An Australian national who suffered severe head trauma following a traffic accident in Orchard Road is seeking $6.7 million for loss of future earnings, based on the unusual claim that he would have gone on to be a commercial pilot had it not been for his injuries.

Mr Jay Mitchell Smith, 31, argued he had a 100 per cent chance of following the footsteps of his father and brother, who were pilots with Tiger Airways, which has now merged with Scoot.

He was on holiday in Singapore on Aug 5, 2011 when he was hit by a car as he was crossing the road opposite the Hilton Hotel.

Rushed to Tan Tock Seng Hospital with head injuries, he underwent surgery in which part of his skull was removed. The court was told the trauma caused great emotional, physical and mental pain which has left him with physical and other residual disabilities.

Mr Smith sued the driver, Mr Abdul Rahim Mohd Akhbar, and the car owner, Resorts World Sentosa, who accepted 70 per cent liability on July 15, 2016, with the sum payable to be assessed.

Most of the items to his claim such as pain and suffering, medical expenses and pre-trial loss of earnings have been settled at mediation and he has received $231,841 so far.

But both parties were deadlocked on the sum payable for loss of future earnings and earning capacity, even with the help of mediators.

In the High Court hearings which began on Tuesday to resolve the impasse, his lawyer Cecilia Lee Thomas said the most painful consequence of the accident was the lost chance to be an airline pilot as well as his fallback job as a landscaper, as his disabilities have limited his job scope.

She argued his claim was neither fanciful nor inflated, given he had grown up aiming to be a pilot like his father, who is now an authorised flight examiner with Scoot Tigerair Pte Ltd, and his younger brother, Simon, who shared similar dreams and is now a Junior First Officer with the same airline.

Based on what he would have earned in the future at 100 per cent liability, Mr Mitchell sought $6.629 million and another $100,000 for the loss of earning capacity, the disadvantage he would suffer in the labour market.

Lawyers K. Anparasan and Sha-ron Lin, for the defendants, countered that a son does not always follow the father and noted Mr Mitchell's passion for landscaping was far more evident than for flying. Mr Anparasan claimed in opening remarks that Mr Smith was paid more in his present job than his brother, and even if he had got his commercial pilot's licence, there was no objective evidence he would have flown with Scoot.

Describing him as a flying enthusiast who had done some hours at a recreational flying school, he noted Mr Smith did not consent to a move by the defence to call a senior airline official to testify on the policy of hiring pilots.

The High Court hearing before Justice Andrew Ang will continue tomorrow.