’s position.
“It would be like people speaking two different languages. Somebody is speaking in one language, but the receiver doesn’t understand that language. And so we had a multitude of problems,” NTSB Chairman Robert Sumwalt said in a press availability with reporters after the board meeting.
“This issue of mid-air collisions and failures of the ‘see and avoid’ have been here for literally my entire life,” Sumwalt said during the meeting. “Sixty-five years we have been talking about this, and probably even before, so I am hopeful that the recommendations we come out with today will help to further drive this continuing problem down and get rid of it once and for all.”
Early Tuesday morning, the board voted to adopt that “the probable cause in this accident was the inherent limitations of the see-and-avoid concept, which prevented the pilots from seeing the other airplane before the collision and in the absence of visual and aural alerts from both airplanes traffic display systems while operating in a geographic area with high concentration of activity.”
The board was also critical of a safety system upgrade implemented in 2015, which actually eliminated some built-in safety features.
“Contributing to the accident were the Federal Aviation Administration provision for new transceivers that lacked alerting capability to capstone program operators without adequately mitigating the risk associated with the consequent loss of the previously available alerting capability and the absence of a requirement for airborne traffic advisory systems with aural alerting among operators to carry passengers for hire,” the board said in its probably cause statement.
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Editor’s note: This article has been updated with additional information.