§ 1. Air-Commodore Harveyasked the Parliamentary Secretary to the Ministry of Civil Aviation if he is aware of the delays caused to incoming and outgoing airliners at Northolt airport; how these delays were incurred; and what steps are being taken to remedy the situation.
§ The Parliamentary Secretary to the Ministry of Civil Aviation (Mr. Lindgren)Yes, Sir. There were unusually severe delays to aircraft movements at Northolt during a spell of instrument flight rule conditions on 14th June, the day after new procedures were introduced in the Metropolitan control zone. Advantage has been taken of the experience gained in instrument flight rule conditions since the system was inaugurated to introduce certain modifications, and this process will continue as necessary.
§ Air-Commodore HarveyIs the Parliamentary Secretary now satisfied that in future these delays will not occur? Is he also satisfied that as a result of the alteration in the control system in regard to the stacking of aircraft a good safety margin is now given?
§ Mr. LindgrenI hope we shall never be satisfied until we reach perfection, 1258 which will take a long time. We are satisfied, in regard to organisation and procedure, that the slight element of risk which previously existed, because of the proximity of the two airports, has been eliminated. With the progressive use of the new procedure, I hope that delays will be reduced.
§ 4. Colonel J. R. H. Hutchisonasked the Parliamentary Secretary to the Ministry of Civil Aviation how many aircraft were delayed in the week commencing 13th June at Northolt airport by the new system of air traffic control and for what total period; and what are the comparable figures for the week commencing 19th June.
§ Mr. LindgrenAs the answer contains a number of figures, I will, with permission, circulate details in the OFFICIAL REPORT.
§ Colonel HutchisonMay I, nevertheless, ask whether this system of traffic control is intended only for Northolt, or whether it is being installed elsewhere?
§ Mr. LindgrenNo, Sir. This system has been dictated by the close proximity of the two airports, London and Northolt.
§ Following are the details:
| BROAD ANALYSIS OF TRAFFIC MOVEMENTS AT NORTHOLT AIRPORT FOR WEEKS COMMENCING— | |||
| Prior to introduction of modified system of air traffic control | Subsequent to introduction of modified system of air traffic control | ||
| Week commencing 6.6.49 | Week commencing 13.6.49 | Week commencing 20.6.49 | |
| Total Movements | |||
| *IFR Take Off | 155 | 119 | 156 |
| Landing | 91 | 111 | 100 |
| †VFR Take Off | 406 | 429 | 382 |
| Landing | 453 | 439 | 432 |
| Grand Total | 1,105 | 1,098 | 1,070 |
| Number of Aircraft delayed | |||
| *IFR Take Off | 114 | 73 | 99 |
| Landing | 80 | 87 | 81 |
| Total delayed | 194 | 160 | 180 |
| Prior to introduction of modified system of air traffic control | Subsequent to introduction of modified system of air traffic control | ||
| Week commencing 6.6.49 | Week commencing 13.6.49 | Week commencing 20.6.49 | |
| Mean Delay (delayed aircraft) | |||
| Take Off | 4¼ mins. | 12 mins. | 4 mins. |
| Landing | 3 mins. | 14½ mins. | 5½ mins. |
| Aggregate Delay | |||
| Take Off | 8 hrs. | 14½ hrs. | 6½ hrs. |
| Landing | 4 hrs. | 21 hrs. | 7½ hrs. |
| Total Delay | 12 hrs. | 35½ hrs. | 14 hrs. |
| Longest Delay | |||
| Take Off | 40 mins. | 59 mins. | 41 mins. |
| Landing | 30 mins. | 70 mins. | 48 mins. |
| Total time when IFR was in operation | 28½ hrs. | 30 hrs. | 44½ hrs. |
| Percentage of IFR aircraft delayed | 79% | 70% | 70% |
| Average Delay (delayed air-aircraft) | 3¾ mins. | 13½ mins. | 4½ mins. |
| Percentage of total movements delayed | 18% | 15% | 17% |
| * IFR=Instrument Flight Rules. | |||
| † VFR=Visual Flight Rules. | |||
| N.B.—These figures may be subject to minor adjustments. |