This white paper discusses the challenges of retrofitting Airbus A320s with sharklet wingtip devices. It describes the multi-phase retrofit process which is challenging due to the level of intrusion and impact on the aircraft's structural integrity. TAP Airlines has developed efficient procedures and strategies to optimize the retrofit's turnaround time and manage constraints. Through continuous improvement, TAP reduced the retrofit time between the first and fourth aircraft by 42%, building an efficient assembly line process.