Air Canada emergency landing at YYZ

[Data Guy]

Some turbine history

Since the TSB has now identified turbine blades, there is some AD history - one created because of eight prior incidents.

AD 2009-25-14. Installed on, but not limited to, Boeing 777-200LR, 777-300ER, and 777 Freighter series airplanes. SUMMARY: The FAA is adopting a new airworthiness directive (AD) for General Electric Company (GE) GE90-110B1, GE90-113B, and GE90-115B series turbofan engines with stage 6 low pressure turbine (LPT) blades, part number (P/N) 1765M37P03 or P/N 1765M37P04, installed. This AD requires initial and repetitive inspections for shroud interlock wear of the stage 6 LPT blades. This AD also requires replacing those blades with stage 6 LPT blades eligible for installation at the next engine shop visit as terminating action to the repetitive blade inspections. This AD results from eight reports of GE90-115B stage 6 LPT single-blade separation events. We are issuing this AD to prevent failure of stage 6 LPT blades, which could result in uncontained engine failure and damage to the airplane

Bold added

AD source link > http://www.airweb.faa.gov/Regulatory...2009-25-14.pdf