Boeing [BA] and BAE Systems are working on an Active Parallel Actuator System (APAS) that will provide pilots more control and tactile cueing so they know they’re approaching the edge of the envelope on their CH-47F Chinook, a Boeing official said.
“Our expectation is that APAS would be retrofittable into existing aircraft,” Patrick Donnelly, director of U.S. and Foreign Military Sales Chinook programs at Boeing, told Defense Daily.
The APAS is the next generation Digital Advanced Flight Control System (DFACS) now integrated into the CH-47F model Chinook and is being fitted on the CH-47G model.
APAS is a joint program with funding from Boeing and BAE, and involves Army Special Forces and the Army Aviation Applied Technology Directorate, he said. The system was demonstrated on a Chinook and an Apache helicopter.
“Pilots have so much going on, this is another cue to help them,” Donnelly said.
Pilots will get feedback from the stick on whether they’re approaching the edge of the flight envelope. Not only that, but Donnelly said APAS is “smart enough” to adjust to different performance characteristics. But if the rotor is straining, the stick will vibrate, the same would happen if an engine temperatures are running hot.
There wouldn’t be a lot of reworking of the system to retrofit APAS. It would mean exchanging some equipment in the flight control closet, Donnelly said.
Boeing and BAE have been developing APAS for a while, he said, the DFACS development piggybacking on an AATD Advanced Vehicle Management System contract.
The Army and U.S. Special Operations Command are interested and anxious to get this equipment, Donnelly said.
“APAS will give them additional power, Donnelly said. Oddly enough, there is enough conservatism in what we tell the pilots to do, so they can utilize more of the engine than they were using before. It raises the limits.”
The technology still needs to be demonstrated on an aircraft, and then it must be qualified so it could go into production, he said. Right now, it’s too early to tell what the production cost would be.
In addition, trade studies are under way for a Chinook Block II, Donnelly said.
The studies look at what is affordable and what priorities are. Under way right now are finding out user requirements and priorities. That will be followed by understanding what technologies are available, assessing them against requirements and priorities and determining development costs.
“The key is the maturity level,” Donnelly said. What they look for is Technology Readiness Level (TRL) 6 for Block II that could be driven to TRL 9, the production ready level, in four to five years, he said.
One thing Donnelly would like to see in Block II modernization is increased payload.
The Chinook has gotten heavier over time, and Boeing will look for new technology to restore Chinook lift.
New composite rotor blades would help, he said, such as the new design Advanced Chinook Rotor Blade. The new blades have a new aerodynamic shape, a new twist, and a new tip design that could give the helicopter 2,000 pounds of lift over what it can do today.
Additionally, “What we’d like to do is take systems already developed,” Donnelly said. That could be something like the electrical system developed by Canada for their Chinook. It is a heavier system but more capable than the one on the current CH-47F.
“As we refine Block II, there will be bits and pieces of interest to many customers, Donnelly said. There’s also interest in APAS from other customers and it also could be transferable to other platforms.