Boeing says 75% of the test plans have been approved, and 25% are “already underway or completed.” Sinnett adds that “we could be back up and going in weeks, not months, but if we find something new there could be some delay. We have a fairly good notion of how long it will take and if we miss it will be by a little, not a lot.”
The system adds around 150 lb. of weight to the aircraft, eliminating much of the weight advantage Boeing originally gained with using lithium-ion technology. However Boeing remains committed to the GS Yuasa-made battery, saying it is the right technology for peak performance.
“We’ve been testing the design features for more than six weeks. Testing has been very good, very positive,” says Sinnett, adding that when the battery vents in laboratory tests the enclosure contains the electrolytes.
The system also has passed ultimate pressure testing at more than three times the pressure “we expect to see in an event. We’ve got over 60,000 hours of test effort behind us in designing test rigs and executing tests. We’re very confident the design we’re promoting does a very good job of providing all three layers of protection,” Sinnett adds.
Boeing plans to complete certification testing and analysis in the next few weeks, and then provide the reports for FAA approval. The designed retrofit and service bulletins then will be produced for modifying the grounded fleet.
After this, Boeing plans to produce dedicated hardware for fleet installation to allow the aircraft to return to flight. “Once that’s complete we will resume production fight tests at Boeing and then resume deliveries to customers,” says Boeing Commercial Airplanes President and CEO Ray Conner.