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.