The Loss of the Akron

By Lieutenant Commander C. E. Rosendahl, U. S. Navy

In summer, in winter, in daylight, in darkness, victorious in many a battle aloft with nature, she had oft been acclaimed the Queen of the Air. And now puzzling events encompassed in but three brief minutes had led to her destruction.

Another crisis in the checkered history of airships.

Even before the startled world yet knew where the Akron rested, if indeed at all, the very ether waves, carrying hopeful news to bewildered relatives and friends, blazed and burned with the condemnation of critics. Others more pensive, counseled delayed judgment pending accurate information and calm appraisal. Airship followers were stunned, puzzled at the mysteries of a situation that had never been considered even remotely probable. But strongest of all, there arose all over the country a wave of feeling that in spite of that fateful April 4, airships were not done for; that having come so far already in their uphill battle for recognition, airships were entitled to carryon to a fair decision. Losses had inevitably occurred in every pioneering venture; any idea of quitting now was un-American, unthinkable, a slur on the memories of Admiral Moffett and those who had laid down their lives in the cause. Letters and even persons came to me advocating the immediate building of a replacement of the Akron and naming it in honor of the gallant Admiral Moffett.

I have been asked a number of times whether I think that on the night of her loss the Akron was being purposely subjected to the existent bad weather conditions as a live-model test to show the airship's capability. The Akron and other airships had previously, they pointed out, taken quite severe beatings from the weather on numerous occasions. Was this to be a further test?

Every thinking person realizes the indomitable strength of many natural forces and phenomena. Experienced aircraft pilots particularly realize and give due weight to the existence of such forces aloft. The atmospheric ocean contains its own "rocks and shoals," "waterfalls," "icebergs." Such, skilled pilots avoid and will probably always dodge just as master mariners at sea exercise similar caution. Unfortunately, our studies aloft have not yet reached the stage where visual and chart examinations reveal the true severity of aerial dangers. A little knowledge may be a dangerous thing in the air as well as anywhere else. Discretion is still the better part of valor in aircraft operations; not so long ago Lindbergh sat his plane down in the desert rather than foolishly hazard a severe storm in his path. Hence, I do not believe that the captain of the Akron would deliberately drive his ship into such unknown forces. His schooling had been the same as that of the rest of us; certainly, he would not jeopardize our only operating airship and the lives of so many besides his own. And we have no reason for believing that he expressed any such intention to any of the three who happened to survive, nor to anyone else. Others aboard would have had a say in such a venture.

One immediate belief had been that lightning destroyed the ship. Many were equally certain that the fury of the storm itself dismembered, tore the ship apart; that she rode a cataract to destruction; that strange aerial quick sands drew her violently into the sea. A dispassionate study of the evidence shows conclusively, however, that the ship flew or maneuvered into the sea tail first and that thereupon inevitable destruction and death followed rapidly. That "weather" in some of its widespread ramifications was an important contributing factor is, of course, undeniable. But it remains a fact also that the Akron was not destroyed by weather itself but, primarily and regardless of how she got there, by terrific forward impact with the sea.

Let's see how the situation developed. At 7:28 P.M. the Akron cast off and rose. Enveloped by fog from 300 to 1,500 feet she broke into open smooth air to see another blanket of clouds at 5,000 to 6,000 feet from which rain was falling. The flying altitude was varied during the night between 1,500 and 2,000 feet to stay just above the fog and to catch glimpses of the surface through holes. The mission of the flight was that of flying in circles about certain radio direction-finder stations in New England, all the while transmitting radio signals for the calibration of those stations. This required good visibility and reasonable ceiling. It was realized that such conditions could not be expected before the next afternoon but there were various other missions that could be executed in the meantime in better weather areas. On board was a fuel supply for over 5 days at cruising speed and the usual generous amounts of food, water, necessities. As the fog extended seaward, the commanding officer, Commander Frank C. McCord, set the initial course westward for Philadelphia where the visibility was somewhat better. From there the course was changed to follow the Delaware River southward to the Capes, the intention being to exercise at other missions in the general New Jersey vicinity. About 8:30 P.M., while in the vicinity of Wilmington, Delaware, lightning was sighted to the south. There being no reason for engaging such conditions, the captain speeded up the engines and turned eastward. Up in the radio-room sat the radioman converting into typed words the incoming signals of the 8:00 P.M. weather map being broadcast to the world by the Arlington Naval Radio Station NAA. In his office adjacent to the radio-room sat the aerological officer and his assistant entering weather symbols on a chart. Early deciphered signals showed a thunderstorm at Washington. Lightning to the westward also influenced the captain to overrule a suggestion to go westward while sparring for time and clearing weather in New England. As the lightning appeared closer at times, the course was changed to northeasterly and then back to east as distance from it was gained. This happened several times. A mistaken interpretation of an ordered change of course as 50° instead of 15° more northerly, as intended, appears to have been of no consequence.

At 9:45 P.M., in the vicinity of Asbury Park, the lightning to the south of the Akron had become quite extensive and to the westward continued also. The upper level of the fog was now at about 1,500 feet; in order to be above it a flying level of 1,600 feet by altimeter was chosen. At 9:46 P.M., NAA (Washington) called the Akron and asked the operator by conventional radio signals, "Have you anything for me?" The Akron immediately replied, "I have nothing for you." On crossing the coast line eastward at about 10:00 P.M., the lightning was quite general and closer, even over the ship. To avoid tempting a lightning discharge from some eager over-laden cloud, the trailing radio antenna wires were reeled in as customary in such conditions. The cloud blanket above still persisted. For an hour longer to seaward the course continued, the captain's apparent intention being to "take it" at sea by running eastward and then southeastward. This should enable the ship to maneuver ahead of and then around the outskirts of an advancing low-pressure area indicated on the weather map just received and expected to move northeasterly.

About midnight, however, the captain appears to have changed his mind for he reversed the course to westward, apparently for the purpose of establishing the exact position of the ship by identification of the coast line through holes in the fog. The navigator could also then take "drift" measurements on lights or other visible objects on the surface and thus determine wind direction, velocity, and other necessary navigating data; the last he had been able to obtain were much earlier when near Philadelphia. Returning now, the coast line was reached much sooner than had been calculated. On the ground below the wind was northeast 40 knots and there also were rain, light fog, heavy thunder, and lightning all around. But before any drift measurements could be obtained, the course was changed to east-southeasterly. This was almost exactly as the midwatch details came on duty-midnight merging into the fateful morrow.

The blinding encircling lightning revealed fantastic forms at the top of the fog-gray, ragged, ghastly specters, bulging masses of moisture. Streaking smoothly southeasterly, the engines humming reassuringly, the ship would hurdle vaporous valleys and precipices; the next moment plunging and piercing nebulous peaks of fog. From the dimmed control car, weather-worn eyes peered into space; in the flashes sharply etched thunderheads, forbidding as graven granite tombs, burst into sight and as quickly vanished. Above, a blanket of clouds smothered the stars and dropped its rain in torrents-no peep of comforting blue sky. Within, other eyes alertly followed silent instrumental sentinels; iron arms, horny hands easily spun the wheels of responsive controls. Completely immersed in fog for minutes at a time, the silent Akron sped along. Abruptly she emerged into open warmer air; the buoyancy would change momentarily, a situation easily met. Then followed swift swallowing-up by gulping caverns of fog, nastiness to test a seaman's soul, uncomfortable but yet no thought of danger. Such situations had been met before.

At 12:30 A.M. the character of events changed greatly, abruptly, with alarming suddenness—the first intimation or perhaps realization of danger. The next three minutes held a totally unexpected climax!

Plunging suddenly into very turbulent air, the elevator man (controlling the altitude) reported the ship falling rapidly, the bow slightly down. His altimeter read 1,100 feet, he reported. Lieutenant Commander Wiley, second in command and a veteran of scores of scenes aloft in thousands of flying hours, jumped from his station near the directional control to the elevator man's assistance. Still falling, the situation demanded strenuous efforts with both ballast and engines. Instantly the engines responded to the captain's signal for "full speed"; at the ballast controls, Wiley dropped water from the midship containers. Not getting the desired response, he grabbed the bow emergency ballast toggles; 1,600 pounds of water in two spraying masses splashed earthward and spread into space. Up came the bow—the remedy had been effective; at 700 feet the sinking altimeter needle paused, then started upward rapidly. All hands in that control car must have sighed relief. Back to "standard" speed were rung the engines Wiley cautioned the elevator man to reduce the very rapid rate of rise; from 1,300 back to 1,600 the altimeter needle moved more gradually. A check on the ship's condition showed her in normal flying condition. Lightning, rain, fog, open air, swept by ill kaleidoscopic sequence.

But short-lived was this truce. Encompassed there in the dimmed small nerve center of the ship, tragedy had whisked aboard unexpected. In only a minute more, again the air was turbulent. Descent began anew. Realizing the ship must then be in or very near the squall area of the progressing storm—its most violent zone, demanding quick, effective action to combat—Wiley ordered the signal "landing stations" that would bring all personnel to their feet at vital posts.

At each of 18 telephone stations throughout that vast interior, five shrill unmistakable shrieks of the alarm signal pierced the inside stillness. At a bare 1,000 feet pointed the altimeter hand and then continued its retreat. Up within the ship, men awakened from normal sleep, wondered "what it was all about." Lieutenant Calnan came into the car and took over the ballast control in his usual calm manner. Wiley returned to his post beside the rudder man. The engineer officer stood alert at the engine telegraphs. Calnan called out to the captain "800 feet." Up within the ship, flashlight beams sprayed here and there as Chief Boatswain's Mate Carl Dean, another veteran, needing no orders, urged all hands forward—the ship was at an unusual angle and falling.

Brief moments followed then, event difficult to correlate. Control-car personnel felt an unusual shock and lurch, no violent, not a gust, something different. In a quick glance Wiley saw limp slack control cables—the lower rudder was gone. Engine telegraph cables showed the same slack uselessness. The ship was up greatly by the nose. Sounds of breaking structure now were heard. Glancing from his window, Wiley sighted waves below coming fiercely up at him. "Stand by for a crash!" rang out his warning to those in the car. Downward with terrific speed and impact came the car and structure above—right on under the surface—submerged.

Continuing his swim under water long as he could after being carried out a window, Wiley came to the surface. In the icy water, lightning flashes revealed a few men struggling. Drifting rapidly from him, broken in two or three places, partially submerged, the proud ship on which he had served from her very launching disappeared into the intermittent gloom, a derelict. A friendly 3-foot board floated near him as if to offer aid. An hour's exposure and then the welcome sight of helping hands aboard the German tanker Phoebus.

There he found three shipmates. Chief Radioman Copeland did not long survive the terrible exposure. Boatswain's Mate Richard E. Deal, a husky veteran of Shenandoah and Los Angeles experience, up within the hull at the crash, had also been carried under. How he got to the surface is a mystery, but as he rose he found himself swimming in gasoline. Keeping himself afloat for some time by swimming, in the lightning flashes he saw a floating gasoline tank coming toward him. To it clung three men. Laboriously he joined them. For nearly an hour, wave after wave knocked loose their icy grips on the tank; time after time they recovered. Exhausted, one man failed to return to the struggle. Then the Phoebus hauled them aboard—Deal, Copeland, and Aviation Metalsmith Moody Erwin. Seeing the inside structure disintegrating about him at the crash, Erwin had dived headlong through the cotton outer cover of the ship; down came the hull over him. Diving again, he swam from under the sinking hulk and twenty minutes later found the friendly floating tank.

Soon the three sole survivors were on their way again by air for the further ordeal by investigation. Each had vivid recollections of what had passed before him. At the center of activity during the entire flight, Wiley’s veteran airship mind had photographed a mass of details. It is unfortunate for future scientific and operating purposes that from his post he could not, as he says, tell the magnitude of the steps taken to check that last descent. It had been the task of others to take weather data and information aboard for the flight. It is also unfortunate that in the rapidly developing scene that night the captain was too engrossed to tell Wiley his reasons for the various courses and to inform him of no more than his bare decisions. He may have told others who did not survive; but in such a situation, streaking through the air, changing position at from 60 to 100 miles per hour, decisions have often to be made instantly. There is then no time for discussion; no time to look for the answer in any book, none but the book of experience.

Were human errors made in getting the ship into the severity of the storm or in her subsequent handling? Once in this predicament, did structural or material failures lead or contribute to destruction?

The Naval Court of Inquiry was fundamentally a fact-finding body to inquire into one particular case-the loss of the Akron. Its opinions of immediate interest are as follows:

(5) The court is of the opinion that about 10 :00 P.M., when the commanding officer observed the weather map which showed a secondary cyclone centered in the vicinity of Washington, D.C., coupled with the previous report of a thunderstorm in that vicinity at 7:00 P.M., and that since 8:30 P.M. lightning had been observed to the southward and westward which lightning approached closer to the ship, the commanding officer committed an error in judgment in not setting such courses as would have kept him in the safe semicircle, thereby probably avoiding the severe conditions finally encountered, and that his error in judgment was a contributory cause of the loss of the Akron.

(6) The final destruction of the Akron was caused by a down current of wind of such magnitude that the lower fin struck the water before the descent could be checked. This contact of the fin with the water resulted in a progressive destruction and sinking of the Akron.

(7) In view of the lack of evidence presented or available as to the static and dynamic condition of the ship, or of other conditions, at the time the fin hit the water, the court is unable to express an opinion as to whether or not, had the ship started her descent from a higher altitude, sufficient time would have been available to completely lighten the ship—provided she was not so lightened, nor If, had she been completely lightened what altitude would have been required within which descent could be checked, nor further whether the descent could have been checked under any attainable condition of the ship and existing weather conditions. In view of the foregoing the court is unable to place the responsibility for failure to check the descent which resulted in the crash of the Akron.

(8) The error in judgment, as set forth in opinion 5, has been made evident to the court by its study of the testimony. The court has but little direct knowledge of the considerations upon which this judgment was based. Everything within the knowledge of Commander McCord at the time his decision was made might have pointed to his plan of action being justifiable. Certainly we know that many conflicting considerations had to be set one against the other, and what subsequent events show to have been an erroneous decision does not, in the opinion of the court, justify a condemnation without more information of the considerations upon which the plan of action was based. This information was lost with the ship.

(9) Immediately preceding and during the destruction of the Akron, the best traditions of the service were maintained.

In reviewing the court's findings and opinions, the chief of Naval Operations declared that opinions (5) and (8), as quoted above, were not consistent. He concurred in the opinion expressed in (8).

Congress, meanwhile, decided upon its own investigation into the

cause or causes of the wreck of the naval dirigible Akron and the wrecks of other Army and Navy dirigibles, to fix the responsibility for the same, to inquire generally into the question of the utility of dirigibles in the military and naval establishments, and to make recommendations to the Senate and to the House of Representatives with respect to the future use of dirigibles for military and naval purposes.

The results and scope of this investigation and its recommendations are of importance to anyone interested in airships from any standpoint, as future results and reverberationsfrom it are not at all improbable. To any person trying to make up his mind on airships, the importance of the committee's report and recommendations is enhanced by a knowledge of the committee's membership. Drawn in a neutral fashion from all over the country, the joint committee of outstanding members included Senators King (Utah), Walsh (Massachusetts), Duffy (Wisconsin), Johnson (California), Kean (New Jersey); Representatives Delaney (New York), McSwain (South Carolina), Harter (Ohio), Andrew (Massachusetts), and Hope (Kansas). Colonel Henry Breckinridge, an internationally known lawyer, with the aid of able assistants, served patriotically and most efficiently as special counsel for the committee. Sitting in the scorching summer heat of Washington, the committee patiently and searchingly heard some S6 witnesses including a former Ambassador, a former Senator, Representatives, generals, professors, doctors, outstanding editors, eminent specialists, aviators, outstanding figures in the aeronautical world, experts of every sort, not-so-experts, unbelievers, and the whole naval scale from bluejacket to admiral.

In a report signed by all members except Senators King and Johnson, the Congressional Committee found:

The proximate cause of the wreck of the Akron was the crash of the stern on the sea about 20 miles off Barnegat Light when in a swift vertical descent caused by a vertical down current of air in the midst of a thunder and lightning storm. There may have been other contributing causes.

Responsibility for the crash was the navigation of the ship into the storm conditions where she was destroyed.

Its recommendations are not within the scope of this article.

With the practically total loss of the ship herself, the log and other data of importance, and all but three of her crew, the available material for judging might not seem abundant. Yet there are significant facts that coupled with operating experience can be molded into a possible sequence of related causes and events.

The early reports that blamed lightning for having wrecked the ship were no doubt colored by its abundance that fatal night. First, it is difficult to believe that a severe bolt of lightning could have struck the ship without knowledge of some one in the crew. There is not the slightest evidence pointing to her having been struck. Next, operating and engineering consensus of opinion is that a rigid airship properly bonded metallically as was the Akron is relatively immune to lightning. Laboratory experimentation shows that a charge made to strike a large model enters by the nose cap where longitudinal members come together, then dissipates itself in the continuous metallic framework. Each metallic part is thoroughly joined to every other, thereby eliminating any chance of arcing or an open electric circuit for a spark to jump. The helium within American airships is entirely non-inflammable. Gasoline vapor, in the remote chance that it should collect in an airship, is, of course, inflammable. But there is no more reason for believing gasoline vapor existed dangerously during the last flight than on any other. Rigid safety regulations are carried out. Eventual adoption of heavy-oil engines when available will practically eliminate the little remaining fire hazard from fuel. In the only case on record wherein even a hydrogen-filled rigid airship was definitely destroyed by lightning, it is known that the ship was exhausting hydrogen in a thunderstorm; the highly explosive and inflammable mixture of air and hydrogen at the open valves needed only a spark to set it off. On the other hand, there is positive proof that even hydrogen-filled ships have been struck by lightning without any dangerous results.

We can be positive that the Akron's power plants up to the time of the last descent were functioning and responding perfectly. Even after the tail hit the water and the engine telegraph wires became slack, emergency signals to the engines were passed and answered. The power plants were probably the last units in the ship to become inoperative. The Maybach engines with long years of development and background in German airships are the best airship engines in the world today. Although American engines for airplanes are unsurpassed, there is yet no American airship engine equal to the Maybach.

Rupture of gas cells and exorbitant loss of buoyant helium, thereby making the ship inordinately heavy, do not seem at all probable at any time on the Akron's last flight. Such loss would surely have been observed and reported by those whose principal duties involved continuous inspection of the gas cells. It would have been evident on the instruments. All in the control car would have known. Deal and Erwin, up within the hull, fully alert, during those last few minutes observed many things but neither saw nor heard of any loss of helium. Wiley is clearly of the opinion that the crash was not due to loss of helium from ruptured cells or escape through the valves.

From early reports, it appeared that the ship might have broken in the air before she struck the sea. Close analysis of available evidence almost entirely closes the door to this suspicion. No major failures occurred until after the tail hit the water. This contact with the surface was revealed to those in the control car only by the limp wires of the engine telegraphs and by the slack control wires indicating the loss of the lower rudder. Even the "different" shock and lurch did not in themselves immediately tell the story of the immersion of the stern. The vertical descent of the ship did not contain sufficient violence to destroy the ship on the water. Of this I feel certain, as no exceedingly rapid rate of fall was noted or reported; and our elevator men are trained to call out any great rate. Wiley would have commented on such.

The immersion of the tail, shearing the after part of the lower fin and carrying the lower rudder with it, caused the collapse of the tail portion of the ship; then through a combination of bending and shear forces, breaks in other parts of the structure followed inevitably. The tail having struck and collapsed in the water, the resulting drag and forward momentum of the upper structure broke her "back" in several places and slapped it all violently into the water. The structural failures noted by Deal and Erwin within the ship are almost certain to have occurred after the unwitting submersion of the tail; but even had these noticed failures happened just previously, in themselves they were not of major caliber and so would not have led to destruction of the whole ship. Wiley is sure the ship was in perfect condition before the second (final) fall.

It should be remembered that with her own air speed and that of a quartering wind of 40 knots, the actual speed of the ship over the surface was easily over 100 miles an hour as she immersed the tail; but burned into Wiley's memory is the fact that later when the control car hit, the ship had practically no forward motion over the water. The dragging tail had snubbed it.

No, the vertical descent is not what wrecked the ship. But the sudden arrest of a 200-ton mass going forward at a speed of over 100 miles per hour is another matter. All that momentum was spent in slapping the ship's hull down onto and into the incompressible unyielding water. It might as well have been concrete. No structure on earth could have survived; none was ever built to. Neither was the Akron.

These facts, coupled with a certainty that no "breaking-up" of the structure occurred before striking the sea, should eliminate from consideration any discussion of earlier structural integrity. But in view of certain previous publicity, this item is entitled to refutation.

In the early history of the Akron there had been accusations of sabotage, faulty workmanship, and inferior materials in her construction. The sabotage phase had been investigated by the Department of Justice, found its way into the courts, and terminated with a recommendation to the U.S. District Attorney that no further steps be taken. The accusation against the accused involved the omission of two rivets from the upper fin structure of the Akron which omission the accused reported to his superiors. Over 6,000,000 rivets went into the structure of the ship. Throughout the building of the ship, the Navy maintained an inspection force of 3 officers and 21 others at the plant. Every piece of material entering the construction was weighed and inspected. Any defects that developed were eradicated and corrected. The Navy's inspection of the Akron would stand the acid test of anybody's fair, unbiased scrutiny. Dr. Eckener, personally familiar with the construction of well over a hundred airships, commented after his inspection on "the superb workmanship apparent in every detail" of the Akron. A congressional committee of 9 members investigated the charges. The only testimony presented was hearsay, secondhand. Two former employees of the builder of the ship, alleged to have made the accusations, did not appear. Some time later, I had occasion as commanding officer of the ship to conduct one of them on an inspection of the Akron. We went widely over the ship including areas of alleged inferior work and materials. Afterwards, in reply to my question of what he now thought of it, his answer was, "It looks all right to me." And so it did to the committee which found no evidence to support the hearsay accusations but did find an abundance testimony that there were neither faulty workmanship nor inferior materials.

One critic expressed his opinion that because of a ground-handling accident in February, 1932, the structure had suffered permanent misalignment and "could never be the same again." The care with which those repairs were effected and checked has never been exceeded. Beginning in May, 1932, the Akron made a 36-day cruise to the Pacific and return. During this very active period, the ship was subjected to a wide variety of severe conditions. No airship ever had a rougher extended trip. No structural defect of any consequence could have remained concealed; none developed. But above all, no operating personnel will ever knowingly operate un-airworthy aircraft. After all, flying is voluntary duty. There are many other interesting activities in the Navy.

"Weather" is today just about the most important factor in flying of any kind. It was a contributing cause in the loss of the Akron; but not in the way commonly supposed. There was no dismemberment, no breaking up into fragments by hands of a Storm King in the sky. "Weather's" contribution came in an insidious, disguised way, as we shall see. Some types of weather, such as helping hands, may be of advantage to flight; others, to a military mission. Weather is a friend as well as a foe. How do we know where favorable or unfavorable conditions exist?

Twice daily, at 8 A.M. and 8 P.M., eastern standard time, the weather bureau receives and then disseminates by radio broadcast on several frequencies compactly coded signals telling many weather facts just previously collected by scores of observing stations over the North American Continent and by numerous ships at sea. Decoding these, the trained aerologist jots down upon a blank map form certain descriptive symbols, colors, and figures that permit him to draw configurations known as high-pressure or low-pressure areas. To one trained in such, the study of weather maps of upper air as well as surface conditions presents a graphic vision of moving air masses of various characteristics, sometimes at peace with one another, more often in conflict. Physical laws, study, experience, enable the aerologist to foretell with considerable accuracy movements and developments and their effect on one's weather conditions.

Important factors in the astounding progress of airplane transport over the American Continent are the splendid systems of marked, lighted, and charted airways, and particularly the abundant gathering and dissemination of weather information. Safety has been widely multiplied thereby; such aids have insured the practicability of overland air transport. Rapid transmission of such information is accomplished by a "ticker tape" instrument, the teletype writer thatreels off its printed messages of the weather at stations on its circuit or airway every hour. A recent development is the "page printer," an instrument whereby every four hours weather signals coming over its circuit are printed automatically on a map in proper places; aerographers then trace in the usual isobars and thus have a regional weather map of fair proportions. These four-hour maps over regions and the hourly news over charted airways supplement the 12-hour weather bureau of 8 :00 A.M. and 8:00 P.M.; they enable the observer to follow closely the developments more fully indicated on the complete eight o'clock maps. At the time in question, Lakehurst had a teletype machine, but no "page printer." However, the data passed out every four hours for the "page printer" map can be requested and obtained via teletype and drawn in by hand.

When the Akron went down, I was at sea in the Pacific as were two other former lighter-than-air officers, Lieutenant Commander Reichelderfer and Lieutenant Orville, both widely experienced postgraduate aerological officers. To satisfy our curiosity as to what happened to the Akron, we obtained copies of the complete weather signals that had been sent out. From these, weather maps were drawn, both for surface and upper-air conditions. Then we made the usual study summaries and forecasts, endeavoring conscientiously to draw the conclusions that would have been formed without knowledge of the Akron's difficulties.

Immediately, Reichelderfer recognized a striking similarity between this map and one of June, 1930, when the Los Angeles in flight had faced a weather situation similar to that of the Akron. The Los Angeles, however, went to sea, allowed the storm to pass between her and the coast, and then came into Lakehurst safely behind it. Reichelderfer was on that flight, as on many others, the ship's aerological officer. I point this out to show that a veteran airship aerologist with complete data regards the 8:00 A.M. map of April 3, 1933, as suspicious at least. It points out the potential value of experienced continuity in pioneering efforts.

Supplementing the 8:00 A.M. map study with the information imparted over the teletype and the page printer at noon and 4:00 P.M. of April 3, we find at 4:00 P.M. positive evidence of a rapid development of the "wave disturbance" then over western North Carolina, into a typical low. While its development and movement within the next few hours cannot be definitely predicted, past experience would warrant a forecast that it could move in a northeasterly direction and bring bad flying conditions to the Atlantic coast from Hatteras northward within the next 12 hours. At 5:00 P.M. the deepening of the low and its orthodox character were apparent from the teletype data, and again at 6:00. The Akron took off at 7:28 P.M. The 7:00 P.M. data verified by the 8:00 P.M. map showed rapid development and definite northeasterly movement of the low, clearly a favorable "set-up" for a moderately intense "orthodox" low. Thunder and lightning were first reported on these 7:00 and 8:00 P.M. maps. From its history and the existing factors, it could be expected to produce "warm-front" thunderstorms followed closely by "cold-front" thunderstorms with a marked discontinuity of air currents.

Just what portion of this complete data and information was taken aboard on paper or in mind just before the take-off remains the secret of the aerological officer and captain of the ship. The 8:00 P.M. map received aboard was "only two-thirds complete," which Wiley interprets to mean that some of the broadcast signals were missed in flight, due to heavy static. Hourly data sent out over teletype circuits ashore after 8:00 P.M. continue to show the rapid advance and development of violence. Yet certainly from even the complete data, it was reasonable to begin the flight if the intentions were to keep in safe areas; but to an experience airship aerologist, the full data indicated bad flying weather in the New Jersey vicinity. By taking the rate of travel of the low from its apparent position at 4:00 P.M. to its 8:00 P.M. position, and projecting it along a continuation of its course at that speed—as high as 50 miles per hour it moved or developed—we find the cent would be located at practically the very spot where the ship went down. The Akron had steered a "collision" course; it must have gone into the worst violence the storm. For this and many other reasons, I feel confident that the commanding officer surely must not have received adequate information to warn him of the storm's path, center, and violence. Why? That is the Akron's own secret.

And yet, even though the ship did tangle up with the very violence of the storm, in what ways did it affect her? The answer has several phases.

In the first place, let us consider the storm's effect on the ship's knowledge of its height above the surface. The altimeter used by aircraft to tell their altitude is but a form of the aneroid barometer, graduated in units of distance instead of the usual pressure units of inches of mercury. In rising 1,000 feet above sea level, the atmospheric pressure decreases by about "one inch of mercury." Or, should the altimeter remain on the surface during the passage of a low-pressure area, the helpless altimeter—actuated as it is, simply by pressure change—would falsify and read some altitude though it actually had not been off the ground! For example, a late August hurricane center passed near Washington with a barometric reading of 28".94. The altimeter of a plane set to zero when the barometer read a normal 30", would, although still in its hangar, as the center arrived indicate an altitude of over 1,000 feet!

When the Akron left Lakehurst, the corrected sea level barometer reading was 29".72. As the storm center and the ship approached each other by various routes, the atmospheric pressure at the surface fell to a recorded lowest reading of 29".40, or a drop from the start of the flight of 0.32 inch. The pressure at flying levels necessarily fell in proportion. Hence, when altimeter read 1,600 feet, the real height above sea level could not have possibly been more than 1,280. Furthermore, in the center of the storm occurs its theoretically lowest possible pressure. We no means of knowing how low this pressure at the storm center actually went unless by mere chance some ship at sea had been directly in and recorded it. But, under the existent conditions, it is perfectly possible that the pressure fell sharply at and near the center, some 0.2 or 0.3 inch lower, the altimeter thereby falsifying some 200 or 300 feet more. Hence, I am inclined to believe that the reported "rapid rise" after the first sharp descent about 12:30 A.M. was not altogether an actual regaining of height above the surface but merely and largely an increased altimeter reading due to rapid approach to the lowest pressure zone of the storm. Thus the recorded altitude of 1,600 feet just prior to the fatal descent may have been not more than an actual 1,000 feet above the surface. There arises the thought that there may have been an error in setting the altimeter on taking off or a mechanical failure during flight. However, to me neither of these is plausible.

We have no other practicable type of altimeter today. There was on board, however, an echo-sounding device for measuring altitude by firing a blank and timing the echo from the surface. It had been used on many occasions before. Its best accuracy lay below 1,000 feet. Why it was not used this night we do not know, but probably because its use involved loud noise in the control car where silence was needed to hear orders.

The abundant existence of vertical air currents in thunderstorms and certain other disturbances is well known. But air currents cannot flow into or out of the earth's surface, and hence vertical currents must lose velocity as the surface is approached. To depict the situation of an airship affected by vertical currents, we must recall that the Akron was 785 feet long. In flight, atmospheric irregularities, such as vertical currents, generally strike or affect the bow first. A descending current would first push the bow downward-diving the ship-and as the ship progressed into the current, the latter would in effect travel aft along the body of the ship. Remedial action to regain lost altitude is, of course, to incline the bow upward and climb back to the previous level. The horizontal surfaces for climbing or diving are located at the stern; hence, the bow is inclined upward by putting these "flippers" up and pushing the stern down and vice versa. The elevator man must be alert and shift the "flippers" quickly at the precise moment so that the rising current generally following a downward one does not further incline the bow upward at an undesirable angle. Control of altitude in rough air thus calls for highly developed skill and co-ordination, which only a small percentage of men have or develop to a high degree.

Anyone who has ever steered a boat or seen a ship turn knows that before the bow gets into the new desired direction the whole craft moves sidewise a bit; with a long ship it may be a great deal. Now picture an 800-foot airship pulling out of a dive. We have a similar situation but in the vertical plane. The whole ship moves bodily downward before the upward climb actually begins.

Other factors also influence the "attitude" or inclination of an airship from the horizontal. Seldom in flight are the buoyancy and the total load carried exactly equal. When the buoyancy exceeds the load, the ship is "light" and flies with her nose down. When the load is the greater, as from rain or snow, the ship is "heavy" and flies with a nose-up and tail-down inclination, the angle being in proportion to the heaviness. More than 15 tons of heaviness could be supported by the Akron flying inclined. When a lighter-than-air craft plunges suddenly into a mass of air, colder and hence denser than that in which it has just been immersed, its buoyancy is temporarily increased. It is somewhat like a boat going from fresh into salt water—the boat has more buoyancy in the latter and floats higher. Going suddenly into warmer, less dense air an airship becomes "heavier" temporarily and takes on more stern-down angle.

Now let's see how these features fit into the Akron's last three minutes.

During the four hours preceding the Akron's destruction, the navigator lacked knowledge of the wind direction and velocity that would have told him vividly of his location with reference to the storm center. But he could not know these without measuring his drift and then deducing from that and other known factors the true wind data. Without a sight of the surface, the measurement of drift was not practicable.

Except when feeling temporary buoyance changes in running in and out of fog (warmer and cooler air) the air was smooth and the ship responded well to her controls. She was "heavy" most of the time, a normal nighttime condition, hence flew with the stern down a few degrees. On first entering the turbulence near the center of the storm, the actual height above the surface was certainly not more than 1,280 feet and by no means the 1,600 feet falsely shown by the altimeter. A downward air current acted on the nose first, started the ship downward bodily. By increasing the air speed to "full," more control was available. It was difficult to bring the nose up but dropping ballast forward started it up. Meanwhile, the "up" elevators were pushing the stern downward (and hence bow upward), but at the same time crowding the whole ship bodily downward. Fortunately, there w enough "sea room" for this vertical displacement in getting the nose up and at 700 feet by altimeter the descent was checked, and the ship started upward again.

Now began what appeared on the instruments as a rapid rate of rise. Some of that, no doubt, was due to an actual climb. But, as previously explained, I believe that although she had regained 1,600 feet on her altimeter after that first descent, the Akron was actually then only about 1,000 feet above the sea.

Then quickly came the second abrupt entrance into very rough air. A burst of rain may have added to the original normal heaviness of the ship. Sudden immersion in a mass of warmer air also would mean additional heaviness, increased angle down by the stern. The effect of a downward air current again started the ship bodily downward. Apparently the effort to rise by dropping ballast, as actually utilized on this occasion, was not adequate. Inevitably, the whole ship moved downward in an arc while trying to climb out by power. It is not impossible that an up current now struck forward, raising the bow still more and before an average elevator man could detect it and shift his wheel and the "flippers" to prevent an undue angle. Recall your simple trigonometry—recall the Akron's length of nearly 800 feet. Picture the relative heights of the ship's bow and stern above the surface when inclined. At an angle of 30 degrees the stern would be 400 feet below the bow. From her real altitude of 1,000 to 1,280 feet, under the influence of the down gust, and the ship's natural vertical movement, at a considerable angle stern down, before beginning to climb sufficient vertical maneuvering or "sea room" simply did not exist. The tail entered the water so comparatively gently that it was almost unrecognized. It took knowledge of the lost lower rudder to confirm the "different" mild lurch and shock and to recognize them as contact with the sea.

Hence, I do not consider that the Akron was abruptly hurled out of the sky, sucked down by aerial quick sands. She was not "torn to pieces by the elements," not "wrecked by the weather," not violently "forced into the sea." It was a combination of factors that destroyed her. They included a lack of sufficient weather information relative to the formation, travel, and intensity of the "secondary low" into which the ship traveled; inability to learn the wind direction and velocity where she was flying; downward air currents of moderate proportions in the turbulent zone, giving the ship her initial impetus on those last two descents; a deceiving altimeter leading to lack of vertical maneuvering room; temporary changes of buoyancy in warmer and colder air masses, together with turbulence making it difficult for an average elevator man to follow such "bumps" quickly enough to keep the ship out of steep inclinations; immersion and collapse of tail in water-all leading to the retardation of the forward motion of the ship and the inevitable spending of a momentum of a 200-ton mass moving at over 100 miles per hour against an unyielding surface. Such was the untimely end of the naval airship Akron.

But, I believe that each of the problems thereby demonstrated is capable of practical solution for the safe and efficient operation of airships in the future.

 

 
 

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