Guy Norris
As progress accelerates on a key visual system redesign, a wing refueling pod certification and the hopes for more international sales, Boeing believes its troubled KC-46A tanker program has finally turned a corner.
Marking a shift away from more than three years of delays, challenges and frustration for the U.S. Air Force, the program's brighter outlook builds on two agreements announced between Boeing and the service last April. The first covered the redesign and retrofit of a fully compliant boom operator remote vision system (RVS), at no cost to the government, while the second released $882 million of withheld payments to Boeing for previous noncompliance in 33 KC-46A deliveries.
“That was a real turning point, and it's been extremely collaborative since then,” says Boeing KC-46A Vice President and General Manager Jamie Burgess. “That's really been cultivated by the agreement that we reached on the new RVS system,” he says, acknowledging the change to the relationship with the Air Force. “For a while, we were at a bit of an impasse in terms of what needed to be done to address the Air Force's concerns. There's a lot of hard work left to go, but it's been a really long relationship now,” he adds.
Boeing is working on a two-phase approach to correct the well-documented RVS deficiencies that were revealed during flight tests. These defects mostly center on the oversensitivity of the aft-looking camera system to direct sunlight, which led to image issues in the hybrid 2D-3D video feed to the boom operator. “The first phase is really just intended to address that distortion piece of it, and that's primarily a software change that's being implemented now,” Burgess says. The fix, dubbed the enhanced RVS, “digitally addresses the distortion around the edges of the picture,” he adds.
The fix will also make viewing the system “more comfortable for the operator when looking through the 3D glasses,” says Sean Martin, KC-46A global sales and marketing leader, referring to the stereoscopic eyewear required for the system. “It makes the image more like what they are used to seeing in real life.”
The second phase, and the subject of the Air Force agreement, is RVS 2.0. Described by Burgess as “a full technological refresh of the system,” the revised package will include new cameras, new displays, a light-detection and ranging (lidar) system and all new supporting computing infrastructure. The redesigned aerial-refueling operator station will feature much larger 40-in. displays compared with the current 24-in. screens, giving the position “much more of a kind of home theater feel to it,” Burgess says. The image will remain in 3D but will be presented in color and 4K resolution. The Air Force has also opted for a collimated mirror projection method over an LCD option, “so we are working with them to mature that design,” the manufacturer adds.
In collaboration with the Air Force, Boeing completed the RVS 2.0 system readiness review in December and remains on track to hold the preliminary design review in the second quarter. The system is due to be fielded around late 2023 or early 2024.
The redesign will also be provisioned for semi-autonomous or autonomous aerial refueling (AAR), satisfying a long-term capability vision of both the Air Force and Boeing. “The computing-system upgrade will be able to handle the processing for future automation,” Burgess says. “In parallel, we're working toward developing all of the computing algorithms that will be required to track the receiver [aircraft] using machine-learning-type software. We will feed that into our boom control laws, so that it can go find the receptacle on that receiver,” he adds, referring to the KC-46A's fly-by-wire controlled boom.
The algorithm development work builds on the company's long-running collaboration with the Air Force Research Laboratory on autonomous refueling as well as other related efforts, such as the unmanned MQ-25 tanker for the U.S. Navy. “We have a lab now where we're developing those algorithms that we can move into KC-46 when the Air Force has a requirement for it,” Martin says. “We want to bring the capability to them, but we haven't received a requirement from them that says they need that. But we're working on it, and we're committed to it.”
Boeing says the end is also in sight for another issue that has overshadowed the tanker development: the long-delayed certification of the Cobham-developed wing air-refueling pods (WARP). The wing-mounted pods, along with a centerline station, form part of the tanker's hose-and-drogue system, which can deliver up to 400 gal. of fuel per minute, compared with 1,200 gal. per minute for the boom.
All KC-46As are provisioned at delivery to carry the pods, but in line with Boeing's initial decision to pursue both military and civil certification for the tanker and its systems, the aircraft cannot be operationally equipped with the system until the FAA approves the WARPs. The pods performed well during flight testing, but “the FAA has required a tremendous amount of testing in order to certify them,” Burgess says. “Similar pods have flown for years on other military aircraft, but they have never been FAA-certified.”
Although Cobham seriously underestimated how much work would be required for FAA certification, Burgess says: “We're at the very end of that testing and are just about done.” FAA approval is expected for the pod by the end of the first quarter. Previously, all certification work related to pods was concerned with ensuring that carriage of such systems was safe and would not affect the control and safe landing of the aircraft. “Now we had to look at certifying it to operate, so all the components—such as the ram air turbine on the front of the pod—had to be cleared for safe use,” Martin adds. “That's been the challenge for them, and they've done a great job stepping up to it.”
Another ongoing area of modification is revising a valve for the boom actuation system to correct a refueling issue specific to the Fairchild Republic A-10 attack aircraft. “The boom flies down and telescopes out to connect with the receiver aircraft, which pushes the boom up into a nominal refueling position,” Burgess says. At altitude, the A-10 with wing stores was only able to generate a force of about 650-lb. thrust resistance compared with the international standard of 1,400 lb. to which the boom was designed.
“We're changing the actuation system to make it just require less force to push it up,” Burgess says. “That's currently going through the critical design review with the Air Force.” He adds that the first qualification units are now being assembled. “We're also building up for a big full-scale lab test, and so that's well underway.”
Boeing is also preparing to design, develop and test a secure communications system, dubbed the Pegasus Combat Capability Block 1 upgrade, and expects to receive a contract for the enhancement package this year. The Air Force is studying which elements to include in the upgrade, and that puts the KC-46A on a path to play a potentially wider role as a battlespace communications node. But Boeing adds that a wing-mounted, podded, radio-frequency countermeasures system is not currently in the Block 1 suite.
With 42 tankers delivered by the end of 2020 and the firm orderbook bolstered by a $1.6 billion contract for the sixth production lot covering an additional 12 aircraft, Boeing is focused on maintaining a smooth assembly flow despite the disruption from the COVID-19 pandemic. The process includes rigorous new quality controls introduced after a series of discoveries of foreign object contamination caused the Air Force to temporarily suspend accepting the aircraft in April 2019.
“It's no secret that we realized that we had an issue as far as foreign object debris [FOD] on airplanes,” Burgess says. “We stopped the production line, and we stopped deliveries for a while and put in place a number of controls. There's a whole lot of work that goes on in the factory around what we call ‘clean as you go.' At the end of the shift, there is a cleanup to make sure that the airplanes that roll out of the factory are perfectly clean.”
The decontamination focus continues when airframes are rolled from the factory into the nearby Everett Modification Center, where all the military equipment is installed. “We do a complete FOD sweep of the airplane when it enters and again when it leaves to go to the delivery center,” Burgess says. “The aircraft delivering today are very clean. It's been a big cultural shift for the program.”
Production is currently split roughly evenly between commercial 767-300F freighters and KC-46A variants—a divide that sustains the line at about three airframes per month. With the latest order, confirmed on Jan. 12, Boeing is now on contract for 79 tankers out of an intended total of 179. The firm orderbook is expected to grow again to 94 when the Air Force awards the next contract for a further 15 aircraft under production Lot 7, which legislators approved in December.
Although program delays held up initial deliveries to the Air Force until January 2019, Burgess says the subsequent flow of operational aircraft to four bases marks an unprecedented pace for any recent modern weapons system. “I'm not aware of any other major military program that's done this,” he adds. “We delivered 28 in 2019. We'll do 14 this year.”
Boeing maintains the flexibility to introduce slots into the production skyline for international sales, the first of which is to Japan. The aircraft, the first of four that the Japan Self-Defense Force has ordered, is due to make its first flight sometime this quarter. The U.S. Congress has also approved the sale of eight aircraft to Israel, and Boeing is pursuing other prospects in Southwest Asia and the Middle East, particularly in Qatar.
https://aviationweek.com/defense-space/aircraft-propulsion/key-upgrades-mark-2021-turnaround-year-kc-46a
