Investigations into the flight on which Emiliano Sala died will focus on the validity of the pilot’s licence.
The Air Accident Investigation Branch’s (AAIB) preliminary report into the crash says David Ibbotson could only fly passengers in the European Union if they were contributing to the cost of the flight, rather than for financial gain.
Pilots with his licence “must have a bona fide purpose for making the flight”, according to the AAIB.
It goes on to say that “the basis on which the passenger was being carried has not yet been established” and that in the past Mr Ibbotson had taken passengers on a non-commercial ‘cost sharing’ agreement.
It also says the plane was not licensed to fly commercially.
It states that it “was not allowed to be used for commercial operations without the owner or operator first obtaining permission.”
Nobody “had applied to the FAA (US Federal Aviation Administration) or the CAA (Civil Aviation Authority) to operate the aircraft for commercial reasons.
“The CAA advised the AAIB that they had no record of an application for permission to operate the aircraft commercially.”
The report also includes previously unseen pictures of the underwater wreckage of the plane, detailing how the Piper Malibu aircraft was “destroyed” and found smashed into three parts on the sea bed.
The parts were held together by electrical and flying control cables. The engine had disconnected from the cockpit area and parts of both wings, the tail and the fin were missing.
Investigators also describe how the plane did not stick to a straight flight path.
Around 15 seconds before the fatal crash the plane plunged at a rate of 7,000ft (2133m) per minute – equivalent to around 90mph (144km).
The AAIB said it had been unable to establish how much flying Mr Ibbotson, 59, had done recently, as his pilot’s licence and logbook had been lost.
Sala, 28, died when the plane crashed near Alderney on 21 January as he travelled from Nantes to Cardiff, having joined the Premier League club Cardiff City for £15m days earlier.
A post-mortem examination found the Argentinian died from head and chest injuries and the striker’s funeral took place in his home country earlier this month.
The report says the wreckage was found about 30m (98ft) from the single-engine light aircraft’s last secondary radar contact, recorded by the radar at Guernsey at 8:16pm.
That was about four minutes after it was last in radio contact at 8:12pm.
The report reveals that in the last 15 minutes, Mr Ibbotson descended four times, telling air traffic control he wanted to maintain visibility.
In his last communication, air traffic controllers asked whether he needed to descend again. “Negative, just avoided a patch there, but back on heading five thousand feet,” he answered.
A private search for Mr Ibbotson’s body, which is still missing, is expected to start soon.
Isolated showers were forecast for Guernsey at the time the plane crashed, and rain was expected to come into the area from the northwest overnight.
Geraint Herbert, from the AAIB, said he was confident the report will lead to a plausible explanation of what happened.
He said a recording of the pilot revealed that weather had played a role in the crash.
Mr Herbert told Sky News: “What we have is a recording of the pilot saying that he would like to manoeuvre to avoid weather, so we think to that extent that the weather was playing a role – it wasn’t the decisive role but it was playing a role.”
He added that investigators would be looking at the flight path in the final stage “because there was a high descent rate followed by a climb”.
“There was unusual rates of descent followed by climb in these circumstances – so there is probably something in there that we can use to build up a picture of what happened.”
The aircraft was built in 1984 and had a valid certificate of registration, due to expire in 2021.
Its last significant maintenance was an annual 100-hour check on 30 November 2018, after which it was signed off back into service.