frequency receiver and transmitter for experimental purposes, and that it was only this particular equipment which enabled us to carry on constant radio communication with the surface during the night that we were practically entirely surrounded by very severe thunderstorms in Texas. At that time the frequencies used were of a confidential nature, and I have no knowledge of what has become of that particular equipment, but the study of that subject should certainly be continued to a satisfactory conclusion.

Colonel BRECKINRIDGE. Do you know whether that equipment was on board the Akron when it crashed?

Lieutenant Commander ROSENDAHL. I do not; no, sir.

Colonel BRECKINRIDGE. Did it operate successfully with you?
Lieutenant Commander ROSENDAHL. It did.

Colonel BRECKINRIDGE. In thunderstorms?

Lieutenant Commander ROSENDAHL. It was the only means by which we could communicate with anyone in the world on that night. Colonel BRECKINRIDGE. Did you encounter a thunderstorm of great intensity?

Lieutenant Commander ROSENDAHL. We were not in the thunderstorm itself, but it was very close to the ship.

Colonel BRECKINRIDGE. Do you think under the conditions that confronted the Akron it would have worked?

Lieutenant Commander ROSENDAHL. That is impossible for me to say, but there appear to be some frequencies which do not suffer as much as others from the influence of static.

The fifth recommendation to begin improvement and replacement and training program, consisting

Senator KEAN (interposing). Excuse me; when you crossed the continent, when you went through this fog in the pass, why, you had a shotgun cartridge on board which you fired to hear the echo so as to determine your height.

Lieutenant Commander ROSENDAHL. Yes, sir; that is a device called the "Behm Echolot."

Senator KEAN. And you used it successfully on that flight?

Lieutenant Commander ROSENDAHL. We used it successfully on that flight.

Senator KEAN. And it was still on the Akron, but there is no proof that it was used when this disaster occurred?

Lieutenant Commander ROSENDAHL. Of course, that instrument does not have a high order of accuracy.

Senator KEAN. No; but it is a good thing to test sometimes other instruments when you are a little doubtful about your own, is it not?

Lieutenant Commander ROSENDAHL. It is a rough check; yes, sir; but the ideal altimeter to which I refer, that I should like to see developed, would be one that would give direct readings rather than to have to check with any such crude devise as the Echolot.

Subdivision (a) of paragraph 5:

(a) To begin construction of a replacement of the Akron on the general design of the Macon, but incorporating an additional bay.

Senator KEAN. Will you read the beginning of that? I did not understand it.

Lieutenant Commander ROSENDAHL. This is my fifth recommendation: To begin construction of a replacement of the Akron on the general design of the Macon, but incorporating an additional bay; that is, 222 meters more in length.

(b) Recommission the Los Angeles for training and experimental purposes and operate her from Lakehurst for these purposes conservatively and wholly with regard to her recognized capabilities.

(c) Construct a training ship of characteristics to be determined by the Navy Department.

(d) Investigate fully and procure and operate, if found desirable, mechanical or other aids in the training of airship elevator men and crews.

Not in the recommendation, but in reference to that, what I mean principally by that is, a device proposed by a German engineer for training of airship crews which was to be built along the lines of a similar device used for training submarine crews. It seems that during the World War the Germans were able to eliminate perhaps some unsatisfactory material and, in general, to train submarine crews to a certain degree before they even stepped into the boats, by means of a device which was really a replica of a submarine conning tower, and artificially produced conditions that would exist in the submarine itself.

It also provided corrective measures which the student was required to use that were of the same nature as those of the submarine itself to pull himself out of the artificial predicament that he found himself in. I know, from talking with Dr. Eckener and others of the Zeppelin Co., that a few years ago there was included in their program the purchase and operation of such a device for the training of the Zeppelin Co.'s own personnel. At that time the price and other characteristics were investigated by the Bureau of Aeronautics, but the price itself was found to be quite unreasonable, as we thought, and consequently we were unable to purchase such a thing. I cannot state definitely that such a device would be of material value, but it is my belief that it could be made so, and by the use of that, if it should work as we expect, we could eliminate in early training personnel who could never learn to handle the controls, and we could likewise expedite the training of elevator men particularly, which is about the most important station in the ship for enlisted men.

My next subrecommendation:

(e) Lay down a policy and begin and continue training of adequate numbers, ranks, and grades of naval personnel to fill necessary details in a complete and logical airship organization, and to care for attrition and for such rotation of duties as would be required by Navy Department policy, this training of personnel to include the training of a limited number of reserves.

(f) Provide adequate numbers and types of airship bases and facilities. (g) Upon completion of the training ship, retire the Los Angeles from active operation but utilize her for what I choose to call full-scale experiment for obtaining data relative to the forces and stresses and other important considerations in an airship moored at a mooring mast and being handled by mechanical means in and out of a shed. This is important for the reason that the relative size of useful models and of existent wind tunnels is such that we cannot get data with a sufficient degree of accuracy, and it would be very illuminating and undoubtedly very helpful to have the full scale data that we could obtain by equipping the Los Angeles under those conditions with extensive recording and measuring devices, and even should the ship be tested to destruction in such a case, it would undoubtedly reveal a great deal of valuable information.

(h) Pass a fair and adequate merchant airship act.

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As to Mr. McSwain's request, I have not completed that yet, but I hope to give you that on Monday.

Representative MCSWAIN. Put it into the record.

Lieutenant Commander ROSENDAHL. In regard to the promotion of officers engaged in aeronautical duties, there seems to have been omitted by all who talked of the matter, a clause that is now a portion, and has been since June 24, 1926, a portion of the law which takes care of that. I will read it.

AIR PROGRAM ACT, JUNE 24, 1926, SECTION 4

(Sec. 3, par. 6. Promotion by selection of aviation officers; additional numbers in grade or rank.)

In view of the statement by Admiral Pratt and Admiral King relative to personnel policies of the Navy, I think this should be brought to your attention:

That any officer of the Navy, line, or staff of the permanent rank or grade of commander or lieutenant commander, at the time of the passage of this act who has specialized in aviation for such a period of time as to jeopardize his selection for promotion or advancement to the next higher grade or rank under existing provisions of the law and whose service in aviation has been in the public interest shall be so notified by the Secretary of the Navy and at his own request be designated as an officer who will be carried as an additional number in the next higher grade or rank not above the grade of captain if and when promoted or advanced thereto: Provided, That selection boards in the cases of such officers shall confine their consideration to the fitness alone of such officers for promotion, not to the comparative fitness of such officers. (44 Stat. 767, ch. 668.)

In other words, there is some provision already made. Representative MCSWAIN. It is restricted to commanders and lieutenant commanders who at the time of the passage of this actLieutenant Commander ROSENDAHL. That is correct.

Representative MCSWAIN. Have already manifested a peculiar interest in and rendered a distinct service to the country by reason of aerial or aeronautical experience.

Lieutenant Commander ROSENDAHL. Yes, sir.
Representative MCSWAIN. It is restricted.

Lieutenant Commander RoSENDAHL. Yes, sir.

Representative MCSWAIN. If that were general, it might be all

right.

Lieutenant Commander ROSENDAHL. That is the reason I offer it, that such a thing might be more applicable in the future.

Representative MCSWAIN. Yes, Commander, I hate to detain the committee a minute further, but in view of your statement that you regard the weather, the storm could be only a contributory and not a direct approximate cause of this disaster to the Akron, it is fair to say that that disaster must have been due to either insufficient operation by the crew or an unfit condition of the ship, or the severity of the storm, one of the three, or all three combined, or any two of the three combined, and cooperating with each other? Lieutenant Commander ROSENDAHL. What was the second, the ship itself-its condition?

Representative MCSWAIN. That is right.

Lieutenant Commander ROSENDAHL. Not of the ship itself, but I do feel that the type of altimeter used, and, of course, there was none other available, is not a satisfactory type, and it did contribute.

Representative MCSWAIN. In that it deceived the commanding officer as to his actual altitude?

Lieutenant Commander ROSENDAHL. Yes, sir.
Representative MCSWAIN. Very well; I thank you.
Colonel BRECKINRIDGE. Any other questions?

Senator KEAN. Well, you feel that the commander did not use very good judgment in putting his ship right across the thunder storm? Lieutenant Commander ROSENDAHL. I do not say that. My contention is, my belief is that he did not have adequate information available. Why not, I do not know, but I think, as I said, one of the most important things that he could have known or should have known, or that would have been of help to him, was the knowledge of where he was with relation to the storm center. We use "storm" too much; it should be "low-pressure center." He had no means, when he could not see the surface, of measuring his drift, and consequently determining the wind velocity and the direction at his altitude; it is physically impossible today to do so, when you cannot see the surface, unless you can get frequent astronomical observations, and in the meantime, with the wind conditions not having changed. I do believe we can develop something that will enable you above the surface of the sea to measure your drift without seeing it. If you can do that you can determine all of the other elements needed for navigation. That would have helped him in knowing what portion of the low-pressure area he was in. Then, naturally, had he suspected he were near the center, he would have regarded his altimeter with suspicion.

Senator KEAN. I have no more questions.

Lieutenant Commander ROSENDAHL. Just one thing more. I am sorry to take the committee's time here, but it occurs to me that in the so-called "comparison ", or the mention of heavier-than-air craft or lighter-than-air craft in the same breath, we may lose sight of the fact that the two types do not in any way attempt to achieve the same end, consequently when we speak of the much greater cost of a lighter-than-air ship as compared with airplanes, we are not talking about the same thing at all. There is an impression that because an airplane may cost $100,000 and an airship four million, you are really spending $4,000,000 to do what you might get for one hundred thousand, but the fact remains that that is not the case, because the airship can do things that no other type can, including the airplane.

If you were asked briefly "Why the airship?" the answer is because it can do something that no other type can possibly do, and because on the development of heavier-than-air craft to eventually supplement lighter-than-air craft, as has been indicated in the opinions of some witnesses here, we can only estimate or approximate. That is all in the future. We know there is a definite limitation at some point beyond which, in the light of present principles and present materials, the heavier-than-air machine cannot be increased in size without losing efficiency. Now, that point has been stepped up considerably in the last few years and may continue to grow. At the same time we do know airships have oceanic range; we also know from our consideration of the matter that we can increase that range very materially, and if the airplane and heavier-than-air craft ever

do achieve corresponding range at higher load carrying characteristics, then they will provide simply another speedier service. That is, I think the airship will always carry a greater bulk of material, whether it is war material or commercial, and the airplane, of course, will always have higher speed and will augment such aerial service as the airship has already provided over the ocean.

Another thing, this is just a brief statement: We have not camouflaged our ships. When we talk about the easy recognition of airship in the air, we must admit there is one thing we have not attempted yet in the naval employment of airships, that is their camouflaging, but there is undoubtedly some way of cutting down their high visibility.

There are naturally dozens of other topics I could touch on, but I believe the subject has been sufficiently covered to convince, one way or the other.

Representative MCSWAIN. Will you furnish for the record a discussion of that general inquiry I submitted to you the other day? Lieutenant Commander ROSENDAHL. I will have that Monday. Representative MCSWAIN. Will you submit it to the committee for publishing in the record?

Lieutenant Commander ROSENDAHL. Yes, sir.

Representative HARTER. I would like to offer, for the purpose of the record, statistical data on the trips of the Graf Zeppelin. (The document is as follows:)

The airship Graf Zeppelin has with its landing at Friedrichshafen on Thursday, November 23, 1932, completed 299 voyages, the distance covered being 530,600 kilometers and the flying time 5,369 hours. This again amounts to an average of 100 kilometers per hour. Seven thousand four hundred and ninetyfive passengers have been carried on these 290 voyages. In the year 1932 there have been made 58 trips, totaling 180,780 kilometers and 1,766.4 hours flying time; 1,218 passengers, 2,745 kilograms of mail, and 2,021 kilograms of freight have been made 58 trips, totaling 180,780 kilometers and 1,766.4 nours' flying Of these 290 voyages the airship made 111 landings at other places than Friedrichshafen, where only untrained men were available. In Brazil soldiers were used, but these men were constantly changed. Only at the last two trips a regular staff of working men had been trained.

The airship crossed the equator 26 times and made 33 transoceanic voyages. Thirteen trips were made to and from South America, of which five were extended as far as Rio de Janeiro. There were four landings at Rio where passengers debarked and came on board.

The longest trip from Friedrichshafen to Pernambuco took 76 hours 35 minutes, the shortest 62 hours 30 minutes, while the return trips took 101 hours on the longest and 67 hours on the shortest trip. The trips were scheduled to last 72 and 96 hours. The average was 71.51 hours and 86 hours, east or westbound.

All trips of this year were carried out according to schedule with only two exceptions. There was a delay of 24 hours in both of these cases, due to the still technically inadequate equipment of the flying field in Friedrichshafen. However, this delay could be made up in both cases on the return from Pernambuco, so that the return trip was made according to schedule, and also the next following South American trip could be started on the scheduled date.

While the first voyage to South America in 1930 has to be considered merely as a trial, three such flights were carried out in the fall of 1931one trip per month-which already showed an increase in the number of passengers and mail carried.

The same was observed at the nine voyages in 1932. There were 10 passengers on board on the first trip, of which a few were guests, while when the airship left Pernambuco on its last trip, 18 passengers were on board to which 3 more were added at Seville.