Boeing is almost ready to bring a series of avionics and engine upgrades to its flagship 747-8 aircraft, claiming a further reduction in burn of 1.8 percent. The airframe manufacturer began flight testing the initial performance of the GEnx-2B Performance Improvement Package (PIP) in May, and is now finishing up the flight test program with the first PIP-equipped 747-8 expected to enter service by the end of the year.
[Boeing 747-8 flight test aircraft. Photo, courtesy of Boeing.]
Testing has also confirmed upgrades to the flight management computer (FMC) software, which has added Required Navigation Performance (RNP) Authorization Required (AR) to the aircraft’s approach and departure procedures.
Additionally, the FMC software upgrades adds an optimal climb feature, which allows for more predictive planning of “winds aloft,” according to Bruce Dickinson, chief project engineer for the 747-8 at Boeing.
“With the FMC, we’ve got the optimum steps feature which allows for some more predictive planning for winds aloft, so you can get to a more optimal altitude based on your winds aloft,” said Dickinson. “We have the RNP AR feature that’s activated that lets us use RNP approach and depart procedures, which are better for efficiency, so that’s fuel and emissions savings that goes with it. The third piece of the FMC is quiet climb, which is auto management for our threshold for takeoff and climb for really noise abatement.”
Dickinson said the aircraft’s tail fuel tank has also been reactivated to provide added range, and a minor software change to extend the length of time the fuel remains in the aft tank will also improve the performance. That and other upgrades introduced since the 747-8 first entered service in 2011 will produce a combined 3.5 percent improvement in fuel efficiency.
Boeing collaborated with Honeywell and GE on the PIP upgrades, as Honeywell supplies the FMC and GE supplies the engines for the 747-8.
The fuel efficiency improvements were more of a result of the engine hardware change, leveraging experience from the GEnx-1B engine, along with a software upgrade for the aircraft’s electronic engine control (EEC), resulting in a fuel savings of $1 million per aircraft per year.
"We absolutely met our targets. Its a million dollars per airplane per year," said Dickinson. "We've been using that as kind of a practical reference point and our fuel burn savings matched our expectation in our flight test program."
According to Dickinson, the software upgrades will also be available to 747-400 operators, although the fuel efficiency improvement only applies to the passenger and freighter versions of the 747-8 because of the engine changes.
Other improvements on the 747-8 since its entry into service include a weight reduction totaling 7,700 lbs. to help increase the available payload.
Boeing is also considering future improvements that could further increase the range of the aircraft and raise fuel efficiency as well.
“We’re quite excited about what it means to the future of the product and it demonstrates all the investment we’re making in continual improvement. We’re as excited as the airlines are to see it up flying,” said Dickinson.
The engine and avionics software upgrades will be standard on new production 747-8s, and delivery of the first PIP-equipped aircraft is scheduled to occur before the end of the year.