The Boeing 787 grounding could be lifted with 100 days of the US Federal Aviation Administration's order on 16 January, or within a week.
The US FAA approved on 19 April Boeing's solution to the thermal and electrical failures that caused lithium-ion batteries on two 787s to dangerously overheat. Boeing was preparing to release a service bulletin a few hours later that authorised airlines to install an improved battery. Installation kits pre-positioned in bonded Boeing storage facilities around the world could now be released to the 50 787s currently parked in nine different countries.
The next step in the process requires the FAA to issue a new airworthiness directive (AD) to supersede the order that grounded the 787s until the battery problem was resolved to the agency's satisfaction.
That step will be followed by a short waiting period to allow the public to submit comments. Boeing officials, however, believe the comment period on the superseding AD could be closed out within the five-day window it takes to install the battery kits, allowing the 787's to resume passenger-carrying flights almost immediately.
But a few important details about the return to flight process are still unclear. While the FAA's new AD will clear United Airlines to resume flights in the USA, other air transport regulators around the world must also accept the US regulator's decision on approving Boeing's solution.
The airlines also may have different procedures to return the aircraft to service. By complying with the new service bulletin, the 787s will be cleared by the FAA to resume operations as soon as the kits are installed. However, some airlines may want to perform their own flight tests before allowing passengers on board with the redesigned batteries, says Mike Sinnett, Boeing's 787 chief project engineer. Some airlines also have pilot and crew training requirements to meet that could extend the return to flight process.
"I think it's going to be in the near-term," Sinnett says.
Despite the few murky details, the future appears bright for the 787 programme for the first time since the auxiliary power unit battery overheated on a Japan Airlines 787 at Boston Logan airport on 7 January.
"It's been a long haul, that's for sure," Sinnett adds.
The overall financial impact on the programme has yet to be counted. Boeing amassed 300,000 labour hours alone to recertify the aircraft with redesigned batteries, to say nothing of the contractual fees it owes to the eight airlines operating the 787 and the several more whose aircraft have been even further delayed.
But Boeing has several reasons to be confident. The company never stopped buildings 787s during the grounding, and indeed quickened the pace to double the production rate to 10 aircraft per month by the end of the year. That means Boeing believes it can still deliver 65 787s in 2013, as it predicted shortly after the battery crisis began in January.
Perhaps most importantly, the FAA has cleared the 787 to re-enter service with 180min extended operations (ETOPS), allowing airlines to fly the same long-distance routes up to 3h flying distance from an emergency landing site.
The 180min ETOPS standard was reviewed by the FAA due to the battery and other electrical system failures that plagued the 787. in repsonse, Boeing used the grounding period to roll-in reliability improvements in several systems, including in power distribution panels and hydraulic tubing, Sinnett says.
The 787 was the first airline fleet to be grounded by the FAA since the DC-10 in 1979, but Boeing insists the type has enjoyed a service reliability standard that exceeds the introduction of the 777 in 1995.
Sinnett showed a chart that compared the number of "reportable events" to the FAA during the first 15 months of service for the 787 and 777. The 787 had 119 reportable events during that period, compared to 280 for the 777. The 777, of course, was never ordered grounded across the fleet despite the disparity in the nubmer of reportable events.