Another Day, Another Little Problem on the Production Line at Boeing

The GE Aerospace turbofans powering the Boeing 777 might have some issues with contaminated iron, with pieces of the high-pressure turbine discs, rotor spools, and compressor seals affected.

A proposed airworthiness directive follows a string of GE Aerospace findings pointing to “iron inclusion” in powdered metal parts. The additional iron represents a weak point in the engine, resulting in parts that fail to meet longevity and strength specifications as designed. Premature failure and even uncontained engine failures are always a wildcard whenever fan blades, discs, spools and the like aren’t up to snuff - and an AD would help to insure that any affected parts stay on the ground where they belong.

GE Aerospace isn’t sour about the issue, saying the AD is ”consistent with existing GE recommendations to operators and reflects our proactive approach to safety management”. They maintain that the affected parts do not endanger flight safety (which is likely true thanks to the relative youth of the 777 fleet), and corrective actions will be put in place to prevent similar issues in its engines going forward. 

The AD is on track to become a final order once the comment period ends on October 20th. Once in effect, it would require replacement of “affected HPT stage 1 disks, HPT stage 2 disks, forward HPT rotor seals, interstage HPT seals, and stages 7–9 compressor rotor spools.”

FMI: www.federalregister.gov