Boeing has billed the plane to its customers as 20 percent more fuel efficient than other mid-sized airliners. That's a big selling point, since fuel is the biggest expense for most airlines.
One question is how much weight Boeing's proposed fix would add. The heavier the plane is, the less fuel-efficient it is.
Having the plane flying as soon as April "would be fantastic news for Boeing," said Carter Leake, an aerospace analyst at BB&T Capital Markets.
If the battery fix ends up being as described, "I don't think it's that difficult to retrofit. I think it would be viewed very favorably" by investors, Leake said. If FAA were to approve Boeing's proposed fix as early as next week, that would be a "home run" for the company, he said.
However, the idea of recertifying part of the design is trickier. Getting certification from the FAA for a particular part or design is an involved process — and one that's likely to make investors nervous.
"Recertification suggests time," Leake said. "Given what most know about aircraft certification processes, six months would be sort of quick."
Leake added: "The FAA takes it slow. You're talking about statistical testing. You're proving through testing that this meets very stringent criteria. That usually involves time, and time is not on Boeing's side."
Among the many unanswered questions is how the 787 battery problems will affect Boeing's effort to win FAA permission for the planes to make flights that venture further from the nearest airport, such as those that travel over wide expanses of ocean. The FAA has tighter requirements for such flights in twin-engine planes because it wants to make sure the plane can keep flying if it loses an engine or encounters other problems far away from a safe landing.
Until it was grounded, the 787 could fly up to three hours away from the nearest airport. That's far enough for flights between the U.S. and Europe and some flights over the Arctic, for instance. But Boeing wants permission for flights up to 5.5 hours from the nearest airport. Its 777 is already certified for such flights.
Boeing said last month before the grounding orders that it was close to submitting a plan for those longer flights.
The grounding has forced airlines that own the 787 to rework their schedules. LOT Polish Airlines has said the grounding of its two 787s is costing it $50,000 per day. Most affected has been ANA, which has 17 of the planes.
Boeing has had hundreds of people looking for the cause of the problem and working on possible solutions.
The mess comes just as Boeing is boosting 787 production from five planes per month to 10 per month by the end of this year. It has said the speedup will still happen, even though it can't deliver the planes — or collect most of their $200 million-a-plane list price from airlines — until they're flying again.
"Even with the FAA review/grounding, we believe it's more likely than not that Boeing continues to build at its planned rate until it's apparent that a fix for the battery issue will require an extended period of time (more than couple of months)," UBS analyst David Strauss wrote in a note this week.
Freed reported from Minneapolis.
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