The US Air Force has suspended its investigation into the 16 November crash that destroyed one of its Lockheed Martin F-22 Raptors and killed the pilot.
Poor weather conditions at the remote crash site near Cantwell, Alaska saw a combined air force and army team suspend its "recovery and restoration efforts", the USAF says.
On 14 January it also instructed accident investigation board officials to enter a period of recess. "The board is set to resume when weather conditions allow further recovery operations of the crash site," the USAF says, adding that "most visible pieces of the wreckage were removed" before the work was suspended.
"The accident investigation board has been unable to determine the cause of the accident with the information and evidence available," the air force said on 21 January. It says it remains "committed to conducting a thorough investigation of the crash site to determine the cause and situation surrounding the crash".
Capt Jeffrey Haney died when his F-22 came down during a night-time training mission flown from the USAF's Joint Base Elmendorf-Richardson in Alaska. Part of the aircraft's ejection seat and several life-support items worn by the pilot were found in a crater at the crash site.
© US Air Force
Last year's mishap is the only operational loss to have involved the air force's most sophisticated fighter.