by Tom Clancy
The rest of the instruments on the control panel are designed so that under blackout conditions they will not impair the pilot’s night vision. Most of them are what are called “strip” indicators, meaning that they show their data as a vertical line, but there are also some circular dials like those you might see on an automobile dashboard. When the Apache was designed, the cockpit layout was considered quite advanced. Next-generation systems (such as the AH-64D Longbow Apache models) will replace most individual instruments with a pair of large multifunction computer-controlled video displays.
The primary navigational system of the Apache is the Litton Attitude-Heading Reference System (AHRS), now standard on most Army helicopters. This inertial reference system works with an ASN-137 Doppler-Velocity Measuring System (a small downward-looking radar which senses the movement of the helicopter over the ground). Over a period of several hours, the AHRS tends to “drift” from an exact positional fix, so most Apaches have a NAVSTAR GPS receiver in the front cockpit that lets the gunner manually punch in corrected data. A modification enabling the AHRS to automatically accept GPS updates will be installed soon.
In the front cockpit are the primary controls for the Apache’s weapons systems. While the weapons can be fired from either cockpit, it is the gunner in front who has the job of putting the AH-64’s ordnance on target. The weapons are aimed by the TADS/PNVS system, which is housed in the lower part of the nose-sensor turret. It is composed of another FLIR sensor, a daylight television camera, a set of direct-view magnification optics, a laser rangefinder, and a laser designator for targeting of laser-guided ordnance. Much like the pilot in the rear cockpit, the gunner has a helmet-mounted sight with a display eyepiece, which provides a targeting view as well as relevant targeting data. Like the pilot’s PNVS, the TADS is slaved to the movement of the gunner’s helmet, and is boresighted to what the gunner sees. To engage a target, all the gunner needs to do is select an appropriate weapon, place the “death dot” of the helmet-mounted-sight-targeting reticule on the target, and pull the trigger. The fill-control system does most of the work after that.
The purpose of any weapon is to kill a target, and the AH-64 can destroy almost any class of target that it can detect. In a turret under the chin of the Apache is an M230 30mm chain gun (built by McDonnell Douglas Helicopter). This gun fires a lightweight 30mm round (rather than the heavy 30mm round used in the A-10’s GAU-8 cannon), based on the Aden/DEFA ammunition family in use since the early 1950s. It fires a shell called an M789, with a tiny shaped charge warhead which can punch through several inches/centimeters of armor. This means that it can disable a tank from the rear or top, or kill virtually any APC or fighting vehicle in use today (except perhaps the Bradley or the British Warrior). The M789 round also has a fragmenting case, which makes it extremely effective against exposed ground troops. The linkless feed system has a 1,200-round capacity.
The rest of the Apache’s weapons are stowed on the two stub wings along the sides of the fuselage. Each wing has two underwing hardpoints for missile and rocket launchers. There are also plans to add a hardpoint on top of the wing for a pair of small air-to-air missiles. On some U.S. Army Apaches, the Stinger missile is used for air-to-air combat. Though nobody had the opportunity to use them during Desert Storm, test dogfights using Stinger and the M230 chain gun indicate that the Apache is equipped to deal with any aircraft that comes within range. This is not to say that AH-64 crews are expected to shoot down high-perfomance jets. But they can kill other helicopters or ground support aircraft, like the Russian SU-25 Frogfoot.
Since the first helicopters were armed, small unguided rockets have been part of their armament. The AH-64 is no exception; it can carry an impressive load of 2.75”/70mm rockets (produced by BEI Defense Systems Company). Known today by their nickname of Hydra-70, these carry everything from a 10-lb/4.5-kg HE (M151) warhead, to smoke (M264) and illumination (M257) warheads, a submunition warhead (M261), and even a flechette warhead (the M255, packed with small projectiles shaped like carpet nails). Each rocket consists of an MK66 rocket motor, a warhead, and an appropriate fuse (point-detonating, delay, or airburst). Hydra-70s are normally carried in nineteen-round launcher pods. The AH-64 can carry up to four such launchers, though during Desert Storm two were usually carried. During deep-strike operations, an extended-range fuel tank can replace one or more of the rocket pods.
A cutaway view of the AGM-114F Hellfire anti-armor missile with its dual-charge warhead.
JACK RYAN ENTREPRISES, LTD., BY LAURA ALPHER
From the very beginning of the Apache’s design, the need for a really long-range anti-armor missile was clearly understood. The TOW missile is effective, but the need to trail a guidance wire limits the range to about 3.7 km/2.3 miles, and the firing helicopter must remain stationary while the subsonic TOW flies out to its target. Thus, as part of the AAH program specification, a new anti-armor missile was defined as part of the system package. Rockwell International and Martin Marietta developed and produced the missile, which is type-classified as the AGM-114 Hellfire.
Hellfire is a larger missile than TOW, weighing in at something like 99.6 lb/45.3 kg. Unlike TOW, it is guided by the laser designator of the TADS/PNVS system in the nose of the Apache, which allows it to have a much longer range (in excess of 5 miles/8 kilometers) and much higher speed-supersonic. It also has a considerably larger warhead than TOW-2, with more than 20 lb/9.1 kg of high explosive in the tandem warhead (two shaped charges, one behind the other) of the AGM-114F version. If you are wondering just how much damage such a warhead can do, consider that the earlier AGM-114Cs, with a single-charge warhead, not only penetrated the armor of Iraqi T-72s, but blew them completely apart at the welds!
A Hellfire finds its target because an optical seeker in the missile’s nose is programmed to look for the spot of laser light “painted” on the target by the TADS/PVNS of the Apache, the Mast-Mounted Sight of the OH-58D Kiowa Warrior, the GLDS system on a FIST-V, or another laser designator. Even the LANTIRN laser-targeting pod on the belly of an Air Force F-15E Strike Eagle can be used to designate targets for the Hellfire.
Unlike a lone fighter-bomber dropping a single laser-guided bomb (LGB) on a single target, many Apaches might be firing many Hellfires at different targets on the same battlefield at the same time. Each Hellfire needs to “know” which spot of laser light to attack. So Hellfire (as well as all other current laser-guided weapons) was designed to home in only on a particular laser spot that is pulsing with a particular digital code set by the firing aircraft. This not only solves the problem of keeping multiple missiles on course to the different targets, but it also enables one helicopter or ground observer to target Hellfires being fired from several helicopters.
This allows the firing helicopter to be behind a hill protected from enemy fire (the Hellfire’s autopilot can be programmed to arch over intervening terrain), while another with a laser designator “paints” the target from a completely different direction. The OH-58D, with its Mast-Mounted Sight (MMS), can poke the MMS head above a tree or ridgeline and guide Hellfires to their targets without exposing any other portion of the helicopter. Another interesting capability of Hellfire is that an Apache can ripple-fire a salvo of missiles with a short interval (say five seconds) between missile launches. If the Apache gunner has a platoon of three or four tanks sitting next to each other, he can direct the laser onto the first until the first missile hits, and then rapidly shift to the next tank, and the next, until he runs out of missiles or targets. Hellfire can even be used as an air-to-air missile, should the Apache be out of Stingers. If an aircraft like a helicopter gets hit by a Hellfire, it is one dead bird!
During its development, Hellfire has stayed on schedule, and pretty much on budget, with few technical glitches; and only a few modifications have been needed. A dual-mode warhead (to overcome the effects of reactive armor) and a new digital autopilot (to allow the gunner to select a high parabolic or low, terrain-hugging path to the target) were ad
ded to the basic -A model to create the AGM-114F variant currently deployed on both the AH-64A Apache and the OH-58D Kiowa Warrior. There are also plans for a millimeter-wave guided version, called Longbow Hellfire, for use later in this decade.
What is it like to actually use this technology? I recently had the opportunity to fly in the front seat of an AH-64A Apache at Fort Hood, Texas, as a guest of the III Corps. My instructor pilot was a chief warrant officer fourth class (CW-4) named Sandy, a lean six-footer who spoke with the vaguely Southwestern drawl that a lot of aviators adopt. From my point of view, the most important part of our preflight conversation was the question “How many hours of stick-time do you have?”
“Oh, about five thousand total,” Sandy replied, and then continued. “Twenty-five hund’rd in Snakes [AH-1s], and twenty-five hundred more in the ‘Pache.”
I knew I could relax. Not always a happy airline flyer, I do like helicopter flying, especially with an experienced CW-4 doing the driving, and Sandy would prove to be as smooth on the stick as the Texan Van Cliburn is on a Steinway. Before my hop that evening, I had the opportunity to get some time in the Apache flight simulator; and I also spent about thirty minutes getting fitted for my flight suit and the helmet-mounted eyepiece sight. Fitting the helmet and sight is not so much difficult as tedious.
As the Texas sun set in the west, Sandy and I headed out to our Apache; and I climbed into the gunner’s position and buckled up. The harness is a five-point restraint similar to those used by race car drivers. All that is needed to get locked in is to push each of the buckles into the central harness lock and tighten up the belts. The straps are released by just twisting the buckle knob, and the belts come free. The seat is extremely comfortable. You feel like you’re sitting inside a large, transparent greenhouse. After I got the helmet on and the sight adjusted, it was just a matter of waiting for Sandy to finish the preflight routines and get the engines running.
While he did all this, Sandy was kind enough to keep me fully posted on the intercom. The start-up sequence proceeded smoothly, and I was able to monitor it on the instruments in the front cockpit. The only unpleasant moment came when we were backing up from our parking position on the ramp to the taxiway. During that time, exhaust from the turbines was sucked into the air-conditioning system and fed through the vents into the cockpit. Sandy had warned me about this. It only smells like a cockpit fire, he told me, but it’s quite harmless. He was right. It smelled like the diesel exhaust you get when you stand behind a transit bus. As a matter of fact, the air-conditioning system is not really there for the comfort of the crew, it’s for the onboard electronics and instruments. Nevertheless, it’s worth the occasional odors, especially when you’re wearing a thick Nomex® (fire-resistant) flight suit.
Taking off in a helicopter is almost exactly the same as the feeling you get the moment a mountain cable car lifts out of its barn—an odd vertical lurch followed by a lean forward. In spite of this, you feel pretty safe in the Apache. For my part, my first impression was that I was sitting in an armored bathtub. There is ample protection around you (it’s designed to stop impacts of projectiles up to 23mm cannon high-explosive rounds, remember). What with that, and the five-point restraint system, you develop a feeling of security that the simple lap belt on an MD-80 just doesn’t provide. (A note to the airlines : Your passengers will stay calmer if they hear what the pilot up front is saying.) Once we had taxied into position and obtained clearance from the tower, we lifted off into the dusky sky, accompanied by two or three other Apaches and a Sikorsky UH-60L Blackhawk carrying several members of my research team. We cruised through the Texas night out to the demonstration area at a smooth 145 knots/265 kph, with the other Apaches and the Blackhawk in trail. The normal ride on a single-rotor helicopter is something like sitting on a chandelier during an earthquake. The aircraft always seems to be vibrating around and from a single point over your head. But because the Apache main rotor has four blades, the ride goes much easier. Once we got to the demonstration area, the first item on the agenda was a demo of what the -64 can do acrobatically. I have to admit that my enthusiasm for this wasn’t exactly unqualified, but with my growing confidence in Sandy, I sucked it in and decided to see what my tolerance limits were.
First we went into a hover at about 1,000 feet/305 meters above the countryside. Strangely—I have no idea why—heights always seem less impressive in a helicopter than they do atop a tall building like the Empire State. Sandy then came on the intercom and told me to stand by while he put his bird through its paces. Rapidly, we transitioned to a series of sharp banks, dives, and climbs. Suffice it to say that the AH-64 has the agility to enrage an enemy gunner on the ground. The physical sensation was about like riding the Space Mountain roller coaster at Disney World in Florida. In Sandy’s skilled hands, the aircraft hovered, turned, soared up, dove down, accelerated forward and back, and most remarkably, did over fifty knots sideways. I have to say that Sandy did all this in such an entertaining way that I was too busy being impressed to turn pale. That agility, of course, is supposed to make life harder on ground gunners and SAM operators and safer for the Apache air crews.
The AH-64 requires a delicate touch, not unlike that of a fighter aircraft. But like a fighter, its sensitive flight controls reward that touch. The precision with which Sandy executed the maneuvers was a message in and of itself. He always told me beforehand what would happen, partially to warn me and partially, I think, so that I could appreciate the skill involved. Having flown the simulator just that afternoon, I did. The aircraft itself radiates a feeling of power and solidity, and an experienced pilot like Sandy only makes it better. Very quickly I was enthralled.
With the preliminaries completed, Sandy headed the Apache off into the Texas night. Because the gunner sits in the front seat of the -64, he surely has the best seat in the house. If you can imagine the view in a particularly well-designed car, then double that sensation and imagine yourself up in the air as well. It’s how an eagle sees the world. If you have an aversion to heights, don’t worry about it. That doesn’t seem to matter if you’re sitting down and strapped in. Suddenly you’re at home up there. In front of you are some of the most interesting tools you’ve ever seen. And they’re not all that hard to use.
Soon you’re no longer an eagle, but an owl. For Apache is most of all a night hunter—except for you as an Apache gunner, it’s not night at all. Outside it was clouding up with an impending thunderstorm; things were starting to look like the inside of a cow. To the naked eye there was no moon or stars, but with the thermal-imaging sight every detail on the ground was clear in the green-and-white display. You have a choice of your field of view. And when you spot something interesting, you can zoom in on it by just clicking a button on the TADS controls. At that point your fire-control systems can (at another flick of the controls) lock on the target, and track the target automatically if it moves. This greatly lightens the workload, and allows the gunner to observe and select other targets if desired. The whole point of the Apache, after all, is to make life harder on the enemy by making it easy on the good guys.
As we continued our flight around the Texas countryside, Sandy took the liberty to show me a little Air Combat Maneuvering (ACM) technique on the UH-60L Blackhawk chase helicopter trailing us. As Sandy yanked the big attack chopper around to get onto its tail, I was quickly able to lock up the Blackhawk and track it through the TADS. Sandy told me that a Stinger, a Hellfire, or the M230 chain gun would all have been options at this point had this been a shooting engagement. All I would have done is keep the “death dot” on the other helicopter, and the ordnance of choice would have inevitably impacted it. While there is some additional technique involved when the target is evading, the basics are quite simple to learn and rapidly mastered.
As the storm gathered around us, it was time to head home. During the approach into the field at Fort Hood, the crosswind gusts grew until the trees on the ground were shedding leaves and leaning into the prairie s
quall that would hit us later that evening. In spite of this, the Apache was steady, and Sandy’s control of it authoritative. Landing in the AH-64 is just a simple flare, and then you are on the ground. Before I even knew it, we were rolling back to the parking ramp, where we’d soon talk over the flight with Sandy and the ground crew. All in all, a thoroughly impressive demonstration of the Apache’s capabilities. Perhaps most impressive of all, though, was that all the things I did that night, I did at night. Sandy clearly had no qualms about operating at night on the fringes of a thunderstorm with a civilian in the front seat; and that shows a tremendous confidence in the aircraft, as well as in his own experience and skill level. Wherever you are when you read this, Sandy, thanks for the look and the ride!
The Apache is clearly the battle tank of the Army’s aerial fleet. Its ability to carry a huge load of different weapons at any time, day or night, and in almost any weather, makes it the weapon of choice for the commander who absolutely, positively has to destroy something hostile. According to Army records, the Apaches deployed during Desert Storm knocked out:• 837 tanks and tracked vehicles
• 501 wheeled vehicles
• 66 bunkers and radar sites
• 12 helicopters (on the ground)
Two green-screen Multifunction Displays (MFDs) dominate the pilot’s station in the AH-64D Longbow Apache. The displays are surrounded by buttons that allow the pilot to choose various options and readout “pages.” The small display above the right-hand MFDs is for the navigational systems. Note the small number of analog backup instruments for use in the event of battle damage or power failure.
MCDONNELL DOUGLAS HELICOPTER COMPANY