New York (AFP) - Boeing's 737 MAX could be brought back into service gradually by government regulators but is still on track to be cleared to fly again in 2019, the company's CEO said Wednesday.
The aircraft was been grounded in mid-March following two deadly crashes but could return to the air on a staggered schedule in different countries.
Boeing Chief Executive Dennis Muilenburg said the company is still working through a number of questions with the US Federal Aviation Administration and other regulators but that "all of that work supports our timeline for an early fourth quarter return to service."
"A phased ungrounding is a possibility," he said at an investor conference in California.
Shares of Boeing rallied after Muilenburg's remarks. The MAX crisis has crimped Boeing's financial performance and dented its reputation. Commercial plane deliveries fell more than 40 percent through August compared with the year-ago period.
The company is addressing questions from the European Union Aviation Safety Agency, which has expressed concerns about a malfunction of the "angle of attack" sensor which triggered an anti-stall system linked to the deadly crashes of Lion Air and Ethiopian Airlines planes.
"I wouldn't see those as divisive," Muilenburg said of the EASA queries. "I just think those are questions that we need to answer as part of the process."
EASA is also among the regulators that have pressed for enhanced pilot training, including simulator training.
US pilot groups also have called for mandatory simulator training saying training on computer tablets was insufficient.
A requirement for simulator training could hamper efforts to return the aircraft to service, because there are fewer than two dozen MAX simulators currently available. In the past, pilots have gotten around this barrier by training on a simulator for the 737 NG, the predecessor plane for the MAX.
Boeing has developed an additional computer-based training module for the MAX that is currently being evaluated, Muilenburg said. FAA officials have said they don't think MAX simulator training is essential to recertifying the plane.
- Production outlook -
Boeing has cut production of the 737 MAX to 42 a month from 52 previously, due to the grounding and said in July it could cut production further or even temporarily halt output if the flight ban drags out much longer.
Muilenburg said the company still viewed a temporary shutdown as a possibility under certain scenarios, but "our bias right now is to maintain a stable rate at 42 a month."
The company's interactions with regulators has come in two phases, the first focusing on the Maneuvering Characteristics Augmentation System, which has been linked to the two crashes.
Muilenburg said Boeing "wrapped up" new software for the MCAS in the middle of the year and is "very confident" in the system after more than 600 test flights.
The FAA in June identified a problem with a microprocessor on the MAX, which led to delays in the recertification process.
Boeing is now "finishing up" additional work following a "holistic system wide evaluation" of the MAX, Muilenburg said.
Shares of Boeing rose 2.9 percent to $380.29 in afternoon trading.