Queen Elizabeth's helicopter was grounded after an in-flight emergency on the way to pick up Princess Anne.
The Sikorsky S-76 aircraft suffered a technical problem just minutes into the flight to Balmoral on Wednesday (25.08.21).
The pilots were forced to abort their trip to the Scottish estate, where The Princess Royal has been staying with the monarch on holiday, and returned to Newcastle Airport - where the fault was still being worked on 24 hours later.
A royal insider told The Sun newspaper: "A safety-first approach was taken and it was flown back immediately for the technical fault to be fixed.
"There were no members of the royal family on the helicopter.
"Luckily, there was plenty of time to find alternative travel arrangements."
Anne, 71, later took another helicopter flight in order to conduct three engagements in the Scottish town of Oban.
The Queen and other senior royals are regular passengers on the chopper, which is based at RAF Odiham in Hampshire. It is owned outright by the royal family and they also lease a similar aircraft.
Meanwhile, the 95-year-old monarch was recently praised by Sarah Ferguson - the former wife of her son Prince Andrew - for "believing in her".
The Duchess of York said: “I think to myself that honestly, my mother-in-law has been more of a mother to me than my mother."
The 61-year-old author also praised the Queen for being so "modern".
She added: “I absolutely admire the incredible way Her Majesty is so modern. And how flexible, and how understanding, and how forgiving and how generous and kind. I absolutely think there is no greater mentor. The consistency of Her Majesty has been a great honour. A huge honour. Makes me want to cry.”