TWENTY YEARS AFTER AN AVIATION Mission Area Analysis identified the need for a new light helicopter, the U.S. Army still waits for the RAH-66 Comanche. The latest program restructuring delays Comanche’s initial operational capability (IOC) until 2009.
Yet despite its Cold War origins and the promise of unmanned aerial vehicles (UAVs), Comanche still makes sense for an Army transforming itself into an agile, deployable, digital fighting force.
Budget politics have restructured the Comanche program a half-dozen times since Boeing and Sikorsky won the Light Helicopter Demonstration-Validation (Dem-Val) contract in 1991. The latest plan follows the two Dem-Val prototypes with four engineering manufacturing and development (EMD) helicopters and five training aircraft. A low-rate initial production (LRIP) decision in December 2006 will give the Army its first Block I production Comanche in 2008.
To justify full production, LRIP Comanches will then have to prove themselves in initial operational test and evaluation, as well as force development, testing and experimentation. As recently as this year, the Army still had an acquisition objective of more than 1,200 RAH-66 helicopters. However, after the program’s sixth restructuring, the service cut back its order to 650. The Army’s current requirement is for 819 helicopters, though the final number may be much higher. Depending on the final number and the production rate approved, deliveries may stretch through 2022.
The nightmare of defense planners in 1982 was a massive combined arms assault by the Warsaw Pact across a German battlefield tainted by nuclear, biological, or chemical warfare. Back then, the U.S. Army had no plans to invade Grenada, Panama, or Haiti. It never expected to prowl the Persian Gulf looking for Iranian minelayers and gunboats. The Cold War Army never predicted a fast-moving desert war in Iraq, nor did it foresee Special Forces pinned down in a decaying Somali city. The Army of the 1980s never expected to police ethnic enclaves in a fragmented Yugoslavia. It certainly never planned to hunt al Qaeda terrorists and Taliban fighters in Afghanistan.
Unexpected conflicts nevertheless happened, and Army helicopters provided essential mobility, reconnaissance, and firepower every time. Over the full spectrum of possible future conflicts, the Comanche still offers the Army a reconnaissance system with high-resolution sensors, precision weapons and digital communications in a low observable vehicle.
That combination remains relevant in an unpredictable world with evolving air defenses. Unlike another controversial weapons system, the canceled Crusader self-propelled howitzer, the RAH-66 fits well into Army Transformation.
The mission is still there
Today’s Army leadership intends to transform the service into a more versatile fighting force for the full spectrum of conflicts. The Objective Force will deploy a combat brigade anywhere in the world in 96 hours, a division in 120 hours, and five divisions in 30 days.
Deployed forces will be more survivable, lethal, and sustainable than Cold War Army formations; they will be expected to exploit a "digital battlefield," where information is a powerful weapon.
The Objective Force is supposed to bring heavy-force firepower into areas today accessible only with light forces. The RAH-66 Operational Requirements Document (ORD) demands rapid deployment. Eight Comanches will fit in a C-5A Galaxy, four in a C-17. The ORD requires that armed scout helicopters be ready to fight 45 minutes after arrival. Today’s Apache takes hours to unload and reassemble.
When strategic airlift is unavailable, Comanche self-deploys 815 nautical miles. This is made possible through the helicopter’s Integrated Retractable Aircraft Munitions System (IRAMS), which reduces drag, and auxiliary tanks that bolt onto the External Fuel and Munitions System (EFAMS). The Army has backed off on its ambitious 1,260 nm requirement to reach Europe via the Azores. Once at its base, the self-deployed Comanche must be armed and off to war in 35 minutes.
In the theater of war, the Comanche should need far less support equipment than the Apache and other Army helicopters. Today’s aircraft are maintained with about 320 standard hand tools. The RAH-66 deploys with just 49 tools. Apache battalions are followed by an Electronic Equipment Test Facility in two big trailers.
The Comanche has integrated diagnostics and prognostics. A notebook-sized Portable Intelligent Maintenance Aid (PIMA) stowed in the aircraft serves as an electronic test set, logbook and maintenance manual. Significantly, the RAH-66 needs no Aviation Intermediate Maintenance facility in-theater.
Equipped with radar, two Hellfire missiles, eight 70mm rockets, and 320 rounds of 20mm ammunition, the stealthy scout has a radius better than 250 kilometers or endurance around 2.5 hours.
Operations in mountainous Afghanistan have underscored the importance of performance at high density altitudes. With the uprated T800-LHT-802 engines and drooped main rotor tips due on production Comanches, the RAH-66 should sustain a 500 foot-per-minute vertical rate of climb at 4,000 feet and 95ï¿½F.
The armed scout scans the battlefield with millimeter-wave radar, a second-generation thermal imager, and a high-resolution near-infrared TV camera. The quality of that sensor suite cannot be matched by the low-cost sensors planned for the Army’s Shadow 200 Tactical Unmanned Aerial Vehicle (TUAV) and other UAVs.
Unlike the Global Hawk loitering offshore at 65,000 feet to stay outside a growing threat envelope, the quiet, low observable Comanche is meant to take a close look at the enemy. While a big strategic UAV can be expected to work through a long chain of command, the Comanche should enable Army field commanders to pinpoint mobile targets and separate friends from enemies for precision fire.
The Comanche also will sweep the battlefield out to 12 km or more with Longbow millimeter-wave radar. The mast-mounted radar sees through smoke and weather that blind even second-generation thermal imagers. It paints a tactical picture of the battlefield with aided target detection/classification (ATD/C), and it can cue its electro-optical sensors to inspect otherwise hidden targets.
Effective sensor integration can help avoid fratricide, and it will enable the Comanche to spot, identify and locate targets for other forces on a tactical internet.
The Comanche will process multispectral imagery with massive computing power and share its tactical picture with other players on a digital battlefield. The core computer clusters at the heart of the Comanche MEP support ATD/C to spot and identify targets for a busy crew.
ATD/C spots tanks, armored personnel carriers, and air defense vehicles with the helicopter hovering or on the move.
Scout and shooter
While the Comanche travels light with the Objective Force, it can still supply heavy firepower. The EFAMS can be attached or removed in 15 minutes and will hike the Comanche weapons load to 14 Hellfire missiles, 62 70mm rockets, or 14 Stinger missiles.
They also carry two crashworthy 230-gallon tanks for extended combat endurance. Maximum weapons load for an RAH-66 with EFAMS would be 13 Hellfires, two Stingers, and 500 rounds of 20mm ammunition.
The Comanche is the first Army helicopter designed for air-to-air combat. It has the power margins and agility to bring weapons to bear in a maneuvering fight. At close range, air-to-air-Stingers and the 20mm cannon can destroy helicopters or fixed-wing aircraft. In other scenarios, millimeter wave radar gives the shooting scout a long-range sensor and a fire-and-forget radar-guided missile.
All those capabilities make the RAH-66 a point air defense asset, especially against small, low-flying threats that are difficult to intercept with supersonic jets.
With the Longbow radar and the Arrowhead electro-optical system, the AH-64D will have sensors on a par with the Comanche. However, even the new-model Apache has a radar cross section about 600 times that of the RAH-66 and retains earlier-generation infrared suppressors. The Comanche was designed to scout, shoot, and survive in the face of smarter, faster, longer-range air defenses.
The end of the Soviet Union did not end the development of air defense threats. Pulse Doppler (PD) radars now see through ground clutter to target helicopters in nap-of-the-earth (NOE) flight. Monopulse radars ignore simple jamming. Cooled infrared, dual-color, or infrared-imaging missile seekers can home in on helicopter exhaust plumes or skin emissions, and ignore conventional decoy flares. Modern air defense systems also mix targeting sensors.
Weapons of different vintages and many nations are available on the global market. U.S. forces have reportedly uncovered stocks of old SA-7 shoulder-launched missiles in Afghanistan. Far more advanced infrared-seeking Man Portable Air Defense Systems (MANPADS) are readily available from Russia, China and even Pakistan. Russia and other countries are exporting their latest air defense radars. Reduced signatures are more important than ever if combat helicopters are to survive.
The Comanche is the first U.S. Army helicopter designed with reduced radar, infrared, and acoustic signature requirements. The stealthy shape of the RAH-66 has been validated by an RCS model with the Longbow mast-mounted radome. The Comanche is nevertheless due for more changes in EMD to optimize RCS and radar performance. With the passive portions of the Suite of Integrated Radio Frequency Countermeasures (SIRFC), the RAH-66 will have the sensors and processing power to locate, evade and target threats on a digital battlefield.
The integrated infrared suppression system of the Comanche mixes hot engine exhaust with ambient air and ducts it down through two slots under the tail shelves. The high-aspect-ratio slots thin the exhaust stream and shift its IR wavelength, and the swirling ribbon exhaust effectively dissipates the exhaust plume.
The Comanche will not have active radar or infrared jammers, at least initially. This fact can be regarded as a measure of the degree to which the helicopter has been successful at signature reduction.
Weapons of mass destruction in the hands of rogue nations or terrorists have renewed the threat of chemical, biological, or radiological war. Comanche is the first Army helicopter designed for such environments, with a pressurized cockpit and MEP bays, as well as a chemical detector.
The helicopter remains the lowest-risk platform for a scout that sneaks and peeks around lethal air defenses in a range of combat scenarios–especially in the urban operations that are likely to occur in future conflicts. Comanche was designed to be the world’s most survivable and lethal combat helicopter. Given the way the world is going, it had better be.