The US FAA has given Boeing 30 days to respond to a proposed $1.05 million civil penalty for "allegedly failing to correct a known problem in production and installation of the central passenger oxygen system" aboard nine 777 aircraft.
"Inspectors discovered that spacers in the oxygen delivery system distribution tubing on the aircraft were not installed correctly," said FAA. "Improper installation could result in the system not supplying oxygen to passengers should depressurisation occur."
According to the complaint against Boeing, the FAA alleged the airframer "did not maintain the quality system in compliance with the data and procedures approved for the production certificate".
"There is no excuse for waiting to take action when it comes to safety," said US Transportation Secretary Ray LaHood. "We will continue to insist on the highest levels of safety from our aircraft manufacturers."
Boeing said it was notified in April 2010 about an issue in its work instructions for the installation of the low pressure oxygen tubing connections on nine 777 aircraft, specifically line numbers 860, 864, 871, 887, 891, 898, 901, 902 and 905.
"We took immediate action and began an investigation. We corrected the issue by updating the work instructions and engineering documentation, which was found to be the root problem," said Boeing. The engineering drawings and instructions were revised in February 2011.
Boeing said the issue was first discovered by the FAA "during the course of performing routine oversight in our factory" not any in-service incidents.
Boeing added that it performed "extensive laboratory testing" and determined that the oxygen tubing connections and installations are "not a safety issue", despite the FAA's allegations Boeing violated its own work instructions and quality system.
Boeing did determine through lab testing that the "angularity" of one of the oxygen tee fittings originally called for in the work instructions was not required and it was removed from the instructions.
Boeing said the requirement initially called for a 2-degree angularity of the installed tee fitting, and testing revealed that a maximum angularity of 10-degrees - the highest possible - would not cause disruption in air flow even at twice the pressure.
"We are working closely with the FAA to ensure we understand and address any remaining concerns," the airframer added.