The planes crashed into Ben Macdui

Closing the case for the defence, Michael Jones QC said the RAF air traffic controller accused of causing the deaths had breached no regulations.

Mr Jones questioned the justice of Flight Lieutenant Malcolm Williams being found guilty of a crime.

He also questioned the strength of the prosecution's case, which he said had changed since the start of the hearing.

Mr Williams, 47, of RAF Leuchars, Fife, is charged with causing the deaths of Lieutenant Colonel Kenneth Hyvonen, 40, and Captain Kirk Jones, 27, who were both based at RAF Lakenheath in Suffolk.

It is alleged that Mr Williams told the Americans to fly below 6,500ft when they requested the "minimum vectoring altitude".

The two pilots died when their F15s crashed into Ben Macdui in the Cairngorms during a snowstorm on 26 March, 2001.

Appearing before the court martial in Helensburgh, Argyll and Bute, Mr Williams denies the charge and an alternative charge of professional negligence.

Mr Jones told the court that Mr Williams had not broken any rules on the day of the crash.

"In the factual context of this case the entire responsibility lies with Lieutenant Colonel Hyvonen (the lead pilot) when we are looking at this viewed through the eyes of an air traffic controller," he said.

"The pilot was wholly responsible for terrain clearance.

"He mistook the snow as white sky underneath and beyond that cloud and flew on into the mountain."

Wing Cmdr. Christopher Foster also said that if he had been supervising Flight Lt. Malcolm Williams at the time of the accident, he would not have been concerned by the information he was providing to the pilots.

But he said he would have asked Williams what the lead pilot had meant when he referred to “minimum vectoring altitude” — a term unfamiliar to RAF air-traffic controllers at the time of the crash.

Foster was giving evidence on the 17th day of a court-martial for Williams, an air controller with the Royal Air Force who is charged with professional negligence and causing the deaths of Lt. Col. Kenneth Hyvonen, 40, and Capt. Kirk Jones, 27, pilots with the 48th Fighter Wing based at RAF Lakenheath, England. The two died when their F-15Cs crashed into the Cairngorm Mountains during a snowstorm on March 26, 2001.

The court was told Williams advised the pilots to descend to 4,000 feet after they had requested the “minimum vectoring altitude.” Foster had previously told the hearing that Williams may have either not heard the term or not understood it.

But when asked whether Williams may have been endangering the safety of the pilots, Foster was quoted as replying: “Under the circumstances, with the aircraft on the radar information service, I would let the situation continue.”

The court martial, before six senior RAF officers assisted by a judge advocate, was to continue Wednesday.

According to a report in the Scotsman newspaper, Wing Cmdr. Christopher Foster, a defense witness, said Flight Lt. Malcolm Williams advised the pilots of the F-15Cs to drop their altitude as he was attempting to transfer air traffic control from his base at RAF Leuchars to RAF Lossiemouth on March 26, 2001.

Williams, an air controller with the Royal Air Force, is facing charges he caused the death of the pilots — Lt. Col. Kenneth Hyvonnen and Capt. Kirk Jones of the 48th Fighter Wing at RAF Lakenhath, England — through professional negligence. He is accused of telling the Americans to fly 2,500 feet below the safety limit in a snowstorm.

Foster, based at a joint civil and military air control center, was giving evidence on the 16th day of the case being heard at a Royal Navy base near Glasgow, Scotland. He was asked by Williams’ defense attorney why Williams had asked the pilots to descend to 4,000 feet, based on a transcript of their conversation.

Foster said Williams had initiated a handover to Lossiemouth while the aircraft were at about 8,000 feet. He said the pilots had asked how far north they could be seen on radar in order to maintain their radar information service, and since the handover had been initiated, requested a descent.

Foster said that the aircraft were rapidly approaching the edge of Leuchars’ normal 40-mile radar range so an initial descent to 4,000 feet would have been sufficient to keep the aircraft in radar coverage of both units.

Foster added that, according to the initial exchanges on the transcript, the handover of the planes was not going well. The process should have taken a few seconds, but had taken nearly a minute, according to the Scotsman report.

When asked if Williams could have foreseen that the jets would hit the mountain, Foster responded that, from a controller’s perspective, the pilots are responsible for terrain avoidance.

The court-martial was to resume Tuesday.

However, a court-martial was told Wednesday, the rules were changed in the wake of the crash requiring the controllers to warn pilots of low-level dangers, according to news reports in the United Kingdom.

The testimony came on the eighth day of the trial of Flight Lt. Malcolm Williams, 47, who was on duty and talking to the American pilots from RAF Lakenheath, England, when they crashed on March 26, 2001, in the mountains of western Scotland. Lt. Col. Kenneth Hyvonen, 40, and Capt. Kirk Jones, 27, were killed.

Group Capt. James Stenson of RAF High Wycombe said Williams was “unwise but entitled” to advise the pilots to fly at an altitude of 4,000 feet when a safe minimum altitude was 6,500 feet, The Scotsman reported in Thursday’s editions.

Earlier testimony placed the responsibility for avoiding dangerous terrain on the pilots.

Stenson testified that he agreed a transcript of Williams’ conversation with the pilots showed the controller acted professionally when he advised the pilots to head toward Montrose to the east where there was a recognized route for low-level descent. Instead, the pilots chose to fly north.

Williams, the father of two children, has been a controller for 20 years with the Royal Air Force.

He is supported in his defense to charges of professional negligence and causing deaths by the Guild of Air Traffic Controllers, which represents both civilian and military air traffic controllers. Many of its members feel Williams is being made a scapegoat.

The U.S. Air Force’s investigation was completed a few months after the crash, but has been held pending the outcome of the court-martial being held at a Royal Navy base near Glasgow.

Flight Lt. Jacqueline Martin told the court Thursday she heard him make the mistake, but he corrected himself, according to a report in The Scotsman daily newspaper. Soon after, the two F-15C fighters from RAF Lakenheath, England, disappeared from radar screens.

Flight Lt. Malcolm Williams, 47, is on trial for professional negligence for his role in the crash on March 26, 2001, that killed Lt. Col. Kenneth Hyvonen and Capt. Kirk Jones of the 48th Fighter Wing. The jets slammed into the Cairngorm Mountains at an altitude of about 4,000 feet.

Williams, based at RAF Leuchars, is accused of telling the pilots to fly 2,500 feet below the minimum safe altitude. Witnesses, including Martin, have testified under cross examination, however, that pilots are not obligated to follow those instructions and are responsible themselves for flying at a safe altitude.

Martin, who was supervising Williams on the day of the crash, said Williams fumbled the effort to hand control of the jets to RAF Lossiemouth by stating the wrong location for the switch. Before she could correct him, he corrected himself.

But contact with the jets was lost minutes later and Williams became agitated, forcing Martin to take over his position.

The trial is being held at Royal Navy base Faslane near Glasgow and is expected to conclude next week.

Flight Lt. Malcolm Williams is accused of causing the deaths of Lt. Col. Kenneth Hyvonen and Capt Kirk Jones of the 48th Fighter Wing at RAF Lakenheath, England. Their F-15Cs crashed into a mountain in Scotland on March 26, 2001, while Williams was on duty and talking to them.

He is accused of telling the pilots to descend to 4,000 feet when the safe minimum altitude was 6,500 feet. The planes crashed at about 4,000 feet in the Cairngorm Mountains.

Trangmar told the court-martial being held at a Royal Navy base near Glasgow that communicating with American pilots was “sometimes like pulling teeth,” according to a report in The Scotsman daily newspaper.

She was asked by the prosecutor, Group Capt. Alastair McGrigor, what she would do if she did not understand a pilot. She said she would try to clarify his statement.

“I say the word ‘try’ because at times it’s like pulling teeth. You may not get the reply you are expecting or want, and depending on how busy you are, it can be very difficult,” she testified.

According to trial testimony, Hyvonen used the phrase “minimum vectoring altitude,” which refers to a safe altitude to avoid terrain. The phrase has been much discussed at the trial, and Trangmar said she would not have understood what it meant had she heard it in March 2001.

The trial is expected to continue into next week.

Flight Lt. Malcolm Williams, 47, is accused of telling the jets from the 48th Fighter Wing at RAF Lakenheath, England, to descend to 4,000 feet. The safe minimum altitude was 6,500, the court has been told. The two F-15C jets crashed into Scottish mountains on March 26, 2001, killing Lt. Col. Kenneth Hyvonen, 40, and Capt. Kirk Jones, 27.

According to a report in The Scotsman daily newspaper, Flying Officer Sophie Green — who was working with Williams in the control room at RAF Leuchars in Scotland — testified, “He was very worried and told me he thought two aircraft may have crashed. He was worried that two contacts with the aircraft had been quite strong and they disappeared. He was very upset.”

She said he then changed the conversation to the recent death of his father. Williams had just returned to work on the day of the crash after taking bereavement leave.

In other testimony, another colleague, Flight Lt. Stewart Grady, said, “We had a conversation in which [Williams] said that in all the times he had been controlling aircraft, this was the first time that he had a bad feeling about the aircraft he had been controlling.”

The court-martial at a Royal Navy base near Glasgow is expected to last into next week.

The court-martial of Flight Lt. Malcolm Williams, 47, began Monday at the Royal Navy base near Glasgow, Scotland, in front of seven senior RAF officers.

Williams, who had been providing radar information from his post at RAF Leuchars in Scotland, is charged with telling Lt. Col. Kenneth Hyvonen, 40, to descend to 4,000 feet when the safe minimum altitude was 6,500 feet, according to published reports Tuesday in the United Kingdom, including the East Anglian Daily Times.

Hyvonen’s F-15C jet later crashed into a mountain at 4,000 feet. The jet flown by Capt. Kirk Jones, 27, also crashed. Both pilots from the 48th Fighter Wing at RAF Lakenheath, England, were killed in the March 26, 2001, crash.

The Herald, a national Scottish daily newspaper from Glasgow, reported Tuesday that Williams had just returned to work on the day of the crash after two weeks of compassionate leave following the death of his father.

Williams is believed to be the first military controller in the United Kingdom to face a court-martial in connection with a crash. If found guilty, he could be jailed, reduced in rank, discharged or fined.

The court-martial is expected to take several days.

The court-martial at Faslane Naval Base in western Scotland will begin at 2 p.m. Monday and is expected to last more than one week, said a spokesman with the RAF in Scotland.

Williams was on duty at the base in central Scotland on March 26, 2001, when two F-15s from the 48th Fighter Wing at RAF Lakenheath, England, crashed into a mountain.

The pilots of the two jets were killed.

They were Lt. Col. Kenneth Hyvonen of the 48th Operations Support Squadron and Capt. Kirk Jones of the 493rd Fighter Squadron. They were on training missions when their jets slammed into the Cairngorm Mountains at an altitude of about 4,000 feet.

The Air Force Accident Investigation Board concluded its report a few months after the crash, but it has been withheld from release until after the trial so as not to prejudice any potential juror.

The Ministry of Defence inquiry includes information that will be released at the court-martial, a spokeswoman said.

The trial has been delayed several times, but is now expected to proceed as scheduled, the RAF spokesman said Tuesday.