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flying operations at the two aerodromes suffer mutual interference and involve an element of risk. We understand that interference with the Air Force training programme at Wigram is already experienced, and expansion of the training programme or increased civil traffic at Harewood will accentuate the difficulty. When Harewood is developed as an international airport and equipped with instrument landing aids it will be impossible to operate at Wigram simultaneously in instrument flying conditions. In our view, there should be a minimum distance of ten miles between two such major aerodromes. 271. While it is not necessary to stop flying at either aerodrome at present, we are convinced that the inevitable growth of traffic will in a few years make it necessary to close one of them, or to regulate flying at the Wigram aerodrome to such an extent that it will cease to serve its purpose as a principal Air Force aerodrome. It could be retained for secondary purposes. It is clearly necessary to face this issue now and decide whether the Harewood scheme should be abandoned in favour of another site, or whether the ultimate closing of Wigram as an Air Force station and the transfer of operations elsewhere should be planned, 272. Any alternative to Harewood which might be selected should not be materially less conveniently situated than is Harewood. We found only one site which would satisfy this condition and at the same time was sufficiently remote from Wigram. This area is seven miles north of the city, near the coast south of the Waimakariri River and immediately south of the locality known as Stewart's Gully. The engineering problems involved in construction on this site are a matter for investigation. The only other possible alternative appears to be about 15 miles north-west of Christchurch, along the south bank of the Waimakariri river. Its remote situation appears to rule it out. 273. If no acceptable alternative to Harewood is available for the international airport, then it is necessary to face the issue that Wigram must be gradually reduced to secondary Air Force activity and the major activities transferred elsewhere. There appear to be two alternatives in the vicinity of Christchurch, both of which were developed as aerodromes during the war, and where the cost of constructing runways, both because of the gravel subsoil and because of the work done during the war, would be minimised. These are Norwood and Te Pirita. 274. We are informed that the capital investment at Harewood is in the region of £350,000, and at Wigram approximately £870,000. We are also informed that, since it is planned to develop the district adjoining Wigram aerodrome as an industrial area, the sale value of the land is estimated at approximately £265,000, and of the buildings and other services £442,000. There would be comparatively little, if any, loss of capital in disposal.