AIR ROUTES. Due to the advance in navigational facilities and equipment, a route between any two airports is now usually flown in a straight line, barring severely inclement weather. Be fore aircraft had the flying range which they have today, air routes as much as possible followed level or good landing ter rain, avoiding mountain peaks and isolated sections. The mod ern transport planes of the world, however, fly through day and night, over great mountain ranges and across oceans and deserts. Their crews are constantly on the lookout for storms but their craft are sufficiently strong and powerful to fly through them or fast enough to skirt them or so equipped with radio that suf ficient advance warning of bad weather ahead is given to permit a landing at one of the many intermediate airports that dot the leading countries.
One chief remaining advantage sought from nature is the as sistance of favourable winds. In long distance flying, prevailing winds have an important influence in the choice of routes for airships and in the choice of altitude or flying level for aero planes. Winds are stronger nearer the ground, although they vary somewhat at different altitudes and, of course, in different re gions of the earth and with the seasons. Hence, the airship often resorts to wide tacking in flight, and the aeroplane, on radio ad vice from a ground observation station, climbs or drops until a tailwind is obtained or a minimum headwind is encountered.
An aeroplane route organization generally consists of (I) ter minal airports equipped with accommodation for the aircraft and operational organization, (2) intermediary fields at intervals de pending on the nature of the route, and (3) the necessary me teorological and radio services and lighting equipment.
Aside from knowledge of weather, a pilot also has the advan tage of radio direction finders and radio "beacons" or "beams," which indicate almost instantly whether he is on or off course. At night he is also assisted by lighted beacons on the ground, the manner in which some of them flash identifying the location, much as a lighthouse does for a mariner at sea.
Approaching a destination, the plane establishes contact with the terminal, and ground wind directions are given the plane and if traffic at the field is busy, a certain portion of the airport may be assigned the incoming craft for its descent.
In 1919 the route distance of the world was 3,200 miles, over which planes flew 1,022,000 miles that year; by 1934 world routes totaled 223,100 miles and miles flown aggregated more than 103, 000,000. Only mail was carried over most routes at the start, but within fifteen or sixteen years, giant multi-motored craft were flying with many tons of weight in passengers, mail and ex press. From about 75 miles an hour or less at the beginning, speeds attained the neighbourhood of 200 miles an hour, and au thorities insisted that 20o miles an hour was only half the speed at which man would eventually travel, in the rarefied air of the stratosphere, if necessary. Even then, Wiley Post, American 'round-the-world pilot, had begun experiments in cross-country flight at six miles or more above the earth, and designers were studying the needs of man and machine for long distance travel many thousands of feet in the sky.
Figures for 1934 showed the United States to be far in the lead of other nations of the world in commercial operations. In that year American transport craft flew more than 44,000,000 miles and carried over 500,00o passengers in addition to almost 3,000,00o pounds of express and 8,000,000 pounds of mail. These totals would have been greater had it not been for the almost peremptory cancellation by the Government of practically every air mail contract held by a commercial operator. The Post Office Department alleged collusion had prevailed between the operators in obtaining the contracts from a previous Governmental adminis tration, but the charges were rather promptly lost in a confusion of reports and investigations that followed three and a half months of mail flying by the Army which cost the lives of a dozen men in sixty-six accidents and $3,767,000 in Government ex penditures for equipment and maintenance. Government officials blamed exceptionally bad weather conditions for the losses, but a majority of the critics asserted that the pilots were not accus tomed to scheduled cross-country flight operations day and night. Moreover, their equipment, being military in character, was not fitted for cargo transport. The episode, however, demonstrated the efficiency of the American commercial systems, and when the mail contracts were reinstated with the commercial operators the Government resumed a generous policy of support to civil avia tion.
Liberal subsidies in the form of air mail contracts have been of invaluable assistance in the development of American commer cial operations. At the same time, the Bureau of Air Commerce carried on a sustained program of construction of navigational and weather facilities, in addition to maintaining strict super vision over airport construction and maintenance. At the begin ning of 1935, the Government had in operation 18,896 miles of lighted airways, with additional miles under construction; pilots in flight could receive weather reports from 71 radio com munication stations, and 91 radio range beacons helped them in keeping a true course. For emergency landings on the Federal air ways between regular airports there were 248 lighted intermediate fields and seven unlighted fields on the daylight routes, and in addition there were 58o marked auxiliary fields for emergency landings. Total landing fields in the United States and Alaska were 2,297.
The United States, in common with other active aviation coun tries of the world, continued its fight against fog as a danger to flying. Instruments and automatic control did a great deal to insure safety once a plane had attained level flight at sufficient altitude, although experimentation continued for a solution for landing in fog-bound areas. Some success has been achieved in this work, but much remains to be done before the lessons learned can be applied on a wide and practical scale.
The Government and the leading commercial operators, recog nizing a problem in the tremendous increase in air traffic, in late 1935 worked out regulations governing flying in overcast weather and particularly in approaching and departing metropolitan fields. The chief content of the requirements was that eastbound planes would travel at altitudes in odd thousands of feet, such as 5,000 or 7,000, and westbound planes at altitudes in even thousands of feet, such as 4.000 and 6,000. These flight levels were to be maintained at all times, consistent with safety.
One of the most spectacular accomplishments of American avia tion was the establishment of the line across the Pacific Ocean from San Francisco to Hongkong and Canton, via the Hawaiian Islands, Midway, Wake, Guam, Manila and the Island of Macao. Only the San Francisco—Honolulu and the Hongkong—Manila portions of the route had been flown previously, and then only in a comparatively few and non-commercial flights, when Pan-Amer ican Airways in the fall of 1935 sent a four-motored flying boat across the Pacific in the first flight to Manila from the American mainland. Only mail was carried on the first scheduled trips, but the aircraft used was capable of accommodating forty-six persons on certain trips. The craft, for all its great size and weight, cruised in the neighbourhood of 15o miles an hour.
The trans-Pacific service was made possible by a Government air mail appropriation of $1,800,000, this sum being designed as a subsidy for approximately seven months after which other and steady allotments were required to maintain the service. At the same time, however, the Government, stimulated by the success of the Pacific venture, looked to regular service across the Atlan tic. The Pacific route had barely been covered in an initial flight when representatives of the British and American governments and Imperial and Pan-American Airways reported substantial progress toward joint establishment of service between the United States and England and the European Continent. Three routes were under consideration : The first and most prominently dis cussed was from New York and Montreal to London via Ber muda, the Azores and Lisbon ; the second via the islands of the North Atlantic, and the third from Newfoundland directly to England. As in the case of trans-Pacific service, huge multi motor flying boats were being built for this latest aerial link in world commerce. The prospect indicated a two-week round-the world service—five days to Manila, seven from Manila to London and two from London to New York. (A map of the air routes of the United States appears in the article AVIATION, CrviL.) British Empire.—Britishair routes to the near European capi tals have been operated since 1919, but it was through develop ment of Colonial and Dominion services that the Empire had attained more than 41,000 route miles at the beginning of 1935, this figure representing an increase of 27 per cent. over 1933.
Steamships had apparently reached the economic limit of speed, and it was only through aircraft that the far-flung units of the Empire could be brought nearer each other and nearer to London. Aircraft was also well suited to the work of opening up territory for surface transportation, and a number of routes of this kind were developed, particularly in Australia.
Thus it was that a policy for creation of British imperial routes found ready acceptance, and in about a half dozen years prior to 1936 lines had been completed from London to Brisbane and from London to Cape Town. The 12,800 mile route to Brisbane ran via Iraq, India and the Malay Straits, with a railroad connec tion extending across Switzerland and Italy from Paris to Brin disi, although the British Government was negotiating with the European countries concerned to eliminate this railroad portion of the route and make it entirely by air. Including the rail con nection the schedule from London to Brisbane required ioj days in late 1935, although with the use of new flying equipment this time within a few years was certain to be reduced substantially. An extension of the eastern Empire service was designed to con nect Hongkong with Penang in the Malay Straits, via Tourane and Saigon, bringing China to about a week's distance from London.
The London–Cape Town route, extending 8,000 miles across Europe and Africa, utilized the railroad to cross the Continent, but from Brindisi south the line was entirely by air, running from Brindisi, Athens and Crete through Egypt and a vast -unbroken strip of Empire territory as far as Cape Town. From Khartoum in the Anglo-Egyptian Sudan, the Imperial Airways also pioneered its way to the Gold Coast, via El Obeid, El Fasher, Fort Lamy, Kano and Takoradi.
Australia.—TheCommonwealth of Australia had 1 2,000 miles of airways in operation at the start of 1935. An Australian com pany takes over operations of Imperial Airways south of Singa pore, running the Empire line into Brisbane via Port Darwin, Cloncurry and Charleville. Other lines complete a circuit of the great island continent, much of the route distance being protected with beacons and radio beams.
Canada.—Atthe end of 1934, Canada had 5,000 miles of air routes, over which only mail was flown regularly. More than ioo,000 passengers were carried, however, in this year when more than 5,000,000 miles were flown by commercial operators who carried 279 tons of mail and 6,446 tons of express. As part of a Canadian transcontinental air route construction plan, the Gov ernment was actively engaged in development of a detailed system of landing fields all the way from Vancouver to Halifax.
Europe.—SixteenEuropean countries, beside Russia, Were oper ating regular air services by 1935. Germany and France were far in advance of neighbouring Continental nations in route mileage, Holland and Italy, respectively, ranking third and fourth, and a dozen others each contributing slightly to the sum of the services within and leading out of the Continent. Progress in Europe has been rapid, most of the lines which were projected in 1929 and 193o having been completed and paralleled, in some instances several times over, within five or six years.
Germany.—TheGerman air system consists of trunk routes and a network of internal lines approximating 25,000 miles. German craft flew to Oslo in the north, to Moscow in the east, London in the west, Sofia, Rome and Marseilles in the south; a German dirigible route crossed the South Atlantic, and steamers supple mented a plane service from the home country to South America. A detailed network of lines touched all the principal cities of the country, and spread out to reach such other points as Paris, Geneva, Milan, Vienna and Warsaw.
German aeronautics had its most spectacular success in the dirigible Graf Zeppelin. This ship completed the first aerial cir cumnavigation of the world, made a half dozen impressive visits to the United States and toured all Europe and England ; after this it was used in regular service between Germany and South America, the dirigible carrying the principal bid of Germany against France for the air commerce favour of the Latin American countries. In the first few years of the service to South America, the zeppelin completed more than oo crossings of the South At lantic, carrying mail, passengers and express each time. Even before this veteran craft had been retired on the Friedrichshafen– Pernambuco–Rio de Janeiro route, the LZ-129 was built, a lighter than-air ship twice as big and much faster than its predecessor. The LZ-129 was designed to carry on where the Graf Zeppelin left off, not alone in helping Germany maintain a hold in South American traffic but to demonstrate the feasibility of airship service across the North Atlantic between the United States and Europe.
France.—From8,3o4 route miles in 1927., France developed its system in the seven following years to 21,295 miles, principally by virtue of an 8,000 mile all-plane line from Paris to Buenos Aires, and a route from the Continent through half of Africa, one line going to Dahomey in French West Africa, and another to Leopold ville on the eastern border of the Belgian Congo and French Equatorial Africa, the latter stage after its establishment being proposed for joint operation with Belgium.
On the South American side of its trans-Atlantic route, France had crossed the Andes and established service to Santiagd, and on the other side of the Atlantic it had built bases at Dakar and Casablanca, which with Algiers and Tunis, was a North African terminal for service across the Mediterranean Sea to a web of French connections to Italy, Switzerland, Germany, Austria, Po land, Czechoslovakia, Belgium, Yugoslavia, Rumania and Turkey.
Other Countries.—Russia has developed a long route across Siberia from Moscow to Kamchatka, with a dozen spur lines run ning to the north and south of the main system; these lines how ever are not flown on regular schedule or equipped for operations such as are maintained in Eastern Europe and the United States. But the routes have been laid out and flown many times and are available for further development should commercial conditions warrant; they also put Russia in direct flying distance to China, across Mongolia, a service that has already been projected.
Holland has established 12,000 miles of airways, and partly in conjunction with the French and British has been maintaining a route to Batavia in the Netherland East Indies where more than 2,000 miles of routes are in operation.
Italy's 9,000 mile system ran through Southern and Central Europe and to the Near East. Belgium had routes from Brussels to London, Hamburg, and Malmo, Cologne and Berlin, and was actively projecting operations through its African territories. Po land had 3,000 miles of routes in operation in Western Europe, and other countries maintaining services included Austria, Czecho slovakia, Denmark, Sweden and Switzerland.
Brazil, with 4,1oo route miles and Colombia, with 3,1oo, led Argentina, Bolivia and Chile among the South American coun tries.
Japan had 2,100 route miles within its islands and to Mukden, but this figure was subject to rapid increase by extensions of service in Manchoukuo and North China.
The following table indicates the speed at which world trans port was operating at the start of 1936: