“_You Have a Fire!_”
Five days after the second successful powered flight we were airborne
again. On this flight we deliberately loitered at altitude over
Edwards to simulate the long trip to the X-15’s ultimate launch point
over Utah. We spent the time on several launch rehearsals. Then we
moved into the real thing, ticking off the items on the check-list
with the precision of long practice.
“One minute to launch,” Jack Allavie called.
The X-15 was humming to perfection. The APUs were churning out
electricity and hydraulic power. My left hand reached for the valve
to shift my oxygen supply from B-52 to X-15. I flicked my wrist, but
nothing happened. The valve was jammed.
Involuntarily I made some unintelligible comment on the radio.
Q. C. Harvey came back instantly: “What’s the matter, Scott?”
“I can’t switch over the oxygen. I’ve got to hold. Hold the
countdown.”
Seldom in my flying career had I been so thoroughly disgusted. That
an elaborate, expensive flight might be canceled by the seizing of a
fifty-cent valve seemed just too much. I worked it back and forth to
try to loosen it.
“This one’s got me stumped, Q.C.,” I said, trying to think of some
way to free it. With both hands I tried to turn it by main strength
and ripped a seam in my left glove from the pressure. Using my
knee-pad as a lever, I tried to crack it free by hitting the pad with
the heel of my hand. My tape recorder picked up the thud of this
futile pounding. The gloves I was wearing on that flight were made
of an experimental material, since discarded. When I tore them, I
had to give up. We could not fly the X-15 without full-pressure suit
protection.
“Q.C.,” I grumbled, “I’m afraid we’re dead.”
A few minutes later the windshield frosted over, a trouble we had
not experienced since the first captive flight. It was solid ice. No
amount of scrubbing with my ripped gloves, no amount of defogging
heat would remove it. If the oxygen valve had worked and we had
launched, I would have found myself in serious trouble indeed,
strapped in the X-15 flying blind. I wondered: Is Someone looking
after us?
* * * * *
In late October the capricious desert weather led us a merry chase.
The rainy season, unpredictable but usually falling in December,
came early. Black clouds towered out of the Edwards basin. Scattered
showers pelted the parched dry lakes, dampening and slicking the
surface. We waited, hoping until the last moment, before canceling
each flight. Much of the time the X-15 was kept mated to the B-52.
With December’s heavy showers, which could close the lake for several
months, drawing ever closer, many of us were anxious, on the eve of
continued success, to keep the team in training.
While chasing the weather during the last week in October, a
situation arose that was obviously ridiculous, yet one that could not
be completely ignored. Security informed us they had received a tip
that Wernher von Braun and I would be assassinated on October 29.
Some people wanted to cancel the flight scheduled for the next day. I
objected. To protect our bird, however, we doubled the guard on the
B-52 and the X-15. The North American Security Force offered me a
bodyguard which I declined. I was worried only that some maniac might
harm Alice and the children. On the afternoon of October 28 I flew
down to Los Angeles and spent that evening and the next at my home in
the community of Westchester, bordering the Los Angeles International
Airport.
October 29 passed with no assassination attempt and we heard nothing
more about the “plot.” Weather again forced a cancellation of the
flight that day and on October 30.
On Saturday, October 31--Hallowe’en--the weather was marginal but
we scheduled a flight. The meteorologists doubted that it would
clear for at least twenty-four hours. But we have all long since
learned that meteorology, like psychology, in aviation is a loosely
organized superstition and that it is foolhardy to schedule flights
according to weather predictions, especially in the desert. Stormy
and I flew from Los Angeles to Edwards in my Bonanza and toured the
area, intently observing the cloud formations. A warm-weather front
was moving in from the east, a rare occurrence on the desert. It
was indeed a marginal situation. I felt it was worth a gamble and
after our survey Stormy agreed. If nothing else, even a captive
flight would be useful and would not waste the efforts and spirits of
our ground crew; they had worked almost continuously for two weeks
keeping the X-15 primed.
We took off late--0940--and by the time we reached launch altitude
the freak easterly front had closed Cuddeback Lake emergency landing
strip. This was our intended launch point. We pressed on. Nearby
Rosamond Lake was still clear. I radioed Q. C. Harvey.
“I recommend we go as quickly as possible into a launch and that I
make a subsonic local flight.” My thought was that as long as we had
come this far, a slow flight of the X-15 was better than no flight at
all and we needed the data.
There were murmurs of protest on the radio. But I voted to continue.
I was not being foolhardy. It’s just that I have an inherent fear
of “cancelitis,” an insidious disease which, as we have seen, has
afflicted many experimental airplane programs. When it sets in, the
program loses its sense of urgency, and apathy seeps clear through
the ranks from pilot to mechanic. We could not afford to let this
happen.
When the ground command post agreed to my idea for a slow-speed
flight, I radioed Q.C. again: “Now I want you to do something for me.
Keep an eye on that front. If it gets one bit farther west, I’ve got
to cancel this flight.”
We began the launch procedure with all hands keeping a sharp eye on
the front. A few moments before launch the ground station detected a
rapid cloud advance. I radioed chase Al White:
“Al, do you think you could see the west edge of the lake from about
15,000 feet downwind?” In other words, I was asking if it would be
possible for me to see to land the X-15.
“Scotty, I can just barely see the lake through the edge of the
clouds.” When I heard Al’s reply I knew we were finished. The front
had moved in.
Sam Richter came on the radio: “We strongly recommend we cancel this
flight.” Sam knew I would read “we” as “Stormy,” who never used the
radio. It was clear that he was anxious. A strong recommendation
from Stormy was, of course, an order. “Okay,” I replied glumly, even
though I certainly agreed.
We shifted to a launch-rehearsal procedure. Just before the simulated
drop I radioed for the wind speed and direction on the lake, an
ironic gesture. Some people on the ground thought I might still be
seriously considering an actual drop. Q.C. quickly came on and said:
“No launch, of course, Scotty.”
After the rehearsal I radioed again in a voice heavy with irony:
“Beautiful launch.”
We jettisoned fuel and Lox and landed. Three hours later, as if
nature were deliberately mocking us, defying us to penetrate the
secrets of space, the lake bed was unpredictably clear. By then it
was too late for a second try.
* * * * *
So far we had conducted most of the X-15 flights--circular
patterns--within about twenty miles of the Edwards base. Now as we
advanced in our flight-test program, we planned to drop the ship
farther out, to enable me to fly in a straight line and subject
the X-15 to high-speed and high-altitude maneuvers to define her
safe-flying limits. We selected the new, more distant launch points
so that a flight would always begin over one of the dry lakes. If the
engine failed or some other malfunction occurred, I could land. If it
performed as expected, I could fly back to Edwards on my own steam
and land on Rogers.
Two launching points that appealed to us were Cuddeback and Three
Sisters Dry Lakes, about seventy miles from Edwards as the crow,
or rather the X-15, flies. But our plan to launch over these lakes
was complicated by the rapidly changing and generally deteriorating
desert weather. Rain dampened Cuddeback and Three Sisters. Some
“experts” said that an emergency landing on these lakes would be like
landing in a marsh.
Everyone who has ever flown at Edwards has his own unscientific and
usually inaccurate method for testing the “dampness” and strength of
the dry-lake beds. One system is to poke a rod in the sand. I flew up
to Cuddeback in a light plane to make my own test. It was damp but
adequate, and since I would land there only in an emergency and I
really did not anticipate an emergency, I proposed the longer-range
launch at Cuddeback, rather than continue to idle around Edwards and
delay the program.
Roy Ferren, North American’s Chief Flight Test Engineer, was against
launching over Cuddeback. He argued for more experience with launches
closer in, over Bouquet Canyon Reservoir, say, which was within glide
distance of Lake Rosamond, then in better shape than Cuddeback.
Ferren made a good case and I conceded he had a point. In light of
the near-disaster that followed, it was probably fortunate for both
me and the X-15 program that he prevailed.
There was nothing in the take-off and pre-launch routine that
day, November 5, to indicate a new and formidable crisis was in
the making. The X-15 and B-52 were tight as ticks: no valves or
regulators were leaking, the nitrogen pressure, APUs, Lox top-off
system, pressure suit--everything--all perfectly tuned, so much so
that I reported by radio:
“Take out the X-15 handbook, Q.C. See what the instrument-panel
gauges should read. That’s what I’ve got.”
We bore down on the Bouquet Canyon Reservoir launch point at Mach
0.82 and 45,000 feet. After thirteen flights in the X-15, including
the launches, I worked almost routinely in the cockpit. I turned on
the rocket-engine master switch, shifted to X-15 oxygen, and finally
flashed the green launch-light in Jack Allavie’s cockpit in the B-52.
I was hoping that day, if all went well, to inch the X-15’s speed to
Mach 2.6 or about 1700 miles an hour, and to fly to 80,000 feet. At
higher speed it was easier and safer to make our demonstration points
and because of this neither NASA nor the Air Force seemed intent on
enforcing the Mach 2.0 speed restriction on North American.
“DROP.”
For the fourth time I heard the familiar “kerchunk.” The X-15 fell
away in free flight. Striving for a fast light-off I leveled the ship
with my right hand and flicked the rocket switches with my left. I
lighted number two and number four barrels on the lower motor first.
Then I flicked number two and number four barrels on the upper
motor. Then number three and number one on the upper. When I threw
the toggle on number three and number one of the lower motor, the
last two barrels, I felt a tremendous jar. The whole airplane shook
violently, an explosion that seemed to be right behind me. My first
thought was that the APU had blown again.
The ship was picking up speed. My eye swept to the APU gauges. They
were in the green. The APU had not failed. I was puzzled. Then I
noticed that the pump for the lower rocket motor was overspeeding
and shutting down, indicating a malfunction. An amber warning light
flashed on in the cockpit. The flight was done before it began. I
shut off the four switches for the lower motor.
About five seconds had ticked by. At that instant chase pilot Bob
White, who was flying his F-104 close by the tail of the X-15,
snapped on the radio: “Looks like you had an explosion in the rocket
motor.” Almost simultaneously a fire-warning light flashed on my
instrument panel.
For a rocket-plane pilot this is a pure and simple moment of truth.
In the past, four rocket planes had exploded and caught fire: the
X-1-A, X-1-D, X-2, and “Queenie.” Each was demolished. Two choices
lay open: to pull the ejection-seat handle and bail out, or to ride
the ship out and try to save her. The thought of a bail out never
occurred to me. I’m paid to bring airplanes back, not throw them
away. My course was set when I first stepped in the airplane.
Working swiftly to minimize the chance that the fire might spread,
and to prevent the ship from flying beyond reach of Rosamond Dry
Lake, I shut down the rocket engines and closed the fuel lines. All
the while I held the ship in level flight.
Chase White, his voice rising with concern, said: “You have a
_fire_!” From his position in the F-104 he could see the flames
streaming from the rear of the X-15.
I had completed the shut-down and was thinking ahead to the emergency
jettison when Bob White, now very worried for me, radioed:
“You have a fire! _Please_ shut down.”
With no thrust to maintain her air speed, the X-15 was sinking
rapidly. I glanced at the altimeter: 32,000 feet. In two minutes I
would be on the ground. I spoke on the radio:
“Going to jettison NOW.”
The heavy stream of Lox and Walc and hydrogen peroxide trailed
through the sky behind me. The fire-warning light flickered out. I
radioed White:
“Bob, I’m going to put down on Rosamond. Please let me know when we
have reached the center of the lake.” I was thankful then that Roy
Ferren had vetoed the Cuddeback launch. It might have been a mess.
“Jettison looks good,” White reported. “I don’t see any sign of the
fire now.”
“Where’d it come from? Could you see?” I asked.
“I think it was the lower engine.”
“Thank you,” I said. That fact tied in with the overspeed and
shutting down of the lower pump. In my mind I envisioned the complex
plumbing system, trying to guess what might have happened. How long
would it take to fix it? How much more delay would these supposedly
reliable engines, with so much time on them, cause us?
The jettison was completed in 114 seconds. There was still a little
fuel left in the tanks. The powerful suction of the rocket engine
usually burns them bone dry. In the less efficient jettison it is not
possible to get all the fuel out. The X-15, I knew, would come in
more than a thousand pounds heavier than the previous three landings.
My thoughts turned to the landing gear. We had been planning to beef
it up following this flight, to give us an added margin of safety.
However, I was confident that the gear would hold.
Chase White radioed: “We’re almost to the east edge of the lake now.”
I was surprised. We should have been approaching the lake from the
south. In another fifty seconds I would be touching down.
“Almost _where_?”
“Pardon me. Almost to the _edge_ of the lake.”
“Thank you.” I could tell from White’s radio transmissions and from
others, that the entire X-15 flight-test group was frozen in tension.
Every man was aware of the potential danger of fire in a rocket
plane. Many of them no doubt expected to see an explosion smear
across the sky at any second. To put them at ease, as I turned on
downwind I cracked on the radio:
“Sorry. I’m going to miss getting the data coming in here.”
Chase White chanted my decreasing altitude on the radio: “8,000 ...
7,000 ... 6,000 ... 5,000....” I blew the ventral fin and got set
for the approach, holding the X-15 nose high. I keyed my radio mike
so that I could no longer receive radio transmissions which might
be distracting. I lowered the tail skids and nose wheel, pulled the
flaps, and felt for the lake bed.
The skids dug in gently. The nose slammed down hard and the ship
plowed across the desert floor, slowing down much faster than usual.
Then she came to a complete stop within 1500 feet instead of the
usual 5000 feet. Something was wrong; the skids failed, I was sure.
Not knowing the cause of the trouble and with the fire still very
much in my thoughts, I remained buttoned up in the fireproof cockpit.
My radio was dead. I sat alone, waiting in silence.
The emergency helicopter reached the X-15 first. I saw North
American’s flight surgeon, Toby Freedman, and Brian Lauffer jump out
of the chopper and run toward the ship. A good sign, I thought. She
wasn’t on fire. I opened the canopy and removed my helmet.
Toby was the first to speak. “The plane’s busted in two,” he said.
“What?” I asked. I couldn’t believe it. Quickly I scrambled out of
the cockpit. What I saw almost broke my heart. The fuselage had
buckled immediately aft of the cockpit, two hundred and thirty inches
back from the nose. Her belly had dragged in the sand, causing the
abrupt deceleration on the lake. The rocket chambers which had
exploded at launch were a shambles.
When Stormy and Sam Richter first heard the report of fire on the
radio, they jumped into a light plane at Edwards and flew immediately
to Rosamond Lake, landing alongside the broken bird. They ran up,
staring in disbelief. A minute later the fire trucks arrived. One of
the firemen, an old friend who had probably met me on the lake in
his truck a hundred and fifty times, cried quietly as he sprayed the
broken plane with water. I felt like crying myself. At first look it
seemed to all of us that that obstinate filly would never break to
bit and was mocking our efforts in the grand plan for space flight.
I flew back to Edwards in the light plane. There was not much talk. I
changed out of the pressure suit into street clothes. Toby Freedman
examined me briefly for the record. Then we all flew back to the
airplane again. By then the wreckers were there and, sad to say,
some newspaper photographers. It was silly, but when they took their
pictures I smiled. It was a vain attempt to laugh away our anguish,
to tell anybody who might care that we were not defeated--not by a
long shot. And the truth of the matter was, we weren’t. Our course
was set on the stars.
* * * * *
In the investigation immediately following the accident, the
explosion was laid to an engine-ignition failure. This was a relief.
At least it was no fundamental weakness in our pioneering airplane,
no design fault. It was simply a piece of bad luck that could have
happened at any time to any rocket airplane, regardless of meticulous
grooming. In retrospect, there was nothing we could have done about
it. But now we would plug this weakness and hope there were no more
like it hidden away.
That flight proved one thing: the X-15 is a tough bird. When we
trucked X-15 number two to the plant in Los Angeles for a close
factory look at her, she was not so badly damaged. The rocket engine
had to be completely replaced and the shattered engine bay rebuilt.
We put a patch--called a doubler plate--inside the fuselage where
she had cracked, and in thirty days, after a lot of additional work,
she was better than ever. This was an airplane repair record, in any
man’s league. Meanwhile, we rolled out X-15 number one, which I had
not flown since the first glide test. Since then we had been making
her ready for a powered trip into the sky before the rains closed
the lakes. We were ready for flight with X-15 number one in the week
following the near-disaster with ship number two.
But there was an unanswered question gnawing at us. Why did the
fuselage buckle? My touchdown had not been hard. The plane, with
off-breed engines, NASA instrumentation, and excess fuel, weighed
an additional several thousand pounds. But none of these factors
added up to a broken fuselage, unless we had goofed terribly in the
structure of the ship, something no one could believe. We postponed
flight operations to conduct an agonizing reappraisal, checking and
rechecking the data, probing, thinking, talking.
It was Charlie Feltz, with his wonderfully intuitive engineering
sense, who came up with an answer that turned out to be correct.
He believed there was something happening in the nose-wheel shock
absorber which denied the airplane the “cushion” it required. Thus,
he said, the strut was unduly rigid at touchdown and that was why it
broke. The laboratory engineers confirmed his theory in a hundred
tests of the nose wheel in the factory. The defect was caused by the
rapid extension of the telescoped nose gear. The gear came down so
fast that the oil in the shock absorber foamed or turned to vapor
which has no shock-absorbing value. Unknowingly, up to then we had
in effect been landing the ship with little or no nose-wheel shock
absorber at all. It was just pure luck that the ship hadn’t broken
before.
We corrected the defect. To be doubly sure, Charlie asked me to lower
the gear a little bit sooner to give the oil time to “settle down.”
But really, I think, his request was to save wear and tear on his own
frazzled nerves while watching the landings.
* * * * *
X-15 number one had been ready for days. But now the rainy season
had set in at Edwards, delaying all flights indefinitely. The first
week of December passed and then the second. The rain thinned out;
the lake beds dried. On December 16, forty-one days after the fire
and explosion, we scheduled our fifteenth flight. My intent was to
make a simple, brief powered flight--the first in that airplane. Then
we would turn the craft over to NASA, approximately three and a half
months behind schedule.
It was cold in the desert. The ground crews were bundled in heavy
jackets. Stormy, Sam Richter, and I huddled in Sam’s van, while I
read through the carry-over list. One piece of navigating equipment,
installed for the deep-space probes, was out. But this would in no
way affect our demonstration flight.
After I put on my pressure suit I sprinted from the van to the X-15
boarding ladder, a vain attempt to instill some life and enthusiasm
in our operation. The morale of the X-15 ground crew was sagging. A
rumor had gotten around that our participation in the flight program
was short-lived. A lot of Monday-morning experts could do it better.
Our highly professional team, they thought, would soon be disbanded.
Many of the men would be looking for other jobs.
We were airborne by 0830, climbing for altitude, intending to launch
over Rosamond. On take-off my radio went out. The others could hear
me key the mike, but not my voice. Routinely Q. C. Harvey shifted
to the mike-clicking system to run through the countdown. One click
from me meant yes; two clicks meant no. While we had this tenuous but
effective communications link, there was no need to cancel. It was a
beautifully clear day. We pulled thick white contrails at altitude.
At 0931 we reached 40,000 feet.
Q.C. said: “If all okay, Scott, give me one click.”
I keyed the mike one click.
Double-checking, Q.C. radioed: “Scott, if you wish to go ahead and
launch without communications, please give me one click.”
I keyed the mike one click.
Again rechecking, Q.C. said: “Do you desire to cancel the launch?”
I keyed the mike two clicks. It’s not possible, of course, but I
tried to transmit a feeling of urgency with those electronic clicks.
They were hard, firm clicks, at least. Why did I need a transmitter?
Its main purpose was to keep people on the ground from getting
lonesome.
Approaching the launch point I prepared the rocket engine for its
first flight. Four minutes from launch time I turned the valve to
pressurize the main fuel tanks, eyes glued to the gauge. The gauge
indicated a rapid rise and then a sudden fall of pressure in the
tanks. The helium regulator was erratic again. I pressed hard for a
launch: we had a job to do and would get it done, if permitted.
Two minutes before launch the fuel-tank pressure began to climb
slowly. Hope!
Q.C. said: “Scott, we understand you still want to launch. If this is
correct, give me one click.”
I keyed the mike once, firmly.
“One minute to launch.”
I tested the flaps and controls. Chase reported they were operating
satisfactorily. I was ready to go. The tank pressure was hanging
within limits, though barely--it would need watching. But at the last
second the tank pressure again began to sag. If I launched, I would
endanger the ship.
Q.C. came on the radio for a final check: “Scott. Reaffirm that it is
okay to launch. If so, give me one click.”
With the greatest reluctance I keyed the mike twice.
“You do _not_ want to launch, is that correct?”
I keyed the mike once. Then I saw a face in the new hemispherical
window of the B-52. I drew my index finger under my throat indicating
we were finished. We jettisoned and returned to base. The Monday
morning quarterbacks sharply criticized us for attempting to launch
without a transmitter. The same quarterbacks had declared a year
earlier that only one transmitter was necessary, and even this one
was not essential to the X-15 pilot’s mission.