Page 24 - World Airnews Magazine January 2020 Edition

ENGINES

GE AVIATION URGES GE90

STATOR SWAPS

GE’s Ted Ingling helped develop the GE90-115B, the
world’s largest and most powerful jet engine in
service. Boeing uses the engine to power its 777 jets

300ER experienced No. 1 engine failure on “It is highly probable that damage to

takeoff from Tokyo International Airport multiple stages of stator vanes and turbine

E has recommended operators of en route to New York’s John F. Kennedy blades of low-pressure turbine was con-
GGE90-115B engines install re-de- Airport. The crew shut the engine down tributed by the fracture of one of LPT fifth

signed stator vane segments to prevent and returned to Tokyo safely. stage stator vanes.”
wear and potential cracking that inves- Investigators found one of the engine’s GE issued an SB in July 2018 recom-

tigators determined was behind a 2017 LPT fifth-stage stator vanes fractured, mending borescope inspections for the

Japan Airlines (JAL) engine failure, a Japan causing downstream damage including affected area.
Transport Safety Board (JTSB) report on the damaged turbine blades and a 6 cm by 1 By April 2019, GE reported cracks and
incident revealed. cm (2.4 in. by 0.4 in.) hole in the turbine wear in 18 stator segments from 14 en-
The issue is linked to spacing between rear frame. The missing vane fragments gines, including two operated by JAL. One

low-pressure turbine (LPT) fifth-stage were not recovered, but investigators of the JAL engines had an LPT fifth-stage
stator segments. Tests conducted by GE in linked the damage to the previously stator with 25 original-spec segments

2013 predicted that binding could cause known wear condition, or “arch-binding,” and one new-spec segment. Signs of arch
adjacent segments in the 26-segment fifth- JTSB said. binding were found on all 25 of the origi-

stage stator to wear, causing stress and “Wearing caused by rubbing of adjacent nal-spec segments, JTSB said.
potentially cracks in vanes. segments was confirmed on ... multi- GE in August last year issued an SB that

Even though the issue had never been ple segments of LPT fifth-stage stator recommended operators upgrade all orig-
linked to an in-service incident, GE vanes,” JTSB said, adding that “repetitive inal-spec stator segments when the LPT is
re-designed the segment to provide more stress associated with engine operation” disassembled, even if the segments do not
clearance. GE introduced the change on the likely caused the crack on the failed vane need to be replaced. The JTSB report said
production line and made the new segment to expand. it is “probable” that the change will reduce

- which can be mixed with the original “It is highly probable that the serious in- the likelihood of arch-binding.
design - available for retrofit. cident was caused by collisions of some of The agency also urged GE to analyse

However, a service bulletin detailing the fragments with the turbine rear frame, its data and determine an “appropriate

the change “did not describe that the which led to generating the hole due to interval” for conducting inspections to

part was design changed as a counter- damage to multiple stages of stator vanes monitor old-spec stator segments and
measure for the in-house test,” JTSB and turbine blades of low-pressure turbine advise operators.

explained in its report. (LPT) of No. 1 (left side) engine immediately JAL is inspecting its engines every 250

On September 5, 2017, a JAL Boeing 777- after take-off,” JTSB said. cycles, JTSB said. Q
World Airnews | January 2020
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