'Things are going extremely well,' says Nats chief officer

After huge delays in IT implementation and a difficult first summer, Colin Chisholm, chief operating officer of Nats, believes...

After huge delays in IT implementation and a difficult first summer, Colin Chisholm, chief operating officer of Nats, believes the UK's main air traffic system is performing impressively. Tony Collins reports

Most IT specialists would like the salary and bonus he has earned this year, but few would want his job.

As chief operating officer of National Air Traffic Services (Nats), Colin Chisholm was one of the three top executives at the company who earned more than £230,000 in 2002. But he is also the man responsible for the air traffic control system at Swanwick, in Hampshire.

"Things are going extremely well," said Chisholm in an exclusive interview for Computer Weekly in which he responded to the recent bad publicity the Swanwick centre has received this year.

"The system has behaved extraordinarily well, with just that one failure way back in April," he said.

"We were somewhat unlucky in a failure of one workstation which affected the local area network (Lan). So the system, in terms of its resilience and robustness, has been remarkably good.

"I say this with some hesitation because you never know with software what is around the corner. But it really has been remarkable."

The system he was praising went live in January - five years late. When it crashed in April thousands of passengers were stranded at airports by delays lasting hours.

A series of internal Nats reports, leaked to Computer Weekly, pointed to other problems. Staff shortages at Swanwick, for example, have caused record delays for airlines this year.

On some occasions aircraft have been asked to avoid the airspaces controlled by Swanwick - hardly a recommendation for a centre that cost £623m, about half of which was spent on new air traffic control software.

A further problem is that air traffic controllers and the Health & Safety Executive (HSE) have expressed concern by about the clarity of text and number on the display screens used by controllers; on 18 January, nine days before the system went live, a principal HSE inspector wrote to Nats saying that the display screens used by controllers might not meet minimum legal standards.

The letter said the HSE had concerns about a number of issues "relating to the readability and clarity of the data displayed on the screens, and of the ergonomics of the workstations".

The letter added, "It is our opinion that operational use of the current equipment could lead to health problems such as eye-strain and musculoskeletal symptoms. It is also our opinion that these design deficiencies may have implications in relation to air safety".

But Nats and the regulator, the Civil Aviation Authority felt that the problems had no safety implications, and the centre was approved to become operational on 27 January.

Since then, internal reports have shown that some controllers have sometimes confused text and numbers on the screens, occasionally misreading the height of aircraft, leading to minor operational mistakes.

To alleviate the problem Nats is due to install a software fix this week that will increase the size and definition of numbers and characters on the screens of more than 300 controllers at Swanwick by deploying Verdana, a font invented by Microsoft especially for computer screens. Verdana is said to work particularly well on older screens or those with a low resolution.

Chisholm said that 90% of the 194 controllers who saw a demonstration of Verdana preferred it to the existing screens. "Verdana helped, particularly with distinction of different characters," said Chisholm.

Whether the new font is large and clear enough to meet the HSE's minimum legal specifications for display screens is uncertain.

A report by air traffic control union Prospect, leaked to Computer Weekly, said that even with the change to Verdana the screens "may well fall short of the health and safety guidelines".

But Chisholm said the HSE's regulations may not apply to Swanwick's systems. "The debate about the [minimum legal] standard was, I suppose, inconclusive and it does not look as though the HSE is pressing that point - which I am rather pleased about.

"It is a rather convoluted debate. The [HSE legal] standard in one sense is drawn up for what are called, technically, [screen display] users; and our people are not, technically, users."

Recently, 300 controllers completed a questionnaire on the health and safety aspects of the new system. In a memo to staff dated October 2002, Swanwick's health and safety representative said the survey indicated that 76% of controllers had experienced eyestrain, 50% had complained of headaches and 36% found it necessary to take medication during or after a shift to combat headaches.

The questionnaire's results were discussed at a meeting last week between Nats and the HSE but Chisholm said the "biased" phrasing of the questions in the survey had invalidated its results, although he accepted that some controllers felt there was a problem with eyestrain and headaches.

"There have been some reports of that and clearly we take those seriously. We do not believe there is any extensive problem in that regard. We have put in place monitoring programmes of health and safety at work issues."

The union, Prospect, says that morale is low and staff are owed a total of about 3,500 days off which they have been unable to take because of staff shortages. Nats says that it needs 41 more controllers - union leaders put the figure at more than 60.

Chisholm said the shortages should be eased by allowing trainee controllers to spend more hours than at present on simulators. This is expected to increase the pass rate for trainees. Nats also plans to boost numbers by recruiting experienced controllers from the military and Ireland.

Criticisms of the Swanwick system have irritated Swanwick's IT engineers who believe that Chisholm, along with the software designers and developers, should be credited with a major success.

They point out that the centre has had few major technical failures, despite the labyrinthine complexity of the software which contains more than two million lines of code and operates as a safety-critical system.

Chisholm agrees. "In terms of people settling down we had a difficult start through the early summer but the controllers are settling into using the system very well," he said. "Our delays [for airlines due to problems at Swanwick] since early August have come down very sharply. Last week we were under the delays for the same week in 2000. We are back into a normal operation here.

"We have got quite a number of things to do - including getting our controller numbers up to scratch - but we have plans for that and I think that that problem [of staff shortages] was exaggerated anyway," he said.

"Without being too bullish I would say that the new centre is settling down well."

Why Verdana should help screen visibility
Microsoft's Verdana font, which is due to be installed this week on the screens of air traffic controllers at Swanwick in Hampshire, was developed specifically for computer screens rather than adapted from print.
The Verdana fonts exhibit new characteristics, derived from the pixel rather than the pen, the brush or the chisel. Commonly confused characters, such as the lower case "i", "j" and "l", the uppercase "I", "J" and "L" and the numeral "1", were carefully drawn for maximum individuality, an important characteristic of fonts designed for on-screen use.

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