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The following story told by Bill Weaver is priceless in conveying the experience of departing an SR-71 Blackbird at an altitude of fifteen miles and speed of Mach 3.2
During the Cold War, there was a need for a new reconnaissance aircraft that could evade enemy radar, and the customer needed it fast. At Lockheed Martinβs advanced development group,Β the Skunk Works, work had already begun on an innovative aircraft to improve intelligence-gathering, one that would fly faster than any aircraft before or since, at greater altitude, and with a minimal radar cross section. The team rose to the nearly impossible challenge, and the aircraft took its first flight on Dec. 22, 1964. The legendary SR-71 Blackbird was born.
The first Blackbird accident that occurred that required the Pilot andΒ the RSOΒ to eject happened before the SR-71 was turned over to the Air Force. On Jan. 25, 1966 Lockheed test pilotsΒ Bill WeaverΒ and Jim Zwayer were flying SR-71 Blackbird #952 at Mach 3.2, at 78,800 feet when a serious engine unstart and the subsequent βinstantaneous loss of engine thrustβ occurred.
The following story told by Weaver (available in Col. Richard H. Grahamβs bookΒ SR-71 The Complete Illustrated History of THE BLACKBIRD The Worldβs Highest , Fastest Plane) is priceless in conveying the experience of departing a Blackbird at an altitude of fifteen miles andΒ speed of Mach 3.2.
βAmong professional aviators, thereβs a well-worn saying: Flying is simply hours of boredom punctuated by moments of stark terror. And yet, I donβt recall too many periods of boredom during my 30-year career with Lockheed, most of which was spent as a test pilot.
βBy far, the most memorable flight occurred on Jan. 25, 1966. Jim Zwayer, a Lockheed flight test reconnaissance and navigation systems specialist, and I were evaluating those systems on an SR-71 Blackbird test from Edwards AFB, Calif. We also were investigating procedures designed to reduce trim drag and improve high-Mach cruise performance. The latter involved flying with the center-of-gravity (CG) located further aft than normal, which reduced the Blackbirdβs longitudinal stability.
βWe took off from Edwards at 11:20 a.m. and completed the missionβs first leg without incident. AfterΒ refueling from a KC-135 tanker, we turned eastbound, accelerated to a Mach 3.2-cruise speed and climbed to 78,000 ft., our initial cruise-climb altitude.
βSeveral minutes into cruise, the right engine inletβs automatic control system malfunctioned, requiring a switch to manual control. The SR-71βs inlet configuration was automatically adjusted during supersonic flight to decelerate air flow in the duct, slowing it to subsonic speed before reaching the engineβs face. This was accomplished by the inletβs center-body spike translating aft, and by modulating the inletβs forward bypass doors. Normally, these actions were scheduled automatically as a function of Mach number, positioning the normal shock wave (where air flow becomes subsonic) inside the inlet to ensure optimum engine performance.
βWithout proper scheduling, disturbances inside the inlet could result in the shock wave being expelled forwardβa phenomenon known as an βinlet unstart.β That causes an instantaneous loss of engine thrust, explosive banging noises and violent yawing of the aircraftβlike being in a train wreck. Unstarts were not uncommon at that time in the SR-71βs development, but a properly functioning system would recapture the shock wave and restore normal operation.
βOn the planned test profile, we entered a programmed 35-deg. bank turn to the right. An immediate unstart occurred on the right engine, forcing the aircraft to roll further right and start to pitch up. I jammed the control stick as far left and forward as it would go. No response. I instantly knew we were in for a wild ride.
βI attempted to tell Jim what was happening and to stay with the airplane until we reached a lower speed and altitude. I didnβt think the chances of surviving an ejection at Mach 3.18 and 78,800 ft. were very good. However, g-forces built up so rapidly that my words came out garbled and unintelligible, as confirmed later by the cockpit voice recorder.
βThe cumulative effects of system malfunctions, reduced longitudinal stability, increased angle-of-attack in the turn, supersonic speed, high altitude and other factors imposed forces on the airframe that exceeded flight control authority and the Stability Augmentation Systemβs ability to restore control.
βEverything seemed to unfold in slow motion. I learned later the time from event onset to catastrophic departure from controlled flight was only 2-3 sec. Still trying to communicate with Jim, I blacked out, succumbing to extremely high g-forces. The SR-71 then literally disintegrated around us. From that point, I was just along for the ride.
βMy next recollection was a hazy thought that I was having a bad dream. Maybe Iβll wake up and get out of this mess, I mused. Gradually regaining consciousness, I realized this was no dream; it had really happened. That also was disturbing, because I could not have survived what had just happened. Therefore, I must be dead. Since I didnβt feel badβjust a detached sense of euphoriaβI decided being dead wasnβt so bad after all. AS FULL AWARENESS took hold, I realized I was not dead, but had somehow separated from the airplane. I had no idea how this could have happened; I hadnβt initiated an ejection. The sound of rushing air and what sounded like straps flapping in the wind confirmed I was falling, but I couldnβt see anything. My pressure suitβs face plate had frozen over and I was staring at a layer of ice.
βThe pressure suit was inflated, so I knew an emergency oxygen cylinder in the seat kit attached to my parachute harness was functioning. It not only supplied breathing oxygen, but also pressurized the suit, preventing my blood from boiling at extremely high altitudes. I didnβt appreciate it at the time, but the suitβs pressurization had also provided physical protection from intense buffeting and g-forces. That inflated suit had become my own escape capsule.
βMy next concern was about stability and tumbling. Air density at high altitude is insufficient to resist a bodyβs tumbling motions, and centrifugal forces high enough to cause physical injury could develop quickly. For that reason, the SR-71βs parachute system was designed to automatically deploy a small-diameter stabilizing chute shortly after ejection and seat separation. Since I had not intentionally activated the ejection systemβand assuming all automatic functions depended on a proper ejection sequenceβit occurred to me the stabilizing chute may not have deployed.
βHowever, I quickly determined I was falling vertically and not tumbling. The little chute must have deployed and was doing its job. Next concern: the main parachute, which was designed to open automatically at 15,000 ft. Again I had no assurance the automatic-opening function would work. I couldnβt ascertain my altitude because I still couldnβt see through the iced-up face plate. There was no way to know how long I had been blacked-out or how far I had fallen. I felt for the manual-activation D-ring on my chute harness, but with the suit inflated and my hands numbed by cold, I couldnβt locate it. I decided Iβd better open the face plate, try to estimate my height above the ground, then locate that βDβ ring. Just as I reached for the face plate, I felt the reassuring sudden deceleration of main-chute deployment. I raised the frozen face plate and discovered its uplatch was broken. Using one hand to hold that plate up, I saw I was descending through a clear, winter sky with unlimited visibility. I was greatly relieved to see Jimβs parachute coming down about a quarter of a mile away. I didnβt think either of us could have survived the aircraftβs breakup, so seeing Jim had also escaped lifted my spirits incredibly.
βI could also see burning wreckage on the ground a few miles from where we would land. The terrain didnβt look at all invitingβa desolate, high plateau dotted with patches of snow and no signs of habitation. I tried to rotate the parachute and look in other directions. But with one hand devoted to keeping the face plate up and both hands numb from high-altitude, subfreezing temperatures, I couldnβt manipulate the risers enough to turn. Before the breakup, weβd started a turn in the New Mexico-Colorado-Oklahoma-Texas border region. The SR-71 had a turning radius of about 100 mi. at that speed and altitude, so I wasnβt even sure what state we were going to land in. But, because it was about 3:00 p.m., I was certain we would be spending the night out here.
βAt about 300 ft. above the ground, I yanked the seat kitβs release handle and made sure it was still tied to me by a long lanyard. Releasing the heavy kit ensured I wouldnβt land with it attached to my derriere, which could break a leg or cause other injuries. I then tried to recall what survival items were in that kit, as well as techniques I had been taught in survival training.
βLooking down, I was startled to see a fairly large animalβperhaps an antelopeβdirectly under me. Evidently, it was just as startled as I was because it literally took off in a cloud of dust.
Bill Weaver
βMy first-ever parachute landing was pretty smooth. I landed on fairly soft ground, managing to avoid rocks, cacti and antelopes. My chute was still billowing in the wind, though. I struggled to collapse it with one hand, holding the still-frozen face plate up with the other.
βCan I help you?β a voice said. Was I hearing things? I must be hallucinating. Then I looked up and saw a guy walking toward me, wearing a cowboy hat. A helicopter was idling a short distance behind him. If I had been at Edwards and told the search-and-rescue unit that I was going to bail out over the Rogers Dry Lake at a particular time of day, a crew couldnβt have gotten to me as fast as that cowboy-pilot had.
βThe gentleman was Albert Mitchell, Jr., owner of a huge cattle ranch in northeastern New Mexico. I had landed about 1.5 mi. from his ranch houseβand from a hangar for his two-place Hughes helicopter. Amazed to see him, I replied I was having a little trouble with my chute. He walked over and collapsed the canopy, anchoring it with several rocks. He had seen Jim and me floating down and had radioed the New Mexico Highway Patrol, the Air Force and the nearest hospital.
βExtracting myself from the parachute harness, I discovered the source of those flapping-strap noises heard on the way down. My seat belt and shoulder harness were still draped around me, attached and latched. The lap belt had been shredded on each side of my hips, where the straps had fed through knurled adjustment rollers. The shoulder harness had shredded in a similar manner across my back. The ejection seat had never left the airplane; I had been ripped out of it by the extreme forces, seat belt and shoulder harness still fastened.
βI also noted that one of the two lines that supplied oxygen to my pressure suit had come loose, and the other was barely hanging on. If that second line had become detached at high altitude, the deflated pressure suit wouldnβt have provided any protection. I knew an oxygen supply was critical for breathing and suit-pressurization, but didnβt appreciate how much physical protection an inflated pressure suit could provide. That the suit could withstand forces sufficient to disintegrate an airplane and shred heavy nylon seat belts, yet leave me with only a few bruises and minor whiplash was impressive. I truly appreciated having my own little escape capsule. After helping me with the chute, Mitchell said heβd check on Jim. He climbed into his helicopter, flew a short distance away and returned about 10 min. later with devastating news: Jim was dead. Apparently, he had suffered a broken neck during the aircraftβs disintegration and was killed instantly. Mitchell said his ranch foreman would soon arrive to watch over Jimβs body until the authorities arrived.
βI asked to see Jim and, after verifying there was nothing more that could be done, agreed to let Mitchell fly me to the Tucumcari hospital, about 60 mi. to the south.
βI have vivid memories of that helicopter flight, as well. I didnβt know much about rotorcraft, but I knew a lot about βred lines,β and Mitchell kept the airspeed at or above red line all the way. The little helicopter vibrated and shook a lot more than I thought it should have. I tried to reassure the cowboy-pilot I was feeling OK; there was no need to rush. But since heβd notified the hospital staff that we were inbound, he insisted we get there as soon as possible. I couldnβt help but think how ironic it would be to have survived one disaster only to be done in by the helicopter that had come to my rescue.
βHowever, we made it to the hospital safelyβand quickly. Soon, I was able to contact Lockheedβs flight test office at Edwards. The test team there had been notified initially about the loss of radio and radar contact, then told the aircraft had been lost. They also knew what our flight conditions had been at the time, and assumed no one could have survived. I briefly explained what had happened, describing in fairly accurate detail the flight conditions prior to breakup.
βThe next day, our flight profile was duplicated on the SR-71 flight simulator atΒ Beale AFB, Calif. The outcome was identical. Steps were immediately taken to prevent a recurrence of our accident. Testing at a CG aft of normal limits was discontinued, and trim-drag issues were subsequently resolved via aerodynamic means. The inlet control system was continuously improved and, with subsequent development of the Digital Automatic Flight and Inlet Control System, inlet unstarts became rare. Investigation of our accident revealed that the nose section of the aircraft had broken off aft of the rear cockpit and crashed about 10 mi. from the main wreckage. Parts were scattered over an area approximately 15 mi. long and 10 mi. wide. Extremely high air loads and g-forces, both positive and negative, had literally ripped Jim and me from the airplane. Unbelievably good luck is the only explanation for my escaping relatively unscathed from that disintegrating aircraft.
βTwo weeks after the accident, I was back in an SR-71, flying the first sortie on a brand-new bird at Lockheedβs Palmdale, Calif., assembly and test facility. It was my first flight since the accident, so a flight test engineer in the back seat was probably a little apprehensive about my state of mind and confidence. As we roared down the runway and lifted off, I heard an anxious voice over the intercom. βBill! Bill! Are you there?β
βYeah, George. Whatβs the matter?β
βThank God! I thought you might have left.β The rear cockpit of the SR-71 has no forward visibilityβonly a small window on each sideβand George couldnβt see me. A big red light on the master-warning panel in the rear cockpit had illuminated just as we rotated, stating, βPilot Ejected.β Fortunately, the cause was a misadjusted microswitch, not my departure.β