Fighters and Bombers Fly Home for Repair

By John Foster, Jr

Associate Editor, Aviation

First complete story on Air Service Command's system for fourth echelon maintenance which gets combat planes back into action with maximum speed and safety.

FLYING FIGHTERS and bombers the thousands of miles from England, Africa, Alaska, or the South Pacific to the middle of the United States for repair is neither a dream nor a stunt, it's the usual thing today — part of the Air Service Command's operation of the world-wide "Keep 'Em Flying" program.

It is not only safer, but faster, to overhaul combat craft far from possible bombing areas, and ASC has eleven major control depots to do the job. A typical depot is that of the Oklahoma City Air Depot, where heavy and medium bombers, attack planes, fighters — even training and liaison planes — get back into action in record time. And when combat crews take the planes over, they are ready to go into battle, for every craft is complete down to the smallest item of equipment. In its role as a supply depot, OCAD's stock includes every one of the 154,000 odd items which our AAF requires. Furthermore, it is but a matter of hours by air to any theater of war. Construction now under way will make it more than a geographic center of operations for the Air Transport Command, which already flies sorely needed parts all over the world on regular daily schedules.

The Oklahoma City Air Depot won't be two years old until next Jan 15, but already it is a multimillion dollar project covering 2,400 acres with a total "population" of some 15,000 civilian and Army personnel — and it is still growing. It is one of the largest under jurisdiction of Maj Gen Walter H Frank, ASC's Commanding General.

Despite this mushroom growth, the entire organization operates under one philosophy: "Let's get the stuff where it's needed." This unwritten code was instilled by Col William Turnbull, OCAD's first commanding officer, and it is being continued by the new chief, Brig Gen Arthur W Vanaman, former commanding officer at Wright Field. The exact number of planes OCAD has put back on active duty cannot be revealed, but an indication of the number can be gained by following through the works a typical plane —a Boeing B-17 Flying Fortress called the AWOL Kid, lately back from England.

As the plane enters one of the repair hangars it first gets a complete steam bath to remove the layers of battle-front grease, mud, or perhaps desert sand. Then it takes its place on the "production line," where it is literally ripped to pieces by men and women from the engine, electric, hydraulic, instrument, and other sections.

The fuselage repair group does all its work on the line, inspecting and repairing everything necessary, as well as checking and overhauling all controls. Many of the planes are, of course, pockmarked with bullet holes, but it has been found that the field patches put on by maintenance crews at the front are entirely satisfactory — it's only the large cannon or anti-aircraft shell holes in vital spots that require replacing at OCAD.

But the depot doesn't stop with major overhaul; it also serves as an ex-officio modification center-intelligence unit. When combat crews bring their planes in, they are questioned by men from the flight test, engineering, armor, and other sections, much as intelligence officers at the front brief them after combat missions. Thus, the Depot is appraised of any idiosyncracies of the individual craft as well as its performance record. And getting these reports direct from the front makes it possible to add the latest developments in armor, armament, and other equipment, with no loss of time.

If, as a ship goes on the line, it is found that a wing has been severely damaged, off it comes to go to the wing section which is equipped to do everything up to a complete re-building job on anything from a "grasshopper" liaison plane to a four-engine bomber. For some types of planes there are permanent jigs, built at the depot from factory blue prints; for others there are portable jigs adjustable to take a variety of types and sizes.

This section also handles the self-sealing fuel tanks and provides one of the first examples of the "let's get it done" spirit pervading all Air Service Command installations. All tanks must be flushed and tested, then dried before being filled with gasoline. Several members of the section at OCAD, using spare parts, built a blower which dries the tanks in but one-fifth the time formerly required. All such gadgets, of course, become the property of the Air Forces, but it doesn't stop the employees from building more.

Meanwhile, members of the electric section have been working side by side with fuselage repairmen, overhauling, inspecting, and correcting deficiencies. To save time, everything which can be repaired in the plane is fixed right on the line, but where necessary the parts are removed and sent to the section's quarters in another building where repair and test equipment is available.

Radios are handled by another section. All sets are removed from the plane and sent to the section's own quarters, a modern, air conditioned unit replete with time saving equipment. Here, as in most all sections, one operator follows a job all the way through. This holds true on all jobs except those which must be finished on succeeding shifts, for OCAD operates 24 hr a day, 7 days a week.

With the plane still in the first station, the hydraulic section has gone to work to get the "lifeblood" system in perfect order. Here, again, is evidence of Air Service Command ingenuity, exemplified by a jack — hydraulic, of course — for raising into position the 500-600 lb main oleo struts of the heavy bomber. By its use one or two men do with greater safety and more speed an operation formerly calling for four and five men. Built right in the OCAD section itself, the jack is adjustable for use on B-17's, B-24's, C-54's, and C-56's.

From this same section came another device — already credited with saving two lives. 1t is a bungee stretcher in which a hydraulic jack stretches the bungees to the point where a spread bar may be inserted. A heavy boiler plate casing protects the worker against injury in case of breaking during the 9,000-1b pull necessary to pull the bungees to their full length.

All along the production line are stock bins containing small supplies of parts for each of the sections doing work on that area, a system which has paid its way many times over in time saved. Early in its progress along the line, the AWOL Kid loses its engines and propellers, which are taken to their own sections for repair. The propeller unit reworks not only all the propellers on planes flown to the depot, but it gets many — in every conceivable condition— from sub-depots and air bases all over the country, each control depot, such as OCAD, serving its geographical area. Using simple, standard equipment, the unit handles everything from small wood training plane propellers up to the fully automatic multiblade heavy bomber types. Its boast is that "they've never yet had to holler for a prop to get a ship back in action." The propeller section has only one separate department, that for blade straightening. Otherwise, one crew follows through from tear-down through repair, polishing, magnafluxing, and balancing.

The engine section represents perhaps the highest degree of mass production technique, since it must turn out one, two, or four engines per plane — mostly the latter — and they range from 65-hp trainer power plants to liquid cooled inline fighter and radial aircooled bomber types. The engine section's March quota, for example, was 300 engines. But 472 was the figure actually reached,

Often the engines get to the section in quite a hurry. Recently, for instance, a five-man crew removed one from a B-17 in 38 min. Upon delivery for overhaul, the engines are mounted on movable dollies and started down one of the two tear-down lines (a third one will soon be in operation) where separate crews perform certain groups of disassembly operations. As the parts come off they are placed in adjacent bins which are moved to another group of workers who key-number them all. Some larger parts will thus have their own metal number tag; smaller ones go in baskets carrying corresponding numbers, so that each engine is maintained, to a large extent, as the same unit throughout.

All parts then move to the cleaning department, where some get steam and soap baths, others get hand cleaning in different types of solutions before starting through the repair and inspection departments. Then, on a tight schedule, they move toward the two (and soon three) assembly lines where different groups of skilled mechanics, spaced in assembly line stations, quickly make complete engines of repaired and new parts.

These assembly lines end near a door, through which the engines go immediately to the test building containing twelve cells which are in operation every hour of the day, every day of the week. Perhaps the best indication of the engine section's efficiency has been found here, where many overhauled engines show a lower oil consumption than they had upon leaving their respective factories.

To keep pace with today's global war conditions, the test building has what is claimed to be the nation's largest manmade weather unit yet put in operation. Any or all the test cells can be changed from 100° F to 40° below in just 6 min, with any degree of humidity desired. Thus, when OCAD or any other depot, sends a plane to Africa, to Alaska, or to the South Pacific, it knows the engines will function no matter what the weather.

When the AWOL Kid first went sections got busy, too. One group, for instance, denuded it of the multitude of engine and flight instruments so essential to modern fighting and long range precision bombing. In the quiet of a modern, air-conditioned shop, each member of the instrument section follows each job all the way through from disassembly to final checking of the instrument assigned him. Most employees in this section — largely men and women from rural communities — are qualified on at least one group of instruments, but to maintain the versatility necessary to meet swiftly changing schedules, many are equipped to repair any instrument on any plane.

The same process was employed by the armament section, which is one of the largest organizations of its kind in the country. Despite the fact that guns are regularly taken out of planes, repaired, tested, and re-installed in 6 hr, there is no trace of slipshod work. This is due both to rigid inspection and to the fact that many employees — a large number of them women — have sons, brothers, or cousins flying the planes that go through OCAD. Here, again, is a good example of the ingenuity so evident in the Air Service Command — a bomb release check rack with which the vital parts can be tested before re-installation in the plane. Conceived in the armament section, it was built with the cooperation of twelve other sections. The net result: More accurate work at a saving of 75 percent in time.

When combat crews bring their planes tn the Oklahoma City Air Depot, they may even leave the parachutes, for there is a section which not only repairs and inspects 'chutes, but checks and ships new ones to the depot's twelve subdepots or any battle-front in the world. In fact, the crews can simply walk away from the planes without even removing their "pin up girls," for a special group will take care of every extraneous item such as the seat cushions, life rafts, and oxygen bottles. These are all renovated, marked, and stored until the aircraft goes through the paint shop, reassembly, and out the door for delivery to the flight and test section.

This section has a record enviable even for ASC installations — not a single injury to date, although its test pilots may be called upon to fly any or all the 50-odd types of aircraft now in service with the AAF. That, of course, is in addition to handling all transient flights, which have gone well over the 1,500 per month mark. When the test flight crew finishes, the plane goes to the firing pit for final check of all guns and is then sent to the "pea patch," a thoroughly restricted one, to get its quota of ammunition and await its combat crew. At this point it is practically a new plane, ready for instantaneous action — and it is but a few hours, instead of weeks or months, from combat zones.

Getting planes ready for this moment with the utmost speed is, then, Oklahoma City Air Depot's main job, and this is typical of the other ten control depots. But this by no means covers all the activities. As a supply depot, OCAD is really big business, as indicated by its stock of more than 154,000 separate items now used by the Air Forces. Each of those parts has its own bin, its own number to expedite delivery. The depot could build complete airplanes. It also could equip the men to fly them, for its clothing department alone has everything from desert sun glasses to electrically heated flying suits. Its size can be judged from the fact that the large main building is one of 37 structures on the reservation. So vast are shipments that a conveyor system has been set up simply for stenciling of outgoing shipments — most of which are in containers made by the shipping section's own box factory — which may range from a roll of safety wire to complete airplane wings.

These shipments go by air, by rail, or truck — any way to "get the stuff where it's needed." Today there are daily scheduled air freight flights of the Air Transport Command. Within a few months, however, a new air freight. terminal now under construction will be able to handle a flight every quarter hour, Already, however, ATC has flown many thousand of tons of "hot freight" per month from the OCAD to fighter. and bomber bases throughout the world.

Doing more than its share of moving material at the lowest possible cost is the motor pool which, with but nine trucks that have consistently moved better than a million pounds a month, appears to be one of the busiest and fastest growing truck lines in the country. Recently acquired equipment is running the total even higher although its routes are not being extended. They can't, for the motor pool has delivered sorely needed supplies to both coasts. With two drivers keeping the trucks rolling at least 16 hr a day, no point in the United States is much more than 48 hr away from the depot. The motor pool's return load record is unusual; careful planning has kept it up to almost 100 percent.

Then there is the reclamation section, doing an outstanding job of saving the taxpayers' money. Suppose, for example, a training plane is "washed out" at a training base in one of the six states covered by the Depot. The damaged craft is trucked in for survey and, if it's more than 75 percent irreparable, it is ordered dismantled. Every usable or repairable piece is salvaged. After thorough inspection — including Magnafluxing — the parts go into storage and are added to the Depot's supplies. An unscheduled visit to the section showed a minimum of scrap parts, perhaps 100 lb of machine shavings gathered from the repair shops, a few propeller rings and bearings on their way back to the factory for re-working, and pounds of safety wire which had been removed from engines brought in for overhaul.

One of the most interesting departments of the salvage section is the highly trained crash crew. So efficient has it become that any plane from the six-state area, faced with a crash landing due to landing gear or other failure, is ordered, if possible, to proceed to OCADO's Tinker Field to make its belly landing. Recently, on a Wednesday morning, this reporter saw a Boeing B-17 which had made a belly landing late the preceding Sunday. All skin replacements had been made, the ball turret restored and installed, the landing gear system had been repaired, the propellers straightened, and the engines were already being swung into position. It meant that a much-needed heavy bomber got back into action less than a week after a crash landing.

Another extremely versatile section is the wood mill, whose members will turn out anything from a section of cockpit flooring to bedroom furniture. The last isn't so remote as it sounds, for wood mill made all the bedroom furniture for "Hotel OCADO," the rooms and dormitory located in one of the hangars to accommodate transient flight crews. In spite of its reasonable rates, Hotel OCADO is getting to be big business, as is indicated by a current expansion program.

Just as important as any of the Depot's operating units is the plans and training department, for skilled workers must be schooled for OCADO's growth. Although all sections and departments are headed by Army officers, all employees are civilians operating under Civil Service. Currently the training division has several thousand students, a number which will be increased, there being greater emphasis on "upgrade" training leading to higher ratings and supervisory positions. The first week of training is largely one of orientation, leading up to a meeting with the testing and planning board for aptitude tests and assignment for eleven weeks' shop practice in the line of work for which the applicant has been found best fitted. By far the greatest number of students are women, whose ages range from 20 to over 50, a clear indication that the depot's present 35 percent feminine employees will soon exceed the 60 percent mark. Here, too, is round-the-clock operation, since the training section tries to keep pace with increasing demands.

The civilian trainees are not the only students, for several thousand enlisted men occupy the vast military area, spending from a few weeks to a few months getting special training for engine and aircraft maintenance both at home and abroad. Although its growth has been phenomenal, the Oklahoma City Air Depot is no temporary, wartime operation. Though it may shrink some from peak employment, there is every indication it will serve a good sized Air Force for a long time to come. Its Tinker Field, with 6,000 ft of paved runways and swiftly growing air freight terminal, can serve the cargo ships of peace as well as those carrying the "hot" freight of war. Its large repair building is a substantial, steel-and-concrete structure, as are the hangars. Its supply buildings have been built to last. Its civilian personnel are mostly men and women from neighboring areas. Air Service Command is playing a vital role in winning the war; and its depots, as permanent service organizations, promise to do just as much in keeping the peace.

This article was originally published in the June, 1943, issue of Aviation magazine, vol 42, no 6, pp 120-123, 364, 367-368, 371-372, 375.
The PDF of this article includes twelve captioned photos; one shows B-24s on the flightline, several show B-17E or F models undergoing repair, and others show details of various processes and procedures at the center.
Photos are not credited, but are probably from AAF.