Can you hear the holding of breath? Boeing finished up the modifications to the battery and battery box on 5 April and sent the paperwork to the FAA. FAA has said nothing, and has a hearing scheduled for 23-24 April on the adequacy of the Boeing fixes. With $200 million airliners piling up at the factory, billions of dollars of sales, American leadership in the jet airliner business at stake, FAA is under a lot of pressure to OK the fixes and get on with it. Even an Obama FAA doesn't want to torpedo American airliner sales, at least I don't think they do.
Boeing's fixes are not confidence inspiring. They never did figure out what caused the batteries to catch fire. They made a number of improvements to the battery, but since they don't know what caused the fires, they don't know if the fixes will do any good. They are putting their real faith in a fireproof stainless steel battery box to contain any fires and vent the smoke over board.
If the FAA approves Boeing's fixes, and more trouble occurs, they will look really bad. And they know it. FAA could decide that nothing less than ditching lithium batteries and going back to something tried and true, like NiCad, or even lead acid will do. If they feel this way, they should have let Boeing know back in January. To let Boeing waste three months, hold up the program for three months, is inexcusable. If FAA want's to be hard ass, they ought to have had the guts to make their feelings clear, back in January. If FAA announces "no good" next week, it will take Boeing another couple of months to do a battery change.
Anyhow, the breath holding at Boeing will continue.