{"id":222,"date":"2022-12-06T09:20:00","date_gmt":"2022-12-06T16:20:00","guid":{"rendered":"http:\/\/pwoodford.net\/blog\/?p=222"},"modified":"2023-11-07T08:45:11","modified_gmt":"2023-11-07T15:45:11","slug":"gravity","status":"publish","type":"post","link":"https:\/\/pwoodford.net\/blog\/?p=222","title":{"rendered":"Air-Minded: A Matter of Some Gravity"},"content":{"rendered":"<p><i>This is an encore presentation of an Air-Minded post I wrote 15 years ago. Yesterday a fellow F-15 pilot, Garry Goff, posted photos of the centrifuge I trained in, jointly operated by the U.S. Air Force and the Japan Air Self-Defense Force at Tachikawa Airfield in Tokyo. I didn&#8217;t take photos when I was there, and came up blank when I searched\u00a0online for photos at the time I wrote the post. Now I finally have some, and have added them to the original post.<\/i><\/p>\n<hr \/>\n<p>Here&#8217;s a way to think about pulling Gs and why it hurts: if you weigh 200 pounds, at 9 Gs you&#8217;ll weigh 1,800. Consider that for a moment. Ready for your centrifuge ride?<\/p>\n<p><center><iframe loading=\"lazy\" src=\"https:\/\/www.youtube.com\/embed\/DMKcO-T5Y4o\" width=\"560\" height=\"315\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/center>Fighter pilots have been battling GLOC &#8230; G-induced loss of consciousness &#8230; since at least WWII, when airplanes began to be capable of pulling more Gs than their human operators. With training, experience, and the right equipment, pilots can withstand high G forces, so long as they anticipate and prepare for them. With rapid G onset (going from 1 to 9 Gs in a second or less, a feat well within the capabilities of modern fighters), even trained and experienced pilots can suffer GLOC.<\/p>\n<figure style=\"width: 320px\" class=\"wp-caption alignleft\"><a title=\"gm510-2-zi\" href=\"https:\/\/www.flickr.com\/photos\/halfmind\/52546828876\/in\/dateposted-public\/\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/live.staticflickr.com\/65535\/52546828876_58988b7a93_n.jpg\" alt=\"gm510-2-zi\" width=\"320\" height=\"318\" \/><\/a><figcaption class=\"wp-caption-text\">Aircraft G meter at 1 G (max recorded: 5.2 positive, 1.6 negative)<\/figcaption><\/figure>\n<p>What happens with GLOC? Basically, the downward force on your body exceeds the ability of your heart to pump blood to the brain. As Gs increase and less blood flows to your brain, you experience tunnel vision, then loss of vision. You&#8217;re still conscious, you just can&#8217;t see. As Gs continue to increase, though, blood flow stops and you suddenly lose consciousness. As you lose consciousness your body relaxes: you involuntarily quit pulling back on the stick, the Gs go away, and you start to come to.<\/p>\n<p>Your &#8220;nap&#8221; typically lasts 10 seconds or so. But you don&#8217;t come to instantly \u2014 after your 10 seconds of unconsciousness, you spend the next 10 to 12 seconds &#8220;waking up&#8221; \u2014 arms and head flailing about, unaware of who you are or what you&#8217;re doing. Aviators call the waking up phase of GLOC &#8220;doing the chicken.&#8221; Here&#8217;s the downside: if you&#8217;re in a dive when you experience GLOC, you may not fully wake up in time to avoid hitting the ground.<\/p>\n<p>How many aircraft and crewmembers have we lost to GLOC?\u00a0No one really knows, because we didn&#8217;t start accurately tracking GLOC incidents and accidents until the 1980s. A good guess, though, is &#8220;plenty,&#8221; and GLOC continues to be a killer.<\/p>\n<p>We always knew GLOC was a serious problem, and pilots have always trained to combat it. We began using G-suits (inflatable leggings that squeeze against\u00a0gut, thigh, and calf muscles) and practicing anti-G straining maneuvers (clenching\u00a0leg, buttock, and stomach muscles while taking short breaths against a closed glottis) shortly after WWII. When I came into the US Air Force in the mid-1970s, this was still the state of GLOC-prevention training.<\/p>\n<p>In the mid-1980s, the USAF started sending new fighter pilots to centrifuge training. Before long they decided to send experienced\u00a0fighter pilots as well. It was advertised as a training program, but one with a built-in gotcha. If you experienced GLOC in the &#8216;fuge, you&#8217;d be grounded for a few weeks, during which you&#8217;d have to exercise daily to increase your anaerobic strength,\u00a0then sent to the &#8216;fuge again. If you failed a second time, your fighter days were over. If you failed egregiously, your flying days might be over. What could be worse than that?<\/p>\n<p>I&#8217;ll tell you what&#8217;s worse: they videotape you in the &#8216;fuge. If you GLOC and do a spectacular chicken, every pilot in the USAF will get to see you in a training tape. And they will laugh at you.<\/p>\n<p>I got into the F-15 in 1978, back before mandatory centrifuge training. When the USAF started sending new fighter pilots to the &#8216;fuge,\u00a0I was in Alaska serving my second F-15 tour, and had more than 1,000 hours in the aircraft. I was safe. A couple of years later, when they started rounding up experienced pilots for centrifuge training, I was serving a joint staff tour at US Special Operations Command \u2014 flying a desk, so still safe. In 1988 I got a third F-15 assignment, to Kadena Air Base in Japan. I expected to be sent to the &#8216;fuge during requalification training, but it\u00a0didn&#8217;t happen. After flying for a year at Kadena with no apparent centrifuge threat, I figured I&#8217;d slipped between the cracks, and damned if I was going to remind anyone I&#8217;d never had the training!<\/p>\n<p>I&#8217;ve pulled a lot of Gs, but have blessedly never experienced GLOC. Like all experienced pilots, when my vision started to tunnel I&#8217;d ease off on the stick and lower the Gs. As long as I\u00a0controlled the G-onset rate, I could pull 9 Gs with the best of them. It&#8217;s important to note, though, that in the airplane, you never pull 7 to 9 Gs for more than a second or two.\u00a0In the centrifuge, it lasts a lot longer. There, technicians control the G loading and you get whatever they lay on you. Unlike flying in an aircraft under your control, you can&#8217;t ease off on the stick to reduce Gs, nor can you control onset rate.<\/p>\n<p>So there I was, starting my second year at Kadena, when my commander\u00a0was summoned to a conference at Pacific Air Forces headquarters in Honolulu. In a conference room full of his peers, they put up a slide showing every centrifuge-delinquent pilot in PACAF. There were only two: Lt. Col. Paul Woodford and Lt. Col. John B______, both at Kadena. The very next day our embarrassed boss\u00a0had John and I on a C-12 to Yokota Air Base in Tokyo. The day after that we were at the USAF\/Japanese Air Self Defense Force centrifuge at Tachikawa.<\/p>\n<figure style=\"width: 640px\" class=\"wp-caption aligncenter\"><a title=\"IMG_1176\" href=\"https:\/\/www.flickr.com\/photos\/halfmind\/52546331357\/in\/dateposted-public\/\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/live.staticflickr.com\/65535\/52546331357_7089db1df1_z.jpg\" alt=\"IMG_1176\" width=\"640\" height=\"416\" \/><\/a><figcaption class=\"wp-caption-text\">Helpful wall schematic at the USAF\/JASDF centrifuge, Tachikawa Airfield (photo: Gary Goff)<\/figcaption><\/figure>\n<p>I was in my mid-40s and John was, I&#8217;ll guess, just turning 40. By fighter pilot standards we were old men. Joining us at Tachikawa for our day of training was a 22-year-old F-16 pilot from Misawa Air Base in northern Japan. John and I decided then and there we weren&#8217;t going to take a nap no matter how tough it got or how many Gs they laid on us. Not in front of that punk-ass kid, we weren&#8217;t. No effing way.<\/p>\n<p>The way it works is you spend\u00a0the morning in academics, taking refresher training in effective anti-G straining maneuver techniques. Then you go into the &#8216;fuge, one at a time, while the pilots waiting their turn watch you on closed circuit TV as you spin through the profile.<\/p>\n<figure style=\"width: 640px\" class=\"wp-caption aligncenter\"><a title=\"IMG_1177\" href=\"https:\/\/www.flickr.com\/photos\/halfmind\/52547270360\/in\/dateposted-public\/\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/live.staticflickr.com\/65535\/52547270360_04732042b1_z.jpg\" alt=\"IMG_1177\" width=\"640\" height=\"433\" \/><\/a><figcaption class=\"wp-caption-text\">USAF pilot helping a colleague strap into into the &#8216;fuge as a JASDF tech looks on (photo: Gary Goff)<\/figcaption><\/figure>\n<p>The profile? After you strap into the seat in the centrifuge, they spin you up to 4 Gs, hold you there for 30 seconds, then spin you back down for a short break. This is to make sure your G-suit is working properly, as well as everything in the centrifuge itself. Now you go into the full profile. They spin you back up to\u00a04 Gs for 15 seconds, then 5 Gs for 30 seconds, 6 Gs for 30 seconds, 7 Gs for 15 seconds, 8 Gs for 10 seconds, and 9 Gs for\u00a010 seconds, during which time you have to track a simulated MiG on a head-up display by controlling a stick with your hand. Not only do you pull a lot of Gs, you pull a lot of Gs for a long time (<em>you<\/em> try weighing 1,800 pounds for 10 seconds!). There&#8217;s no break between 5 Gs, 6 Gs, 7 Gs, etc \u2014 you go straight from one G loading to the next, all the way up to 9 Gs, and the onset rate for every increase is almost instantaneous. You&#8217;d never do anything like this in an actual airplane \u2014 if you did, you&#8217;d GLOC yourself to death! But in the &#8216;fuge, you have to do it, and you don&#8217;t dare lose consciousness.<\/p>\n<figure style=\"width: 640px\" class=\"wp-caption aligncenter\"><a title=\"IMG_1178\" href=\"https:\/\/www.flickr.com\/photos\/halfmind\/52547091874\/in\/dateposted-public\/\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/live.staticflickr.com\/65535\/52547091874_52e3a6a81e_z.jpg\" alt=\"IMG_1178\" width=\"640\" height=\"424\" \/><\/a><figcaption class=\"wp-caption-text\">Tachikawa centrifuge at speed, its occupant approaching 9 Gs (photo: Gary Goff)<\/figcaption><\/figure>\n<p>John went first and did fine. I went second. Damn, it was punishing \u2014 probably the hardest physical straining I&#8217;ve done in my life \u2014 but I didn&#8217;t pass out either, and in fact I tracked my MiG better than John did. The kid went last,\u00a0and\u00a0GLOC&#8217;ed between 7 and 8 Gs. John and I\u00a0watched him come to and do the chicken. We laughed and laughed.<\/p>\n<p>We had the night off in Tokyo, so John and I went out on the town, exhausted though we were. We took a taxi to a hole in the wall place in the Ginza, where two beers and two plates of gyoza, plus the taxi ride, cost a month&#8217;s worth of flight pay. As I reached out for my beer I noticed the underside of my arm was covered in little red spots. John held up his arm and he had &#8217;em too. Later that night, back in my room at Yokota, I undressed and discovered the same spots all over my butt and down the backs of my legs. The technical name is petechia, but pilots call &#8217;em G-measles \u2014 they&#8217;re what happen when you pull so many Gs you rupture your capillaries.<\/p>\n<p>Am I glad I took my turn in the centrifuge after all? Yes, I guess I am. Would I ever want to do it again? Hell, no!<\/p>\n<p>p.s. About the F-16 kid from Misawa: John and I didn&#8217;t think about it as it was happening, but over beer and gyoza that night realized we&#8217;d just watched a young man wash out of his dream assignment in fighters. The kid would have had to pass centrifuge training before he ever got to fly a Viper, so for him to be at the &#8216;fuge with us meant he must have GLOC&#8217;ed on a training flight at Misawa and been sent to Tachikawa for evaluation and retraining. For him, it was a do or die scenario. May god forgive us for laughing at him earlier in the day \u2014 although looking at the bigger picture, his bad day at the &#8216;fuge probably saved his life.<\/p>\n<p><em data-rich-text-format-boundary=\"true\">\u2014<a href=\"https:\/\/pwoodford.net\/blog\/?page_id=14450\"><strong> back to the Air-Minded Index<\/strong><\/a><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Here&#8217;s a way to think about pulling Gs and why it\u00a0hurts: if\u00a0you weigh 200 pounds, at 9 Gs you&#8217;ll weigh 1,800. Consider that for a moment. Ready for your centrifuge ride?<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1960,3,14,2],"tags":[157,595],"class_list":["post-222","post","type-post","status-publish","format-standard","hentry","category-air-minded","category-flying","category-military","category-personal","tag-air-minded","tag-centrifuge-training"],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/pwoodford.net\/blog\/index.php?rest_route=\/wp\/v2\/posts\/222","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pwoodford.net\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pwoodford.net\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pwoodford.net\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pwoodford.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=222"}],"version-history":[{"count":21,"href":"https:\/\/pwoodford.net\/blog\/index.php?rest_route=\/wp\/v2\/posts\/222\/revisions"}],"predecessor-version":[{"id":34183,"href":"https:\/\/pwoodford.net\/blog\/index.php?rest_route=\/wp\/v2\/posts\/222\/revisions\/34183"}],"wp:attachment":[{"href":"https:\/\/pwoodford.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=222"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pwoodford.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=222"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pwoodford.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=222"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}