By Andrew Tangel and Andy Pasztor
Boeing Co. and federal regulators said they have identified a
new software problem on the 737 MAX, further delaying the process
of returning the troubled jet to service.
The new issue involves software that is separate from changes to
the aircraft's faulty flight-control system called MCAS, according
to people familiar with the matter. The software system in
question, though distinct from MCAS, is related to an emergency
procedure that can be used by pilots to address MCAS malfunctions,
these people said.
The plane maker disclosed in a securities filing on Wednesday
the Federal Aviation Administration's request to address the new
problem, which it said wouldn't be covered by planned changes to
the MCAS system.
Boeing said it agreed with the FAA's decision and request and is
working on the required software fix.
The software issue involves an emergency procedure that would be
used to counteract MCAS if it malfunctions, erroneously pushing the
plane's nose down, according to the people familiar with the
matter. The FAA identified the problem last week during simulator
tests, these people said, after an agency test pilot determined
that the procedure took more time than was acceptable to
execute.
It wasn't immediately clear whether the new problem was related
to software that was original to the aircraft or postcrash
revisions in conjunction with changes to MCAS.
Boeing believes it can resolve the issue with a software tweak,
these people said. Otherwise, they added, there is a chance that
the company would have to replace a computer chip in all 500 MAX
planes that have been delivered or built, a process that would add
significant delays.
Certification flight tests, an important step before regulators
around the world allow the MAX to fly again, had been expected to
begin as soon as last week, according to people familiar with the
details.
"Boeing will not offer the 737 MAX for certification by the FAA
until we have satisfied all requirements for certification of the
MAX and it's safe return to service," the company said in its
filing.
An FAA spokesman said the agency is following a thorough process
and has no timeline for allowing the 737 MAX to return to service.
"The FAA recently found a potential risk that Boeing must
mitigate," he said.
A total of 346 people died in two 737 MAX crashes in Indonesia
and Ethiopia. Regulators around the globe grounded the aircraft
after the Ethiopian crash in March.
United Continental Holdings Inc. on Wednesday became the latest
U.S. carrier to strike the MAX from its schedule through Labor Day.
United said it is pulling MAX flights out of its schedule until
Sept. 3, following similar moves by American Airlines Group Inc.
and Southwest Airlines Co. United said it is trying to minimize
disruptions by swapping out aircraft and using bigger planes in
lieu of the MAX, but it will still have to cancel some 1,900
flights in August, or 60 a day.
Wednesday's developments illustrate how unexpected complications
can upset months of painstaking preparations to get the MAX fleet
back in the air. Boeing originally submitted an MCAS software fix
to the FAA in January, and since then the Chicago plane maker has
been on a roller-coaster ride of shifting timetables and deadlines
for getting the green light from the FAA.
Boeing previously hasn't submitted filings about last-minute
changes and delays to the Securities and Exchange Commission.
It isn't clear how long this latest delay may last. The biggest
variable, according to one of the people familiar with matter, is
whether Boeing can make the required changes entirely through
software revisions. FAA officials still have to be convinced that
is feasible, this person said. If a new microprocessor or other
electronic component is required, the person added, the delay could
stretch into months rather than weeks.
In particular, people familiar with the matter said, the
software issue relates to how quickly pilots can use electric
switches on the control column, or yoke, to get the aircraft into
more level flight.
Stabilizing the aircraft is an early step in the emergency
procedure, which later calls for hitting separate switches to cut
off power to MCAS and the plane's system for electronically moving
its rear-horizontal stabilizer that controls the angle of the
plane's nose.
The emergency procedure has come under scrutiny in the wake of
the crashes.
After a Lion Air 737 MAX crashed in Indonesia in October, Boeing
and the FAA emphasized that pilots should use the procedure to
disable MCAS in the event it misfired. Pilots in that accident
don't appear to have followed the procedure.
But after an Ethiopian Airlines 737 MAX crashed in March,
investigators and executives at the plane's operator said the
pilots followed Boeing's emergency procedure.
That claim, however, has been sharply disputed by outside
pilots, aviation industry officials and safety experts, who say the
Ethiopian Airlines pilots didn't appear to have adequately followed
the procedure's steps and apparently turned MCAS back on before its
fatal nosedive.
--Alison Sider contributed to this article.
Write to Andrew Tangel at Andrew.Tangel@wsj.com and Andy Pasztor
at andy.pasztor@wsj.com
(END) Dow Jones Newswires
June 26, 2019 21:10 ET (01:10 GMT)
Copyright (c) 2019 Dow Jones & Company, Inc.
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