14 Three Up &
Three Down
Four experienced experimental test pilots made
maximum zoom flights in the AST but Bob
Rushworth was the only one to come down with his
nose pointed down every time (once), then he had
a lot of experience and benefit of simulators on
X-15. We other three could not make that claim.
It is of interest to look at the circumstances
to gain some insight into the causes, in the
order they occurred.
Jack Woodman’s Loss of Control
Jack lost control on his only max zoom, but he
got to 118,400 feet, which proved he was on
profile during the entire powered ascent, the
period where proper control of pitch angle under
aerodynamic conditions was key to altitude.
Therefore it was what happened in the space
region that caused his mishap. He obviously
lost control then and two possibilities
existed. Either, the RCS improper wiring that
caused me to have a terrible time controlling
flight may not have been corrected, or Jack was
unable to fly the airplane because of
unfamiliarity with the dynamics and stability in
space.
The wiring problem was recorded and known by
Jack and many in the company and it is
inconceivable it would have been ignored, and
Jack would not have allowed that. That airplane,
in which we had only zoom tests remaining, made
11 zooms in its final month of contractor
testing, and only three other flights, an engine
functional test and two others logged as
Directional stability testing. That was
consistent with the test plan where the other
airplane #756 was used for all verifications of
performance within normal F-104 capabilities and
the zoom airplane #760 never flew zoom missions
until delivered to the Air Force.
Jack flew 756 that same afternoon that I wrote
it up, described in Lockheed logs as a stability
test, however one can safely infer this was an
RCS repair checkout, after maintenance to fix
the wiring write up. That makes sense,
especially since the stability tests described
in the log were all well inside the envelope
which we had already completed on the other test
airplane.
The next morning Jack zoomed to 118,400 feet,
which resulted in his falling 85,000 feet out of
control from its apogee. Jack had later
mentioned to me that he fell out like that, but
didn’t mention the altitude. He also told me
about the cause of my problem, the wiring
discovery in that same conversation, but didn't
attribute it to RCS mis-wiring.
As I look back it provides an enigma, because he
followed that last zoom with another stability
test in the airplane, his last ever flight in
the AST, and again that
last flight was logged
as another stability test, again duplicating
test conditions he had flown previously on AST
#756, the stability aircraft.
I know that I could never have successfully
controlled on my record flight with misconnected
controls had I not been educated in aeronautical
engineering and especially in space dynamics.
I doubt that I would have been successful even
had the controls been wired properly, without
the training.
Jack told me, the next time I saw him about
losing control and never mentioned RCS as a
problem. I zoomed that same airplane later, with
no difficulty. That pretty well eliminates
the mechanical problem or it seems he would have
said he encountered the same control problem.
Jack was a proven test pilot, well experienced.
That leaves the only other probability, that
Jack did not understand the theory of flight
outside the atmosphere and suffered control loss
, the singular difference being that Jack flew
the aerodynamic profile perfectly, stayed on the
climb schedule properly and attained maximum
peak.
That is a probable scenario, from an engineering
standpoint, as well as a logical conclusion,
because a lot of control motion when above the
dense atmosphere did not add enough to the very
low drag to reduce the altitude significantly,
as my flight with the controls mis-wired had
demonstrated.
Changing flight path at lower altitude, as Chuck
Yeager did, however, would entail great energy
waste. If nothing else that gave Jack a
different reentry attitude than Yeager, and
obviously it was almost 20,000 feet higher than
Chuck’s. There is little doubt he would have
applied nose-down RCS in that region where it
would have been effective for an extended period
but Chuck Yeager never made it high enough for
effective RCS, which may account for Jack’s
being able to recover and land.
In order to get more confident with that
assessment, I recently contacted astronaut Vance
Brand, who sat at the desk next to Jack and was
a Lockheed test pilot, during that time. Vance
is a veteran astronautt having flown as pilot on
the Skylab mission in the Russian Soyuz and
later he commanded 3 Space Shuttle
missions.
As V.P. and General Manager of the Shuttle Tank
Program for Martin Marietta, I had monitored
Shuttle launches, up to the Challenger accident,
from the Launch Control Center. I had sent
Vance a fantastically beautiful color picture of
his E.T. falling away at separation from him and
pilot Bob Overmyer, with astronaut scientists
Joe Allen and Bill Lenoir, as they went into
orbit above a spectacular earth view, on the 4th
Shuttle flight. I called him to reminisce about
Jack and learned that Jack was not deep into the
engineering aspects of test, but rather felt it
his job to be extremely attentive to the
instructions of the engineers and dedicated to
satisfying their test plans to the letter of the
test card and the best of his ability. This was
typical, with few exceptions, of the period of
the 50’s, when he started test flying in
Canada. That information, and Jack’s experience
and education, reinforce my conclusion that Jack
probably did not understand RCS control usage in
flight, just as Chuck Yeager didn’t. I suspect
that the Lockheed engineers, like me, assumed he
knew it and I would never have been so
presumptuous as to instruct Jack, who had
frequent contact with Lockheed experts.
If Jack were trying to fly the max zoom based
solely on his own prior flight experience, and
not even briefed on space dynamics and control,
then he was not qualified, which I never
considered until I recently read his biography
and learned the final sequence of events.
I’m sure he found himself in the same situation
as Chuck Yeager, but had controlled his climb
angle well, which most probably made the difference in
the outcome, by falling in the No Spin zone of
space.
As comparison, the X-15 pilots had an
operational simulator to learn on and practiced
their profile before every mission but we had
none. They were also dealing on a project with
specialists in the engineering of such flights
and could study the actual and detailed flight
data from every flight, and their simulator was
updated from the flight data.
Outside the Envelope
I described my effort to expand the envelope of
the AST without due diligence of a gradual and
progressive increase of the climb angle. I had
no time left to logically expand it before Chuck
Yeager would begin his attempt at a record and I
would get to fly no more tests. That was my
reason, but not a valid excuse! It was not bad
judgment but abject stupidity, as I look back.
The outcome was in no way a blemish on the AST,
which was probably my major reason to not
advertise it, because I have never been bashful
of my goofs.
No one at Edwards was aware of that flight
except a couple of tracking operators to whom it
meant nothing and were used to giving me my
plots to review after I zoomed, and I only told
friends about it over the years. I’m not proud
of such a dumb decision, but if I didn’t mention
this and others like it I wouldn’t have enough
to write this segment much less my complete
autobiography based on flying successes only!
What the heck, show me a pilot who hasn’t made a
really dumb decision and I’ll show you either a
dead one or a liar.
Other than my own foolhardiness, that particular
case of loss of control proved nothing adverse
to the AST. It demonstrated the envelope of the
AST was not unlimited and the instrumentation
could not relate all things to the pilot,
trivial conclusions for any craft.
Unfortunately, it added nothing to finding AST
limits, but that soon became moot. The only
excuse and a weak one, I offer for such a
foolish move was the precipitous decisions made
by those far more experienced than I, who
stopped the test program in mid-stream: A
ladder that climbed the Air Force hierarchy all
the way, which forced my hand and I drew for a
full-house instead of a pair of Aces.
The two flights Jack and I made to confirm the
envelope as defined by Lockheed were not trivial
nor were they a complete test undertaking.
Lockheed had only one objective and that was to
demonstrate a successful max zoom flight,
requiring only one successful flight for the
design mission, which my flight provided them.
Jack nearly repeated it a day later, and
although his completion with abnormal recovery
would not have satisfied the requirements his
was a notable accomplishment. All the preceding
flights demonstrated the AST had the
in-atmosphere capabilities of an F-104, and
those more mundane tests were the majority of
their testing plus some low altitude zooms for a
safe build up.
Lockheed had 3 months and 38 flights to do that
testing.
On the other hand, my job for the Air Force test
program, as instructed, by Col. Pete, was to
find the safe limits and confirm or expand the
optimum mission profile. And ultimately we both
anticipated that I would get to break the
existing Russian altitude record. After all it
was tradition that the primary test pilot on a
program always got such opportunity. The
encouragement that America would be breaking a
long-standing
USSR
record made me want to test the AST to its
ultimate, to secure an “untouchable” record.
There were no limitations on my tests and no
definitive test plan, which without resources
for data reduction and analysis precise bounds
were impossible to estimate. When I got
comfortable with the zooms, I expected to
gradually raise the climb angle until the AST
itself let me know I was nearing the limit. I
believed that would be safe and provide some
warnings with incremental increases in the pitch
angle and then pull-up g. With three airplanes,
it would not have taken long to get the crew up
to speed, in fact they were outstanding in our
brief efforts, and there was probably less than
10 degrees, to incrementally increase pitch, the
primary controlled variable, beyond reasonable
limit.
I had anticipated trying 3-degree jumps in
pitch, and, how I wish that I had stuck with
that. The way the airplane responded on my
other zooms, I am sure it would have worked,
safely. I would have been advised by the AST
itself as I increased the angle in small
increments, either by no increase in altitude or
having to use constant pitch demand at the
apogee to stay on 16 degrees alpha, an absolute
display of maximum apogee. The decision for
Chuck to fly the record disturbed my common
sense and my careful planning.
As a result of the sudden change in plans, the
entire Air Force test program and complete
envelope expansion lasted only 39 days from 28
October to 12 December in which I flew only 15
flights, two of which were not maximum zooms but
post-maintenance checks. Contrast that with
Lockheed’s 78 days and 38 flights with only two
max zooms. Our crew’s members had to get up the
learning curve, while Lockheed’s grew up with
the AST, but in my long career I found there
were no better and more skillful workers than
flight line crews, anywhere.
Conducting so few tests as I did in the
significantly unfamiliar flight regimes on a new
and unique airplane of such demanding
performance was unique, if not unreasonable, for
any airplane. Especially a trainer, even one
for experienced test pilots as student pilots.
The problems were exacerbated, because test
results were degraded by unavailability of funds
for data to plan test flights and extrapolate
results to their limits, which made quality test
planning impossible.
Enough of the excuses, I screwed up and will
never live it down in my life, like another more
serious shortcoming in my flying career, that
one at age 22.
Bob Rushworth’s AST Flight
Bob Rushworth, the lead X-15 test pilot at that
time and ultimately the one with the most
flights, flew one flight in the AST, a maximum
zoom to 112,000 feet altitude, shortly before
Yeager flew it. Bob was a college graduate in
engineering and had been trained in the X-15
simulator and flown many X-15 flights before his
uneventful AST zoom. His only flight, like 13
of mine in which I intentionally stayed within
the envelope, made a strong case for the
suitability and safety of AST for max zoom with
an experienced test pilot, trained also to be
aware of space stability and control, within the
design mission This was a very strong
argument against Yeager's contention of some
unexplainable airplane problem causing his
accident. Chuck's attitude in the
circumstances can be understood, but the board
chairman, Guy Townsend, ignoring such facts was
inexcusable.
Chuck Yeager’s Accident
Chuck Yeager found himself in a spin, which went
flat because of the high altitude spin entry
with low engine rpm, and could not recover,
forcing his bail out. He was there by his own
doing, an effort to revitalize his image, which
had been diminished considerably by time, a
natural event for all heroes. Surprisingly, he
was able to turn the accident into great press,
which proved as effective or more than a
successful record, because of the risk factor.
Chuck Yeager had proven that he was the master
of airplanes, many times. In my close dealing
with him in attempting his zoom flights he
proved another thing. In briefing him
repeatedly, I began to fear that he could not or
would not accept that he needed to learn new
techniques to fly a craft into a space-like
environment. But as his attempts progressed I
noticed that he was unable to perform the vital
and necessary job of accurately flying a very
steep climb, totally on instruments. He failed
miserably on that and it caused his accident and
loss of the airplane, and ultimately the loss of
that project. I was terribly concerned that he
was not equipped for the space portion of the
flight, but we never had the chance to find that
out.
I have compared the technical realities and my
AST experiences to many of Chucks claims in his
1985 autobiography “Yeager”, below. By his own
account he displays a lack of understanding, not
only of space flight technology, but aircraft
stability and control. In so doing, he confirms
the stand of an officer from his past who had
refused to graduate him from test pilot school
for lack of understanding of the technical
aspects of stability and control, the bread and
butter of a test pilot. Such a statement
is certainly argumentative with Chuck's
accomplishments, but one difference may be in
the fact that the AST zoom climb was totally on
instruments in the most critical phase from the
beginning of the pull-up until diving in
recovery. Absolutely no view of earth was
available for orientation which is not an
ordinary situation for experimental testing.
AST Performance In Conclusion
There was compelling evidence, as a result of
all the maximum zoom flights attempted with the
AST, that it was capable of performing the
design mission well within the expected safety
margins so long as two criteria were followed.
First, all flyers were to be experienced test
pilots who had mandatory training and academics
to fully understand aerodynamics and space
control and dynamics. Second, an Air Force test
program that would bound and confirm the safe
limits of the AST in a gradual envelope
expansion. Those rules had been implicit, in
the AST program from its inception at the ARPS.
The school would train all the pilots for the
AST and their program already met criteria one.
The AFFTC demanded that it fly the testing,
selected a pilot who met the first criteria and
would have completed a proper envelope
expansion, where it not truncated by decisions
made at the highest level of the Air Force.
Every successful event of the actual testing
corroborated those rules. Likewise, every one of
the failures and near failures, however they are
categorized, did too!
The Yeager accident, exacerbated by the actions
of Colonel Townsend, masked the positive
accomplishments of AST, in a haze of deceit and
lies. |