1. WHITE PAPER
A320 Sharklet In-Service Retrofit Challenges
by Ricardo Carvalho
INTRODUCTION
The A320 Sharklet In-Service Retrofit is one of the most challenging modifications launched in
the last decades for civil aircraft to be accomplished by the MRO community.
The ultimate purpose is to save fuel with lower CO2 emissions, but it also increases the
operational life (operational service goal extension) of the aircraft in 36.000 flight hours (avoiding
the activation of the ESG), increases payload/range capacity and higher residual value of the
aircraft.
In order to install the Sharklet on the legacy in-service fleet, the aircraft needs to be structurally
reinforced to be able to sustain with the wing increasing loads induced by a heavier component.
Additionally it is required to upgrade several avionics components like the PDB, SEC, ELAC, FAC,
FCDC & FWC to cope with the different wing lift capability.
We were involved with this modification since the beginning of the project, culminating with TAP
being the first European Airline to embody this Retrofit in one A320 aircraft of its fleet.
MODIFICATION PHASES
The Retrofit has several steps that can be grouped in the following main phases:
- Access removal and aircraft preparation
- Legacy wing structural components removal
- New structural components adjustment & pre-installation
- New structural components final installation
- Bottom Skin reinforcement by cold working
- Sharklets installation
- Avionics upgrade
- Close and Tests

2. MRO CHALLENGES & RISKS
TAP works closely with the Original Equipment Manufacturer (OEM) and with other suppliers in
order to find the best practices for the modification embodiment.
We have developed internal procedures and strategies specifically dedicated to the Sharklets
Retrofit, allowing a greater flexibility and organizational responsiveness oriented for Turn Around
Time (TAT) & Man-hours optimization with the highest quality standards.
One of the main challenges is to understand the critical chain in order to identify and manage
constrains. For example, which are the tasks that can be done in parallel and the number of
resources allocated at each main phase.
Due to the high number of days during which the modification occurs it is relevant to address the
mechanics motivational aspects. The challenge is to make it easier the most demanding tasks
and to manage the knowledge in order to keep the workers confident with their performance as
well as providing state of the art conditions and tooling.
Our efficient solution is based on the experience of several aircraft modified (for TAP and Third
parties), material handling, tooling, job cards, knowledge management and planning & production
control.

3. A320 Sharklets Retrofit Success Factors
Continuous Improvement Process for A320 Sharklets Retrofit
The level of intrusion of the modification and the large number of small details that must be
executed simultaneously highly increases the risks of embodiment for any MRO once it strongly
affects the structural integrity of the aircraft, namely at the wings level. This modification not only
requires strong skills in sheet metal structures but also in managing the several areas that
supports the work itself.
Jobcards &
knowledge
Planning &
Production
Control
Material &
Tooling
Planning
Modification
Production
Measurement
& Control
Phase &
Blocking Points
Analysis
Processess
Improvements
Implementation

4. PLANNING
Since the Sharklets Retrofit project can be embodied in parallel with other projects like, C-check,
it is important to use a planning control tool to have a clear view of the work evolution, throughout
the project and between projects, to monitor and manage the critical chain.
In Aircraft Area, TAP uses the critical chain concepts– CCPM - Critical Chain Project Manager a
tool of Theory of Constrains (TOC), to prepare, plan and manage physical and human resources
allocated to the organization projects, like aircraft C-checks or Sharklets retrofits modifications.
In these projects we had to deal with uncertainties, variability, complex & unpredicted flow paths
and unpredictable supplier response times driven from the C-check tasks that can influence the
Sharklets Retrofit.
With the CCPM, it is possible to define the rules that effectively manage projects, setting the
appropriate pipeline, reducing multitask, establish the WIP (work in progress) control and
managing priorities by using buffer analysis for capacity decisions. The CCPM is part of our
Continuous Improvement Process (CIP) that contribute to reduce TAT in each Sharklets Retrofit
performed.
We gain a 42% reduction between the first and the fourth Sharklets Retrofit
SUMMARY
TAP knows since 1945 how the ground time of an aircraft is important for an airline company
competitiveness, and so we build the first Sharklet In-Service Retrofit “Assembly Line” for the
Airbus A320, allowing our customers to safely incorporate Sharklets to their legacy fleet, avoiding
substantial investments with tooling and additional costs with repairs.
Our CIP has enabled TAP to build an efficient process, not only in the basic goals (quality and
TAT) but also extending to all other areas that influence the work in the hangar shop floor (tooling,
logistics, engineering, planning and resources).TAP is going to continue its workflow optimization
with the purpose of not only offering to our customers the most experiment retrofit, but also the
most attractive and competitive Sharklet In-Service Retrofit solution worldwide.
1ª A/C 2ª A/C 3º A/C 4º A/C
Sharklets Retrofit-TAT reduction
-11.6%
-27%
-10.5%