Douglas A/B-26 Invader


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During the war the AAF required four technical specialists for every man who flew. The ratio of total ground personnel to flying personnel was nearly seven to one, and for every man actually committed to air combat there were sixteen individuals who served within the AAF on some noncombat assignment. Individual training of technical specialists was the responsibility of the Technical Training Command (TTC) from its establishment in March 1941 until July 1943, when its successor, the Training Command, inherited the job. In addition, the Air Service Command provided individual training for many of the specialists required for its own activities, and the four continental air forces found it necessary to operate schools for special training of personnel of other arms and services on assignment with the AAF (ASWAAF). In this last category, however, the men were frequently assigned to the branch of origin-for example, the Signal Corps or the Chemical Warfare Service-for individual training and return to the AAF. Unit training, and such combined training of combat and maintenance organizations as might be necessary, was conducted by the continental air forces or by the ASC.

In the early days of the Air Service, practically all enlisted technicians, whether or not they were concerned directly with the maintenance of aircraft, had been known as airplane mechanics. But as the work of technicians became more and more specialized, the term "airplane mechanic" was gradually restricted to men who maintained airframes, aircraft engines, and accessories integral to the plane; these accessories included such equipment as propellers, hydraulic and electrical systems, carburetors, and generators. Technicians who specialized in such equipment as armament, cameras, and radio devices--equipment not considered strictly as parts of the aircraft--came to be known by special names and were trained in separate programs. The primary responsibility for aircraft maintenance in the AAF during the war belonged to teams of enlisted mechanics, each team working under the direction of a noncommissioned officer called a crew chief. Before the war it had been customary for each pilot to supervise the maintenance of his own airplane, but after 1941 this responsibility was assumed by a nonflying squadron engineering officer. Maintenance activities in the squadron were limited to the first and second echelon, that is to say, to regular servicing of aircraft, routine inspections and adjustments, and minor repairs. For the more difficult jobs, including periodic overhauls, the squadron depended upon depots and subdepots serving the needs of more than one combat unit for what was officially designated third and fourth echelon maintenance. Though the distinction between these several levels of service depended in no small part upon a difference in equipment, some of the depot work required more highly trained specialists.

During the year 1938-39 fewer than 900 men had been graduated from the basic mechanics course of the Air Corps Technical School at Chanute Field. Between July 1939 and August 1945 graduates of courses in maintenance given by or for the AAF totaled more than 700,000. Although this number includes many who graduated from more than one course, it serves to suggest the staggering proportions of the maintenance training that had to be provided. In the earlier stages of this great expansion the AAF depended upon three major types of schools: its own technical schools for basic airplane and engine mechanics courses, and for some advanced training; civilian mechanics schools, which provided basic instruction as well as training in third and fourth echelon maintenance for depot specialists; and factory schools, which gave training on the equipment of particular manufacturers. When it became apparent in the spring of 1943 that the initial demand for mechanics was nearly satisfied and that casualties among ground crews were proving extremely light, the number of trainees was drastically curtailed. Accordingly, after June 1943 students were no longer entered in civilian mechanics schools, and the number of factory schools and AAF technical schools was reduced to the following.

  • Individual Training in Aircraft Maintenance and Engineering

  • Individual Training in Communications

  • Individual Training in Aircraft Armament

  • Individual Training in Aerial Photography

  • Individual Training in Weather

  • Individual Training in Arms and Services Specialties

  • Training of Ground Echelons of Combat Groups

  • Unit Training of Arms and Services Personnel

  • Service and Depot Group Training

A large number of special units were trained in the course of the war, over and above the production of regular service organizations. One of the most interesting was the floating aircraft maintenance unit, which was developed as a part of the Army aircraft repair ship project. This project was conceived as an answer to the peculiar geographical conditions of the Pacific. Since repair facilities could seldom be moved forward quickly in that area by means of conventional land transportation, the AAF desired floating repair facilities which could be moved easily during campaigns and which could provide maintenance to combat aircraft until the arrival of land-based service groups. The project involved the conversion of six 10,000-ton Liberty vessels for service as repair ships, as well as eighteen smaller auxiliary vessels. Each ship, furnished with modern equipment and highly trained personnel, could support several combat groups, and each auxiliary was capable of servicing one group. Almost every type of repair except complete engine overhaul was performed in the shops of these vessels. The training of personnel for the floating units, which was conducted during 1943 and 1944, differed considerably from standard service-group instruction. Individuals had to be prepared to perform more than one specialty in order to insure maximum usefulness of these organizations. Final unit training was carried on in mock-ups which were replicas of shops on board the repair ships; the last stage of preparation involved a month of marine training on the vessels themselves. The floating unit program, in which the Navy and other branches of the Army cooperated, was under jurisdiction of the Mobile Air Depot, Air Service Command.

Original article

Beech Aircraft Corporation, Wichita

In 1943, the rising demands on the Douglas Aircraft Company caused them to look to the Beech team to produce more than 1,600 complete sets of wings for the A-26 Invader attack bomber. On Sunday, November 5th 1944, the entire wing assembly for the army’s new Douglas A-26 Invader attack bomber was being made in Wichita by Beech Aircraft.




McClellan AFB

In December 1941, soon after the attack on Pearl Harbor, P40s, B-26s and B-17s began arriving at the field to be armed and prepared for immediate shipment overseas. Some B-17s came direct to McClellan from the factories. During this time most of the Army Air Forces planes that went to the Pacific Theater were prepared and mantained at McClellan.



Long Beach, California

During its 65-plus-year history, the facility produced more than 15,000 airplanes, including the A-26 Invader.

Donald W. Douglas opened the Long Beach facility on the eve of World War II, having run out of production space at his plant in Santa Monica, Calif., as well as at a second facility in El Segundo, Calif. He also started production lines in Chicago, Ill., and Tulsa and Oklahoma City, Okla. Altogether, the Douglas Aircraft Company produced more than 45,000 airplanes during its long history.

In 1941, when Douglas opened the new aircraft assembly plant adjacent to Daugherty Field in Long Beach, the company was a major supplier to allied air services in World War II. During the war, it delivered and maintained more than 31,000 aircraft, including the C-47 Skytrain (a version of the DC-3), SBD dive-bomber, C-54 transport (the military version of the DC-4), A-20 and A-26 attack bombers and B-17 bomber. Military support after the war included high-speed research aircraft; the AD Skyraider, A3D Skywarrior and A4D Skyhawk attack planes; and F3D Skyknight and F4D Skyray fighters for the Navy and Marine Corps.




On Mark Engineering Co.

7929 Hayvenhurst Avenue
Van Nuys Airport
Van Nuys, California 91406

Located in the southeast corner of the former WWII Army Air Force Base Unit facilities, On Mark Engineering Company was formed in 1954 and specialized in the modification, repair and overhaul of the Douglas A-26 Invader aircraft for the civilian executive transport business.

On Mark A-26 conversions include the On Mark Marksman and the On Mark Marketeer.

In 1962 On Mark undertook the conversion of a Boeing Stratocruiser on behalf of Aero Spacelines, Inc.  The aircraft would become known as the B-377PG Pregnant Guppy.  The first flight occurred on September 19, 1962 at Van Nuys Airport.

On Mark Engineering Company completed conversion of  40 Douglas A-26 Invaders to On Mark B-26K Counter Invaders for the CIA and the USAF during 1963 and 1964.

In 1965 On Mark undertook the conversion of a Boeing C-97J on behalf of Aero Spacelines, Inc.  The aircraft would become known as the B-377SG Super Guppy.  The first flight occurred on August 31, 1965 at Van Nuys Airport.


  • On Mark / Aero Spacelines B-377PG Pregnant Guppy (1 aircraft produced)
  • On Mark B-26K Counter Invaders (40 aircraft produced) and maintained.
  • On Mark / Aero Spacelines B-377SG Super Guppy (1 aircraft produced)

The On Mark Engineering Company hanger was located at the southwest corner of Arminta and Hayvenhurst Avenue. 

In the late 1970's through 1982 the former On Mark Engineering Company site was operated by Volpar Inc.


Grand Central Aircraft Company

Grand Central Airport was developed from the Glendale Airport which was built in 1923. Grand Central was the first official terminal for the Los Angeles area. Many written accounts and aviation records state "Los Angeles" when they should actually should say Grand Central (Glendale) or United Airport (Burbank) The first business on the field was the Kinner Airplane & Motor Corporation. Burt Kinner sold one of his airplanes (Airster) to a young Amelia Earhart. The first commercial west to east transcontinental flight was flown by Charles Lindbergh from Grand Central's runway.

Just across the Los Angeles River (seasonal, mostly dry) was the Los Angeles Airport in Griffith Park. Early builders and flyers who moved to Grand Central included Jack Northrop and Howard Hughes. Hughes built his H-1 Racer in a small building at 911 Air Way, on the edge of Grand Central Airport. This building burned in the late 1990's. Northrop started his 'Avion Aviation' company in Glendale. Al Menasco showed William Boeing Northrops 'multi cellular' metal structures and Boeing bought his business and moved it to United Airport in Burbank. Early maps of the United Airport in Burbank state "Northrop Factory" at the south west side of the airport near Empire Ave. The Northrop-Burbank buildings were torn out in the late 1960's.

Major Moseley established a Curtiss-Wright overhaul facility at Grand Central. Several dozen brand new Curtis-Wright engines were shipped in crates to the school where they were completely overhauled before being used in Doolittles' raid on Tokyo. Mosely's contract school trained young men to fly at Grand Central airport (also at Chino, Fox Field and 2 others). As WWII came to a boil those students were well received in Europe as the all volunteer Eagle Squadron who flew against Hitler after the Battle of Britain had decimated the ranks of RAF pilots.

When Pearl Harbor was attacked, Grand Central Airport (and all other west coast airports) was immediately closed to civilian aviation and it became an important maintenance and defense base for Los Angeles, Ca. Soon a P-38 fighter base was built on the west side near the former home of the California Aero Club. The 319th Fighter Wing was trained and stationed here; it was eventually sent to the ETO. During the war, the one runway at Grand Central which originally ended at Sonora Ave., was lengthened to Western Ave. to accomodate the new P-38 fighters coming over from Burbank.

After the war, hundreds of P-51's, C-47's, B-25's, A-26's and others transitioned through Grand Central Airport in Glendale for refurbishment and reconditioning. Larger aircraft, like the B-29, were sent to the Grand Central Service Center in Tucson, Arizona. In the 1950's Major Mosely did some early rocket development and testing amonst the old concrete revetments left over from WW II.

Grand Centrals' runway was shortened after WWII, which denied newer and larger aircraft from landing there. The largest aircraft ever to land at Grand Central was a Lockheed Constellation. After the Korean war the entire airport area went into decline and in 1959 the airport was closed.



AMARC, or the Aerospace Maintenance And Regeneration Centre, is a joint service facility managed by the US Air Force Material Command located in the town of Tucson, Arizona, USA.
Often referred to as 'The Boneyard', AMARC is an aerospace storage and maintenance facility adjoining Davis-Monthan Air Force Base which provides a service to all branches of the US military (Air Force, Navy, Marines, Coast Guard and Army), as well as other national agencies.

The reason the Boneyard reference exists is due to other work that AMARC carries out, that of reclamation of spare parts and the eventual disposal of spent airframes. The Center can be divided into 2 distinct areas, the RIT (Reclamation Insurance Type) area located to the east side of Kolb Road is littered with aircraft in various states of completeness. The junkyard appearance belies the fact that these aircraft are controlled by a process of careful part reclamation, both to a schedule and to ad-hoc requests. On careful examination many of these aircraft can be seen re-sealed to protect the remaining components from the dirt and heat.


AMARG was established in 1946, shortly after World War II as the 4105th Army Air Force Unit to house B-29 and C-47 aircraft. Davis-Monthan Air Force Base was chosen because of Tucson's low humidity, infrequent rainfall, alkaline soil and high altitude of 2,550–2,900 ft (780–880 m), reducing rust and corrosion. The hard soil makes it possible to move aircraft around without having to pave the storage areas.

In 1948, after the Air Force's creation as a separate service, the unit was renamed the 3040th Aircraft Storage Depot. In 1965, the depot was renamed the Military Aircraft Storage and Disposition Center (MASDC), and tasked with processing aircraft for all the US armed forces (not just the Air Force). In the 1980s, the center began processing ICBMs for dismantling or reuse in satellite launches, and was renamed the Aerospace Maintenance and Regeneration Center (AMARC) to reflect the expanded focus on all aerospace assets.

Storage procedures

There are four categories of storage for planes at AMARG:

  • Long Term - Aircraft are kept intact for future use
  • Parts Reclamation - Aircraft are kept, picked apart and used for spare parts
  • Flying Hold - Aircraft are kept intact for shorter stays than Long Term
  • Excess of DoD needs - Aircraft are sold off whole or in parts


Planes that are to be mothballed, if only temporarily, go through a meticulous process to prepare them for exposure to the desert environment. On arrival, the planes are inspected. Fuel tanks are filled with heavy oil, which provides a protective coating for engine parts. Canopies, engine intakes and other openings are sealed with layers of “Spraylat,” a latex-based, permanently flexible substance that is easy to remove.

The top layer of “Spraylat,” which is white, reflects enough solar heat to keep a plane’s interior at nearly the same temperature as the outside air. Without Spraylat, the interior could quickly heat up to 200 degrees Fahrenheit during hot summer days. The coatings protect the plane’s most vulnerable parts against sun, wind, dust and nesting animals. Every four years, the planes are brought into an open hangar for a checkup.


Four Categories of Mothballed Planes

Most of the airplanes that sit in desert graveyards today date from the Vietnam era or later. They are divided into four categories, depending on their future prospects.

  • Category 1000 planes are preserved with an eye toward possibly flying again, should international political conditions warrant.
  • Category 2000 planes are maintained for spare parts. Some parts from older aircraft, are available nowhere else.
  • Category 3000 planes are kept in near ready-to-fly condition, awaiting a more-than-likely new deployment.
  • Category 4000 planes are destined for “static display” in museums, town squares or Air Force base entrances. Most, however, will be sold as scrap metal, eventually finding new life as razor blades, soft drink cans or car fenders.

An aircraft going into storage undergoes the following treatments:

  • All guns, ejection seat charges, or classified hardware are removed.
  • The fuel system is protected by draining it, refilling it with lightweight oil, and then draining it again. This leaves a protective oil film.
  • The aircraft is sealed from dust, sunlight, and high temperatures. This is done using a variety of materials, ranging from a high tech vinyl plastic compound, called spraylat, of a opaque white colour sprayed on the aircraft, to simple garbage bags. The plane is then towed by a jeep to its designated "storage" position.

After World War II more than 7000 retired Army bombers, fighters, and training planes were left standing row to row at the old Kingman Army Airfield, 5 miles east of Kingman Arizona, now Storage Depot 41 of the War Assets Corporation. It was the worlds greatest concentration of aircraft in one area at one time, covering five square miles. Kingman Army Airfield was a gunnery base which once had an Army population of 17,000 officers and men.

5437 of the planes, offered for competitive bidding with the provisions that they would not be used for flight purposes since they were not adaptable for civilian use, were purchased for $2,780,000 by Martin Wunderlich, of Jefferson City, Missouri, a contractor.  It is rumored that the fuel from these aircraft was sold for more than the purchase price of the planes.

At one time the Kingman storage records showed 2567 B-24 Liberators, 1832 B-17 Flying Fortresses, 478 P-38 Lightnings, 200 P-38 photo-recon planes, 37 B-29 Super Fortresses, 141 B-25 medium bombers and hundreds of P-47 Thunderbolt's, P-40s and A-26s.

Depot Prices:

  • P-61 Black Widow    $6,000
  • B-17 Flying Fortress    $13,750
  • B-25 Mitchell    $8,250
  • A-26 Invader    $2,000
  • P-47 Thunderbolt    $3,500
  • P-40 Warhawk    $1,250
  • A-24 Boston   $1,650

No one but American citizens could purchase the planes at Kingman, and before being offered for sale the airplanes were stripped of all confidential equipment such as bomb sites, radar and some radio installations.