The F-104 was literally
a kick in the butt to fly in comparison to the old
subsonic birds we had been flying up until that
time. When I say "that
time" I am talking about
1957, which is when I started flying the
F-104. Going fast was no problem for the
F-104 but going slow was, so they installed a
BLC system, or Boundary
Layer Control, on the airplane. This
system enhanced the boundary layer air flow over
the F-104's wings, allowing the 104 to be more
easily controlled at lower airspeeds, such
as take-off and landing. But the new
BLC system had its weaknesses.
On
this day I had picked up
a new F-104 at the Lockheed factory located near
Palmdale. Another jock by the name of Don Dickman
was also taking delivery of a new 104.
We were both delivering them to James Jabara's
squadron at Westover AFB, so we decided
to fly across the country in formation. Don and
I took off and headed for our first fuel
stop at Kirtland AFB in Albuquerque.
I was leading and Don was flying wing.
Even today that flight is clearly imprinted
in my mind because I came within a fraction of a
second and only a few feet from
being killed during that base to final turn for
landing at Kirtland.
I think I'd better explain a bit
about the BLC (Boundary Layer Control)
system and how it worked in conjunction
with the F-104's wing
flaps. The aircraft was built
to go FAST and had very small wings (7
feet in length each)
and thus a very high approach
and landing speed. So Kelly Johnson,
Lockheed's famous chief engineer, and
his "Skunk Works" guys
came up with something new to lower the F-104's
approach speed by about
forty knots or so. They designed a system
which bled-off excess air
from the jet engine turbine's
9th stage high-pressure air compressor ***,
re-routing this high-pressure air through
small metal tubes integrated into the
wings ahead of the wing flaps. These
tubes had numerous holes in them allowing high-pressure
turbine bleed air to flow out
and over the 104's landing flaps to improve
lift, increasing the velocity of the wing's
boundary-layer air flow and basically "fooling"
the wing into thinking it was going much faster. As
the F-104 slowed and its wings
approached a stall condition (loss of lift),
the pilot lowered the flaps to the fully extended LAND
position with simultaneous high air pressure
from the BLC now delaying the stall and allowing
lower approach speeds.
The 104 had three wing
flap positions: UP, TAKE
OFF & LAND (T.O.
& L), and LAND. A
military airfield's 360-degree*
Overhead Traffic Pattern
was normally entered at 1,500
feet AGL (Above Ground Level) and
in the 104 you entered the Overhead at 325
knots indicated airspeed (fast). After
passing mid-field over the runway you
performed a 180-degree "pitch
out" maneuver, then rolled
the wings to straight and level after turning 180
degrees to the Downwind
leg. The book (104 Flight Manual) said
to lower the landing gear and
T.O. & LAND flaps on downwind
(opposite the direction of landing). Farther
downwind, when the end of the
runway is approximately 45 Degrees behind your shoulder,
you start your descending Base-to-Final
turn, pretty much one continuous descending
turn, 180 degrees around to the
short Final Approach leg to the runway.
(*180-degree pitch-out plus 180-degree base-to-final
turn = 360-degree overhead pattern!)
After approximately 90 degrees of the 180
degree Base-to-Final turn,
the book said to select
the LAND flaps position, where both leading edge
and trailing edge flaps extend down to their
full 45 degrees
of extension, creating more lift at slow speeds, and the
BLC air system cuts in,
creating even more lift. I did all that.
But fate reared its ugly head.
With Don just 5 seconds behind me, I was
turning onto final when I moved the
flap lever to the LAND flaps position. The
flaps neared full-down position while
passing through 800-900 feet AGL with
30-40 degrees of left bank. As the
flaps neared their full-down position
the Boundary Layer Control air system "KICKED
IN!"
Completely on its own, the aircraft ROLLED
HARD LEFT turning me past the runway heading
and rolling its wings well-past
vertical.
Reacting instantly with full
right rudder and as much right aileron as
I dared use (due to adverse yaw)
I could not stop the left roll.
I was quickly going inverted. I thought about ejecting "upward" (the
early F-104A had a
downward ejection seat and my
104 was nearly upside-down) but the
nose was too low...and getting lower.
I immediately knew the BLC had
to be the problem. I slapped the flaps switch
up one notch to T.O. &
LAND position to cut off the BLC and
simultaneously slammed the throttle into afterburner
to give me all the thrust I could get. I'd instantly
stopped fighting the left roll and used
both rudder and ailerons to expedite
the forced roll quickly back to wings-level (right-side
up).
As the wings rolled level, I delicately started
applying up elevator (pulling back on the
stick gently to avoid a stall) until
I felt a "burble"
(near-stall buffet on the wings) while
noticing that the pitot tube
on the tip of the 104's nose cone appeared
to be threading through the sage
brush. Soon the nose began to rise a bit and
the aircraft started accelerating and climbing
out, away from the ground.
According to Kirtland's
tower controller my afterburner blast was kicking
up a terrible cloud of dust. They figured I was
rolled up in a ball of fire out there and immediately
dispatched crash and rescue crews.
Circling overhead, Don was amazed to see my beautiful new
"Zipper" climb out
of that horrible-looking mess down
there.
Don
joined up with me and we climbed up to 10,000
feet and took a few minutes to calm our nerves.
I then asked for permission to enter the pattern
for a straight in approach with T.O. & LAND
flaps only, not full flaps, so as to prevent
further use of the BLC system.
After
landing and taxiing in to parking the maintenance
folks came out and checked the BLC tubes in both
wings. Sure enough, the tube in the
trailing edge of the LEFT wing was badly warped
while the remainder of the BLC air tubes
were fine. That meant I was getting full BLC
enhanced lift air blowing on
the RIGHT wing while the LEFT
BLC was not blowing air and this was
destroying lift on the LEFT wing.
No wonder it had rolled hard
left...
I got on the
phone to Tony LeVier, Lockheed's famed chief
test pilot, and I suggested (read:
INSISTED) that Lockheed submit a change
to the F-104 Flight Manual
and immediately put out a RED LETTERED message to
all users to go to LAND flaps (with
BLC) while still at 1,500
feet AGL on DOWNWIND LEG, to
check for any BLC rolling tendencies, and NEVER
wait to select LAND flaps until
down lower in the final
turn.
Tony
agreed and made the changes.
***
Boundary Layer Control (BLC) uses air from the
engine compressors last stage, the 17th stage.
Copywrite by Warren
Hunt
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