Mr Bollier said he booked a ticket from Zurich for Tripoli for 18 December, 1988, but said he was unable to get a direct return flight home and had to travel back to Switzerland via Malta on 21 December.
The revelation came as Edwin Bollier, who has admitted that one of the timers made by his company was used in the bombing, faced further questions at the trial in the Netherlands.
Mr Turnbull then said that just because Mr Bollier had not been charged did not mean he was not involved.
The businessman, a partner in the company Mebo, has been giving evidence about how he travelled from Libya to Malta the day before the Lockerbie disaster in December 1988.
Defence objection
David Burns, for the defence, said that if the Crown planned to inquire further about Mr Bollier's movements and suggested he was a co-conspirator they would be forced to object as they had not been given notice of that position.
"The decision not to include him as a co-conspirator is not a recognition that he has nothing to do with the matter.
"The extent of his involvement is yet to be developed in evidence. It may be he has involvement in what occurred, but unless the Crown is able to adduce evidence that places him in the conspiracy, it is not appropriate to libel him as a co-conspirator."
The prosecution has alleged that the bomb which destroyed the jumbo jet Pan Am Flight 103 over the Scottish town of Lockerbie came from Malta and was detonated by an MST-13 electronic timer supplied by Mr Bollier.
Trip to Tripoli
Mr Bollier's company designed the timers, hoping to win a large order from the Libyan military.
He told the court he took 20 prototypes to the headquarters of the Libyan Secret Service in Tripoli.
Mr Bollier said he booked a ticket from Zurich for Tripoli for 18 December, 1988, but said he was unable to get a direct return flight home and had to travel back to
Switzerland via Malta on 21 December.
Mr Turnbull asked Mr Bollier why he had to stay in Tripoli so long and told him: "I am wondering why you didn't arrange to come back on December 19 travelling via Malta."
Mr Bollier said: "I don't think there was a flight, I don't remember."
He said he would have preferred to take a direct flight back, but was unable to.
Military trials
During his trip to Tripoli he was taken to the desert city of Sheba where he saw his company's timers being used in military trials to detonate explosions.
Mr Bollier has waged a campaign in the media and on the internet denying any involvement in the Lockerbie bombing.
In court, he has sought to claim fragments of a timer circuit board found in the crash site could have been made by an American firm which supplied the CIA.
But under persistent questioning by Mr Turnbull, he had accepted that could not have been possible.
Mr Bollier earlier revealed he had met one of the accused, Mr Megrahi, several times.
He believed him to be a major in the Libyan military, possibly a relative of the country's leader, Colonel Gadaffi.