Home' Asian Aviation : AAV April 2017 Contents AsianAviation | April 2017 39
MAINTENANCE, REPAIR AND OVERHAUL
tenance, and procedures (CMP) documents — the latter element
better known as extended twin-engine operations (ETOps). Airbus
has also synchronised revisions of different documents.
Almost 2,400 Airbus A320-family aircraft operating in Asia-Pacific
include more than 250 flown in India, among them the 15 oldest
examples forming part of Air India’s ex-Indian Airlines fleet (each
distinguished by their four-wheel main-undercarriage bogies).
The latest MRB Report (MRBR), published in March, includes
requirements generated during A321 Neo certification and A321
ESG development. The previous MRBR revision — in June 2016 —
covered optimisation of systems-section tasks and requirements for
CFM International Leap-1A-powered A320 Neos.
A320 maintenance schedules were last revised in 2010, with
extension of C-check intervals to 7,500FH and/or 5,000FC and/or
24 months (MO) from 6,000FH and/or 4,500FC and/or 20 months.
Previously, in mid- 2004, heavy-maintenance visit (HMV) intervals
had been increased from five years and 10 years to six years and
12 years, while A-check periods were raised eight years ago.
Airbus’s philosophy is to evolve “hard”
maintenance requirements to less rigid inter-
vals, permitting operators to group inspections
to suit operations. For example, more than
100 C-check intervals were deleted or raised
to 36 months (or FH/FC equivalent). In the
six years before (and between) A320 HMV
checks, requirements covering airframe struc-
tural inspection can be accomplished during
an overnight stop. The policy of MPD opti-
misation has stimulated this year ’s planned
light-maintenance review, although Airbus
ambitions remain conservative. Roeger says
the manufacturer has focused on establishing 36-month (or equivalent
FH/FC) base-check intervals: “ Then, we need to collect data from task
performances at the increased interval. There are no plans for the next
steps, [which] will be driven by in-service feedback”.
Reflecting moves to synchronise MPD changes, last June’s revi-
sion coincided with the latest MRBR and ALS updates; SIL and SB
changes comprised “less than 10 percent of revised MPD tasks”,
according to Airbus. The majority of ALS changes cover A320
Neo requirements, although the manufacturer acknowledges that
significant changes arose from introduction of widespread fatigue
damage (WFD) requirements and sharklet-retrofit tasks.
To accommodate increased loads, retrofit installation of the new
sharklet wingtips on “legacy ” in-service aircraft requires structural
reinforcement of the A320 wing. Sharklet retrofit can be performed
in isolation or simultaneously with C-checks and painting without
increasing the planned turnaround time, according to Airbus.
To cope with different wing-lift capability, several avionics com-
ponents also must be upgraded. These include the performance
database, and elevator/aileron, flight-augmentation, flight-control
data, fault-warning, and spoiler/elevator computers.
Maintenance jobs introduced in last year ’s MPD revision covered
checks of the modified wing; for example, A319s/A320s reaching
42,000FC or 84,000FH (and then at every 10,400FC/20,800FH) must
undergo detailed inspection of certain outer-wing bottom-skin string-
ers. Similarly, the A320 corrosion-prevention and -control programme
(CPCP) details inspection of sharklet wing-tip lugs during 12-year
maintenance. The manufacturer has analysed requirements for the
A320 Neo and claims a large reduction in related engine and nacelle
maintenance costs. (As well as the CFMI Leap-1A , the new variant is
available with Pratt & Whitney PW1100G geared-turbofan engines.)
“ Thanks to cooperation with suppliers, a significant reduction of
scheduled [engine and nacelle] maintenance requirements [has
been] achieved,” says Roeger. “For redesigned parts (including
powerplant and related systems), direct maintenance costs are 54
percent lower [than for the] A320 Current Engine Option (Ceo),
achieved by [fewer] tasks and longer intervals.”
For Neo variants, the A320 MPD has introduced outer-wing rear-
spar, thrust reverser, and pylon-reverser fitting inspections. For
example, all Neos must receive ultrasonic
checks of the rear-spar forward face at land-
ing-gear support Rib 5, and at pintle and re-
traction-jack fitting-attachment points. Like-
wise, on PW1100G-engined aircraft, detailed
checks of thrust-reverser primary sliders and
tracks will be required at 12-year inspections.
For machines with Leap-1A engines, the MPD
specifies general visual inspection of pylon
With the oldest active A320s now about 28
years old, some have already undergone four
or five HMV checks, while increasing num-
bers of airframes are being broken up for spares following withdrawal
from use. Well over 100 A319 and A320 variants have overtaken the
manufacturer ’s original “design service goal (DSG)” — 48,000FC and/
or 60,000FH — since the first such occasion (by an A320) in 2014, and
are operating in so-called “extended-service goal (ESG)” conditions.
Roeger expects the most-active A321s to exceed the DSG
flight-cycle threshold in the early part of this year, almost two years
after the first A319 did so. The much younger A318 model is not pre-
dicted to reach the mark until about 2020-21 (FH), or 2024-25 (FC).
According to Airbus fleet statistics last October, the A320 family
FC fleet leader had notched up over 52,000 flights, with a different
machine having logged most time in the air: almost 83,500FH. After
reviewing A320 fatigue-related maintenance items, the manufacturer
has been developing a planned fatigue-monitoring programme (FMP)
that is expected to “completely replace” earlier fatigue-damage (FD)
sampling policy, says Roeger. “ The number of in-service aircraft
and reported experience feedback” has encouraged the company
to simplify its fatigue-inspection requirements. Previous sampling
requirements were no longer justified and the A320 MRB has deleted
them from the MPD.
As the oldest A320s
approach 30 years of
operation, Airbus has
been busy developing
maintenance tasks for the
New Engine Option...
AAV_April 2017.indd 39
30/03/2017 4:23:27 PM
Links Archive AAV March 2017 AAV May 2017 Navigation Previous Page Next Page