More than a week into the grounding of the Boeing 787, a clear path to putting the fleet into the air again still appears to be some way off. And although investors and airlines claim they remain optimistic that Boeing can resolve the issue soon, the reality could be distressingly different.

“This is something we are expecting will not be solved overnight,” says U.S. NTSB Chairman Deborah Hersman. During a Jan. 24 press conference, Hersman confirmed that the lithium-ion battery that burned on a Japan Airlines Boeing 787 on the ramp in Boston experienced thermal runaway and short circuits, though investigators continue to search for contamination or defects that may have set one or other of the problems in motion. “We haven't said if this is cause or effect,” Hersman said. “We know there's something wrong, but we have yet to identify it.”

The NTSB and Japan Transport Safety Board (JTSB) continue to pursue their separate investigations into the Japan Airlines (JAL) and All Nippon Airways (ANA) battery incidents this month that prompted the FAA's Emergency Airworthiness Directive which grounded the 787. Yet, since the last of the 50 in-service aircraft shut down its engines on Jan. 17, conclusive indicators of the problem's cause and how to fix it remain elusive.

JTSB officials have concluded that the ANA battery fire shared similar characteristics to the Jan. 7 JAL fire at Boston but admit they are unsure where to look next for answers. Reporting on its initial findings on Jan. 23, JTSB Chairman Norihiro Goto said that “on the surface, it appears there was no overcharging.” He added that “we are finding it difficult trying to figure out what kind of investigative stance we should take.”

Investigators in Japan have visited GS Yuasa, the Kyoto-based manufacturer of the 787's two 32-volt main lithium-ion batteries, while in the U.S. the NTSB has been studying the burned JAL unit. NTSB has also been working its way through evaluations of other battery-related elements of the electrical system, including the charging system and auxiliary power unit controller.

However, while the search through the ancillary systems for a “smoking gun” remains prudent, initial findings seem to point to the battery itself and the safeguards built in and around it. Thus, the root cause could derive from manufacturing flaws in individual units or problems with systems designed to prevent the battery from over-discharging.

In its latest report on Jan. 24, the NTSB says detailed radiographic inspection using computed tomography (CT) and other techniques revealed thermal damage to all eight cells in the battery from the JAL aircraft. The battery is made up of eight 3.7-volt cells, six of which have so far been scanned and disassembled at the NTSB's Materials Laboratory in Washington. The final two cells were due to be similarly analyzed in the coming days, says the NTSB. Although the implications of the scale of the damage to all the cells remain unclear, it is widely expected that the findings will again implicate the battery rather than the supporting infrastructure.

In the case of the auxiliary power unit (APU) main battery which caught fire in the JAL aircraft, the unit is connected through the large motor power system in which a controller handles the input from the 235-volt alternating current (VAC) starter/generators on the main engines, external power (from the ground) and the battery itself. The forward (main) battery, which is the focus for the ANA investigation, is connected to the electrical system via a 28-volt direct current (VDC)/235-VAC power converter. The charger system was developed by Tucson, Ariz.-based Securaplane, which bills itself as a “pioneer” of lithium battery technology on commercial aircraft.

Amid the continuing uncertainty of the investigations, many investors, airlines and Boeing itself still appeared to believe late last week that the grounding will soon end, with the manufacturer working on proposals to meet the authority's concerns.

Bjoern Kjos, CEO of Norwegian Air Shuttle, says Boeing has been communicating to customers that a fix will be in place soon. Boeing has also assured Norwegian that the planned delivery of its first 787 in April is not threatened. Although it has stopped 787 deliveries pending the outcome of the investigations, production continues. Kjos's comments reflect the official position of most 787 customers, which have publicly backed the program and given no hint of order cancellations or deferrals.

Analysts have been commenting calmly as well. “We take the battery failures on the 787 over the past two weeks very seriously, but we believe the most likely outcome is that Boeing will identify and fix the problem over the next several weeks or months at most,” says Joseph Nadol of JP Morgan. He argues that even if an alternative battery needs to be retrofitted, “this should not represent a severe financial hit.” Additional weight of another battery type would “not make a major difference on its own” for the aircraft's performance,” Nadol says.

“We believe Boeing will resolve this hurdle and maintain its production schedule,” writes Merrill Lynch analyst Ron Epstein in a research note. He sees no impact on the backlog and considers the faults “another teething issue Boeing will work through.”

Meanwhile, 787 operators continue to adjust their schedules. Most have interim schedules in place until the end of January. ANA, hardest hit with a fleet of 17 aircraft, canceled its Tokyo-San Jose, Calif., service until Jan. 28. The airline is dispatching Boeing 777s on some Seattle-Tacoma services, but it had to cancel several roundtrips. ANA also canceled some regional flights for which the 787 should have been used due to a shortage of aircraft.

Other carriers with smaller fleets were not forced to pull services, at least not to the same degree. United Airlines replaced its 787s mostly with 737s on domestic routes and with 777s on long-haul roundtrips. Its Houston-Lagos, Nigeria, service will be operated by 777s until mid-February. LOT Polish Airlines is using 767s for its Warsaw-Chicago flights, and Qatar Airways is replacing the 787 with A330s on its European runs.

Despite the public display of support, some 787 operators are understood to be asking Boeing for compensation. LOT and Qatar Airways in particular have made clear to Boeing that they will not accept further aircraft without a credible fix. Airbus is confronting similar claims over the lengthy permanent A380 wing repair that will become a major issue for airlines this year.

Boeing and the FAA could also face more negative publicity if Sen. Jay Rockefeller (D-W.Va), chairman of the U.S. Senate Commerce, Science and Transportation Committee, carries through with his call for a hearing on the 787 battery issues. The committee says it will look into the FAA's decision to certify the 787 with lithium-ion batteries as part of its previously planned examination of U.S. aviation oversight.