The Ethiopian Intercept

by R G Ainslee

  We worked late. No one went to the pub.

  Sunday AM, 5 February: RAF Mildenhall, United Kingdom

  Major Santini and another Air Force officer, Captain Barker, attended the morning staff meeting. Wilson seemed more confident than the day before and asked the major to report on the latest intelligence from Ethiopia.

  Santini opened a folder and checked his notes. "According to sources on the ground in Addis Ababa, a new unit on the Soviet side of the main air base reached full operational status three days ago. It appears this unit is from the elite air defense regiment referenced at our earlier meeting. A security lock down was instituted at the same time and unfortunately we have no further information since that time."

  Wilson asked about the newly arrived Soviet officers. Santini said they appeared to be associated with a major arms delivery to the Ethiopian army and not connected with the air defense regiment.

  Mack intervened with a skeptical tone, "Just how credible is your source?"

  Santini glanced at Wilson and paused a few seconds. "I am not in direct contact with the informant. This information has been passed on to me by the… an agency stateside."

  We all know who that is. I bit my tongue.

  Mack continued, "Are we’re dealing with second hand information?"

  Santini, now visibly uncomfortable, said, "In a manner of speaking, but I would—"

  Wilson interrupted, "Thank you Major Santini." He ignored Mack’s incredulous expression and motioned to Simmons. "Captain — your report."

  Simmons recapped the latest preparations and Sam asked technical questions related to tanker deployment and weather. Simmons assured him tankers would be airborne on schedule and the weather report promised optimal conditions all the way.

  Mack informed the colonel a new set of data from Huachuca would be available for the flight. We were ready on our side of the equation, but a lingering doubt remained.

  Captain Breyer reported the security integrity of the mission was intact. Our compact group didn't have a high profile on base and COMSEC (communications security) was tight. Super-secret sorties were routine occurrences at Mildenhall. The CID investigation did not turn up solid evidence of a security breach. Nevertheless, Al Oldham continued to be isolated from mission preparation. Wilson called it a prudent precaution.

  Wilson thanked Breyer, glanced around the table, and asked, "Are there any pertinent questions?" He emphasized the word pertinent, most likely for Mack's benefit.

  A few questions lingered in the back of my mind, but it seemed best to keep my mouth shut. Out of the corner of my eye, Mack shifted uncomfortably in his chair.

  Wilson stood. "Gentlemen, the situation on the ground in Ethiopia is fluid and the window of opportunity is limited. Flight conditions are optimal. The equipment is ready. We cannot afford to waste any time. It appears we are ready." He glanced at the clock. "H minus twelve hours. Make your final preflight preparations. The sortie, Raven-One, will fly tonight.

  Chapter 5 ~ The Intercept

  Sunday PM, 5 February: RAF Mildenhall, United Kingdom

  Sam and I arrived at the hangar four hours before takeoff to perform preflight checks. Technicians downloaded standard mission and special Cochise Project identifiers and powered up the black boxes. Inside the cockpit, we loaded tape and film into the recording systems and ran final tests.

  Wilson and his staff arrived at H-minus two hours for our last briefing. Simmons informed us the deployment of the KC-135Q/T tankers had begun. The weather forecast was favorable over the refueling areas. Due to the importance of the mission, extra tankers would be on station at each refueling point. They were taking no chances.

  Without hesitation, Wilson issued his go no-go decision, "The sortie will proceed as scheduled. Good luck gentlemen."

  The maintenance crew completed pre-flight preparations with a long list of checks. The SR-71, equipped with analog instrumentation and a small number of redundant systems, needed an elevated level of maintenance expertise. When a problem occurred, technicians corrected the fault on the spot.

  Checklist completed, the crew began pre-flight procedures and purged the fuel system with nitrogen. JP-7 fuel is a kerosene-based mixture with a low flashpoint, ignited by a catalyst, tetraethyl borane (TEB). To start the engine during spin up, the pilot injects a stream of TEB into the combustion chambers. On the tarmac, the airframe is loose at ground temperature and the Blackbird leaks fuel. Once the aircraft gains operational altitude and speed, intense heat expands the fuel tanks to seal leaks.

  The Physiological Support Division crew helped us with our astronaut like S1030 flight suits. Essential protection in case of sudden cabin pressure loss at operating altitudes. They hooked us to a portable air-conditioning system and sat us in large recliner chairs. To avoid the bends, we breathed pure oxygen for a half hour to purge our bloodstreams of nitrogen.

  We rode in a van out to the Blackbird hangar on the flight line. The ground crew helped us into the cockpits and connected our suits to the aircraft's oxygen and radio systems. Cockpit hatches closed and pressurized.

  A motor tug hooked to the nose wheel and pulled the craft out to the concrete apron. Air Force technicians rolled starter carts, equipped with twin-Buick engines, under the nacelles of each engine. Sam performed a run-up, spun the engines to 3,200 RPM, injected a shot of TEB, and brought the jets to life.

  The sleek SR-71 taxied to Runway 29 and waited in the dark for a visual signal from the tower. Per instructions, we operated under strict radio silence.

  The SR-71 Blackbird had flown out of RAF Mildenhall for two years. Permission from the British government was required for each sortie flown. I never found out if our mission obtained the proper clearance.

  A steady green light beamed from the control tower. Sam, a true professional with a dry sense of humor announced, "Hold on to your hats ladies and gentlemen, Blackbird Airways Flight Raven-One is ready for takeoff. Please extinguish all cigars and fasten your seatbelts." He was always helpful and, best of all, didn't have an attitude. He understood his job: fly me to the target and get the data home.

  Sam stood on the brakes and eased the throttles to full military power. A steady high-pitched whine grew to a deafening roar as engine RPM climbed to a point just short of afterburner. Brakes released, and we started to roll. Seconds later, Sam lit both afterburners and the Blackbird shot down the runway powered by 66,000 pounds of thrust from the huge Pratt and Whitney engines. My body compressed into the molded seat as the Blackbird accelerated and became airborne after a mile. Sam retracted the landing gear before the craft exceed 300 knots, the maximum airspeed allowed with gear-down.

  The pilot began his near vertical climb up to the tanker. The lights of the base disappeared from the side windows leaving me in a black world dominated by thunder and vibration. The Blackbird took off without a full load of fuel and only needed enough to climb to the first refueling stop over the North Sea. All doubts, qualms, and misgivings about the mission evaporated.

  The Blackbird maneuvered into position behind the tanker. The boom operator quipped, "Cash or credit?" Sam responded and eased the Blackbird up towards the extended boom. The process may have been routine for Sam and the tanker crew, but for me, a tense operation. The entrance to the fuel vent sat right behind my position.

  After filling up, Sam climbed to 33,000 feet, nosed down, broke the sound barrier at 28,000 feet, and climbed to the mission altitude below 85,000 and feet with a cruising speed of Mach-3.

  Normally the Blackbird flies with two crewmembers: a pilot and a Reconnaissance Systems Officer (RSO) responsible for operating the aircraft’s monitoring and defensive systems. The RSO compartment sits behind the pilot’s cockpit, with only two small side windows. The occupant is unable to see forward.

  Outside the small window, only inches away, loomed the cold intense blackness of near outer space, temperature minus sixty degrees centigrade. Friction developed by our supersonic speed heated the leading edges of the aircraft
to plus 300 degrees.

  On this flight, my sole responsibility was to manage the special package of black boxes carried in the nose. Normally, the RSO would help with navigation. I didn't have time to become competent for the task. Sam would pilot the craft all by himself, a formidable job, one for which he was exceptionally qualified.

  The days at Beale had been busy and intense. The radically shortened training program and my lack of experience made the mission even more challenging. The Air Force assembled a special team of instructors and repeated everything learned before. Normally, only the best pilots in the Air Force qualify for selection to the program. The typical SR-71 trainee has logged 2,500 hours of jet time. The sum-total of my experience: a glider pilot's license earned in Germany and a few hours logged in pursuit of a powered aircraft rating.

  The first days consisted of hours in the briefing room pouring over hundreds of crucial details in an abbreviated course of instruction. The final week spent in the flight simulator. The simulator operators put us through almost everything that might happen during a mission including emergency procedures. Finally, the instructors reluctantly certified me mission ready.

  * * *

  One hundred miles west of Gibraltar, we descend to 25.000 feet to link up with our next refueling. Sam slowed to subsonic speeds to complete the operation. As our speed decreased, the craft began to cool. The Blackbird’s skin panels shrunk. Leaking fuel formed a long vapor trail as we followed the tanker.

  The task completed, Sam disconnected, relit the afterburners, broke the sound barrier, and climbed. The altimeter recorded our upward progress to our cruising altitude just under eighty-five. He veered the big bird sixty degrees to the east, on course for Gibraltar

  Past the Strait, lights from European cities flickered in the distance on the port side, the darkness of the Sahara to starboard. Above the curvature of the earth, dark clusters of brilliant stars filled the sky.

  A brief respite, time to think, the great unknown lay ahead. After refueling south of Crete, a quick snack and drink from the thermos, we would soon be in position to start our run.

  Southwest of the divided island nation of Cyprus, the process of going on watch began, time for a final check on the equipment. Tapes and film received calibration signals. The central time unit, which placed a precise time marker on all recordings, started and tested. After opening entries in the intercept log, at last, time to go on watch.

  * * *

  At the prescribed point, south of Cyprus, Sam turned south to execute a run over the Sinai, the most air defense active area we would traverse, even more active than Ethiopia. Both the Israelis and Egyptians could detect us with their radars, but lacked practical options, our presence not worth a protest.

  The SR-71, designed around a stealthy shape with a low radar cross section, generated a radar image the size of a small boat. However, the bird was detectable, the superheated exhaust stream returned significant radar and infrared heat signatures.

  The Blackbird carried a sophisticated array of electronic countermeasures or ECM arrays capable of dealing with all currently deployed Soviet surface-to-air missile systems. They projected shadow or ghost images away from the aircraft making use of range gate stealing modes. We didn't expect to use the defensive systems.

  I signed on watch as Raven-One and began to receive signals. My attention divided between the intercept scopes and the performance indicators in the cockpit. The RSO instruments included digital readouts of longitude and latitude, speed, and heading. The airspeed indicator read Mach 3.2, over 2,300 miles per hour.

  Over the Sinai, audio from several radars confirmed the phosphorus green readouts on the scope. I didn't need the Electronic Order of Battle Handbook to identify the signals, the same sounds I had listened to over the years and could do the job with my eyes closed. A normal mission would be devoted to identifying latest changes, additions, and relocations to the electronic order of battle. My specialty was finding new types of signals.

  The first signals emanated from Egyptian early warning radars. Outdated but effective Soviet made A-band P-12 Spoon Rest and E/F-band P-35 Barlock land-based surveillance systems. Minutes later, an E-band PRV-11 Side Net height-finding radar came on line.

  An operator can identify the radar type by its pulse repetition frequency as displayed on the pulse analyzer scope. Long-range Barlock radars send out fewer pulses per second than shorter-range missile tracking radars. They also have a lower scan rate. The scan rate, or how often the radar beam scans the horizon, often one or two revolutions per minute, is indicative of high-powered long-range search radars.

  A green luminous blip appeared on the cathode ray tube, an observable representation of invisible electrons sweeping the sky. Electronic pulses radiating from a G-band Fan Song radar, a predator seeking prey. Fan Songs provide guidance for SA-2 Guideline surface to air missiles.

  Radars associated with missile systems rapidly scan a much smaller area and display different search patterns. Interceptor aircraft radars also produce distinctive audio signals. It is important to distinguish between search and tracking modes. The telltale raster scan or spiral search patterns of airborne radars produce markedly different sounds.

  Adrenalin began to pump when a target tracking system came on line. I anxiously listened to the audio of signals to identify any sign of a ground-to-air missile site switching from tracking to firing modes. The distinctive whine of a missile guidance system always focuses your attention.

  A change in scan rate and pulse repetition rates in different operating modes is detectable by listening to the audio signal. Acting quickly on this knowledge is often the key to survival in a combat situation. No one bothered to track us, and we flew on unimpeded.

  Over the Sinai, a change in audio signal, the pulse quivered on the console's panoramic display. The distinctive sound of an airborne-intercept radar resonated in my headphones. The pulse analyzer display confirmed the presence of an RP-5 Izumrud Scan Odd radar in search mode from an Egyptian MiG-19 jet. The obsolete MiG’s operation altitude was almost five miles below us, and his top speed less than half that of the Blackbird. The interceptor continued in search mode until overridden by a much stronger signal in the I-band.

  Through my headphones came an unmistakable sound, a distinctive whine broke through the jumble of signals. An instantaneous burst of adrenalin, danger rode our tail. The high-powered signal, NATO code name Firefox, belonged to a supersonic MiG-25 Foxbat interceptor. It had to be Soviet, the Foxbat not a part of the Egyptian aircraft inventory.

  "Sam, we got a Foxbat on our tail."

  "Say again."

  "There's a Foxbat on our tail — MiG-25."

  "Copy. You sure about that?"

  "Affirmative — he just locked on!"

  A boost of speed, Sam goosed the engines to full power.

  "Don't worry. He can't get close enough to fire a missile. His time-frame is too small, only has a window of a second or two to pop-up close enough for a firing solution."

  "Hope your right."

  "No problem. His missiles are useless above 88,000 feet and we're well above that now. In any case, they lack the velocity to overtake us if fired in a tail chase."

  "You sound pretty sure."

  "Experience — plus we study their capabilities. We don't just stay alive by speed alone. If he's carrying a couple of missiles, his max altitude is well under 80,000 feet."

  The Foxbat was special to me. In 1976, a Soviet pilot flew his MiG-25 from Sakharovka air base near Vladivostok to Hakodate in Japan. I spent a week at the Air Force Foreign Technology Division at Dayton, Ohio assisting in an analysis of the radar system.

  A few seconds later, the signal disappeared. My heart rate stayed high, fingers tense. The danger passed, I refocused on the full array of signals. Both sides continued to track us over the Sinai.

  The high-pitched sounds from Egyptian early warning radars faded. Down the coast of the Sudan, a blip from a surveillance radar popped up. The
remaining signals were routine and in previously known locations. A few moments to relax, but not too much, potential danger lay ahead.

  Sam seemed confident, but my nerves were on edge. We passed over the targets, in the danger zone, not from afar. The presence of the Foxbat concerned me. It wasn't supposed to be there. The potential security breach lingered in the back of my mind.

  We turned to fly over the southeast corner of the Sudan and started our course over the central highlands of Ethiopia. It was an eerie feeling to be over a now hostile land, one I had loved and wanted to visit again.

  Past the Ethiopian border, I switched to the UHF band expecting to find a P-15 Flat Face early warning radar. Wilson had suspected a new deployment of the SA-3 Goa air defense system with an operational altitude of almost 60,000 feet. The band was silent.

  A signal from a previously uncharted radar materialized in the E-band. A P-40 Long Track target acquisition radar associated with mobile anti-aircraft defense systems. I checked for associated signals. Thin Skin height finding radar, no signal. In the H-band, Pat Hand fire control and guidance radar for the SA-4 Ganef system, no signal. A further check of the G-band revealed no signal from Straight Flush fire control radar for the SA-6 Gainful system.

  Apparently, the Soviets had moved in a mobile system, a likely scenario given the short time frame. I was sure the Long Track had detected us and surprised to find no height finding or tracking signals. The possibilities ran through my head: the SA-4, a high-altitude system, the SA-6, effective at lower altitudes. Neither presented a threat to the Blackbird, at least theoretically.

  The Long Track pulse repetition frequency stayed steady and signal strength increased, we were closing in. The Blackbird passed over the suspected location. An unexpected sound resonated through the headphones. The hair on the back of my neck stood at full attention — a short burst, a rasping whipsaw buzz — then silence.

  I sensed danger. The audio returned, the pitch changed, the buzz became a solid tone, and went silent. Seconds later, a glimmer caught the corner of my eye.