NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
B-52 navigators in Vietnam
From: Paul Hirose
Date: 2010 Oct 05, 16:03 -0700
From: Paul Hirose
Date: 2010 Oct 05, 16:03 -0700
"U.S. Air Force navigators and bombardiers have long labored under the shadow of pilots, their contributions misunderstood or simply unknown to the public. This was especially the case with the B-52 non-pilot officer aircrews in the Vietnam War. Yet without them it would have been impossible to execute nuclear war strike plans or fly conventional bombing sorties. Here, one of their own reveals who these men were and what they did down in the 'Black Hole.'" So says the dust jacket of "Flying from the Black Hole," a 2009 book by Robert O. Harder, who served in the U.S. Air Force from 1966 through 1970. Harder had wanted to be a pilot, but slight myopia meant he became a navigator instead. ("The eye test was an absolute deal killer; if one did not have 'perfect' vision, one was simply not admitted to Undergraduate Pilot School.") In the mid-1960s, the USAF conducted UNT (undergraduate navigator training) at Mather AFB near Sacramento, California. "The young men were streamed into their new work on a dead run, and that intensity did not let up in the slightest over the next thirty-eight weeks." After a few weeks of ground training with charts, plotters, dividers, and the MB-4A computer, students were ready to start the 40 scheduled flight lessons. About midway through the course, celestial with an MA-2 sextant replaced radar as the primary fix technique. "Becoming proficient in night and day celestial was at the heart of navigator school; once successfully accomplished, the student was on the home stretch. For most men, the celestial phases were the most satisfying part of their entire training — deliciously elemental disciplines that relied almost wholly on an individual's wits for success." Their flying classroom was the T-29, a military version of a twin piston engine airliner. It had 14 work stations, each with a table, instrument panel, and radar scope. Students shared five periscopic driftmeters and four astrodomes. Three or four instructors supervised. The work environment was difficult: "constant and very fatiguing engine and slipstream noise, bumpy air, poor cabin lighting, student congestion in the aisles upsetting tight shooting schedules, balky observation dome safety harnesses making one even more late for the precomputed shot that couldn't wait, and the inevitable, pitiless instructor hovering over a shoulder -- red pencil at the ready." Graduates from UNT were ready for assignments in transport aircraft. But those headed for the B-52 continued with NBT (Navigator Bombardier Training), "an exhaustive study of bombardment systems, weapons and their ballistics, and really hard-core radar mapping and celestial navigation." At NBT there was a fork in the road. Some students trained on the ASQ-48 bomb-nav system, installed in the early model B-52s, while others took the ASQ-38 route that led to the late model B-52s. (Harder never found out why the more advanced system had a lower numbered designator.) The systems were so different, a man trained on one could not operate the other. During the Vietnam war this caused hard feelings among the ASQ-48 group because the B-52D carried the brunt of the war. Thus, the ASQ-48 navigators served tour after tour in Southeast Asia while the ASQ-38 guys stayed home with the B-52G and H. NBT lasted about half a year. The next stop was three weeks in survival school, learning how to evade capture and live off the land after an ejection. At this point students had been training almost two years but had not yet flown in a B-52. That would change at the next assignment, Castle Air Force Base in central California. After the usual irritating weeks of classroom work, the big day of the first flight in a B-52 finally arrived. The senior navigator (the instructor, on this training flight) on a B-52 is called the "radar navigator" or "RN" and sits on the left. He has the big 10 inch radar scope and periscopic bomb sight. At his right, at the 5 inch scope, sits the "nav", the junior navigator. Harder's first job comes during the takeoff roll when the pilot says SEVENTY KNOTS, NOW. The nav starts a stopwatch and, after a certain time (it depends on takeoff weight, runway altitude, air temperature, etc.), says something like FOURTEEN POINT EIGHT SECONDS, NOW, at which point the pilot checks airspeed. If it's above a certain value, the B-52 is accelerating as it should. If not, there's enough runway to chop throttles and stop safely. But when the seventy knots call comes, Harder is busy correcting a potentially fatal mistake the instructor has noticed. The lanyard that automatically opens his parachute after ejection is improperly attached. Fortunately the instructor was expecting this, and has started his own stopwatch. Once airborne, Harder keeps the chart updated, or pretends to. By the time the B-52 reaches 12000 feet, the warm air in the compartment and the bomber's rough ride are too much. He vomits on the chart table. A minute later he vomits on the instrument panel. The third time he vomits in his lunch box. His first flight lesson is a failure due to severe airsickness. Faced with washing out after coming so far, Harder begs for permission to refly the mission. "Fortunately there was a war on. Refly granted." He did well on that mission and the succeeding ones, and never again got airsick in a B-52. After graduation from NBT, an assignment to an operational Strategic Air Command unit finally marked the end of the student days. Well, almost. A new crew might need two or three months of training before they were designated combat ready. And all crews flew practice missions to keep their skills sharp. These usually began several days before, when the nav picked up the mission profile at Base Operations. It was only the bare bones -- times and locations of key events such as takeoff and landing, air refueling, and simulated bomb releases. The nav had to work out all the altitudes, headings, speeds, and turn points. This took a full day of work while the other five members of the crew could sit around drinking beer. Although B-52s carried the usual radio navigation equipment, it wasn't used much. SAC's assumption was that in the event of nuclear war all U.S. and Soviet stations would be down, so only celestial and radar would be usable for fixes. It was the EWO (electronic warfare officer) who actually took the sextant shots. He had initially qualified as a navigator, wasn't busy during the celestial legs of the mission, and his station was closer to the sextant port on the B-52's upper deck. The nav would give him the precomputed azimuth and altitude of the body, then reduce the sight. It did seem a little unfair that he did the hard work while the EWO got the fun part of the job. The ASQ-48 latitude and longitude counters (mechanical readouts similar to odometers) could be updated from a celestial fix, or by putting the radar crosshairs on a target of known coordinates. Between fixes the system would dead reckon with Doppler or, lacking that, true airspeed from the pitot static system, heading, and winds. That last was manually input in a pair of counters as east and north wind components. A "memory point" run could correct these values. After setting the radar crosshairs on some sharply defined target and letting them drift off, you used the radar hand control joystick to put them back on target. If memory point mode was active, this hand control input also changed the wind counters. Flying in SAC demanded precise timing. Navigators got nervous if they were more than 15 seconds off at an air refueling rendezvous. These were usually head-on, tanker and receiver flying reciprocal courses but offset laterally. The tanker would execute a U-turn, timed to finish neatly in front of the bomber. The rendezvous and hookup were done in radio silence, though radar beacons helped the navigators identify their refueling partners. To lose or gain time, there were preplanned doglegs ("timing triangles") in the route. You could cut off more or less from these to adjust timing without deviating from optimum cruise speed. (In 1965, the first B-52 raid of the Vietnam war turned into a disaster when the lead 3-plane "cell" was early at the tanker rendezvous and, for some reason, circled to kill time. They flew through the following cell and two B-52s collided.) Navigators wore two watches for redundancy. One was government issue, the other personal property, in the 1960s typically a Seiko. Fancy "pilot watches" were not popular. The watch merely needed to keep good time and have a sweep second hand you could stop and start at will in order to set it precisely. The lead B-52 of each cell was responsible for navigation. The other two planes flew 1 mile and 2 miles in trail, offset a little to the left and right, 500 and 1000 feet above the leader, cruising at about 440 knots true. Their ASQ-48 radars would be in air to air "station keeping" mode. Of course the trailing navigators would monitor the performance of the lead nav. The usual charts were black and white strip charts, folded accordion style, with little except a lat/lon graticule and a course line. B-52s flying from Guam to Vietnam would refuel on the outbound part of the mission, at "Point Golf" (N20 20 E122 50) near the Phillipines. If the cell lead nav missed the rendezvous by more than a few seconds, he wouldn't be lead nav next time. Much of the bombing (not only by the B-52) in this war was aimed by ground controllers rather than equipment on the aircraft. The technology was basically what SAC had used for years to evaluate their simulated bomb drops on American cities. A precision radar at an RBS (radar bomb scoring) site tracked the incoming bomber, which transmitted a continuous tone by radio during the bomb run. At the moment of simulated release the tone stopped, enabling the RBS site to compute where the bomb would have hit. The Combat Skyspot system had a ground controller with similar equipment giving steering instructions and a release countdown to the bombers. Accuracy was superior, and it overcame the lack of manmade "culture" in Vietnam, which made target recognition difficult with airborne radar. Duty at the ground site could be dangerous. In fact, last month the USAF awarded the Medal of Honor to a sergeant killed in 1968 during an attack his site. (http://www.af.mil/news/story.asp?id=123223213) When bombing by Combat Skyspot, the B-52s maintained cell formation. Only the lead plane was tracked by the site and got the release call. The other two relied on stopwatch timing, so a precise trail distance was critical. Perfect technique would result in three parallel and equally spaced impact strings. Bombing with the onboard equipment ("synchronous bombing") was more work for the nav team. There were extensive preflight computations. (Harder shows a worksheet from one of his NBT training missions in 1966.) These could be a matter of life and death, as many strikes were close to friendly troops. Coming up to the bomb run, the RN was responsible for the radar crosshairs while the nav concentrated on calling the final turn so the B-52 would roll out precisely on the planned course. Then he verifed the RN's crosshair placement before bomb release. Although the autopilot could follow the heading error signal from the ASQ-48, accuracy was better if the pilot manually "flew the needle". After bombs away, SAC procedure was to execute a 50° bank, combat breakaway turn, as if a nuke had been dropped. (This unnecessary maneuver would have fatal consequences during the great raids on Hanoi in December 1972.) Following the breakaway, the cell would reform for the trip home. For B-52s flying out of Guam, a complete mission was 12 or 13 hours. Adrenaline made time pass pretty fast on the outbound trip, but the return was maddeningly slow for the deeply fatigued crew. Celestial observations were about the only break from the monotony. Harder flew 145 Operation Arc Light missions from 1968 to 1970. That was in addition to his regular duties as part of the SAC deterrent force at home, flying training missions, participating in exercises, and standing nuclear alert. By the end of his career, morale was low in the B-52D units. Crews were worn out. In 1965 who would have guessed that Arc Light would last eight years? The repeated six-month rotations to Southeast Asia, with no end in sight, were a major reason Harder resigned from the USAF in 1970. And he was a bachelor. You can imagine how tough these rotations were on the military families. Unfortunately for his readers, Harder was out of the Air Force by the time of the climactic Operation Linebacker I and II raids in 1972. Although he devotes much space to Linebacker, the Gulf War, and the war on terror, the post-1970 chapters lack that extra something that comes from personal experience. Nevertheless, I'm sure anyone interested in air navigation will enjoy "Flying from the Black Hole". I came across it in a bookstore one afternoon. About 2 o'clock the next morning I finally forced myself to quit reading and go to bed. --