The story you are about to read is true. The names have not been changed to protect the innocent...
On a cold, clear afternoon at Edwards Air Force Base, another flight test for evaluating the excellence for conducting and supporting research and development is on a final countdown. Like hundreds of other tests over many years, the specifics for this particular flight is to boldly go where no pilot has ever gone before, and therefore not just a split infinitive and cliche phrase coined by a popular sci-fi television series that will make its debut a few years later. Today’s flight will indeed knock on heaven’s door some 100,000–feet above sea level and attempt to go much higher. To get there, however, not only requires a so-called boom and zoom aircraft design that can manage the stupendous feat, but also an ideally-suited test pilot who knows how to get the maximum performance from the supersonic airplane, as well as from himself. The pilot, of course, figures he has such qualities, and therein lies part of the problem for this particular test in 1963.
Major Bob Smith, another test pilot at Edwards Air Force Base, and a friend walks into a cafe. They are dressed in olive–green flight suits. Jets can be heard overhead. The two take a seat. We see a portrait on a wall of President Lyndon Johnson. They order lunch and settle in for the wait, talking quietly. It’s the look on Smith’s face that betrays his concerns today, as well as other personal matters he bears. What’s mainly on his mind is an upcoming flight test by a fellow test pilot, and he is not optimistic given the pivotal outcome. Of course, with the recent mournful loss of President Kennedy, the mood describing most Americans is somber. This President also happened to support the kind of flight testing operations at Edwards. Indeed, the pilot chosen for today’s flight is someone President Kennedy was familiar with, at least by name and reputation, the same as most people on the planet are familiar with the pilot’s celebrated accomplishments over the years.
All flight tests at Edwards are unique in scope. Today’s scheduled flight is even more unique, for it entails flying an Aerospace Trainer (AST) on an attempt at a world altitude record. That being said, Smith doesn’t think the test pilot can handle it. Smith has candid reasons for fostering this opinion. On three previous attempts, the test pilot pulled up too shallow, then attempted to compensate for the error by eventually pulling up to the correct climb angle, but in the process losing a tremendous amount of energy. As a result, the maximum altitude that the test pilot could ever obtain was well below what even Smith himself had flown.
Maj. Smith would consult with the test pilot on the proper flight procedures, but the test pilot respectfully brushed off the advice. All test pilots have rather oversized egos, but this particular test pilot had an ego that was larger than life. Smith got the feeling that the test pilot had the attitude he never met an airplane that he couldn’t conquer. However, this wasn’t an ordinary flight. And it certainly wasn’t an ordinary airplane. Indeed, this specific airplane had a literal rocket in its tail, allowing a pilot to climb to altitudes 100,000 feet Mean Sea Level (MSL) and above. This heaven-bound altitude also meant the airplane would be subjected to reduced aerodynamic pressure (q), causing the flight control surfaces to become ineffective. At this point in the flight, the airplane is acting more like a spaceship, and that’s what got Smith worried this December afternoon...
The AST was a unique solution to a unique problem, which was how to train pilots to become astronauts. Specifically, how to place a pilot into as close to a space–like environment as possible, so that he can practice stability and control without using airplane controls, which is to say, by using a Reaction Control System (RCS) which are mini rocket engines. The X–15 was the obvious answer, because it actually flew into space itself; what better way for pilots to practice in a space–like environment than actual space? Until one looked at the outrageous costs involved for just one X–15 flight. There had to be a more economical way to go about it. And there was...
Some aeronautical engineering geniuses had come up with a very clever plan: stick a rocket in the tail of a badass F–104A, and put an RCS package in its nose. Voila! The NF–104A AST was born.
When Smith first saw the AST, he fell in love, and in a way non–pilots will never understand. Being an aeronautical engineer himself, he understood everything about the AST; specifically, the flight profile needed to get to its maximum theoretical altitude of 120,000 feet MSL and above. The parabolic flight would begin with a 3.5 g pull–up to a 70 degree climb angle, at which point the rocket would be switched on. At the end of the climb, the airplane would enter a region of low q, where it no longer acted like an airplane, but more like a spaceship. That’s where his aeronautical engineering background would take over, because he would no longer be a pilot: he would be at this point an astronaut.
Maj. Smith previously took the AST to a maximum altitude of 118,860 feet MSL. However, the AST could go much higher, and an attempt at the world record was begun. So, of course, they just had to get another test pilot to attempt the record.
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As it turned out, alas, the test pilot couldn’t get to the 70 degree climb angle until later in the climb, and was always falling short of the world record altitude. He would barely get to 100,000 feet MSL, because of all the energy lost trying to compensate for the lack of precision flying necessary for this flight. But that’s not what worried Smith.
What worried Smith was what would happen once the test pilot eventually got to 120,000 feet MSL. He was sure that the test pilot would be out of his realm, lose control of his spacecraft, and, as he entered into the lower and denser atmosphere, would not be able to regain control. But this test pilot was highly skilled in aeronautics, even if his formal education in that area was a bit spotty.
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After lunch, Smith goes to the flight line to fly chase for the fourth attempt at the world record. But his airplane malfunctions, and so he goes to the radio shack instead, where he can hear the progress of the flight.
As the test pilot is calling out that he is caught in a flat spin, Smith and another pilot rush to a helicopter and lift off to the crash site. Another chase airplane has spotted the parachute canopy, and is directing the helicopter towards it. They spot the still-smoldering airplane, with the test pilot calmly standing next to it, just waiting. He is badly injured, but he will survive. Flown to the base hospital by helicopter, the pilot is treated for his injuries. In time, he makes a full recovery.
But Smith was right all along. Well, at least partially right. He thought that the test pilot would fail in the space environment, and not during the aero environment. It turns out that the test pilot couldn’t even fly the proper aero profile, and thus got himself into trouble, because his RCS would not work at the lower, more denser altitude.
But what was even more amazing was the fact that the test pilot who screwed the pooch turned out to be, as it were, un–screwable!
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The test pilot was world famous for his exploits in the air. He was what is called a “natural–born stick–and–rudder” man, which refers to airplane controls. He had set various other world records, and had basked in the glory and fame that came with them. He was indeed America’s poster boy of all test pilots, then until now!
However, that was yesterday, and sometimes the American audience can be so... fickle.
Now here was his chance, or so he thought, to reclaim some of those glory days. The AST presented itself with a golden opportunity. Despite his skill in the cockpit, he had been passed up by NASA for not only the X–15 program, but for the new Mercury program as well. Why, he had been part of the X–plane program virtually from the start! While the AST wouldn’t be going into actual space, it was going into an environment that was close enough. He would be able to know what it was like to be an astronaut, AND get to set another world record. Likely he had this notion in mind: “That’ll show those astronaut boys.” I mean, how hard could it be?
Smith keeps up the briefing before every world record attempt. However, this Smith fellow, who means well, just doesn’t understand. The test pilot had been in this business for a while now, and he didn’t need any coaching from these newcomers with their fancy aeronautical engineering degrees.
Except... it turns out that it was indeed just a wee bit harder than he had first imagined.
The fly in the proverbial ointment comes down to the finer point that there is just so much to do on the way up to the top of the arc! The 3.5 g pull–up was no problem, but maintaining that 70 degree climb angle, while monitoring the Navy instrument that tied a pitot tube to the glide slope and glide path indicators, was a bit sticky. He would eventually get to the proper angle, but not right away. During the climb, his engine would begin to overheat due to the ever–thinning air. Consequently, that part of the flight not only had to be monitored, but eventually the jet engine had to be shut down while the rocket was still firing. The rocket eventually is shut down, with the test pilot intersecting and maintaining a 16 degree angle–of–attack, and using the RCS to push the nose down, enters the thicker lower altitude, restarts his jet engine, and lands back at Edwards.
On this flight, the RCS worked as advertised, but the nose of the AST would not come down. This was because the pilot had not flown the proper flight profile, and had arched over at too–low of an altitude, still stuck in the denser air. The atmosphere was just thick enough to overcome the downward force of the RCS. Thus, the nose was stuck pointing up while on its way down. This was double–trouble: the nose needed to be pointed down so that the air scoops could spin the jet turbine blades so that he can restart his engine. Worse, flying essentially backwards, he would be out of control and might even enter into a flat spin, which was notorious for this type of aircraft.
Sure enough, the flat spin happened, the pilot had no control over his aircraft, and he had no choice but to eject. Scratch one AST. That left only two others remaining in that small fleet. The test pilot was seriously injured, even if he amazingly did walk into the helicopter under his own volition. He and Smith talked about the crash and what happened on the way to the base hospital. As mentioned, the test pilot eventually fully recovered from his wounds, and even returned to flight duty.
In the end, the inquiry into the mishap was just as efficiently scrubbed, sterilized, and sanitized as the hospital he stayed in.
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Maj. Smith, as Instructor Pilot (I.P.) of the AST, was blamed for the accident, since he had obviously not instructed the test pilot adequately to fly the AST to the prescribed 120,000-foot altitude. Of course, Smith was never assigned I.P. duty from his superiors, and he had taken it upon himself to try to coach the test pilot on the proper flight profile of the AST. But all of that was unofficially. Officially, it was all Smith’s fault.
Smith could not get the accident board to understand that the test pilot simply could not fly the proper flight profile, resulting in the loss of the aircraft. His proof was the maximum altitude the test pilot could obtain; by not flying the proper profile, the airplane lost too much energy on the way up, resulting in a lower maximum altitude. The proper verdict: pilot error. However, the very thought of even verbalizing that the cause of the accident was pilot error seemed to horrify the board. So it must be, nay, it just had to be something else.
And so, something else it was. Smith was to fall on his sword, the AST would be deemed unsafe to fly in this particular mode, resulting in a kinder and gentler flight profile, which meant no training in a space–like environment, and the case was closed. In the final analysis, it turns out that both Smith and the AST were to share the blame for the accident, all because it wasn’t to be pilot error. It just didn’t make any sense that it was. The test pilot was just too good, and as it turns out, too famous, to be blamed for the accident.
After all, it was just simple logic; who wouldn’t think that Chuck Yeager could fly anything?
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by Joe Maness and Richard Kerry Holtzin, Ph.D.
This diary was first published at S.T.E.M. For the Classroom
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