T-BIRD BOMB BURST

BY GEN. MERRILL A. (TONY) MCPEAK

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Del Rio could be the movie set of a West Texas border town. It’s windy, and the weather tends toward seasonal extremes. A large U.S. Air Force Base 6 mi. east of town is named after 1st Lt. Jack T. Laughlin, a B-17 pilot and Del Rio native killed over Java within a few weeks of the Japanese attack on Pearl Harbor.  Our Thunderbirds Team flies into Laughlin on Oct. 20, 1967, for an air show the next day, honoring 60 or so lieutenants graduating from pilot training. We go through the standard preshow routine. Lead and 5 do their showline survey, while the rest of us make the rounds of hospital and school visits and give interviews. Next day, proud parents watch as new pilots pin on wings.

At noon, we brief at Base Ops. As usual, an “inspection team” comprising base and local dignitaries joins us for a photo session before we step to the jets. The film Bandolero! is in production near the base, and its stars, Jimmy Stewart and Raquel Welch, show up in the inspection team. Jimmy Stewart is a USAF Reserve brigadier general, a founder of the Air Force Assn. and a big hero to all of us. Raquel Welch is…well, she’s Raquel Welch.

We’re wearing white show suits, my least-favorite outfit. Lead can choose from among gray, blue, black or white, but today, we look like Good Humor men. Plus, I work hard during the demonstration and sweat soaks my collar. This wouldn’t matter much, except we do a lot of taxiing in-trail. With only 6 ft. between the end of my pitot boom and No. 5’s afterburner, I take a load of engine exhaust in my cockpit. Soot clings to the dampness, leaving a noticeable “ring around the collar,” when I wear white. At Del Rio, I follow my usual routine and roll the collar under once we have taxied away from the crowd. After the show, I’ll roll it back out again, the chimney-black still there, but now underneath, out of sight.

We taxi short of the runway for a “quick check” pre-takeoff inspection by a couple of our maintenance troops.

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From December 1966 to December 1968,

McPeak flew the F-100 Super Sabre

 in almost 200 Thunderbirds performances

as solo and lead solo pilot.

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As No. 6, I’m flying F-100D serial number 55-3520.

We take the runway, the four-aircraft Diamond in fingertip and Bobby Beckel and I in Element, 500 ft. back. The Diamond releases brakes at precisely 1430.

Bobby and I run up engines, my stomach tightening against the surge of isolation and exhilaration that comes with every air show takeoff. By this time in the season, the Team is really clicking. We have a lot of shows under our belt and know what we are doing. Twenty-one minutes into the event, it’s going well–a nice cadence and rhythm. We approach the climax, the signature Bomb Burst. My job is to put “pigtails” through the separating formation, doing unloaded, max-rate vertical rolls.

Even a few vertical rolls require establishing a perfect up-line; more than a few also requires starting the rolls with a ton of airspeed. I grab for altitude as the Diamond pirouettes into the entry for the Bomb Burst, and at just the right moment, dive after them, hiding behind their smoke. Airspeed builds rapidly. I have to be mindful of a hard-and-fast rule: don’t go supersonic during an air show. The Thunderbirds switched to the F-100 in 1956, making us the world’s first supersonic flying team. The next year, the FAA banned public demonstrations involving supersonic flight. No booming the crowd. So, I want to be subsonic, but just barely–say, Mach 0.99.

The biggest mistake I can make is to be early. The Diamond is about to break in all four directions, so if I get there too soon, I don’t have an exit strategy. (In a pinch, I’ll call the break, rather than wait for Lead to do it.) Today, my timing looks good, so I light the ‘burner and start a pull into the vertical. We don’t have a solo pilot’s handbook, but if we did,

 

The USAF Thunderbirds flight demonstration team inadvertently uncovered a wing-structure flaw in the supersonic F-100D fighter fleet during a 1967 airshow performance.

 

 

it would say this is a 6.5-g pull. If I get it right, I’ll hit the apex of the Bomb Burst 5 sec. after the Diamond separates, snap the throttle out of ‘burner to get the smoke going, be perfectly vertical and very fast. As the Diamond pilots track away from one another to the four points of the compass, I’ll put on those lazy, lovely pigtails. Then I’ll get the smoke off and figure out how to do a slow-speed vertical recovery. But at Del Rio, it doesn’t turn out right. I start the aggressive pull into the vertical—and the aircraft explodes.

Now, F-100 pilots are accustomed to loud noises. Even in the best of circumstances, the afterburner can bang pretty hard when it lights off. It’s also fairly common for the engine compressor to stall, sometimes forcing a violent cough of rejected air back up the intake. Flame belches out the oval nose–which will definitely wake you up at night–and the shock can kick your feet off the rudder pedals. Any F-100 pilot who hears a loud “BANG!” automatically thinks, “compressor stall,” and unloads the jet to get air traveling down the intake in the right direction.

So, instinctively, the explosion causes me to relax stick-pressure to unload the airplane. By now, I’m fully into one of those fast-forward mental exercises where seasons compress into seconds, the leaves changing color while you watch. I move the stick forward lethargically, even having time to think, “That’s no compressor stall.”

Now there’s fire, and I don’t mean just a little smoke.

 Flames fill the cockpit.

 I have to eject.

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In retrospect, the airplane had already unloaded itself, making my remedy superfluous, but there was some pilot lore at work here. No matter what else happens, fly the airplane. Forget all that stuff about lift and drag and thrust and gravity, just fly the damn airplane until the last piece stops moving. Good old 55-3520 has quit flying, but I have not.

Now there’s fire, and I don’t mean just a little smoke. Flames fill the cockpit. I have to eject. I grab the seat handles and tug them up, firing the canopy and exposing ejection triggers on each side of the handles. I yank the triggers and immediately feel the seat catapult into the slipstream. Seat-separation is automatic and too fast to track, the seat disappearing as I curl into a semi-fetal posture to absorb the parachute’s opening shock. Jump school helps here; I congratulate myself on perfect body position. For one elongated moment, I imagine how proud they’d be at Ft. Benning.

Then the chute snaps open–much too quickly–jolting me back to real time and short-circuiting the transition from stark terror to giddy elation, the evil Siamese twins of parachute jumping. My helmet is missing. Where did it go? I look up and see a couple of chute panels are torn, several shroud lines broken, and there’s one large rip in the crown of the canopy. I’ll come down a bit quicker than necessary, but there’s not much altitude left anyway. Going to land in the infield, near show-center. Have to figure out the wind, get the chute collapsed fast, so as not to be dragged. Heck! On the ground and being dragged already. Get the damn chute collapsed! Finally, I stand up, thinking I’m in one piece. And here comes a blue van with some of our guys in it.

Then it begins to sink in. In 14 years and 1,000-plus air shows, the Team has been clever enough to do all its metal-bending in training, out of sight. This is our first accident in front of a crowd and the honor is mine.

I gather my gear and climb into the van. Somebody wants to take me immediately to the base hospital, but I say, “Let’s go over and tell the ground crew I’m OK.” So we stop, I get out of the van, shake hands, toss the crew chiefs an insincere thumbs-up. Jimmy Stewart is still there and comes over to say nice things, but Raquel hasn’t stayed for the show, so no air-kiss. I’d given our narrator, Mike Miller, some ad-libbing lines to do in the middle of his presentation, and he stops to say maybe we should leave “that thing, whatever it is,” out of the show sequence. That’s when I learn I’d pulled the wings off the airplane.

 

My flying boots, ordinarily pretty shiny for an

ROTC grad, were charred beyond repair.

I never wore them again.

 

On most modern fighters, the wings are well behind the pilot. You can see them in the rearview mirror or if you look back, but otherwise they’re not in your field of view. Of course, I had been watching the Diamond, ahead and well above me. I hadn’t seen the wings come off. All I knew was the airplane blew up.

The F-100 has a large fuel tank in the fuselage, on top of the wing center section and forward of the engine. When the wings folded, a large quantity of raw fuel from that tank dumped into the engine, which exploded. The shock wave from the blast propagated up the air intake and blew the nose off, removing the first 6 ft. of the airplane. The tail of the jet also was badly damaged, liberating the drag chute. As it came fluttering down, some in the crowd thought my personal parachute had failed.

After it exploded, the engine started pumping flames through the cock- pit-pressurization lines. Conditioned air enters the cockpit at the pilot’s feet and behind his head. My flying boots, ordinarily pretty shiny for an ROTC grad,  were charred beyond repair. I never wore them again. Where I had rolled my collar underneath to protect show-suit appearance, my neck got toasted.

I have no idea how fast I was traveling at ejection. I was certainly barely subsonic when the wings failed, but with the nose blown off, the F-100 is a fairly blunt object and would have slowed quickly. On the other hand, I remained with the aircraft no more than a second or two after it exploded, so there wasn’t time to decelerate much. When I came out of the jet, windblast caught my helmet, rotated it 90 deg. and ripped it off my head. It was found on the ground with the visor down, oxygen mask hooked and chin strap still fastened. As the helmet rotated, a neck strap at the back rubbed the burned part of my neck, causing some bleeding.

The Team keeps a zero-delay parachute lanyard hooked up during the air show, giving us the quickest possible chute deployment. That explained why my chute opened fast—too fast, as it turned out. I didn’t get enough separation from the seat, which somehow contacted my parachute canopy, causing the large tear. The immediate, high-speed opening was certainly harsher than normal, and as my torso whipped around to align with the chute risers, the heavy straps did further damage to the back of my neck, the body part apparently singled out for retribution.

Walking into the base hospital, I’m startled by my image in a full-length mirror. Above, a sign says: “Check Your Military Appearance.” Mine looks like I’ve crawled into a burlap bag with a mountain lion. The white show suit is a goner, the cockpit fire having given it a base-coat of charcoal gray accented by blood and a final dressing of dirt, grass and sagebrush stain. Being dragged along the ground accounts for the camouflage, but I hadn’t realized my neck was bleeding so much. I look like the main course in a slasher movie—The Solo Pilot From Hell.

They keep me in the hospital overnight. The Team visits, and Mike Miller smuggles in a dry martini in a half-pint milk carton. Everybody’s leaving for Nellis AFB the next morning. I tell the hospital staff I’m leaving, too, and ask our slotman, Jack Dickey, to pack my stuff at the motel. The 1967 show season is over.

 

The F-100’s wings mate into a box

at the center of the fuselage,

the strongest part of the airplane.

 

After I jumped out, my aircraft continued on a ballistic trajectory, scattering parts and equipment along the extended flight path. Most of the engine and the main fuselage section impacted about 2 mi. downrange from my initial pull-up spot. All the bits and pieces landed on government soil, and there was no injury or property damage. My aircraft was destroyed–I signed a hand-receipt for $696,989–but if there is a good kind of accident, this was it. Nobody was hurt, and all the scrap metal was collected for post-game analysis.

The F-100’s wings mate into a box at the center of the fuselage, the strongest part of the airplane. When my aircraft’s wing center box was inspected, it was found to have failed. North American Rockwell, the manufacturer, tested the box on a bend-and-stretch machine, and it broke again at an equivalent load of 6.5g for the flight condition I was at when the wings departed. It shouldn’t have happened, since the F-100’s positive load limit is 7.33g, but my F-100’s wing center box broke along a fatigue crack, and there were about 30 more cracks in the vicinity.

Some then-recent F-100 losses in Vietnam looked suspiciously similar. The recovery from a dive-bomb pass is a lot like my high-speed, high-g pull-up into the Bomb Burst. In the Vietnam accidents, the pieces had not been recovered, and the aircraft were written off as combat losses.

Later, specialists discovered considerable fatigue damage in the wing center boxes of other Thunderbird aircraft. USAF immediately put a 4g limit on the F-100 and initiated a program to run all the aircraft through depot modification to beef up the wing center box. My accident almost certainly saved lives by  revealing a serious problem in the F-100 fleet.

Gen. Merrill A. (Tony) McPeak flew F-100, F-104, F-4, F-111, F-15 and F-16 fighters, participated in nearly 200 air shows as a solo pilot for the Thunderbirds and flew 269 combat missions in Vietnam as an attack pilot and high-speed forward air controller (FAC). He commanded the Misty FACs, 20th Fighter Wing, Twelfth Air Force and Pacific Air Command, and completed his career as the 14th USAF chief of staff.

Reprinted with Premission of AWST ,  Via  Bill Scott  2016

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Joe Kates

Joe Kates is the founder of Photorecon. Joe has been into aviation since he was a child and has a incredible amount of knowledge to do with planes or aviation in general. Today Joe is the owner and Managing Editor of Photorecon.

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