Lockheed’s chief test pilot for the SR-71 Blackbird overcame numerous inflight emergencies during his career and never failed to bring an airplane back to earth.
In the early afternoon of December 22, 1964, Lockheed’s legendary aircraft designer Clarence “Kelly” Johnson shook hands with his chief test pilot and wished him well. Robert J. Gilliland mounted the ladder and strapped into the cockpit of Johnson’s finest creation, the yet-unnamed and untested SR-71 Blackbird. Few were present for its top-secret first flight, but all who were knew its importance in maintaining the United States’ supremacy in manned aviation amid the tensions of the Cold War. Following clearance for takeoff from Air Force Plant 42 in Palmdale, Calif., Gilliland eased the Blackbird into the sky, taking it out to Mach 1.5 at 50,000 feet and into the annals of aviation history.
Bob Gilliland would go on to personally fly each of the 32 Blackbirds built as they became operational, in the process logging more test flight hours at Mach 3 than any other pilot. The SR-71 would go down in history as the world’s fastest air-breathing manned aircraft.
Born in Memphis, Tenn., in 1926, Gilliland graduated from the U.S. Naval Academy in 1949 with an engineering degree. He took a commission in the U.S. Air Force in order to immediately attend flight school, and in 1952 volunteered for a combat tour in Korea, flying 25 missions in Republic F-84 Thunderjets. After the Korean War, he was selected for the elite Air Force research and development team at Eglin AFB in Florida, piloting virtually every aircraft in the USAF inventory, including the groundbreaking Lockheed F-104 Starfighter. Gilliland used that experience as a springboard to become an F-104 instructor pilot for Lockheed, training such highly accomplished aviators as German World War II aces Günther Rall and Johannes Steinhoff, as well as Canadian Wing Cmdr. Kenneth Lett and USAF Brig. Gen. John Dunning. During his time flying the F-104, he made five successful dead-stick landings, an impressive accomplishment considering the Starfighter was said to glide “like a toolbox.”
“Since I had flown the F-104 in various tests, I was in a position to be considered for the SR-71 programs,” Gilliland said. “The Starfighter had a very tiny wing—only seven feet from wing root to wingtip. It had the highest wing loading of any aircraft known to man. They used the F-104 on approach practices to simulate the X-15. It was the first aircraft to simultaneously hold the world’s altitude, speed and time-to-climb records. No other aircraft had achieved anything like that, and the F-104 still holds the low-altitude world speed record.”
Gilliland made significant contributions to the SR-71’s development. He met with Lockheed engineers on a regular basis, and briefed the original cadre of 10 Air Force pilots chosen to fly the new Mach 3 aircraft. Gilliland kept them informed of design developments and later personally checked them out in the SR-71. He also spent a lot of time with the engineers involved with the cockpit layout, which was a concern for him due to his 6-foot-3-inch frame. Before the cockpit mock-up was laid out, the necessary corrections were made to comfortably accommodate a 6-foot pilot. Years after the Blackbird became operational, many of those who flew it commented about how roomy and well designed the cockpit was.
“Leading up to that first flight, we had to plan to do everything just like we were going to take off, except we did not take off,” Gilliland recalled. “When all the instruments checked out OK, I did a high-speed run down the runway, deploying the chute and testing the brakes, jettisoning the chute and taxiing back to the ramp. All the instruments had to be checked and double-checked by the engineers to make sure they were working properly….Once we were given the green light, I taxied out, went through all the procedures and then took off.
“On that first flight, there were 379 open items yet to be resolved on the ‘Article,’ as Kelly referred to it. Several of the rear seat panel instruments were mounted in the forward cockpit, since I would be the only pilot on the initial test flight. We had three chase planes [F-104s]. One of them was a single-seater and the other two were two-seaters with Lockheed photographers in the back seats. Their assignment was to record every detail of the flight. I told them not to fly too close because I was going to be so busy in the cockpit that I would not have the time to keep an eye on them or even talk to them on the radio.
“We were able to accomplish a lot on that first flight. I wore a orange flight suit instead of the usual ‘moon’ suit, and kept the plane under 50,000 feet pursuant to the flight profile and insurance requirements. On subsequent test flights, we had this Velcro rig on our space suits, and we would have a list of items that we were going to do—things Kelly and I had previously agreed on—and nothing more. That was professionalism at its best. The chief engineer would draw up a list, and if I agreed with him, both of use would sign it. If there were any items that were in dispute, we would get Kelly involved to give us a ruling. We actually never had any problems with this list because we all knew what had to be done.
“Once everything checked out [during the flight], I would turn around and head back toward the base, then go supersonic. This allowed a safety factor in case you had emergencies while at supersonic speed, since you wouldn’t have to worry about turning around. In the Blackbird turning around was extremely difficult at high speeds. This way, you had more time to focus on any emergency that might crop up.
“The only significant emergency I experienced on that first flight happened as I was turning over the Sierra Nevada mountains and heading south again. As I was accelerating through Mach 1.2, this big red light on the instrument panel lit up, indicating that the canopy was unsafe. I came back to minimum burner just in case. Knowing the guys who had done such a great job designing the canopy, I figured it had to be just a low-pressure area, aerodynamically, coming over the canopy and it lifted the canopy just a bit, triggering one of the micro switches and causing the red light to come on. I thought about it for a few seconds and then added power again, all the while with the red warning light on. Of course, once you get back on the ground, the engineers come out of the woodwork and say, “What do you think we put those warning lights there for anyway!’” (In this case, the warning light turned out to have resulted from an improperly wired switch.)
On the first flight, Gilliland continued, “I kept climbing until I got up to 50,000 feet, and that was where my cut-off was. I had climbed up to this altitude at a healthy 1.5 Mach, and it didn’t take long. It would be very difficult to describe in words the enormous power that the Blackbird had.”
The first flight revealed a great number of things that had to be corrected or adjusted before the second flight could even be attempted. The aircraft and systems were so radically new that nothing could be taken for granted. Engineers who had an issue that needed to be addressed worked through official service bulletins, ensuring the problem was corrected before a date was set for the second flight.
As one might imagine, it took some time to work out all the Blackbird’s bugs. “There were several inflight emergencies on just about all of the test flights,” Gilliland said. “One time I lost both engines up at 85,000 feet. I could not get either one lit until I was down to about 12,000 feet. I was very close to punching out, and that would have been very dangerous for me because we had about a 30-knot wind on the ground. There is an old saying about ‘shaking hands with a Joshua tree at 30 knots.’
“I had other emergencies, like one where I had an electrical failure and could not transfer any fuel. As you go supersonic, your center of gravity moves aft. Therefore, we try to design our center-of-gravity system so that the tanks aft of the pilot are used up in a special sequence. [That way] as we fly, to keep the ailerons trimmed up right and have minimum drag, the CG stays within the bounds where you can get the most range and efficiency from the airplane. If you fly around with the ailerons sticking up, it is like flying with your speed brakes out. The CG is automatically programmed, and if it doesn’t work properly, the pilot gets in the loop and programs it.
“We have to have the alternator working to run the fuel forward to tank no. 1—this puts the CG within limits so that when we landed, we would have positive stability. It was very squirrelly to land and very hard to control because it tended to rear back like a praying mantis….”
The Blackbird could not have attained its impressive speeds without the specially developed Pratt & Whitney J58 engine. “The hybrid engines gave an outstanding level of performance and contributed heavily to the SR-71’s image,” Gilliland said. “It was half turbojet and half ramjet; that is where it achieves its efficiency….With a turbojet, the faster it goes, its efficiency is reduced, and a ramjet is just the opposite—the faster you go, the greater the efficiency….[A]s we start going down in efficiency, then we go into bypass mode. You have to remember that we had to make this efficient or we’d have no chance of getting the range we wanted. Kelly originally stated that he would be happy if we got a range of 1,200 nautical miles, and he ended up getting twice that! We did a lot of things trying to optimize range….The optimal design speed for the SR was 3.2 Mach. If you fly faster than that, you go at the cost of efficiency. If you go slower than 3.2 Mach, then you do that also at the cost of efficiency. The aircraft could move up to 3.5 Mach and still maintain good stability.”
The SR-71 relied on speed and altitude to keep it safe from surface-to-air missiles and fighter interception. To understand why a Blackbird at maximum altitude and top speed was nearly impossible to shoot down, consider that it’s traveling faster than a .30-06 rifle bullet while a SAM must make a standing start, with a tremendous lead angle. The window of launch opportunity was typically only about four seconds. In order to hit the Mach 3 airplane, the missile crew had to get a radar lock-on, and at the SR-71’s operating altitude that was next to impossible. As the SAM accelerated into the vicinity of the target, it needed to keep a lock on the Blackbird and then do a terminal guidance and what’s called a “curve of pursuit.”
“Mathematically, the odds of getting a hit against the SR-71 are almost nonexistent,” said Gilliland. “It would not even have raised my blood pressure, back in the Cold War days, to have known that a SAM was being fired at me. As a matter of fact, you could have announced in advance when and where you were going to fly over—altitude, speed, etc.—and there was absolutely nothing the Soviets could have done about it. They might have gone broke sooner by shooting more SAMs, as those weapons are very expensive. I know for a fact that the Russians and their satellite countries have fired between 4,000 and 5,000 SAMs at the Blackbird without even a close hit.”
For their work on the SR-71 Blackbird program, in 1964 Gilliland and three other test pilots won the Ivan C. Kincheloe Award from the Society of Experimental Test Pilots. When SETP president Joseph Tymczyszyn announced the winners that year, he said he couldn’t describe what they had accomplished because it was top secret, “But believe me, they deserve the award.”
Warren Thompson conducted the interview with Bob Gilliland on which this article is based in 1998. On October 28, 2017, Gilliland was inducted into the National Aviation Hall of Fame. For further reading, Thompson recommends: SR-71 Blackbird: Stories, Tales and Legends, by Rick Graham; and SR-71 Blackbird, by Paul F. Crickmore.
This feature originally appeared in the September 2018 issue of Aviation History. Subscribe today!