United Airlines latest adoption of the Performance Improvement Package retrofit kit for its 52 Boeing 777-200 is adding to a list of 17 airlines combining 350 aircraft that will receive the upgrades. PIP has been initiated by Boeing in 2008 in order to allow 777-200. 777-200ER and 777-300 to benefit from advances in aerodynamics refinements introduced with the newer Boeing 777-300ER and Boeing 737NG but not available on older 777-200, -200ER and -300 models. Introduced at a time when high fuel price is becoming the industry most pressing issue, the retrofit kit would in theory provide a 1% reduction in fuel consumption on a typical 777 trip along with lower emission of CO2 and NOx. Boeing has argued that an airline like United could save up to $200,000 per year with the new kit installed. United is following in the foot steps of Continental Airline with whom it is merging. Continental Airlines, the long established operator of 22 Boeing 777-200ER adopted the package in 2007. Greater return on the upgrade can be better realized by fleet-wide adoption by operators with sizable 777 (non-777-300ER) fleets. Naturally the notoriously larger 777 operators have already been mentioned as key adherents to the upgrade program; such as Air France, KLM, El Al, Austrian Airlines, Air New Zealand and Delta.
The retrofit consists of three combined engineering changes that can provide either a greater range or an increase in maximum take off weight or a lower consumption of fuel on typical flight. The first modification consists of a software-implemented aerodynamic reduction of drag encountered on the aircraft outer wing. The new software code would produce a 2 degree droop of the wings outer aileron causing the wing to twist slightly. This new aerodynamic attitude would trap undesirable air flow away from the 777 already very efficient wing tips during cruise further reducing overall drag. The second engineering improvement is the replacement of all 32 vortex generators with newly redesigned, more efficient vortex generators already well proven on the Boeing 737NG. The Vortex generators are small aerodynamic devices that are installed at specific points of an aircraft skin to channel airflow efficiently for aerodynamic benefits. In the 777 case they will also contribute to overall reduction of drag. The final portion of the upgrade involves installing new air inlet and exhaust mechanisms to the environmental control system (ECS). On most aircraft air is provided to the ECS via intake and exhaust located underbelly by the center wing section. Boeing found that on the 777, a redesigned ram air inlet door working in concert with variable-position exhaust louvers can generate additional thrust thus lowering fuel burn.
In period of escalating fuel prices, the scope of work required to complete the overall upgrade can decide on the package commercial success, especially if it must be implemented throughout an airline entire fleet. Boeing is providing a quick upgrade path that can be incremented by combining the vortex generators replacement and droop nose software installation in a few hours. This is very appealing to airline as combining these two upgrades delivers already up to 60% of the performance goals promised by PIP. Applying the new components to the Environmental Control System, a work requiring an aircraft to be taken out of service temporarily can only be conducted during heavy maintenance work. With operational expediency in mind, many airlines would opt for the two-phase upgrade ino order to begin partially offsetting high fuel cost. Overall the Performance Improvement Package is a solid life cycle extension package for airline which are hard pressed to replace early 777 on a still recovering credit markets. The 777 represents 919 deliveries for 1182 orders of which 635 are eligible too receive the PIP.