highly cherished tradition of airmen around the world.
The crew enters the Bone by climbing a retractable ladder built into the nose wheel well. An interesting feature here is the 'alert start' button. Since SAC originally expected to launch under conditions of nuclear attack, a single big red 'bang' button on the nose wheel strut can start all four engines and begin alignment of the inertial navigation system, so that the aircraft would be ready to roll as soon as the crew was strapped in. Now that the B-1Bs no longer operate in the nuclear deterrent role, nobody uses the panic start button anymore, and there's time to work through the preflight check-list methodically. You have to be a bit careful going up the ladder, because the aisle is narrow and the headroom is limited. The flight crew consists of a pilot and copilot, who sit side by side in the front, with an offensive avionics operator (who fills the role of bombardier/navigator) and defensive avionics operator in a separate compartment behind them. The backseaters have small side windows, but their attention is dominated by large electronic consoles. The original B-1A design incorporated a complex crew 'escape capsule'; the entire cockpit compartment would separate from the aircraft and deploy stabilizing fins and a parachute. But on the B-1B this was replaced by simpler, lighter, and more reliable ACES II ejection seats. Blow-out panels above each crew position are triggered by the ejection mechanism, which has a surprisingly good record for crew survival in emergencies. The in-flight refueling receptacle is built into the nose, just forward of the windshield; flight crews with B-52 experience find this a bit disorienting at first.
The controls, while not quite as advanced as those on the F-15E or F-16C, are quite easy to use, and very functional. You sit in the pilot's seat, with the fighter-style control stick fitting in a nice, neutral position that is designed to reduce crew fatigue. While there is no HUD, the mission data is easily read from several MFDs located on the instrument panels. The throttle quadrant is located on a pedestal between the pilot and copilot positions, with other common controls like navigation and flight management systems being positioned there for easy access from either position. Engine, fuel, and other indicators are of the 'strip' type, much like an old-style mercury thermometer. These visual readouts make it easy to see if an engine or some other system is operating within 'green' (safe) parameters or in a 'red' (danger) situation. There is also a small panel of enunciators, which show system status and warning lights for things like engine fires or low hydraulic pressure.
B-1s prefer to operate as lone wolves. Any escorting fighter that is not stealthy is likely to increase the risk of enemy detection. In low-level penetration missions, when the autopilot is coupled to the TFR mode of the APQ- 164, speed is life. At 500 feet/152.4 meters altitude, the B-1's cruising speed is about 550 knots/1,006 kph., and at full afterburner it can be cranked up to just a hair over the speed of sound. Maximum takeoff weight is 477,000 lb./ 216,365 kg., with a maximum altitude of over 50,000 feet/15,240 meters.
No fighter in the world can overtake a B-1B operating at low altitudes. Over rough terrain, any fighter pilot who tries to stay on the B-1's tail is likely to have a highly detrimental intersection with the ground. In addition to the APQ-164's TFR radar mode, what makes this possible is a pair of small downward-slanted vanes on the nose, just forward of the cockpit. (From some angles, they make the plane look like a catfish.) Everything on an aircraft gets an acronym, and these little fins are part of the SMCS: Structural Mode Control System. Flying at low altitude means an aircraft is going to encounter turbulence even in good weather. This can make the aircraft dangerously hard to control, fatigues the crew, and causes flexing of the airframe that drastically shortens its service life. To reduce this problem, a set of accelerometers mounted in the aircraft sense the turbulence, and a computer rapidly moves the fins to compensate. The effect is to limit the vertical accelerations felt by the crew to no more than three Gs.
Just behind the pilot's position is a space, about the size of a large packing carton, which pretends to be a toilet. This is not of the flush variety, but simply a canned chemical 'pack' which allows a crew of four to function for about twenty hours. For the longer 'Global Power/Global Reach' missions, which can last more than thirty hours, a second toilet pack is kept in the stowage compartment just behind the copilot's position. Also kept here are things like food, water, coffee, personal equipment, engine inlet covers, and anything else that can be crammed into the space. For crews used to the relative roominess of the old B-52s, the B-1B can be somewhat confining and spartan. In fact, where the B-52 had crew rest bunks, B-1 crews tend to just lay a couple of engine covers in the aisle between the front and rear compartments and snatch catnaps as time and events allow. Mission endurance is, in fact, virtually unlimited. With aerial refueling, B-1s have flown completely around the Earth in thirty-hour marathons.
In the after part of the crew compartment, on either side of the crew entry hatch, are the positions for the offensive avionics operator (bombardier/ navigator) and defensive avionics operator (electronic warfare officer). Sitting in their own ejection seats, they each face a large vertical panel which controls the various sensor and electronic warfare systems. The electronic systems of the B-1B are tied together by a quadruple-redundant MIL- STD- 1553 data bus. The health and status of all systems are continuously monitored and recorded by a central integrated test system, which greatly simplifies troubleshooting for ground-based mechanics. There are a number of IBM AP-101F computers, based on the 1960s-vintage computers, installed in the B-52G; two are dedicated to terrain following, one is for navigation, one for controls and displays, one for weapons control, and one for backup. By modern standards these computers are pretty feeble — they share a total mass memory unit with only 512K of magnetic core memory (less than the cheapest portable computer you could buy today); but these systems are hardened against the electromagnetic effects of a nearby nuclear explosion. Just try that trick with your desktop PC or Macintosh. Continuing upgrades of the computers and software are likely, if government policies do not cripple the highly specialized radiation-hardened chip industry.
On the right is the position for the offensive avionics operator, who controls the radar, navigational, and weapons-delivery systems of the B-1B. The nose-mounted Westinghouse APQ-164 radar of the Bone is derived from the APG-66 used on the F-16A. Actually composed of two radars (one to control the terrain-following autopilot, the other to provide an attack sensor) stacked one on top of the other, the APQ-164 has matured a great deal since coming into service ten years ago. Updated software provides for up to thirteen different radar modes to provide ground mapping, navigation, weapons targeting, and all-weather terrain following. The APQ-164 can also operate in an SAR mode, to take the same kind of target-mapping photos that can be obtained from the APG-68 on the F-16C, and the APG-70 on the F-15E. Recent software improvements in SAR mapping radar mode are dramatic. 'You could pick out fence posts before; now you can practically see the wire,' said one Rockwell executive in a recent trade journal interview, and the crews from the 34th BS confirmed this claim. One of them told us that with the attack system he could resolve the structural legs of high-tension power towers, and deliver 50 lb./227.1kg. iron bombs
One thing that B-1B crews have desperately needed is an improved navigation system, preferably one based around the NAVSTAR GPS satellite constellation, which was recently completed. Composed of 24 satellites, it provides super-accurate navigation and timing information to users equipped with relatively cheap, small, and lightweight GPS receivers. Unfortunately, unlike fighters like the F-16C, which were among the first to get the Rockwell Collins MAGR, the B-1B bomber force has languished without this badly needed black box. While there are future plans to add the MAGR to the Bone's avionics fit, the crews decided to take matters into their own hands, and thus are the roots of a story. Several years ago, when faced with exactly the same problem, the crews of U-2 reconnaissance aircraft, whose navigation must by nature be extremely accurate, began to get impatient for their own GPS upgrade, and started to look at some commercial options. This led them to our old friends at Trimble Navigation, the makers of the famous SLGR GPS receiver which was used extensively during Desert Storm. (See my previous book
