On Thursday, the search for the plane, which disappeared over the Channel Islands on Monday, was called off following one of the biggest operations of its kind in modern times.
Overnight it has emerged that the pilot, David Ibbotson, held a private pilot’s licence and the plane was registered in the USA.
US law states that private pilots cannot make a profit by carrying passengers.
‘We are looking at all operational aspects of the flight including licensing,’ an Air Accidents Investigation Branch spokesman told the BBC.
Aviation commentators have also questioned whether Mr Ibbotson was sufficiently familiar with the Piper Malibu aircraft.
In a Facebook post two days before the flight, the 60-year-old said he was a ‘bit rusty with the ILS’ or Instrument Landing System, which is a cockpit aide designed to help guide pilots down to airports and airfields.
The search was called off at lunchtime on Thursday. Despite three planes, five helicopters and two lifeboats scouring an area of 1,700 sq miles, rescuers failed to find any trace of the aircraft.
But Mr Sala’s sister Romina Sala has pleaded with rescuers to keep looking for him.
‘Emiliano is a great fighter – I know he hasn’t given up and he is waiting for us,’ she said in a press conference.
Guernsey Harbourmaster Captain David Barker said he was aware Mr Sala’s family were not content with the decision, but he was confident that nothing more could have been done to find the plane.
The single-engine plane disappeared as it passed close to Alderney at 2,300ft while en route from Nantes in France to Cardiff. The sea in the area is estimated to be 100 metres deep.
In the moments before the plane went missing, Mr Sala, who signed for Cardiff for a reported £15 million last Saturday, sent an audio message to his family saying it felt like the plane was ‘falling to pieces’.
During the search, rescuers covered the area from the north of Alderney to the north coast of Jersey. Although numerous pieces of debris were found, none of it came from the stricken aircraft.
Announcing the decision to end the search, Captain Barker said: ‘Despite the best efforts of air and sea search assets from the Channel Islands, UK and France, which has covered an area of approximately 1,700 sq miles – with a significant amount of this searched more than once – and having examined mobile phone data and satellite imagery, we have been unable to find any trace of the aircraft, the pilot or the passenger.
‘There has been over 24 hours of continuous searching, with 80 hours combined flying time across three planes and five helicopters. Two lifeboats have also been involved, as well as assistance from various passing ships and fishing boats.
‘We reviewed all the information available to us, as well as knowing what emergency equipment was on board, and have taken the difficult decision to end the search. The chances of survival at this stage are extremely remote.’
He said that the operation had been ‘very thorough’ and had involved ‘exemplary co-operation from all countries involved’.
Captain Barker added that although the active search had ended, the incident remained open.
‘We will be broadcasting to all vessels and aircraft in the area to keep a look out for any trace of the aircraft. This will continue indefinitely,’ he added.
It is not known what caused the tragedy, although some commentators have speculated that it could be weather-related.
