Shadow and Stinger: Developing the AC-119G/K Gunships in the Vietnam War

8. Technical Modifications

C h a p t e r 8 technical Modifications additional technical and Structural Modifications w HIlE tHE PrEVIoUS topical chapters have dealt with the most significant subsystem issues that arose during Combat Hornet, many other less visible, yet equally important, situations also cropped up. one of those affecting the aC-119K proved to be the delivery of all of the aerospace ground equipment items. Even as the general modification process proceeded, engineers determined that the two 20-mm cannon were not affixed in the best position on the aircraft. they delayed the installation of the 20-mm gun stand, cradle assembly, and ammunition loading set until they could relocate the gun position. to this end, the WraMa engineers helped their contractor counterparts to redraw the aircraft’s interior design blueprints to reflect the transfer of the 20mm cannons. this change did not delay the reconfiguration process since the manufacture of the components at the source was also held up. Both problems were quickly solved, however, and these last aGEs were delivered in the spring of 1969 to the K model production line. the overall program was once again moving smoothly. Even with the delay, the value of the 20-mm cannon was such that making sure they 1 Shadow and Stinger were designed properly and placed for maximum effectiveness cannot be overestimated. the relocation proved ideal as enemy truck drivers would discover in the early 1970s.1 Ailerons, Flaps, and Tabs as a result of the addition of jet engines to the K model, the modification design personnel changed the aileron, flap, and tab configuration during the overall alteration conversion. this, in turn, necessitated new stock and part numbers for these airframe components. Under the provisions of the overall contract, F09603-68-C-1633, Fairchild personnel effected the engineering work and prototyping for these modifications based on data that WraMa provided. the new parts program managers also had to purchase new spares to support the airframe additions. What helped speed up this part of the program, especially procurement, was the urgent need for the early operational deployment of the aC-119Ks. In the end, these changes did not delay the K model deployment further since the workers and designers blended the alterations into the general program.2 airborne illuminator retrofit as the modification began, engineers and technicians in the aC-119 program office considered retrofitting the SN-1 through SN-9 airborne illuminators. this process began with officials in the Warner robins Service Engineering Division evaluating the environmental qualification test procedure, which they eventually rejected. at the same time, Fairchild, unaware of the division’s rejection of the test process and under pressure to complete the program rapidly, went ahead with its own qualification analysis of the illuminators. When the company received word that the test procedures had been disqualified, Fairchild realized its test report had been invalidated. Some of those in the program office wanted to proceed with the retrofit without the qualification test and gamble that later trials would validate the retrofits. rather than repeat the costly and time-consuming process, the Service Engineering Division experts recommended to the aC-119 program office that they wait until later to start the retrofit, when there was more time to properly perform the qualification test. they presented a compelling case to the program office, expressing their concern over the very idea of retrofitting items before an acceptable teChniCal ModifiCationS 1 test procedure had been developed and a report was received. they believed that this was not only inappropriate but also that, by performing an accurate qualification analysis, they would find and be able to fix unexpected flaws during the trials and then incorporate the repairs into the retrofit process. this, they argued, would dispense with potentially extensive and expensive component changes and redesign alterations. as one memo noted, retrofitting these items before qualification and before knowing whether changes needed to be made would require “additional time to recycle SN-1 through SN-9” back into the production process in order to “bring them up to a qualified design.” In the end, all of the WraMa managers agreed that, although the retrofit was necessary, they should wait and perform a proper qualification test and only then initiate the retrofit.3 Forthenextyear,analystsreworkedtheprovisionsoftheenvironmental qualification test procedures and finally found the time and money to have Fairchild conduct the correct analyses. the illuminators had been gleaned from numerous sources, and...