Regulators began reviewing Boeing’s technical
documentation within the last week, and the
audit has not been completed. The review
involves specifications for software to use a
second flight-control computer, not just one, on
all flights.
Boeing spokesman Gordon Johndroe said
the MCAS documentation was presented in a
format used in the past, but regulators want it
in a different form, and the company is doing
that. He said the company is continuing to work
with FAA and other regulators while the audit is
being conducted.
“It’s too early to speculate on how this might
affect the schedule” for returning the Max to
service, Johndroe said.
Boeing has already taken months longer than
expected to make fixes to the plane, but it
still aims for Federal Aviation Administration
approval of its changes before the end of the
year. The most important upgrade deals with
software in a flight-control system called MCAS.
Before both accidents, a faulty sensor triggered
MCAS and caused it to push the plane’s nose
down; pilots were unable to regain control.
Pilots were not told about MCAS until after the
first accident — it was not described in pilot
manuals for the Max. Boeing assumed that
pilots would use longstanding procedures for
handling a nose-down pitch of the plane even if
they didn’t know what caused it.
“We build those manuals to try to train the pilots
on how to respond to the effects of failures
rather than diagnose failures,” Boeing CEO Dennis
Muilenburg said at a New York Times conference.