SITES COMPARED

Timaru Herald, Volume CXXXIX, Issue 20095, 30 April 1935, Page 9

SITES COMPARED

PROPOSED AIRPORT FOR TIMARU

REPORTS TO COUNCIL At a recent meeting of the Timaru Borough Council, held in committee, reports were discussed concerning a proposed airport for Timaru. The Minister of Public Works (Hon. John Bitchener) wote enclosing a copy of a report by Mr T. G. G. Beck, assistant engineer of the Public Works Department, dealing with the possibility of constructing an airport at Saltwater Creek from an engineering point of view, and also the report of the engineer supervising aerodrome construction and the Controller of Civil Aviation. It would be seen that quite feasible to make a good airport there as far as ground conditions were concerned; that was to say, the drainage difficulty could be overcome, but the cost was considerable, being £12.640 in addition to labour costs Which were estimated at £12,472. It was, of course, for the Council to decide whether or not the construction of an airport there was warranted at that cost when one could be obtained so much more cheaply at Washdyke and would moreover, apart from the ground access viewpoint, be in a more favourable situation. The improvement to the Otipua Domain, and the reclamation of a tidal marsh which might be somewhat of a menace to public health, might, of course, have some influence on the Council’s decision in the matter. Wing Commander T. M. Wilkes, controller of Civil Aviation reported that in his opinion there was not the slightest doubt that, purely from a flying, point of view, the alternative site at Washdyke was to be preferred. On the other hand, Saltwater Creek, if developed as proposed, could not be rated other than as an “A” class aerodrome but. under certain weather conditions such as mist, fog or low cloud ceiling, this site would in his opinion be denied to aircraft more frequently than would Washdyke which was surrounded by low' lying country. The formation of the country round Saltwater Creek site would also tend to cause mists and fog to hang over the aerodrome. The question raised as to conditions when there was a light north-west wind was also of importance. There was greatly reduced lift in this wind and in addition to the fact that it was always bumpy, and as a climb was necessary to get over the higher country lying in that direction, it was possible that in hot weather heavily laden aircraft would experience difficulty in making the grade. To say the least of it, the take off would not be pleasant for pilot and passengers. Factors Bearing on Choice Mr E. A. Gibson, engineer supervising aerodrome construction, reported that, viewed solely from the angle of surface area at this proposed airport, the possible ground space available, 800yds. in all directions, was adequate for" an A class aerodrome, but other factors having a very material bearing on the choice of a site for Timaru should be fully considered. Owing to the situation, really a "pocket” in a narrow but shallow valley, in certa’h winds air conditions were liable to be much more turbulent and tricky near ground level than would be the case on a site situated on the adjacent plains. Moreover, the possibility of low fogs and at night and the early morning ground mists, was real and very much more likely than in a more open situation. While the surrounding low hills wen outside the minimum clearance angle laid down, in light north, west winds when turbulent air conditions prevailed considerable difficulty might be experienced with a fully laden machine in clearing the obstructions in an up valley direction, and in any case the experience under such conditions would be most unpleasant and disturbing to passengers. The final point that must have an ever increasing importance on the selection of any site was its suitability or otherwise for approach by aircraft under night or bad weather conditions when blind flying aids to navigation would require to be used to the fullest extent. Unquestionably it was only a matter of time when blind flying would be necessary on regular operated air routes in this country to ensure the regularity of operation that was at present achieved abroad. With the railway embankments on the seaward side and the ‘ completely surrounding low hills on the other three sides of this area, it was extremely doubtful if the aerodrome could be approached safely in conditions of very low visibility. This meant that when blind flying became general on the main inter-island air route, any service having Timaru as a port of call would be unable to enter or leave the airport under such conditions, no matter which, of the present aids to blind flying were in use. In view of the development that had taken place in the application of blind flying aids to the operation of regular schedules abroad, that aspect could not be overemphasised, and the Saltwater Creek site, irrespective of all other good or bad points it might have could therefore only be classed as a site which could be made suitable for use in reasonably clear weather. In his report Mr T. G. Beck set out two proposals, the first for an outlet to the south end and the second for an outlet to the north end. There being not sufficient difference between the estimates of cost for manual and mechanical methods to warrant the adoption of the latter in face of the unemployment situation, he recommended that the work be done manually. The questions for which specific answers were required by the Timaru Borough Council were:— The probable success or otherwise of the present scheme of drainage. If the present method be unsuitable, what work should be undertaken to ensure that the area would be free from flooding. The estimated cost of any suggested works, together with the annual costs of maintenance, if any.

Summarised answers to these questions were:— The present drainage works will not provide the necessary degree of drainage because of (a) inadequacy of the waterway provided in the culvert, and (b) absence of means of building up sufficient head of water to open the culvert without flooding the aerodrome. The area can be successfully drained by (a) providing a larger culvert and forming a stopbank and diversion channel to carry flood water away, and (b) providing a system of internal drainage with gravity and pump outlets. Estimates of the cost of two proposals— (1) Draining out at south end, and (2) draining out at present site, are: Manual Mechanical work. work. Proposal No. 1 £25,112 £20,092 Proposal No. 2 £27,641 £19,460 The estimated annual maintenance charges are:— Proposal No. 1 £152 Proposal No. 2 £167 On the motion of Crs. P. B. Foote and H. J. Mathers, it was decided: “That this Council is sufficiently impressed with the possibilities of the Redruth area as an airport 4? s_eek

further information as to financial and other points.” It was further agreed on the motion of Crs. Foote and W. G. Tweedy: “That Councillors W. H. Hall and Mathers be a sub-committee to inquire into the question of private land required for the airport. The subcommittee to report in writing as to the land required and the probable cost.”