U.S., Europe at odds over aerospace composite repair strategies

Aviation Week and Space Technology reports that the U.S. FAA permits bonded repairs for composite primary structures on craft like Boeing's 787 and Airbus' A350, but Europe's EASA requires a metallic bolded repair.

Aviation Week and Space Technology (AWST) reported on Nov. 11 that the U.S. Federal Aviation Administration (FAA) and the European Aviation Safety Agency (EASA) are in disagreement over repair techniques to be used on composite structures on aircraft like the Boeing 787 and the Airbus A350 XWB.

The report notes that the FAA, lead certification authority on the 787, permits a bonded repair solution for composite primary structure, but EASA will not. This means EASA-regulated operators will need a metallic bolted repair for damage to the 787's composite primary structure. Further, the reports says it's possible that composite transports with bonded repairs cannot be brought onto the registers of European Union countries.

Andreas Pakszies, director of aircraft system engineering at Lufthansa, told AWST that "bolted metal repair methods must be available because bonding in the primary [composite] structure is not allowed" [by EASA] so specific tools and technicians will be needed, noting that bonded repairs are not permitted because there is no test to verify them.

Justin Hale, Boeing's former 787 chief mechanic and now a regional director in product marketing, told AWST that bolted repairs using titanium are a "permanent Category A damage-tolerant repair," but added that using aluminum as the repair material, while also a permanent fix, will require periodic inspection because of corrosion issues.

Hale also told AWST that Boeing has patented a technique that allows it to bond 70-plus plies in one cure, and that it would be possible for Airbus to devise a similar repair for the A350 XWB.