Aerospace technology is typically an incremental game of inches. Most new aircraft or spacecraft designs consist primarily of proven technologies sprinkled with a few new ideas to nudge the limits a little at a time. It is rare to unveil a design that leaps ahead by using numerous unproven concepts. The Lockheed SR-71 Blackbird was one very notable exception. First flown in 1964, the Blackbird was an aircraft so advanced that it still had no peers when it was retired 34 years later.
What made the Blackbird so unique was its ability to fly very fast (Mach 3.3) and very high (85,000 feet). This performance allowed it to overfly nearly any area of the world and take surveillance photos with relative impunity. Intercepting fighter pilots could only shake their fists as the SR-71 flew high above their reach. To escape surface-to-air missiles, Blackbird pilots would just ease the throttles forward and outrun them.
Throughout its service life, the SR-71 was a very closely-guarded and coveted asset. Not only was it stuffed full of proprietary technology, it was also extremely expensive to purchase, maintain, and operate. The US Air Force wouldn’t let just anyone fly their prized machine. It implemented a very rigorous selection and training process for the pilots and Reconnaissance Systems Officers (RSO) that would fill the Blackbird’s seats.
Terry Pappas was one of those pilots who earned the title “Habu” – the unofficial name given to the SR-71 and its flight crew in a nod to the venomous snake that the airplane is said to resemble. Pappas spent more than 5 years in the SR-71 program and flew numerous operational missions over hostile airspace. His book, SR-71, The Blackbird, Q&A, explains the full gamut of his time in the Blackbird.
Here are some of the most interesting bits I learned from his book, as well as a few follow-up questions I was able to ask Pappas directly.
Pappas often speaks to groups about his career in aviation, which also includes several years in the corporate jet scene and a stint at NASA. Rather than a chronological biography, his book is a collection of the most common questions that he receives at his speaking engagements. As I read the book, I thought that the Q&A approach was a refreshing way to present historical topics. It really cuts to the chase. The tradeoff is a little bit of repetition as there is some overlap necessary in order for each question/answer to stand alone.
I fancy myself to be something of an aviation geek, yet I learned numerous facts about the SR-71 that I was previously unaware of. For instance, it was common for the afterburners on the Blackbirds two engines to light at slightly different times during takeoff. The temporary asymmetric thrust could instigate a white-knuckled, meandering path down the runway.
Of particular interest to me was the process for aerial refueling of the SR-71, a frequent endeavor thanks to the Blackbird’s thirsty engines. During refueling, the KC-135Q tanker would be flying at its maximum speed just to get a slight overlap with a SR-71’s minimum flying speed. In order to stay airborne behind the tanker, the Blackbird was forced to fly nose-high at full military power. This all worked fine when fuel started to flow. As more JP-7 filled the SR-71’s fuel tanks, additional power was needed to keep the Blackbird flying. Lighting both afterburners would have given too much thrust. The solution was to light just one afterburner and create the same asymmetric thrust condition that caused skipped heartbeats during the takeoff roll. Until all 80,000 pounds of fuel was transferred aboard the SR-71, the pilot would have to maintain a thrust-induced sideslip to stay on station just a few feet away from the tanker. That’s dicey stuff for sure, but apparently it was all in a day’s work for Habus.
I don’t want to spoil too much of the book for the rest of you. So, I’ll save the details about his experiences trying to spot aerial tankers in thick clouds with his fuel tanks nearly empty. You’ll also have to read the book yourself to learn about the time he lost an engine over arctic Russia. What I would like to share, however, are the follow-up questions that I asked Pappas after reading his book. Reading his first-hand accounts of flying the SR-71 rekindled my interest in the airplane. I contacted Pappas and asked him to fill some remaining gaps in my knowledge of the Blackbird and his career.
You were flying B-52s at the time you applied to become an SR-71 pilot. Do you think you would have stayed in B-52s if you had not been accepted to the SR-71 outfit? If not, what was your plan B?
Pappas : I really didn't have a plan B. I never realized that until you asked this question. I may have tried to transition to the KC-135, the air refueling tanker support team, eventually. Flying the B-52 is a very demanding job. It will make an old man out of you quickly. There was literally no human engineering designed into the BUFF (Dunn note : BUFF = Big Ugly Fat F**ker – a backhanded term of endearment coined by B-52 crews). The missions were over 12 hours long, and generally uncomfortable. It was 105 db in the cockpit. So, you had to wear a helmet or headset just to communicate.
Your book goes into detail about the time you went hypoxic and fell unconscious while flying an SR-71. Thankfully, you were in the SR-71B dual-control model with an instructor pilot. Do you think it would have been fatal for you and your RSO if you had been flying a standard SR-71A model with only a single set of flight controls?
Pappas: I'm sure that if I'd been in an A-model Blackbird when I became incapacitated, I wouldn't have survived it. My RSO would have been able to successfully eject however.
Did you find it difficult alternate between piloting the T-38 and SR-71?
Pappas: I personally didn't find it difficult to fly the T-38 at the same time I flew the SR-71. Of course, I had over a thousand hours in the T-38 before I got to the SR. That may have helped some. There were some subsonic speed and handling characteristics in common between the two aircraft, which also made them compatible. But mainly the SR was just too expensive to fly for proficiency. So, we had to fly something else. And the T-38 was a very good choice.
Flying the Guppy meant being low and slow, and frequently getting bounced around in the weather.
Pappas: It was much more challenging at NASA because I flew five very different aircraft at the same time. I remember flying all of them in a two day period more than once. The eye-height at landing is very different for each aircraft. Pilots must use their eyes heavily during a landing. And the picture that you try to 'burn in' differs greatly for each aircraft. The handling characteristics for each aircraft were vastly different too. One of the more difficult aircraft to fly, and therefore enjoyable for me, was the Super Guppy. It was 170,000 lbs, with a top speed of 205 knots, indicated airspeed. Faster, and the air over the top became supersonic. Flying the Guppy meant being low and slow, and frequently getting bounced around in the weather. It had no auto-pilot and no hydraulic assist on the flight controls. You just had to manhandle the beast. And anything approaching 15 knots of crosswind, and it wanted to weathervane and go for the grass. It was built based on the 1940's era KC-97, with the original cockpit and controls. I could fly a modern glass cockpit in the morning and then later that day, leap 60 years back in time in the Guppy. It was a blast.
When you were travelling at Mach 3+ in the SR-71, you were at very high altitude. Were there any visual cues or other sensations to tell your brain how fast you were going, or was it a matter of watching the gauges and just knowing?
Pappas: Usually, it was a matter of watching the gages very carefully in order to know and appreciate just how fast the SR was moving. There are no clouds that high in the atmosphere (70,000-85,000 feet). Normally the SR-71 does not generate a contrail of steam behind each engine the way airliners often do, because of the higher level of moisture in the air at lower altitudes (30,000-45,000 feet) where they often fly. I did have a mission off the coast of Russia, above the Arctic Circle, once in which we did generate a rare contrail. When I looked behind the aircraft, in the small periscope designed for that purpose, I could see two huge contrails being formed behind the engines, and they were falling away at over three times the speed of sound. That was impressive.
What are some of the requirements and responsibilities of a NASA pilot?
Pappas: NASA Research Pilots must have military jet experience in order to handle the T-38 and the formation flying that goes with it. It’s simply too expensive to train someone to do that when you can hire qualified people. Beyond that, NASA is simply looking for pilots who have distinguished themselves throughout their flying careers. We had 22 such pilots when I was there. About half were retired USAF or Navy pilots. The ones who had not retired were usually in the reserves and eventually became retired military as well. They typically only hire one pilot every few years. So, they can be very selective.
Primary duties include being a T-38 Instructor Pilot (IP) to astronauts and sometimes cosmonauts or other foreign nationals. We would train them from scratch in the T-38, give them their annual check rides, and conduct ongoing training and testing. It was easy when teaching a military test pilot who was one of our astronauts. Doing the same for someone who had never flown, and may have had a PhD in microbiology, was another matter. It could take the latter two years to become fully qualified in the T-38. If they were in a non-pilot role (Mission Specialist, MS) then they could fly the aircraft, but they were not allowed to perform takeoffs or landings. MS astronauts flew exclusively from the back seat of the T-38.
As IPs, we flew many of the seven different types of aircraft that supported the manned space flight operations at NASA JSC in Houston. We also flew the Gulfstream III to Russia and/or Kazakhstan several times a year to retrieve astronauts coming back from the Space Station.
Name an airplane or two on your bucket list that you've never had a chance to fly. Pick anything back to 1903.
Pappas: I was in USAF pilot training during the Vietnam War. Only one guy from my class went, since the war was winding down by the time I got my wings. One of the aircraft I wanted to fly if I had served there was the Douglas A-1 Skyraider, mainly due to its attack mission supporting our ground troops, and its search-and-rescue missions. The second aircraft on that list is the F-22 Raptor. Throughout most of my Air Force career, the hottest fighter jet was the F-15 Eagle. It is a phenomenal aircraft. I flew my last flight in the Air Force in an F-15. A USAF test pilot, friend of mine flew the F-15 operationally, and he worked on the F-22 development team. He told me that the F-22 is to the F-15, as the F-15 is to the WWII-era P-51 Mustang!
The Blackbird definitely enjoyed a long and spectacular career. It has earned its iconic status among aviation enthusiasts. My thanks to Terry Pappas for shedding light on his unique experience with this aircraft. I recommend his book for those who would like to learn more. I think that the development of the SR-71 is an equally interesting story. For that I suggest Skunk Works, A Personal Memoir of My Years at Lockheed by Ben Rich. Mr. Rich was the successor to the legendary Lockheed engineer, Kelly Johnson, and his book details his experiences while developing the U-2, SR-71, and F-117.