to be repaired at the gate, with no electricity required, in just a short time. “This was a big change in the way we repaired airplanes, and many people were skeptical,” said Aydin Akdeniz, a Technical Fellow in Commercial Aviation Services’ 787 Structures Services Engineering group in Everett, Wash. “We knew there had to be a way to do this quickly, within a few hours.” Akdeniz and other engineers at Boeing for years had considered ways to develop a pre-cured repair patch for composite airplane surfaces. When the 787 entered development, it gave the engineers at Commercial Aviation Services, which supports customers throughout the life cycle of an airplane, a new reason to focus on composite repairs. Fleming gave his support to the technical challenge after engineers indicated they thought a quick repair process could be developed, said Steve Blanchard, 787 service engineer for Structures and a member of the Commercial Aviation Services team. “This was a big change in the way we repaired airplanes.” —Aydin Akdeniz, a Technical Fellow with 787 Structures Services Engineering, Commercial Aviation Services “He understood the impact of this for customers,” Akdeniz said of Fleming. “Mike was one of the first champions of support.” A quick repair patch for composite skins has to do more than cover up a scratch. It has to be strong enough to restore the damaged surface, restore the structure’s load-carrying capability, and seal the defect to prevent further damage until an airline can schedule a permanent repair, Blanchard said. Critical to meeting those criteria was choosing the right adhesive. The team began with 150 candidate adhesives and over time whittled those to 10, evaluating them in laboratory tests during a four-year period, he said. The adhesives were subjected to extreme hot and cold thermal conditions and tested for their shelf life, curing temperatures and bond strength, among other parameters. “It was a challenge to find an adhesive with the right characteristics,” said John Spalding of Boeing Research & Technology, a Technical Principal and PHOTO: Structural repair technician Mary Vargas, left, and Technical Fellow Russell Keller spread quick composite repair paste onto a test panel in a Boeing Engineering, Operations & Technology lab in Seattle. The two are inside the lab’s large freezer, where engineers tested the quick composites repair process to make sure the adhesive could be applied in cold weather. Frontiers February 2014 19
Frontiers February 2014 Issue
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