It is an exceedingly rare privilege for anyone aside from highly trained military pilots to don the yellow pressure suit and fly along the very edge of outer space in the infamous U-2 spy plane.But I was one of those lucky few...but first a story that may have led to this envious opportunity.
So there I was...a typical day in the clinic when suddenly, all of my companion phones and radios began to ring in chorus. I was the flight surgeon on call at Beale Air Force Base north of Sacramento. It was an in-flight emergency (IFE). There had been an incident in the skies over Northern California involving one of my guys.
Usually when we get a call for an in-flight emergency (IFE), the call terminates as a false alarm before we even cover the 5 mile distance to the flight-line by ambulance. However, this IFE felt different from the start. Multiple calls all simultaneously? That's unique. I stared down at the screen on the call phone, unsure of what fate lied on the other side.
I cautiously swiped the green slider and was greeted by an anxious voice on the other end. “Is this the flight doc on call? We have a problem. One of the U2 pilots is having joint pain in the jet.”
"I'll be right over." I said. My suspicions were correct. This was an unusual IFE call. However, this was a call I had been preparing for years.
U2 pilots are esteemed as the most talented and revered pilots in the skies - sometimes to demigod status in the aviation world. They fly into the stratosphere up to 70,000 feet above the earth's surface in a full pressure suit - alone, unarmed and unafraid. But this activity carries undeniable physiological risks. Nitrogen gas, which is normally dissolved in your blood at ambient atmospheric pressure, can easily transition to gaseous phase with reductions in air
pressure. These nitrogen bubbles, often terms the “bends” in scuba divers, can then lodge anywhere in your body causing major problems. The spectrum of this disease is known as Decompression Sickness (DCS). These small nitrogen air embolisms can lead to a variety of symptoms including rash, joint pains, loss of sensation, CNS symptoms, or even death. The symptoms experienced depend on where these bubbles ultimately settle in the body. While severe symptoms are more common in scuba divers, aviators are also susceptible to DCS with any “decompression” event such as the sudden loss of cabin pressure. Arterial Gas Embolism (AGE) is similar to DCS, but in these cases there is typically damage to the blood vessels in the lungs which allow introduction of gas directly to the arterial blood supply. U2 pilots routinely fly to high altitudes - heights that are incompatible with human life. Altitudes that will literally make water boil at room temperature. If the cabin pressure drops to an equivalent of the air pressure at 35,000 feet or above (which isn’t uncommon in the two seater version of the U2), the pilot's yellow pressure suit is his or her only lifeline.
On this particular day, the diagnosis was evident. Judging by the symptoms and ascent to high-altitude, the most worrisome cause of this pilot’s joint pains was decompression sickness, a potentially disastrous malady for any aviator as sole pilot in a single seat aircraft, and in this case one controlling a multi-million dollar military aircraft. I had read about several previous cases of DCS in U2 pilots but never been involved with a case as the treating physician. A senior U2 pilot at my base had experienced a case of neurological DCS several years ago with lingering effects to this day. I knew the potential consequences.
Fortunately in this case, the pilot was able to safely land the aircraft. The Dragon Lady (as the U-2 is affectionally called by the squadron) pulled into her parking spot on the taxiway. I eagerly awaited next to the jet to greet the pilot after engine shutdown, something I routinely do after every operational mission. Still in a cumbersome full pressure suit, the pilot gingerly stepped down the howdah and onto the hot tarmac. I could see the condensation lining the inside of his helmet - he was not comfortable. We slowly climbed into the transport van together to head back to the squadron. Immediately my clinical acumen kicked into high gear - was he mentating properly? The helmet is still sealed at this time under 100% O2, which made it difficult to hear the pilot. But I could see the apprehension on his face.
I felt dozens of eyes on me as we slowly made our way to the medical exam room. Despite the calamity, a sense of pride swept over me. This was my moment - the moment I had trained for, the moment I had always known was coming. After slowly getting him out of the suit, I could see the anxiety begin to fade. Seeing a familiar face is everything for these pilots - a doctor they know and trust is paramount in flight medicine - flight docs have the power to “ground” pilots for a number of reasons and are often labeled as the bad guys. But, a familiar, calming doctor reins supreme in emergency situations.
I completed my neurological assessment - thank goodness it was normal and his vital signs all stable. However, the joint pains in the knee and hip persisted on 100% O2 at ambient pressure. Without any history of injury or excessive exercise in the past 72 hours, the diagnosis of exclusion was indeed DCS. This case would require a trip to the hyperbaric chamber.
At the hyperbaric chamber, we set him up for a 'dive' to 2.8 atm. My pilot’s symptoms soon resolved and never resurfaced. I was so grateful. I share this story because it was one of the most fulfilling days of my career as a USAF Flight Surgeon. And it highlights the physiologic demands our country places on these pilots. However, U2 pilots aren’t the only aviators at risk of DCS - any pilot who experiences a sudden, or rapid, loss of cabin pressure is susceptible to this same threat. This is why its so critical that all aerospace medicine doctors be trained in diagnosis and treatment of this unique environmental condition.
It wasn't long after I treated this DCS case that I got the opportunity that very few USAF flight surgeons will ever experience. One of the most memorable experiences in my life. My flight in the back of the Dragon Lady (SEE POST ON WHY FLIGHT SURGEONS FLY)- a privilege only ~1350 souls have ever realized. The infamous yellow suit was awkward; impressively lacking in dexterity, movement, and ability to control one's temperature or freely ventilate. Previously I wondered why the pilots loved the cockpit so cold while flying (under 40F), but now I understood as the sweat oozed from my pores and froze into ice on the interior of the canopy. The rubber face seal wrapped tightly around my face led to hints of claustrophobia as each audible breath entered and left my lungs. The cramped cockpit felt like it was built in the 1960s (it was) - showing it’s old age with faded paint, quirky instrument panels, a seal latch casually positioned directly next to my left knee, and a myriad of scuff marks on the transparent canopy above. Witnessing an approach and landing of the winged bicycle (the U-2 has very unusually placed center line landing gears) from the cockpit proved to be even more impressive. While the U2 loves to gain altitude and flies tremendously well in thin air, flying at lower altitudes requires a serious amount of rudder and yolk inputs - and this was all observed and experienced in a full pressure suit.
Soaring over 13 miles above the ground, relishing in the absolute bliss of seeing our expansive planet (and it’s curvature) below me, I couldn’t help but feel sentimental. For over three years, I’ve been watching my pilots disappear into the stratosphere, in absolute awe of what they’re able to do. After riding in the Dragon Lady myself, my respect for these aviators has only grown. When asked about my high flight after stepping down the howdah, all I could verbalize through my delighted stupor was simply:
"Now I understand.”
Needless to say, it is an experience I will cherish forever. Hail Dragons!
