Sala, 28, died when the plane carrying him from Nantes to Cardiff crashed on January 21. Along with Sala, pilot David Ibbotson was also killed in the crash.
A spokesperson for the Dorset Police in UK informed that the 64-year-old man from North Yorkshire had been arrested and released while investigations continue.
"As part of this investigation we have to consider whether there is any evidence of any suspected criminality and as a result of our inquiries we have today, Wednesday 19 June 2019, arrested the man from the North Yorkshire area on suspicion of manslaughter by an unlawful act," the BBC quoted Detective Inspector Simon Huxter, of the force's Major Crime Investigation Team, as saying.
"He is assisting with our inquiries and has been released from custody under investigation," he added.
Earlier, it was reported that the pilot was not qualified to fly at night.
Regulatory authorities had said that Ibbotson was thought to have been colour-blind, which prevents pilots from flying at night. They had confirmed that Ibbotson, from Crowle, North Lincolnshire, did not hold a "night rating" on his UK private pilot's licence.
While Sala's body was recovered from the wreckage of the plane in February, Ibbotson's body remains to be found.
( With inputs from IANS )