The investigation into the sudden mid-air nosedive by a flight from Sydney to Auckland this week is reportedly focusing on the movement of a flight-deck seat.

LATAM Airlines said the airliner suddenly dropped due to a “technical fault” before stabilising, with the force of drop injuring 50 passengers and crew as people were thrown around the cabin.

Alleged details from inside the investigation, leaked to aviation industry publication Air Current, cite a senior airline safety official briefed on the incident as saying it was understood the movement of a cockpit seat was “pilot induced, not intentionally”.

Another anonymous official was quoted as saying “the seat movement caused the nose down” pitch of the airliner, adding that the possibility of an electrical short was also under review.

At least a dozen people – including four Australians – were taken to hospital and scores more were injured when LATAM Airlines flight LA800 dropped abruptly mid-flight above the Tasman on Monday.

The Boeing 787 Dreamliner, carrying 263 passengers and nine crew and on its way to Santiago via Auckland, landed safely in Auckland.

Passenger Brian Jokat said the pilot came to the back of the plane “in shock” after the incident and recounted how “gauges just blanked out, I lost all of my ability to fly the plane”.

Dozens of people were injured when the flight dropped suddenly. Photos: Supplied

Brisbane woman Clara Azevedo, who was also on the plane, said it felt like a “miracle” when the pilot gained control of the plane after feeling it “free-fall” for what she thought was 10 seconds.

“We were not sure if we were going to make it or not,” 28-year-old Azevedo told the NZ Herald.

Air Current said the loss of gauges was not the main focus of the investigation.

The Air Current article, written by veteran aviation journalist Jon Ostrower, also explained how pilot seats on the Boeing 787 can be moved, including via a button on the back of the seat.  

LATAM Airlines, responding to the report, told Reuters news agency it “continues to work in coordination with the authorities to support the investigation”, adding it was not appropriate to comment on any speculation.