6 fatalities
13 May 2019: De Havilland DHC-2 — Mountain Air Service LLC — Ketchikan, AK
On 13 May 2019, a De Havilland DHC-2 operated by Mountain Air Service LLC was involved in an aviation accident near Ketchikan, AK. 6 people were killed. Investigators recorded the probable cause as: The inherent limitations of the see-and-avoid concept, which prevented the two pilots from seeing the other airplane before the collision, and the absence of visual and aural alerts from both airplanes’ traffic display systems, while operating in a geographic… This summary draws on records from NTSB; 12 related events involving the same aircraft type or operator are linked below.
Probable cause
The inherent limitations of the see-and-avoid concept, which prevented the two pilots from seeing the other airplane before the collision, and the absence of visual and aural alerts from both airplanes’ traffic display systems, while operating in a geographic area with a high concentration of air tour activity. Contributing to the accident were (1) the Federal Aviation Administration’s provision of new transceivers that lacked alerting capability to Capstone Program operators without adequately mitigating the increased risk associated with the consequent loss of the previously available alerting capability and (2) the absence of a requirement for airborne traffic advisory systems with aural alerting among operators who carry passengers for hire.
— NTSB Determination
Contributing factors
PilotPilot of other aircraftCentral warningFAA/RegulatorDesignEffect on operationIncorrect use/operationOperator