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FAA Codifies Updated Guidance For Radomes, Other External Mods

The in-flight connectivity craze pushes certification limits, and FAA pushes back.

In mid-June, the FAA released a draft policy statement containing guidance intended to explain the certification criteria for antennas and other external modifications that are becoming more frequent as operators embrace ever-more-sophisticated in-flight connectivity systems.

The proposed policy statement will replace an issue paper—Structural Certification Criteria for Large Antenna Installations—that the agency used for the last decade to help industry with compliance guidance.

The policy codifies several of those changes, including expanded bird- strike testing requirements. In the past, the FAA often accepted analysis in lieu of bird-strike tests in situations where applicants could prove that aerodynamics or other factors made a bird strike impossible. While analysis can still take the place of tests, the agency has become far more stringent.

“Compliance with the bird-strike requirements must be shown by tests, or validated analysis,” the policy explains. “The failure modes of composites [which the antenna covers are made from] in a dynamic non-linear event such as a bird strike are not easily predicted by analysis. Therefore, if analysis is used, it must be validated by sufficient testing.”

Bird-strike testing “must be considered unless it can be shown that a bird cannot strike the modified structure at any airspeed up to the speeds required by” Part 25 requirements, the FAA continues. “Probabilistic arguments (for example, the likelihood of impact based on consideration of frontal area, flight phase, aircraft speed and altitude) are not acceptable by the FAA as a means of showing compliance to the bird-strike requirement . . . or as the basis for not complying with this requirement,” the agency clarifies.

In early 2014, LiveTV’s Ka-band radome cover, a 63.4-in.-wide X 113.7-in.-long composite structure supplied by General Dynamics, became the first to pass FAA’s revised standards—technically a new interpretation of longstanding rules—that call for the bird-strike test. Upon being struck by a four-lb. bird fired from a cannon, the radome’s forward section collapsed inward and returned to form in a fraction of a second. The radome’s structure, which protects three antennas—one for in-flight Internet, one for satellite TV, and one to offload technical information when the aircraft is on the ground—stayed intact.

The policy statement was sent out for comment until early July. The FAA will then review the feedback and issue a final version. 

Jay Pardee’s Path

Seminal contributions to aerospace’s progress are often easy to pinpoint: major flight-test milestones, groundbreaking engineering designs, or market-shifting business strategies. Sometimes, however, they become apparent only after years of small steps that come together to reveal a clearly identifiable path that led to meaningful change. 

Jay Pardee spent more than 40 years laying such a path—leading to a safer aviation system. He was still making progress when he died suddenly on June 12 at age 68.

The former manager of FAA’s Engine and Propeller Directorate (EPD), Pardee is perhaps best known for his contributions as an original member of the Commercial Aviation Safety Team (CAST). He also was the driving force behind the Aviation Safety Information Analysis and Sharing program, which is helping FAA transition to a proactive, data-driven safety-oversight approach.

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His 44-year FAA career included serving as a dedicated member and tireless advocate of CAST, which cut the U.S. airline fatality risk 83% from 1998-2008, exceeding its lofty goal of an 80% reduction. Pardee was also part of the CAST team that earned a 2006 Aviation Week Laureate Award and the 2008 Collier Trophy.

“I believe it’s fair to say that the impressive achievement in commercial aviation safety over the last 20 years is directly attributable to Jay’s work,” wrote Peggy Gilligan, FAA Associate Administrator for Aviation Safety (AVS) and CAST government co-chair, in a message to her staff. “His vision and dedication over the years forged a remarkable government and industry partnership that became the model for the world.”

Gilligan noted in CAST’s early days, many deemed the 80%-reduction target as “simply beyond our reach.” That CAST exceeded its mark “really defines Jay’s career: He always took on the impossible and made it possible,” she said.

Pardee also understood the FAA’s key role in working with industry, not just regulating it.

“Jay was always supportive of mutually beneficial meetings,” says Sarah MacLeod, executive director of the Aeronautical Repair Station Association. “He never dismissed the industry’s concerns or solutions merely because they weren’t aligned with the agency or his own view of a situation. With his ability to listen and understand multiple positions, the solutions he endorsed were always feasible.”

Pardee’s most recent role at FAA was as chief scientific and technical advisor for vulnerability discovery and safety measurement programs, where he continued to push the boundaries of using data to drive proactive improvements in aviation safety procedures, processes, and oversight.

Pardee spent most of his four-decade-plus career working to make his industry safer. His contributions will pay dividends for decades to come. 

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