AIR TRAFFIC CONTROL |
31. LATCC at West Drayton will need to remain in
service until the Swanwick Centre is open. After that en-route
control will pass to NERC while terminal control functions will
remain at LATCC for some time before moving to Swanwick. In recent
years LATCC has had to cope with a continuous increase in air
traffic movements. In the years 1994-96 traffic grew at an annual
rate of 5%. Just over a million air traffic movements were handled
by LATCC in 1989; the figure in 1997 was well over 1.5 million.
Traffic has sometimes grown faster than NATS has predicted:
London Area and Terminal Control Centre:
Actual and forecast movements
(figures are in thousands and cover controlled
ACTUAL 94/95 - Forecast figures for this period
were produced in August 1994.
ACTUAL 95/96 - Forecast figures for this period
were produced in August 1995.
ACTUAL 96/97 - Forecast figures for this period
were produced in August 1996.
FORECAST 97/98 - Forecast figures for this period
were produced in August 1997.
*Estimate for 97/98 is based on actual traffic to
the end of February 1998.
Pressure on controllers
32. GATCO believed that this continually rising level
of air traffic was placing increasing stress on controllers at
busy ATC centres. This was the consequence not only of high traffic
levels, but of exposure to such levels for increasing lengths
of time. The Guild was concerned that additional stress might
lead to an increase in errors made by ATC staff, and thought that
it might already have been a factor in some incidents.
Mr Burlyn, an air traffic controller who gave evidence on behalf
of the ASG, agreed that there was a serious and perhaps increasing
problem of controller error at busy ATC centres which was the
effect "not only of high traffic levels, but of being
continuously exposed to those levels at all times during each
period of operational controlling during a working shift. Previously,
controllers could expect to work at reduced traffic levels for
some periods during each shift but with the exception of night
shifts, increased traffic has now resulted in controllers working
to capacity for much of the time".
The IPMS did not deny that there was "growing pressure"
on the system, but believed that that pressure was "not leading
to an unsafe system at the present time".
The union estimated that the air traffic control system was working
at 100% of its capacity at certain times and at 90% of capacity
Chief Executive of NATS agreed that the workload of controllers
had increased, but pointed out that the number of operational
controllers at LATCC had risen by a hundred since 1993.
We were also assured that "NATS will not compromise on safety.
If traffic demand were to exceed the capacity of the system, the
effect would be felt in increased delays not in a degradation
of safety standards."
33. The ASG sent us information implying that NATS
managers were refusing to acknowledge the concerns of controllers
about the lack of spare capacity in the LATCC system, were countermanding
the decisions of traffic managers to impose 'flow control' at
busy periods at Gatwick, and had created a culture within the
organisation that treated staff who complained about such things
as inadequate. It claimed that "A number of NATS air traffic
controllers have expressed these concerns but are inhibited in
speaking more openly because of their perceived fears of being
subjected to punitive action".
During our inquiry we have also received a number of anonymous
reports, claiming to be from air traffic controllers, saying that
the London air traffic control system was very close to its absolute
capacity and controllers were being put under too much pressure,
both of which made an accident more likely. These reports also
claimed that some NATS managers were overbearing or unsympathetic
with controllers who raised concerns about the level of traffic
and the pressure on the system.
34. NATS responded to the allegations of the ASG.
It said that "Staff have never been subject to punitive action
for reporting their concerns at West Drayton and never will be.
No one has been punished for reporting safety related incidents
of any kind ... the idea is inherently ludicrous. Clearly, there
is concern on the part of several individuals about current loading
on the system, and a belief that management at West Drayton refuses
to acknowledge their concerns ... these allegations and issues
are being addressed".
After explaining its procedures for dealing with concerns of controllers,
it concluded: "It is a fact that increasing traffic levels
have meant that the demands on the system are high. Because of
the increase in traffic, it is also true that a number of changes
are being made at LATCC ... and some staff find this process unwelcome.
There is understandable concern and uncertainty about working
with new systems, and the effects of delay to the NERC project
... Bringing all of these factors together, it can be understood
why there is a climate of concern, but the safety of the system
has not been compromised".
35. The CAA's Safety Regulation Group (SRG) said
that it had received no reports of indifference or intimidation
by managers at LATCC. If it became aware of any, "this would
be regarded as a serious issue and the appropriate actions would
The Director of Safety Regulation at the SRG said that he did
not believe that the allegations of the ASG reflected his perception
of what was happening at LATCC, since incident rates had fallen
there, but that he had been alarmed enough by them to ask his
regulators to examine these issues.
The workload at LATCC had increased, but the SRG would notice
if there were a risk of controllers being overloaded by the traffic.
36. The Confidential Human Factors Incident Reporting
Programme (CHIRP) is an independent organisation funded by the
CAA which lets pilots and air traffic controllers report incidents
confidentially. It is in addition to the mandatory system for
reporting certain incidents. GATCO had no reason to think that
CHIRP was not working satisfactorily.
Morale of controllers
37. GATCO was "concerned that the New En Route
Centre will not be ready for at least another two years. The existing
system ... is reaching capacity and despite the changes which
are being made we are still not convinced that the existing system
will cope without the addition of extra flow control measures
The Guild was also worried that controllers who had moved to Hampshire
in expectation of the transfer to Swanwick were having to travel
to West Drayton every day and might not be fit for duty after
such a journey.
38. Mr Burlyn believed that the morale of controllers,
particularly those who were being relocated to the south coast,
was not good. The
IPMS agreed that controllers who were uncertain when they would
have to relocate were unhappy. He also felt that the "constant
pressure" on controllers, which made them worried about the
amount of traffic they had to control, was having an adverse effect
on their morale.
Industrial relations were "fairly good" but there had
been difficulties in recent years with the previous chairman and
chief executive and as a result of cuts in the number of engineers
and air traffic control assistants.
GATCO believed that in recent months there had been "a realisation
that mistakes have been made by people for whatever reason and
there is a definite will now right from the top to look at it
and to take into account seriously what people are saying".
39. The Chief Executive of NATS told us that "There
is no doubt that our system is under pressure ... There is no
doubt that in some areas I would wish the morale to be slightly
better than it is, but we are working quite hard on that. We are
working quite hard to try to get the controllers involved in what
it is we are doing and get them confident in what it is we are
trying to do and thereby raise the morale. The question of morale
is a very complex issue. There are several things around in the
company at the moment which are causing people to be uncertain
... We are being successful in improving morale and a number of
the uncertainties which are around are now coming to a conclusion
and that will all help".
40. The SRG does not monitor such indicators of controller
morale as sickness and absenteeism rates or applications for early
retirement or transfer, as it believes that these are matters
for NATS as the employer. Nor does it directly monitor the morale
and attitude of controllers, again because this is regarded as
a matter for NATS. However it told us that it would take regulatory
action if it were shown that low morale or poor attitude were
leading to a lowering of safety standards.
41. One of the concerns of a number of witnesses
was the incidence of 'airproxes'. These are incidents where aircraft
pass closer than allowed to each other, and are classified according
to whether they are reported by pilots (Airprox P) or air traffic
controllers (Airprox C) and to the risk of collision they caused.
All are investigated with a view to learning the lessons and taking
corrective action, but by different bodies according to whether
they were reported by pilots or controllers. The annual number
of airproxes (risk-bearing and non risk-bearing) in the UK has
been between 208 and 217 in every year from 1993 to 1997.
Other figures have been provided to Parliament which show that
between 1991 and 1996 the number of risk-bearing airproxes per
100,000 commercial air transport hours flown fluctuated between
0.4 and 1.5 for Airprox (P)s and between 2.0 and 2.9 for Airprox
42. The British Air Line Pilots Association told
us that "the number of high risk bearing airprox incidents
is on the increase".
The ASG drew our attention to a number of serious airprox incidents
between 1995 and 1998 which it believed indicated a need to review
the management and regulation of NATS. It said that in a number
of cases remedial action had not been taken by NATS or enforced
by the SRG.
43. NATS responded by saying that "the number
of airprox incidents where a NATS error is a causal factor continues
to decline" and that in 1997 there were 31 such airproxes.
It assured us that "All such incidents are treated with the
utmost seriousness. All such incidents are immediately investigated
by NATS, as well as by the external agencies, in order to put
in place any remedial measures identified ... The recommendations
of external bodies are always acted upon expeditiously."
The SRG told us that the ASG's comments regarding the CAA's actions
in response to airprox recommendations were "incomplete and
44. The Director of Safety at the SRG told us that
the method of reviewing airproxes "has some shortcomings.
It is not a terribly scientific approach. We do have two separate
bodies which are essentially assessing the same sort of events".
A review of the investigation of airproxes was announced on 13
January 1998 which would see whether the two processes should
be amalgamated. He personally would prefer that as a means of
obtaining greater consistency, particularly in the classification
of the severity of accidents.
Delays to aircraft
45. Delays to flights attributable to UK air traffic
control are expected to worsen slightly this year. At the moment
8% of flights in the UK are delayed by NATS restrictions, and
those flights are delayed by an average of 13 minutes. The average
delay for all aircraft is one and a half minutes. The increase
in traffic this summer is likely to lead to 9% of flights being
delayed for an average of 15 minutes each.
DETR pointed out that delays to flights were still less than they
were ten years ago, and that air traffic control only accounted
for a little more than 20% of all delays.
British Airways maintained, though, that air traffic control was
still the single largest cause of delay and cost the company £50m
per year. It was not always clear to the company which country's
ATC system had caused any particular delay.
It added that NATS had undertaken to airlines that it would mitigate
delays over the next two years or until NERC became operational.
The British Air Transport Association said that domestic flights
seemed to suffer worse delays than international ones, although
it was not sure whether this was because NATS did not control
UK airspace adequately or because NATS gave international flights
preference. It told us that some airlines had increased their
block times on routes
where there were regular air traffic control delays, especially
on short routes where there was little chance of recovering much
46. Accordingly, in order to increase the capacity
of LATCC and reduce delays as far as possible, NATS intends to
reorganise the 'Clacton' sector of airspace controlled by LATCC
for introduction in winter 1998/99. This section of airspace had
"emerged as a major bottleneck with an unprecedented 20%
growth in demand over the past two years".
This change, and others already in hand, would give LATCC the
capacity to handle traffic until 2000, when NERC was due to be
47. Although air traffic is presently growing at
5-7% per year, NATS
expected an annual 3.1% increase in area control
movements at LATCC over the next five years, with a high range
of 4.8% and a low range of 2.8%. For terminal control,
the figures were 3.6%, 4.1% and 2.9% respectively.
NATS claimed that Swanwick would give it 40% more capacity immediately
and that further predicted capacity gains would allow the centre
to cope with air traffic growth up to 2015. By then Swanwick would
need to be fundamentally re-equipped.
48. GATCO said that Heathrow was working at capacity
from 6.00 am to about 7.30-9.00 pm, and that runway capacity was
the fundamental constraint on capacity, although air traffic control
problems could arise if more aircraft arrived than were supposed
to. Since 1994 an
attempt has been made to allow more landings at Heathrow and Gatwick
by reducing the minimum separation between arriving aircraft from
three to two and a half miles in certain closely defined circumstances.
It is no longer a trial and the SRG has said that it may continue
indefinitely. However the SRG told us that it had not been sanctioned
as a national procedure because it did not yet have enough data
about its effects. NATS estimated that the reduced separation
was used only about 5-10% of the time.
49. General Aviation (GA)
sector representatives were keen to ensure that the interests
of large commercial operators were not favoured at the expense
of those of their own members. The Aircraft Owners and Pilots
Association felt that GA operators were increasingly being priced
out of some airports and it feared that a privatised NATS might
adopt a similar policy.
Any new organisational structure for the CAA and/or NATS should
be capable of representing the views of all airspace users and
not just those of the large airlines.
50. It appeared that improvements were being made
to the way in which consultation was undertaken with airlines.
The British Air Transport Association (BATA) had been pressing
for a mechanism that involved the users in direct consultation
and negotiation with NATS and the DETR. Previous requests had
been refused by NATS.
BATA said that in the past, "consultation was more presentation,
we were presented with surprises".
The need for more effective consultation had been taken seriously
and NATS was establishing a strategy group for this purpose, which
would include airline representatives.
ATC 03. Back
39 ATC05. Back
ATC 15. Back
ATC 03B, para 6.5. Back
ATC 13A. Back
ATC 03B, para 5.1. Back
Ibid, para 6.2. Back
ATC 28. Back
ATC 28C. Back
Official Report, Written Answers, 21 January 1998, col.
Official Report, Written Answers, 21 January 1998, col.
ATC 24. Back
ATC 13 and 13A. Back
ATC 03B, para 6.5. Back
ATC 28. Back
Q523; CAA News Release, 13 January 1998. Back
The advertised time from an aircraft leaving a stand to its arrival
at the stand at the destination. Back
ATC 04A. Back
ATC 03, paragraph 4.7. Back
ATC 28A. Back
That is, control of upper airspace over 25,000 feet. Back
That is, control of areas established at the confluence of airways
in the vicinity of one or more major aerodromes. Back
ATC 28A. Back
QQ1,4&7; ATC 03A. Back
QQ526-8; ATC 03B. Back
'General Aviation' embraces all civil aviation operations other
than scheduled air services and non-scheduled commercial air transport
ATC 12. Back
ATC 04A. Back
ATC 04A. Back