By Andrew Tangel and Alison Sider
Boeing Co. was planning to strengthen protective engine covers
on its 777 jets months before a pair of recent serious failures,
including one near Denver last weekend, according to an internal
Federal Aviation Administration document.
The plane maker and regulator had been discussing potential
fixes even longer -- for about two years, according to people
familiar with the matter. The talks began after two failures in
2018, one on a 777 operated by United Airlines Holdings Inc. and
the other on a Southwest Airlines Co. 737.
Because potential modifications to 777 external engine covers,
commonly known as cowlings, had various shortcomings, "Boeing has
decided to redesign the fan cowl instead of trying to modify
existing fan cowls to address both the structural strength
concerns" and moisture issues, according to the internal FAA
document reviewed by The Wall Street Journal.
"Boeing will be manufacturing new fan cowls and providing
service instructions for operators to remove and replace the fan
cowls," according to the document, part of a routine Aug. 6, 2020,
update on efforts under way at the agency's Seattle-area offices.
Boeing and the FAA declined to comment on the engine-cover plan's
status Wednesday.
Separately on Thursday, the FAA said Boeing would pay $6.6
million for failing to meet its obligations under a 2015 settlement
and to resolve two enforcement cases.
Such changes to airplane parts can require years of design,
testing and regulatory approvals. Some aviation-safety experts and
regulators have been growing increasingly concerned about whether
engine covers are robust enough to withstand the impact of a fan
blade's breaking off and shooting outward during flights.
While rare, such engine-cover damage has come up in a handful of
recent engine failures. Pilots train to land a plane operating on
one engine, which can be done safely, but large pieces of metal
from covers can put other parts of the aircraft -- and passengers
-- at risk. The engine-testing process hasn't beenfully accounted
for that possibility, according to some safety experts and reports
by the National Transportation Safety Board.
Jim Hall, chairman of the NTSB from 1994 to 2001, said recent
incidents should have prompted regulators to look "very
aggressively" at issues surrounding engine covers.
"I have yet to see indication this was done," he said.
Boeing said it would continue to follow the FAA's guidance on
777 engine covers, and it is "engaged in ongoing efforts to
introduce safety and performance improvements across the
fleet."
An FAA spokesman said reducing the risk of engine fan-blade
failure that could lead to cowling damage has been a priority --
the focus of agency directives following the 777 incidents in 2018
and last week. FAA officials have said the agency was working with
Boeing on a design change for a different type of engine that
failed on the 2018 Southwest flight -- killing a passenger -- and
reviewing the need for changes to other engines.
"Any proposed design change to a critical piece of structure
must be carefully evaluated and tested to ensure it provides an
equivalent or improved level of safety and does not introduce
unintended risks," the agency spokesman said.
The 777 engine failure last weekend came shortly after the plane
-- as in one of the 2018 incidents, operated by United -- took off
from Denver International Airport. An apparently weakened fan blade
broke off and seemed to have sheared a second blade roughly in
half, according to the NTSB, which is leading the investigation.
The engine's cover was ripped away, leaving a trail of debris in
the town below.
It resembled two recent failures of certain Pratt &
Whitney-made engines on a subset of Boeing 777 aircraft -- the 2018
United flight and one in December of 2020 operated by Japan
Airlines Co. Authorities in the U.S. and Japan attributed both to
fan blades that snapped off and battered engine covers.
In all three cases, the planes landed safely without any
injuries.
After the 2018 failure on the United 777, the FAA mandated that
fan blades on the type of engine involved undergo special
thermal-acoustic image inspections -- using sound waves to detect
signs of cracks -- every 6,500 flights. The engine that failed over
the weekend had made about 3,000 flights since its last inspection,
according to people familiar with the matter.
The FAA on Monday ordered immediate thermal-acoustic image
inspections for fan blades on certain Pratt & Whitney engines
on some Boeing 777 jets. Pratt & Whitney is a unit of aerospace
company Raytheon Technologies Corp.
But a design change to fortify engine covers is a longer, more
involved process. The internal FAA document said Chicago-based
Boeing had presented its 777 engine-cover findings to FAA
specialists in the Seattle area in early August.
Aircraft engines and their protective covers are supposed to
constrain broken fan blades and other metal parts, preventing them
from damaging structures needed to keep the plane aloft. Detached
engine covers that don't fall to the ground could create
aerodynamic drag, safety experts said. That could increase
consumption of fuel if the plane is flying less efficiently, a
concern for long flights over water with few options for emergency
landings, one of these experts said. The FAA document cites "fuel
exhaustion" as a potential safety hazard.
Engines' certification tests have focused on making sure that
broken fan blades don't shoot out the side of an engine and
puncture the plane's fuselage. Less attention has been paid to the
prospect that a blade could shoot forward and damage the front part
of the engine covers. Those covers aren't required to be attached
during tests of how engines cope with broken fan blades so the
blades remain visible.
"When you lose big pieces like that, that's a hazard," said
Jeffrey Guzzetti, a former director of the FAA's accident
investigation division. "There was never a requirement to consider
this before -- it just never really happened that much."
The FAA offered few details of Boeing's alleged violations when
it announced new penalties Thursday. The agency's administrator,
Steve Dickson, said he has "reiterated to Boeing's leadership time
and again that the company must prioritize safety and regulatory
compliance."
Boeing didn't immediately respond to a request for comment. The
plane maker has said it will follow FAA guidance on "all matters
related to safety and compliance."
Write to Andrew Tangel at Andrew.Tangel@wsj.com and Alison Sider
at alison.sider@wsj.com
(END) Dow Jones Newswires
February 25, 2021 19:15 ET (00:15 GMT)
Copyright (c) 2021 Dow Jones & Company, Inc.
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