• U-2 navigation equipment versus South Vietnam's aids to navigation.
• Delayed maintenance.
• Many large thunderstorms.
• Severe lightning effecting radio and radar reliability.
Background Information
A short explanation about air navigation in Vietnam versus U-2 navigation equipment: Lockheed's U-2 designer, Kelly Johnson, and the Central Intelligence Agency (CIA) installed navigation equipment compatible with “world-wide covert” U-2 operations. This meant World War II technology. A “radio compass” receiver pointed toward military and commercial broadcast stations, radio ranges and beacons and a very high frequency (VOR) omni directional radio used by most developing countries.
The early U-2s navigated over large cloud-covered areas and oceans using the same procedures Columbus used when he discovered the New World in 1492 – Dead Reckoning (DR) and celestial observations using a sextant mounted on top of the nose. Precision navigation required for photo mapping was accomplished by aiming a “spy glass” referred to as a viewfinder or drift sight ahead and below the aircraft to maintain the desired course. It was mounted under the nose. The viewfinder allowed the pilot to observe horizon to horizon 360 degrees under the Dragon Lady. GPS had not yet been developed. In Vietnam, the US military had installed the latest “state of the art” Tactical Air Navigation System (TACAN). All military aircraft were equipped with a TACAN providing both direction and distance to the transmitter. However, it was not possible to install the TACAN in the U-2 because there was no space available in the cockpit. The transmitters were located next to the runway on most airfields. In South Vietnam there was only one weak VOR located at the old French airport in Saigon; the US called it Tan Son Nhut Air Base. In addition, three Ground Control Intercept (GCI) radar sites covered Southeast Asia. They had an effective range of 250 miles. A Ground Control Approach (GCA) radar was located at Bien Hoa Air Base. The GCA radar controller “talked” the pilot down to the end of the runway by giving heading and altitude instructions. During poor visibility weather conditions, GCA was the only way a U-2 pilot could make a precision instrument approach to the runway at Bien Hoa.
A pilot designated as the U-2 mobile officer was a backup to the primary pilot. On all operational missions both the primary pilot and the mobile officer prepared to fly the mission. Both went on the twelve hours crew rest, ate a pre-mission meal and had a pre-flight physical with a Flight Surgeon. However, if the primary pilot failed his physical, the mobile officer had a physical and became the mission pilot; the roles reversed and the primary pilot then became the mobile officer. Following the physical was the mission briefing with actual and forecast weather conditions, latest intelligence, including code and recall words. The mobile officer delivered the mission kit to the aircraft, performed the preflight, and set up the cockpit to the start engine checklist.
Capt Bob Birkett at Bien Hoa AB, 1966.
The Physiological Support Division (PSD) technicians assisted the mission pilot dressing in the partial pressure suit. The cockpit of the early U-2 models was not large enough to accommodate the full pressure suit worn by astronauts. The U-2 pilot was fully pressurized from the neck up and physically constrained from the neck down by a skin-tight suit similar to a corset. The transition between the two suits was accomplished by a rubber bladder the pilot pulled down around his neck and tucked back under, it then resembling a turtleneck sweater.
Positive oxygen pressure against the tight bladder combined with body moisture formed the seal for the tiny pressure chamber for the pilot's head. The full body partial pressure suit was required because blood boils at 63,000 feet altitude, and we were subject to pressurization failures, such as flameouts, canopy seal problems, etc. above 70,000 feet.
To prevent “the bends” the pilot breathed 100% oxygen a minimum of 30 minutes before takeoff to remove the nitrogen from his system in case of loss of cabin pressurization. Normal cabin pressure was 29,000 to 29,500 when cruising above 70,000 feet. Thirty minutes prior to takeoff a PSD technician drove the pilot in an air conditioned van to the aircraft. A canopy on wheels called a houdah covered the cockpit; in warm weather a large air conditioning duct blew cold air directly on the pilot. The PSD technicians adjusted the pilot's parachute, attached a survival kit to the parachute, buckled him into the ejection seat, connected the radio cables and transferred him from portable oxygen to the aircraft system. Ten minutes prior to takeoff the mobile officer checked the pilot and his oxygen lines, closed and locked the canopy. The pilot started the engine.
Capt Bob Birkett at Bien Hoa AB, 1966.
The mobile officer's job was then to supervise the maintenance crew who followed the U-2 on to the runway to recover the pogos (outrigger wheels) that fell off during takeoff. The mobile officer monitored the pilot's flight on UHF radio in the mobile truck or in the operations office. Once the aircraft was out of UHF range, the Strategic Air Command (SAC) with worldwide HF radio coverage could relay information to/ from the pilot. One of the HF antennas was mounted on the side of the crew trailer. The pilot could send an “A-OK” code word at key navigational points or other signal as appropriate. The operating location (OL) commander or SAC Headquarters could recall the pilot by broadcasting the recall code word on the HF net. The mobile officer monitored weather conditions and base status to ensure no surprises awaited the pilot after being airborne for ten or more hours.
U-2 Quonset supply hut following the rocket attach, Bien Hoa AB, Vietnam.
If there were any potential problems with the recovery phase, the mobile officer consulted with his operations officer and/or OL commander and offered a recommended solution for the pilot prior to his entry for landing. For example, the pilot could be advised to divert to an alternate base, to land on a crosswind runway or to hold at altitude until a storm had passed. Fuel consumption at altitude was about 100 gallons per hour and about double that amount at low altitude. At the completion of a mission, the aircraft had only about 200 gallons of fuel remaining.
Landing the Dragon Lady was the most critical and most difficult task to master during training. Of the original 55 U-2 aircraft, nearly half of them crashed during a new pilot's first flight. The early U-2 models with the J-57 engine going from idle to full power took as long as 17 seconds. It felt like a lifetime waiting for the thrust to kick in and save your butt. The pilot did not have instant power for a “go around” and try again.
On final approach, the mobile officer called the distance above the runway to the pilot. As the pilot approached touchdown speed, he could not see the runway ahead of him, but had to rely on his peripheral vision and mobile's radio calls to adjust for height above the runway until the aircraft stalled. If the nose wheel touched down first, the gear strut would compress and then expand, pitching the nose up causing a slight skip or a porpoise, a condition to be avoided. A porpoise could result in a crash driving the main gear up into the fuel tank and forward engine compartment, a potential disaster for sure.
When the new and larger U-2R models were built in the late 1960s, these critical landing problems were minimized by design changes and a two-seat trainer was built. The partial pressure suit was replaced with a full pressure astronaut suit and the sextant was replaced with a TACAN.
When safely on the ground, one wing would drag on the runway. The maintenance crew in a vehicle behind the mobile officer manually lifted the lowered wing and reinstalled the pogos to allow the pilot to taxi to the ramp.
The Storms
On December 8, 1966 I flew a mission above 70,000 feet altitude north of the Demilitarized Zone (DMZ) that took me over Laos and North Vietnam, just south of the Chinese border. The weather had been clear in the “area of interest,” but as I passed the DMZ headed south, I passed over scattered thunderstorms. I was soon over solid cirrus clouds with the tops of some storms reaching 65,000 feet. The radio compass needle pointed in the general direction of Bien Hoa, but was erratic as it pointed toward the numerous lightning flas
hes. The radio compass carried a delayed maintenance write up which meant no parts were available to resolve the problem. When I called the mobile officer, Ted Rose answered. He and the U-2 Ops Officer, Charlie Kern, were en route to the weather station to check the radar. “Stay at altitude. A big storm is over the base,” he directed. Ten minutes later Ted told me to start descent immediately. One storm was passing over and another was predicted to move in the area within twenty minutes. He said the northwest area looked best, but there were thunderstorms in all quadrants.
Capt Bob Birkett at Bien Hoa AB, 1966.
At this time the radio compass needle swung indicating I was over the station, and I turned northwest to start a rapid descent. In retrospect, I believe I had passed over a severe thunderstorm fifty miles north of Bien Hoa. The lightning may have caused the radio compass needle to swing, leading me to believe I was at that time over Bien Hoa. The sun was now just setting at altitude and as soon as I started down into the clouds, it became dark except for the lightning flashes. I had called GCI for “flight following,” a request for them to monitor my progress. GCI advised their radar antenna had just taken a hit and was out of commission. My last observed position was northwest of Bien Hoa, and I was told to contact Saigon Approach Control. I advised Saigon Approach Control I was passing 50,000 feet and would start a left turn at 40,000 feet. Their radar was out and they told me to contact Bien Hoa GCA when I got lower. Bien Hoa GCA was loaded with aircraft landing between thunderstorms, and I was busy trying to avoid the storms in the dark. I was down about 10,000 feet trying to descend below broken clouds so I could pick up the lights of Bien Hoa and Saigon.
GCA was not as busy now, and they asked me to squawk the emergency code and make several identification turns. To my disappointment, they advised me that their radar had been hit by lightning and was out. Ted reported the second storm had hit, and it was too late for me to land. The mobile radio faded out as I descended lower. With the GCA not picking me up on their radar, I realized I could be a lot farther away from Bien Hoa than I thought. I was down to 4,000 feet and unable to avoid the storms any longer. I retracted the gear and speed brakes, slowed to best speed for turbulent weather conditions and started a slight climb in the storms. The radio compass was useless for navigation, and with GCA out, I turned thirty degrees to the right toward Tan Son Nhut VOR. As if I didn't have enough to worry about, the “low level” fuel warning light came on indicating I was down to forty gallons, about twelve minutes to flameout.
It was now dark with heavy turbulence and lightning. I didn't need to look at the wings to know the effect of the turbulence; I could feel the wings flexing. I had been hand flying from start of descent, sheer pilot muscle manipulated the flight control surfaces. The autopilot was designed for maintaining high altitude, straight and level flight, for optimum camera results. It was designed to disengage in turbulent conditions because the flight controls were not power assisted.
My plan was to advise the mobile officer when I passed over the VOR and the direction I was headed. I was planning my bailout between storms. It would at least give Search and Rescue a general idea where to look for me. As I came out the side of the storm, I passed over the VOR and the low clouds to my right were illuminated by the lights of Saigon. It was a most welcome sight. I called Tan Son Nhut tower and declared an emergency. I was the only aircraft still up so I had their full attention. I spiraled down, circling the VOR through the clouds and made visual contact with the runway at 3,000 feet in a medium rain shower.
The stall strips would not extend on my first attempt because of ice on the leading edge of the wings. I landed into a thunderstorm that moved down the runway towards me; I was able to clear the runway on a “high speed turn off.” I shut the engine down with seven gallons on the fuel counter, only three minutes of flight time. The big storm then hit and pelted the area for thirty minutes. During this time I flew the wings and held the brakes while the rain and wind buffeted the aircraft.
Soon all the storms in the area dissipated. Ice that accumulated on the wings fell off when the wing flexed in the turbulence. Some of the ice had damaged the leading edge of the horizontal stabilizer.
When I arrived back at our compound later that night, I stuck my head in the commander's trailer to tell him I was back safely. I said, “Sir, it got pretty exciting up there tonight.”
He replied, “Exciting up there? You should have been down here.”
As the pilot, I had ultimate responsibility for my aircraft. About an hour had elapsed from the start of my descent above 70,000 feet to landing at Tan Son Nhut Air Base. What had it felt like being in those storms with the LOW fuel warning light on, no ground radar assistance and turbulence all around during descent? In a couple of words, busy and focused. Many turns were 45 to 60 degree bank angles, approaching 90 degrees a few times. In the moderate to severe turbulence, a couple of steep banks were not intentional. As conditions deteriorated, I had but one goal: Find a runway and land. If I had flamed out before landing, I would have had only once choice. Eject.
The next day I talked with one of the weather forecasters; he told me he had been at Bien Hoa for a year. He had never seen so many thunderstorms pop up at one time. I knew it was bad, but maybe it was better I didn't know just how bad it was. A portable VOR was installed at Bien Hoa Air Base shortly after this incident.
The Rocket Attack – Bien Hoa Air Base, Republic of Vietnam, May 12, 1967
The following is an excerpt from my diary of that day:
RVN—Mortar attack at 0100 (1:00 a.m.) this morning. 7 pieces of shrapnel came through my end of the trailer. I had left the room seconds before it hit. Approx. 160 inbound rounds of mortar, rockets and recoilless. 6 people were killed, approx 50 injured, a Quonset hut burned, 6 airplanes destroyed.
Our compound was a special security area assigned to the U-2 and DC-130 TDY units of the 100th SRW from Davis Monthan AFB, Tucson, Arizona. It was surrounded by an eight-foot high barbed-wire fence and a 24-hour sentry. Within the compound were two air-conditioned trailers. One trailer housed the two U-2 pilots and the operations officer, and the second one was for the operating location (OL) commander and the DC-130/drone operations officer. Two open-air barracks called hutches were residence for the DC-130 and helicopter crews, flight planners, intelligence officer, flight surgeon and tech reps. Rounding out the compound was a Quonset hut for operations and two sandbag bunkers.
The DC-130 launched the reconnaissance drones, and the helicopters recovered them inflight as they parachuted down over the Gulf of Tonkin after flying over the Hanoi area. The OL commander, a bird colonel, and his operations officer spent 95 percent of their time coordinating and managing the complex DC-130/drone/helicopter operation while the single engine U-2 operated relatively problem free.
The first inbound woke me, and I immediately dressed in my flying suit and boots. I was ready to go out the trailer door headed for the bunker when the next rocket hit forty yards away damaging our compound. A visiting Headquarters SAC colonel had just arrived and was assigned to our trailer where he slept on the couch. After sixteen hours of jetlag, he did not even wake up for the first incoming rocket. From the door, I shouted at him to get to the bunker immediately. As I turned to go out the door, the next rocket hit, jolting our trailer.
The bunkers were dark and very crowded. One of the DC-130 crew took a small piece of shrapnel in his upper right thigh as he ran to the bunker. The incoming mortars and rockets gradually became less frequent and less intense. From inside the dark bunker, we heard emergency vehicles and shouting around our compound. There was no means of communication to or from our bunker. About thirty minutes after the last mortar, Charlie Kern and I left the bunker before the “all clear” signal to see if we could help. An Air Police barracks a couple of blocks away had taken a direct hit. We assisted a couple of the troops with minor wounds. It was only a short time before the emergency response team had the situation under control.
The two of us surveyed the
damage and reported to the OL commander in the other bunker. Although he was glad to receive the information, he was unhappy his U-2 operations officer and a U-2 pilot left the bunker before the “all clear.” When the “all clear” signal was sounded, we returned to our trailer. Outside our trailer adjacent to the door was a four-inch galvanized iron pipe with an HF antenna mounted on top. A piece of shrapnel had gone through the pipe at shoulder height and left a 1 1/2 inch hole. If I had not stopped to wake the visiting colonel, I could have been next to the pipe when it was hit. In my room, several small pieces of shrapnel had lost most of their energy penetrating the end wall.
Barracks at Bien Hoa AB, May 12 1967.
I have photos of the destruction inflicted on the base that night. An A-1E prop aircraft was totally destroyed in a concrete bunker and the U-2 supply Quonset hut burned. Closer to home, pieces of shot shrapnel landed inside my trailer on my pillow and sheet where I had been sleeping moments before the mayhem. Outside the rockets left a hole in the street four-feet deep by six to eight feet across.
Remembering the Dragon Lady: The U-2 Spy Plane: Memoirs of the Men Who Made the Legend Page 38