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Wednesday, June 1, 2011

Next Generation Tanker

Boeing’s winning bid for the KC-46A refueling tanker borrows system and design characteristics from the airframer’s 787 Dreamliner

By James W. Ramsey

After a long and controversial bidding and contract process, Boeing won the long-awaited U.S. Air Force (USAF) KC-46A aerial refueling tanker contract, bringing with it a long list of avionics suppliers to equip the aircraft.

In a program to replace 179 of the Air Force’s 400 KC-135s which first entered service in 1956 Boeing received a $3.5 billion fixed-price incentive contract on Feb. 24 for development and delivery of the first 18 combat-ready tankers by 2017. All told, the overall program for 179 tankers is valued at upwards of $30 billion.

The tanker program has undergone a series of bidding rounds in the last three years. In 2008, European EADS and its partner Northrop Grumman were awarded the initial contract over Boeing, but after complaints about the bidding process, the Defense Department reopened the contract.

“Boeing has always been committed to the integrity of the competitive process, and the men and women across our Boeing commercial and defense teams and our entire supplier network are ready to extend that commitment to delivering these tankers on time and on budget,” said Jim Albaugh, president and CEO of Boeing Commercial Airplanes.

Revising its earlier plans, after losing a previous competition, Boeing based its winning bid on its commercial 767-200. The KC-46A will be equipped with “an advanced KC-10 (tanker) boom with an expanded refueling envelope, increased fuel offload rate and fly-by wire control system,” said Boeing spokesman William Barksdale. The aircraft is also being designed to transport cargo, passengers and patients.

The aircraft includes a digital flight deck featuring Boeing’s 787 Dreamliner cockpit displays “and a flight control design philosophy that places aircrews in command rather than allowing computer software to limit combat maneuverability,” Barksdale said.

According to the Air Force, the tanker must meet nine performance parameters refueling capabilities; fuel offload and range; communications, navigation, surveillance, air traffic management capabilities; airlift capability; receiver air refueling capability; force protection; net-ready; survivability; and multi-point refueling. With a maximum fuel capacity of more than 212,000 pounds, and the ability to transfer more than 207,000 pounds of fuel, the KC-46A has a refueling receptacle that allows the aircraft to receive fuel from other boom-equipped tankers at the rate of 1,200 gallons per minute, according to the Air Force.

Digital Flight Deck

A key element of the aircraft’s digital flight deck is Rockwell Collins’ Large Display System featuring four 15.1-inch LCDs developed for the 787 Dreamliner. Rockwell Collins was also chosen to provide the tactical situation awareness system (TSAS), which combines the traffic alert collision avoidance system (TCAS), Mode S transponders, terrain awareness warning system (TAWS) and weather radar functions into a single unit. As in the 787, all the weather information from the receiver/transmitter is processed along with the TAWS and TCAS for display on the flight deck.

Rockwell Collins was also chosen to supply the communications and navigation equipment including the UHF-VHF radios/tactical airborne navigation system (TACAN). It is assumed this navigation package will also include localizer and glideslope marker beacons and VOR and that the communications system will also include sitcom capabilities. It is also anticipated the KC-46A will feature dual head-up displays to be provided by Rockwell Collins’ Flight Dynamics Unit.

Raytheon is supplying the military GPS portion of the navigation system.

Honeywell is supplying the air data inertial reference unit for the navigation system. The air data system software includes remotely located air data modules that connect to pitot probes and other sensors. It relays that information digitally to the air data computational software hosted by the central computing system.

France’s Thales Avionics is providing the Integrated Standby Flight Display (ISFD), a LCD that presents aircraft pitch and roll attitude, heading and landing approach deviation data in a format similar to the primary flight displays. The same Thales display is found on all Boeing’s newer aircraft.

The Rockwell Collins Central Maintenance Computer consolidates all maintenance information coming from all the airplane systems and then helps isolate faults and provide troubleshooting directions to a maintenance technician, according to the company.

GE Aviation is supplying its TrueCourse Advanced Flight Management Computer/Multiple Purpose Control Unit. It is expected to be similar to GE’s Common Core System for the 787 Dreamliner, which replaces multiple computers, hosting a number of avionics and utility functions.

“We are committed to bringing our next-generation technologies to this new tanker platform,” said Lorraine Bolsinger, president and CEO of GE Aviation Systems. “The flight management system will enable the aircraft to perform with navigation precision not currently available to the tanker fleet. Our technologies will help enhance operational efficiencies and will enable the aircraft to perform to the demanding mission requirements of the USAF Tanker.”

Teledyne Controls, based in El Segundo, Calif., is equipping the aircraft with its Aircraft Condition Monitoring System (ACMS) software and digital flight data acquisition unit (DFDAU), which samples conditions and digitizes the flight data for use by the aircrews and maintenance technicians. (The ACMS function is also an engineering tool designed to set up trend monitoring and screening routines for engines and electrical buses.)

Teledyne last October was picked by Boeing to supply its DFDAU as a key component in Boeing’s Airplane Health Management (AHM) system for the next generation 737 aircraft.

“Teledyne’s DFDAU combines functions of mandatory data acquisition and recording with the aircraft condition monitoring system (ACMS), hosting a set of custom ACMS applications designed to acquire and output data into ground analysis tools. This aids operators in protective maintenance and enhanced operations,” said Armen Nahapetian, vice president, aircraft data and information systems at Teledyne.

An enhanced warning electronics/thrust management computer is being provided by BAE Systems Controls, based in Irving, Texas. Telephonics Corp., of Huntington, N.Y., is providing the audio control panel/ audio management unit for the aircraft, according to Boeing.

Aircraft protective systems on the KC-46A will include radar warning receiver/data transfer units produced by Raytheon.

In addition, the tanker will have large aircraft infrared countermeasures (LAIRCM) for protection from heat-seeking missiles. These systems are provided by Northrop Grumman’s Defense Systems Division in Rolling Meadows, Ill.

Innovative Solutions & Support (IS&S), based in Exton, Pa., has been selected to supply the aerial refueling operator control display (AROCD), although the contract had not yet been finalized, according to David Green, of IS&S Military Programs.

Cobham has been selected by Boeing to provide hose and drogue aerial refueling systems for the tanker. These systems will be manufactured by Cobham Mission Equipment at its new specialist air-to-air refueling facilities in Davenport, Iowa. Cobham said it expects to equip each aircraft with a centerline drogue system.

About 30 tankers will also be provided with a pair of wing-mounted aerial refueling pods, according to Greg Caires, Cobham’s vice president of media relations. The company has delivered more than 1,000 systems designed for tactical and strategic “tanking” for fixed wing aircraft and helicopters.

Tanker Boom

The USAF air fuel transfer method is through the boom and receptacle air refueling technique. The U.S. Navy, Marines and NATO aircraft have traditionally used the hose and drogue refueling method to refuel aircraft including F/A-18E/F Super Hornet and AV-8B Harriers.

The KC-46A features an advanced aerial refueling boom, provided by Boeing, based on the KC-10 Extender. It will be an advanced fly-by-wire boom with a 1,200-gallon per-minute offload capability. (This compares with the KC-10’s maximum rate of 1,100 gallons per minute transferred to the receiver aircraft during boom refueling operations.)

The KC-46A boom has a refueling envelope three times the size of the KC-135 boom, Boeing said, and features an electronic independent disconnect system (IDS) that eliminates nozzle binding and brute force disconnects, as well as a full-time automatic load alleviation system (ALAS) designed to reduce the workload of the boom operator and virtually eliminate nozzle binding. The new tanker will also have a permanent centerline drogue system and two removable wing air refueling pods featuring 400-gallon per minute offload capability that provides simultaneous multi-point refueling.

The KC-10, a modified DC-10 tri-engine jetliner, entered service in 1981 and is a tanker and cargo aircraft used by USAF’s Air Mobility Command. Using either the aerial refueling boom, or a hose and drogue system, the KC-10 can refuel a wide variety of U.S. and allied military aircraft. It has seen recent service in Afghanistan and Iraq, where it flew some 1,390 missions delivering critical air refueling support to numerous joint and coalition receiver aircraft, the Air Force said. Some 59 KC-10 tankers are in the active Air Force inventory.

The KC-10’s boom operator also controls refueling operations through a digital fly-by-wire system. Sitting in the rear of the aircraft, the operator can see the receiver aircraft through a wide window. The KC-10 also has an automatic load and alleviation system and independent disconnect system to enhance safety and facilitate air refueling. The KC-10 can be refueled by a KC-135 or another KC-10A to increase its delivery range.

There were 20 KC-10s modified to add wing-mounted pods to further enhance aerial refueling capabilities. Ongoing modifications include the addition of communications, navigation and surveillance equipment to meet future civil air traffic control needs.


KC-46 Avionics Suppliers

Supplier System
AMETEK Integrated Cabin Pressure/Duct Pressure Indicator
BAE Systems Controls Enhanced Warning Electronics, Thrust Management Computer
Flight Line Electronics Brake Accumulator Pressure Indicator
Hamilton Sundstand Air Supply Control System, Cabin Air Conditioning and Temperature Control System, On-Board Inert Gas Generation System, Electrical Power Generation System
Honeywell Air Data Inertial Reference Unit
Rockwell Collins Tactical Situational Awareness System, UHF-VHF Radios, Tactical Airborne Navigation, Large Display System, Central Maintenance Computer
Teledyne Controls Aircraft Condition Monitoring System, Software, Digital Flight Data Acquisition Unit
Telephonics Corp. Audio Control Panel/Audio Management Unit
Thales Avionics Integrated Standby Flight Display
GE Aviation P31/32 Power Panels, Advanced Flight Management Computer/Multipurpose Control Unit
Raytheon Military GPS, Radar Warning Receiver, Data Transfer Unit
Northrop Grumman Large Aircraft Infrared Countermeasures
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