The GEnx engine deployed on the Boeing 787 and 747-8i was designed as a “green” engine, with advanced technology to reduce emissions and noise. GE has made a significant investment in green technology, and to their credit, emissions and efficiency on the 787 and 747-8i are beating initial expectations.
Unfortunately, despite nothing showing up in extensive certification testing, there have been cracks in the fan midshaft of two GEnx engines for the 787, and while not yet confirmed, an engine failure on a GEnx engine on an AirBridge Cargo 747-8i that is suspected to be a similar problem.
This has resulted in an FAA Airworthiness Directive requiring an inspection every 90 days that will require about 9 man-hours per engine to complete. Using initial findings to date, GE has already changed its production process and will replace its new environmental friendly coating, without lead, to an older dry film coating currently used on the GE90 with lead to protect against cracks caused by galvanic corrosion in a moist environment. They have also changed a lubricant in the manufacturing process.
We are confident that GE will continue to push the frontier for green technology, and that this minor setback is quickly resolved as more 787 and 747-8 models enter service. We applaud GE’s efforts in utilizing more environmentally friendly coatings in the engine, and hope that a solution can be found that isn’t a trade off between reliability and environmental performance as they move the GEnx program forward.
two steps forward one back is one forward