AIR TRANSPORT — ^DURAND 525 



will be required. All of this means, of course, extra weight of plane 

 and mechanical equipment, and here is where the limitation will 

 enter with reference to extending such operation to extreme altitudes. 

 But this is only the beginning of difficulties. The excessive cold of 

 these higher altitudes means again artificial heat for the personnel, 

 trouble with gasoline and lubricants, with possible serious trouble 

 in de-icing windows and pilot's lookouts. 



However, all these are merely hurdles to be passed over and in 

 the very near future we may expect to see such flights on a com- 

 mercial basis, at least in the lower altitude ranges. 



The first plane, presumably, to achieve this distinction will be the 

 Boeing No. 307, which has been designed definitely with reference 

 to this character of service. As already noted, this plane has an 

 ordinary cruising speed of 175 to 180 miles per hour. With 9,200 

 pounds of pay load, including 33 passengers, it will have a range of 

 about 1,000 miles. The cost of this plane is given as $300,000 and 

 it is understood that a certain number of these so-called "strato- 

 liners" will very soon be put into actual service. 



I have listed comfort as one of the requirements of air transport, 

 but I shall not tarry long over this feature. It will be enough to 

 say that the developments during the past 10 years have held 

 constantly in view increased comfort and convenience for the pas- 

 senger. Soundproofing, reclining chairs by day or bunks for sleep- 

 ing accommodations by night, meals as usual, the attentions of 

 courteous and capable stewardess-hostesses — these, especially in 

 modem large transport planes, have gone far to give to the air 

 passenger a close approach to Pullman accommodations by rail, 

 though naturally with less freedom of personal movement. Comfort 

 and convenience, though counted on to attract and hold passenger 

 patronage, are, after all, of minimum interest technically. It will 

 always be a simple matter to provide these features, up to the limit 

 of weight and space available, in competition with other and per- 

 haps more important requirements. 



We have thus passed rapidly in review some of the problems in 

 modern air transport with indications of the direction of recent 

 advance. We must now turn to what is, after all, the most important 

 consideration of all, and that is safety. 



If we ask what is the most common menace to safety, the natural 

 answer will be the weather. But the weather is simply one of the 

 conditions under which the plane must render its service. Our guid- 

 ing principle, in the matter of the relation between weather and 

 safety, should, I think, be this: We must strive to secure a degree 

 of safety in what we may call "proper flying weather" which will at 

 least approach that in the safer modes of land travel; and we must 

 strive to perfect our methods of observation and analysis of weather 



