Two men were killed when a light aircraft crashed due to possible “structural failure,” an inquest was told.
Pilot Nick Jeffries, 54, and his friend Scott Pennington, 25, plummeted into the field near Builth Wells, Powys, and both died from their injuries.
The pair were airborne for less than 30 minutes when the silver Evektor EV-97 EuroStar crashed in September.
The inquest heard a failure with the structure of the plane may have been to blame.
Robert Carter, principal inspector of air accidents at Air Accidents Investigations Branch, told the hearing that a report into the accident was due to be published later this year.
He said: “The report is aiming to be published later this year.
“It is taking a bit longer because the accident does seem to involve an in-flight structural failure.
“That has been quite difficult to tie down what the causes and effects are. It has been quite complex.”
The pair from Holmes Chapel, Cheshire, died in the field at Cwmbach, near Builth Wells, Powys.
One Direction singer Harry Styles was a close family friend of Mr Jeffries, who took him on flying lessons in his single-engine two-seater plane decked in the Union Flag colours.
Senior coroner Andrew Barkley adjourned the inquest until August for more reports.
He said: “Clearly much hinges on the report.
“The final report may then dictate that other people may join the inquest process.
“Until I see the final report it is difficult for me to define what the scope of the inquest will be.”
The hearing in Aberdare, South Wales, was adjourned.
See full story in the County Times