Capacity problems

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.[38] Traffic has sometimes grown faster than NATS has predicted:

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.[39] 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".[40] 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".[41] The union estimated that the air traffic control system was working at 100% of its capacity at certain times and at 90% of capacity continuously.[42] The 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.[43] 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."[44]

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".[45] 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".[46] 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".[47]

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 commence immediately".[48] 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.[49] The workload at LATCC had increased, but the SRG would notice if there were a risk of controllers being overloaded by the traffic.[50]

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.[51]

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 being imposed".[52] 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.[53]

38. Mr Burlyn believed that the morale of controllers, particularly those who were being relocated to the south coast, was not good.[54] 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.[55] 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.[56] 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".[57]

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".[58]

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.[59]

Airprox incidents

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.[60] 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 (C)s.[61]

42. The British Air Line Pilots Association told us that "the number of high risk bearing airprox incidents is on the increase".[62] 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.[63]

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."[64] The SRG told us that the ASG's comments regarding the CAA's actions in response to airprox recommendations were "incomplete and inaccurate".[65]

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.[66]

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.[67] 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.[68] 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.[69] It added that NATS had undertaken to airlines that it would mitigate delays over the next two years or until NERC became operational.[70] 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[71] on routes where there were regular air traffic control delays, especially on short routes where there was little chance of recovering much time.[72]

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".[73] This change, and others already in hand, would give LATCC the capacity to handle traffic until 2000, when NERC was due to be ready.[74]

47. Although air traffic is presently growing at 5-7% per year,[75] NATS expected an annual 3.1% increase in area control[76] 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,[77] the figures were 3.6%, 4.1% and 2.9% respectively.[78] 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.[79]

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.[80] 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.[81]

49. General Aviation (GA)[82] 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.[83] 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.[84] BATA said that in the past, "consultation was more presentation, we were presented with surprises".[85] 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.[86]

39  ATC05. Back

40   ATC 15. Back

41   Q331. Back

42   Q347. Back

43   Q469. Back

44   ATC 03B, para 6.5. Back

45   ATC 13A. Back

46   ATC 03B, para 5.1. Back

47   Ibid, para 6.2. Back

48   ATC 28. Back

49   Q551. Back

50   QQ524-5. Back

51   Q399. Back

52   Q333. Back

53   Q335. Back

54   Q166. Back

55   Q380. Back

56   Q374. Back

57   Q377. Back

58   QQ461-2. Back

59   ATC 28C. Back

60   Official Report, Written Answers, 21 January 1998, col. 555. Back

61   Official Report, Written Answers, 21 January 1998, col. 554. Back

62   ATC 24. Back

63   ATC 13 and 13A. Back

64   ATC 03B, para 6.5. Back

65   ATC 28. Back

66   Q523; CAA News Release, 13 January 1998. Back

67   Q515. Back

68   Q89. Back

69   QQ204-7. Back

70   Q219. Back

71   The advertised time from an aircraft leaving a stand to its arrival at the stand at the destination. Back

72   ATC 04A. Back

73   ATC 03, paragraph 4.7. Back

74   ATC 28A. Back

75   Q77. Back

76   That is, control of upper airspace over 25,000 feet. Back

77   That is, control of areas established at the confluence of airways in the vicinity of one or more major aerodromes. Back

78   ATC 28A. Back

79   QQ1,4&7; ATC 03A. Back

80   Q360. Back

81   QQ526-8; ATC 03B. Back

82   'General Aviation' embraces all civil aviation operations other than scheduled air services and non-scheduled commercial air transport operations. Back

83   ATC 12. Back

84   ATC 04A. Back

85   Q218. Back

86   ATC 04A. Back