Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 777 airplanes. This proposed AD was prompted by reports of discrepancies between the center wing tank (CWT) fuel quantity, as indicated by the fuel quantity indicating system (FQIS), and the refueling truck uploaded fuel amount, followed by certain engine-indicating and crew-alerting system (EICAS) messages. This proposed AD would require installing new software in the fuel quantity processor unit (FQPU), or replacing the FQPU with one that includes new software, depending on airplane configuration; and doing a software version check and FQPU operational check. This proposed AD would also prohibit the installation of certain FQPUs on certain airplanes. The FAA is proposing this AD to address the unsafe condition on these products.