The Naval Air Systems Command (NAVAIR) considers the Marine Corps CH-53K Heavy Lift Replacement helicopter a derivative of the hard-flown CH-53E in operation today. In fact, new avionics, engines, transmission, structures, rotor blades and fly-by-wire (FBW) controls make the Sikorsky ’53 Kilo an ambitious stretch of existing technology.
The Kilo integrated cockpit and open system architecture build on the Rockwell Collins Common Avionics Architecture System (CAAS) in the U.S. Army CH-47F and UH-60M Upgrade, and the Avionics Management System (AMS) in the commercial Sikorsky S-92 and Canadian Forces CH148 helicopters. The new “glass cockpit” also uses hardware and software in the Marine Corps CH-53E CNS/ATM (Communication Navigation Surveillance/Air Traffic Management) upgrade and German CH-53G.
“We’ve taken a lot of the best pieces from other programs and put them together for the ’53K,” said Sikorsky avionics/electrical Integrated Product Team lead Kyle Delong.
The Marine Corps plans 200 CH-53Ks to retire CH-53Es and CH-53Ds. The three-engined Heavy Lift Replacement helicopter passed a Critical Design Review last summer and should fly for the first time in late 2013. To implement Marine Sea Basing and Ship-to-Objective Maneuver concepts, the Kilo version has to sling-load 27,000 pounds over 110 nautical miles at sea level more than twice the load of today’s CH-53E yet fit the same amphibious assault ships. The ’53K is also expected to carry four times the payload over the same distance at high density altitudes like those in Afghanistan. For all its brute power, the Kilo with fly-by-wire flight controls has to be easier to fly than the ’53E and cost half as much to operate and support.
Development of the CH-53K was initially paced by the fatigue lives of the CH-53E fleet. NAVAIR ultimately accepted a ’53E Service Life Extension Program and slipped Kilo Initial Operational Capability from 2015 to 2018 to reduce development risk.
More measured development makes the program more efficient in qualification testing, according to Michael Torok, Sikorsky vice president and chief engineer for Marine Corps programs.
“I really think the key here is the extent of the up-front work we’ve done with the fleet customers, combined with the lessons learned from the S-92, the Canadian program, the Black Hawk M and MU, and a real system engineering focus to really get this right, right off the bat,” Torok said. “The ’53 has the luxury of following these other programs.”
Flight-worthy hardware and production-representative software are now in CH-53K Systems Integration Labs (SIL) located at Sikorsky Aircraft in Stratford, Conn., and Rockwell Collins in Cedar Rapids, Iowa. Qualified hardware will be delivered early next year for test aircraft.
The development program flies four Engineering Development Models. Production deliveries for the Marines stretch from 2017 to 2028, and the new heavy lifter has already drawn interest from potential international customers.
Sikorsky chose principal subcontractor Rockwell Collins in 2006 to give the CH-53K an Avionics Management System like that in the successful S-92. AMS controls and displays and mission computing resources themselves evolved from the CAAS in Chinooks and other helicopters.
“We’re technically not a CAAS cockpit,” said Dan Toy, Rockwell Collins principal marketing manager for rotary wing aircraft. “We’re kind of a CAAS derivative based on the ’53E and ’53G.”
CNS/ATM Upgrade
The CH-53E CNS/ATM upgrade flown last November mixes five portrait-format Multi-Function Displays (MFD) and dual center-console Control Display Units (CDU) with some electromechanical gauges.
“The Marines were trying to leverage what had been developed for the Army cargo helicopters, and we provided a very affordable solution to upgrade the ’53E,” said Toy, of Rockwell Collins. Production of the CNS/ATM upgrade for Marine CH-53Es has been deferred, but the partial glass cockpit may be applied to Navy MH-53E minesweepers around 2012.
Separate from the CNS/ATM upgrade, Rockwell Collins gave the German CH-53G cockpit landscape-format cockpit displays and new performance management functions. “It started close to CAAS but evolved with a lot of German-unique requirements for production and certification,” said Toy. “The German ’53 system has headed off on its own path largely, away from the ’53E and ’53K.”
Compared to the ’53E CNS/ATM and ’53G upgrade, the Kilo cockpit uses next-generation MFD and CDU hardware and customized software. Like the CAAS in Army Chinooks, the Kilo AMS has five 6-by-8 inch portrait-format MFDs, compatible with night vision goggles, to present integrated flight and navigation symbology for IFR operations at night. The interchangeable displays can show the embedded Harris digital map and imagery from the Raytheon AN/AAS-29A Forward Looking Infrared (FLIR) gimbal. Together with the CDUs and two Multi-Function Control Units, they enable the crew to access UHF/VHF/SATCOM communications and Defensive Electronic Countermeasures (DECM). Addition of a troop commander’s display planned for the Kilo cabin has been deferred.
Marine CH-53K requirements call for CNS/ATM compatibility to navigate civil airspace, ETAWS (Enhanced Terrain Avoidance Warning System) functionality and embedded training capability.
They also call for the cargo helicopter to exchange digital data in network-centric warfare scenarios. Rockwell Collins provides the ARC-210 multi-band radios that are standard for Navy/Marine Corps aircraft. The fifth-generation ARC-210 in the CH-53K supports the latest Variable Message Format waveforms and SATCOM links. Link 16 capability for the CH-53K has been deferred for now, but the heavy lifter will have a Multifunctional Information Distribution System (MIDS) terminal to implement Link 16 with software. “All the network capability is there as soon as they designate which waveform they want to use and what radio they want to run it through,” said Brian Cyr, Rockwell Collins CH-53K program manager.
Like CAAS, the CH-53K AMS uses MFD 268 multifunction displays and CDU-7000 control/display units, and an integrated processing cabinet. “A lot of the software is different. The PVI (Pilot-Vehicle Interface) is different. We have a lot of (software) re-use, but how it gets presented to the pilot is different,” Cyr explained.
Kilo displays, for example, show dial formats rather than the vertical tape readouts in the ’53E CNS/ATM cockpit. The CH-53K AMS will also perform Center-of-Gravity calculations tied to fuel consumption.
Sikorsky conducted 25 Crew Station Working Group meetings with NAVAIR and fleet operators to formulate CH-53K flight displays. Marine pilots evaluated external cargo/load, RNAV and other symbology for the Kilo AMS on synoptic displays using desktop computers at Stratford and Patuxent River, Md.
“They don’t have to have a mental model of the system; they can actually see it,” said Sikorsky’s Delong. The desktop simulators continue to feed changes back into Kilo cockpit requirements. “We keep those up to date to make sure they’re seeing the same thing in the real aircraft,” Delong said.
Desktop symbology migrated to the Sikorsky motion-base simulator in Stratford with CH-53K displays and fly-by-wire cyclic and collective inceptors. The new Marine helicopter capitalizes on FBW hardware and software developed for the Army UH-6M Upgrade and Canadian CH148. The triplex flight control system has dual self-checking processors on each of the three channels working redundant hydraulic main and tail rotor actuators. Hamilton Sundstrand flight control computers interface with BAE Systems active inceptors a sidearm cyclic and limited-travel collective that give the pilot tactile cues based on control, power and structural limits.
The CH-53E CNS/ATM provides no flight director and no direct interaction between mechanical flight controls and cockpit displays. The ’53K AMS takes flight guidance cues from the FBW system and embedded GPS, and runs system diagnostics. “This is a fly-by-wire aircraft, and our cockpit has major workload reduction features integrating our fly-by-wire system as well,” Delong noted.
Marine pilots have so far conducted three part-mission evaluations with the Kilo cockpit tied to FBW flight control models. “We have high-fidelity flight control laws that can be evaluated in our facility. Where prudent, we modify the design to meet their needs,” Delong said.
The Sikorsky motion-base simulator is one of five SILs outfitted with actual CH-53K hardware and software. A ribbon-cutting ceremony last October opened the Sikorsky Avionics/Electrical SIL to test the AMS with the DECM and other Government Furnished Equipment.
An electrical SIL has the CH-53K main generators and auxiliary power unit and can run independently or with the Avionics SIL. Rockwell Collins set up its own Avionics SIL at Cedar Rapids identical to that in Stratford. A Sikorsky Flight Control SIL that was undergoing system-level checkout ties the Kilo cockpit to actual aircraft servos to check FBW software and hardware changes before they go to the real aircraft.
Open Architecture
CAAS and AMS in all their forms use a distributed processing architecture with “smart” displays and controls. The CH-53K AMS has 18 Power PC processors in nine line replaceable units (Weapon Replaceable Assemblies). A high-speed Local Area Network carries AMS internal communications between processors. Data Concentrator Units under development by Curtiss Wright Controls in City of Industry, Calif., will convert discrete inputs from engine, transmission, fuel and other aircraft sensors to digital signals for databuses to feed the AMS.
Legacy equipment such as the radios and MIDS terminal are controlled through a Mil-Std-1553B databus. The DECM suite has its own 1553B bus to integrate the Northrop Grumman AN/ALQ-24 Directed Infrared Countermeasures set, Northrop Grumman APR-39B(V)2 radar warning receiver, Honeywell AAR-47(V)2 missile/laser warning receiver and BAE ALE-47 improved countermeasures dispenser.
Like other Rockwell Collins Flight 2 avionics, the CH-53K AMS provides a Modular Open System Architecture with PCI backplane interfaces for hardware and a Posix operating system for software applications from different suppliers.
AMS displays show Raytheon FLIR imagery from an analog video interface. The system hosts Warning/Caution/Advisory software from Sikorsky, digital map software from Harris, and ETAWS software developed by NAVAIR. Most software is field-loadable to upgrade systems without removing them from the aircraft.
CH-53K processors and databuses also have room to grow. “Our customer requirement is 50 percent for most systems,” Delong said. “For the AMS, we have a 65 percent requirement for memory and processor reserve. We have a lot of software already accounted for in those reserves, like Link 16.”
The CH-53K has been designed to look after itself to reduce life cycle costs. Design-for-the-maintainer working groups helped optimize wire harness and equipment installations for easy access.
The Kilo AMS hosts Integrated Vehicle Health Management System (IVHMS) software from Goodrich in Burnsville, Minn., to generate comprehensive systems information. “It’s certainly a carryover from the S-92 with lessons learned,” said Delong. “What’s new and significant is the 95 percent requirement for fault detection; we also have a 90 percent requirement for fault isolation.” The Kilo Integrated Supportability System displays health data on a maintainer’s handheld computer.
CH-53K AMS fault isolation/fault detection functions are the same found in CAAS. “We have one of our software apps on every processor,” said Cyr, of Rockwell Collins. The health monitor application polls software and hardware and feeds results to the IVHMS for maintenance decisions.