Boeing’s engineering team of more than 300 personnel already has started to install battery kits in 10 of the 50 grounded 787s and nine of the 25 787-8s produced since the FAA ordered a halt to flights mid-January, says Chairman and CEO James McNerney.

During the company’s April 24 first quarter earnings conference call, McNerney said the company has a “high degree of confidence that we’ll get through it by mid-May.” Deliveries are expected to begin early next month.

Meanwhile, the race is on to determine which carrier first resumes 787 services, although Ethiopian Airlines expects to gain that honor with an April 27 flight from Addis Ababa Bole International Airport to Jomo Kenyatta International Airport in Nairobi.

Also reporting return-to-service goals are Qatar Airways, which has scheduled a May 15 flight from Doha International Airport to London Heathrow Airport, and United Airlines, which expects to return some of its 787s to domestic service May 31. United also expects to launch service between Denver International Airport and Tokyo’s Narita International Airport June 10, although a spokeswoman tells Aviation Week, “that will depend on successful completion of planned modifications ahead of that date.”

It is unclear when the industry’s two largest 787 fleets at All Nippon Airways and Japan Airlines will resume service, but Japan’s Civil Aviation Bureau is not expected to approve flights until June.

Despite losing more than a quarter of the year’s delivery schedule, McNerney says Boeing still expects to deliver more than 60 787s this year. The 25 awaiting delivery include 20 at its Everett, Wash., factory and five in North Charleston, S.C.

CFO Greg Smith says Boeing has spent only a “minor” amount of its research and development fund to devise the 787 battery fix, but he declined to state the amount.

Separately, after months reporting the high level of customer acceptance for the 787-10X, Boeing’s second stretched version of the twin-aisle jet, the company still is hesitant about confirming a launch date. “I anticipate that sooner rather than later we’re going to be making a call” for launch this year, McNerney says.

Boeing is still evaluating its supply chain and factory readiness to take on the new model as its two 787 assembly lines climb toward 10 aircraft per month by year end. It needs to “get through what we are going through now,” McNerney adds.

McNerney also says Boeing is evaluating design and production locations for the 777X, raising the prospect that its North Charleston facility could play a big role in the product update. Boeing currently produces and assembles the entire aircraft in Everett.

Boeing recently agreed to invest $1 billion and hire 2,000 more workers in North Charleston in exchange for training and tax breaks from the South Carolina legislature. Boeing, however, has not specified what additional work is to be performed at the facility.

“We have figured out by and large what airplane to build,” McNerney says of the 777X. “The question is where to assemble and build the major components,” including a new composite wing. “We’re in the middle of that process,” the CEO adds.

Boeing reported a 24% increase in earnings per share of $1.73 for the quarter. Revenues were down 3% year-on-year to $18.9 billion, largely because of the 787 grounding. But operating margins were up 11.4% for commercial airplanes and 10.3% in defense, despite pressures from decreasing defense budgets.