The Final Mission of Extortion 17

by Ed Darack

  One of the most important concepts in helicopter flight, Tom Renfroe noted, is “ground effect.” Also experienced by airplanes and race cars, ground effect is basically a cushion of air beneath a vehicle, in this case generated when a helicopter hovers. “When you are hovering close to the ground, air molecules pass through the rotor system and almost immediately hit the ground, and when they stop, those coming down on top of them have nowhere to go,” he explained. Ground effect has important ramifications for power management, as hovering a helicopter above ground effect (called an “out of ground effect,” or OGE hover) requires upward of 17 percent more power than hovering it fully in ground effect (IGE hover), depending on the airframe.

  Another important concept of helicopter flight is translational lift (relative lift by moving). While able to launch and land vertically, helicopters fly most efficiently when they are moving forward. When at a hover, each spinning rotor blade passes through turbulence caused by the preceding rotor. The helicopter’s power system must work much harder when spinning in turbulent air—which some pilots call dirty air—to achieve sufficient lift to maintain the hover. As the helicopter moves forward, however, each rotor blade encounters a bit more fresh air. As the helicopter accelerates, the individual rotors of the main rotor system function more efficiently, requiring less power output from the engine(s) to maintain a given altitude. Helicopters do have a forward airspeed limitation, however, due to the asymmetrical lift of the retreating blade, which above a certain forward speed simply cannot produce sufficient lift.

  One of the key concerns of Bryan Nichols and Dave Carter as they waited to return to the Tangi Valley—power loss—does not necessarily mean disaster for a flying helicopter. Even after experiencing a total power loss, a pilot often can safely bring a helicopter to the ground, regardless of altitude or forward airspeed, through a technique called autorotation, which all Army aviators learn at Fort Rucker. “At a low hover, we simply let the helicopter settle to the ground as the rotor slows down,” Tom explained.

  At higher altitudes and airspeeds, pilots must take additional steps to safely land without power. “We will quickly lower the collective control to the floor and let the helicopter plummet out of the sky. What this does is provide airflow up through the rotor system to keep it spinning, much like blowing on a pinwheel fan.” Once close to the ground, a pilot pitches up the nose of the helicopter, converting some of the airspeed to lift and arresting descent. Timing and location are everything with autorotation, however. As Tom pointed out, “If everything is timed correctly and you have a good landing area, you can successfully land a helicopter with no engine power whatsoever.”

  Joyce Peck remembers Memorial Day 1981 with great fondness. “That was the day I gave birth to Pat.” Born in Sioux City, Iowa, Patrick Hamburger moved with his family to Bellevue, Nebraska, a suburb of Omaha, just eight days later. When Pat was four, the family relocated again, to Lincoln, Nebraska, where he spent every Fourth of July in a friend’s yard. His friend’s father, a Nebraska National Guardsman, purchased a dump truck’s worth of sand every year and piled it on his front lawn to make a mock battlefield where Pat and other neighborhood kids played war. Pat and his young friends learned the most basic of battle tactics and then enjoyed the fireworks’ polychromatic bursts in the summer evening sky.

  Another childhood friend’s father, also a member of the Army National Guard, later introduced Pat to fixing and refurbishing engines and entire cars, the start of a lifetime love of all things mechanical. Pat began his journey into the world of mechanics by simply disassembling basic household items. “I had so many nonworking appliances for so many years until he could figure out how to put them back together,” his mother said, laughing. DeLayne Peck, Patrick’s stepfather, remembered that “he’d mess around with lawnmower engines and his bike. Eventually he was spending every weekend at his friend’s dad’s shop, fixing cars, and he loved it.” Pat memorized instruction manuals and worked on the respective parts. DeLayne recalled that he could turn to any page in a manual and ask his stepson any question about a part, and Pat would immediately and comprehensively explain it. “He was gifted.”

  Learning by doing excited and inspired Pat, but he had little interest in school and homework. Like Spencer Duncan, Pat struggled through school, not because of lack of ability but due to his interest in other pursuits. Both boys loved to get out and do, not sit and read textbooks and listen to teachers discuss topics that they thought would probably not be of use to them after the next exam. Pat’s mother said school simply bored Pat and that, like Spencer, he looked to serve others.

  Patrick Hamburger in 2007. Credit 13

  His friends’ fathers and the sand battleground inspired Pat’s drive toward the military from his early years. With his keen and burgeoning interest in mechanics, service, and military aviation, Pat decided to follow their path at only 17, while still a junior in high school. He enlisted to become a Chinook mechanic in the Nebraska Army National Guard’s 2nd Battalion, 135th Aviation Regiment, at Grand Island, Nebraska. He attended boot camp the following year. “A string-bean boy went away, and this huge man came back. He had a sense of pride and still that wicked sense of humor that he’d always had,” his mother recalled.

  Pat loved the Guard. He loved working with others in his unit, and most of all he loved the Chinook, especially maintaining and flying in the complex helicopter. Like fellow Chinook FEs Alex Bennett and Kirk Kuykendall, Pat reveled in the CH-47D’s forms and functions from the earliest moments of his career. Like virtually all other CH-47D crew and pilots, he gained an instant affinity for the D-model Chinook at his first sight of the aircraft: a boxy fuselage painted woodland green, with a bulbous cockpit and two rotor-crowned pylons on either end of its fuselage sporting six nearly two-foot-wide black rotor blades that droop and cast long shadows when the craft is at rest on the ground. Powerful turboshaft engines on each side of the taller rear pylon are fed by fuel tanks in lengthwise protrusions at the base of the aircraft. Fixed landing gear of two rear and four forward wheels gives the helicopter a slightly nose-up attitude. It has a squatting stance, as if ready to leap into the air in a second.

  The Chinook, a tandem-rotor helicopter developed by aviation pioneers spanning decades, sports a hulking form, but that silhouette belies one of its greatest strengths: its speed. Pat was amazed by the Chinook’s spaciousness the first time he stepped aboard one. With a seating capacity of nearly three dozen, the Chinook can carry more than 50 people and their gear in a pinch. Should a situation require a quick single-ship insert, as with Extortion 17’s possible return to the Tangi, the aircraft’s design would enable it to ferry a full force of men into battle.

  The Chinook is ultimately utilitarian in its form, created for instant mechanical diagnosis and access, and Pat came to know all its hydraulic lines, cable bundles, fittings, and controls. The formers and stringers of the interior’s open frame resemble the innards of a wooden sailing ship, with yellow and gray corrosion-resistant paint carefully applied to the aluminum of the aircraft and contrasting with its mosaic of components, conduits, and assemblages.

  Pat, like Alex, helped maintain the Chinook’s two Lycoming T55-L-714A engines as well as the aircraft’s combiner box and transmissions, which deliver the power of the two turboshaft motors to the aircraft’s rotating wings. He disassembled and reassembled the two triple-bladed rotor systems, the business end of the power plant and drivetrain systems. Pat also learned about the APU, the small turboshaft that powered the radios Extortion 17’s crew monitored as they waited for further orders. He became deeply familiar with the aircraft’s avionics system, including the various radios and diagnostic gauges monitored continuously by Bryan and Dave during the infil of the assault force. And he had a detailed understanding of the Chinook’s cargo handling/winch and hoist mechanisms, the elements from which the crew “hookers” derived their nickname. The Chinook proved a dream for Pat, and he relished the hookers’ culture. Like FEs in all Army avi
ation platforms, this love of the aircraft was a bloodline connecting him back to Fort Rucker, and like FEs everywhere, Pat had both an easygoing, calm demeanor and an intense focus on his mission.

  Patrick Hamburger, holding a flashlight with his mouth, adjusts his NVGs inside an Extortion Company CH-47D Chinook prior to launching on a nighttime mission; this photo was taken in 2011, a few days before the downing of Extortion 17. Credit 14

  “He loved, absolutely loved his job. He got along great with others in his unit,” his mother said. Pat advanced quickly through the ranks, progressing from Chinook repairer to crew chief to FE. In 2006, at the age of 25, with wars raging in both Afghanistan and Iraq, he faced a crucial decision: should he reenlist? He sought the advice of his mother. “He said, ‘Mom, I could die in a car accident, and it wouldn’t mean anything. And I could die for my country, and that would mean something tremendous,’ ” Joyce recalled. “And I slugged him in his arm and said, ‘Don’t ever talk about dying again!’ ” Pat reenlisted.

  “Pat came naturally to the defense of others,” said his stepfather, adding that he frequently helped out his two younger brothers when they were bullied at school, just as Spencer Duncan’s parents had observed about their own son. “And that value is essential to a soldier, a soldier who would step forward for our society and defend it, and others less fortunate around the world.” His stepfather also recalled Pat’s sense of humor, noting that he had no filter or limit. Joyce agreed: “People loved him for that, and for his big smile and caring personality. Every time he came into a room, he really lit it up. It was always a guaranteed good time if Pat was going to be there.” After Joyce had divorced his biological father, Pat would check on her every day, always asking to see if house repairs needed to be made, or just spending time with her.

  His mother also noted an irony in Pat’s love of helicopter aviation: he was scared of heights. But his love of the Chinook and of working with those around him melted that fear away. His favorite place to ride during flights was on the loading ramp. During his predeployment training prior to embarking for Afghanistan in 2011, Pat called his mother late one night. She could barely hear him. He was in the air on a training flight and described the moonlight reflecting off the mountains below as he sat on the ramp. The conversation lasted just 45 seconds. “He said that it was just so beautiful that he had to call and tell us about it. You should have heard him; he was just in awe,” she recalled. He told his mother that the moonlit scene, in this region with no artificial light pollution, was the most beautiful sight he had ever witnessed.

  Joyce recalled the night she had said goodbye to her son, at that point a sergeant, just prior to his departure for FOB Shank, where he would join Extortion Company. The two walked outside his home, casually talking in the peaceful night. As they spoke, Pat seemed to have an instinctual premonition of the words his mother was about to utter, so he spoke first. “He said, ‘Okay, I know I’m going to get the mom lecture.’ And he was right. I reminded him that he was my first child, and that I made some mistakes, and that I was sorry for those mistakes.” They hugged, Joyce trying not to reveal her emotions in front of her son and struggling to fend off tears. Pat then told his mother of his wish if he did not return from his deployment: a headstone reading “Sergeant Patrick ‘Paddy’ D. Hamburger,” the nickname given to him by his fellow Nebraska Army National Guardsmen. “That was a conversation I never thought I would be having, and I will remember every single word he said, and even where we were. It’s burned into my brain.”

  Her son’s 2011 Afghanistan deployment created a void in her life. “My fallback guy was gone. I guess I didn’t realize how much I depended on him,” Joyce said. “Most people don’t realize it, but when a soldier goes to war, the family goes to war also.”

  Crewmembers such as Pat, Spencer, and Alex, and pilots such as Dave and Bryan, have proven the Chinook to be invaluable—perhaps irreplaceable. Its combination of versatility, power, and efficiency remains unmatched in the world of aviation, and it is ideal for supporting a wide variety of mission types. The story of the Chinook, and its role in the mission flown by those of Extortion 17, goes back nearly to the dawn of aviation.

  Although Igor Sikorsky, known as the “the father of the helicopter,” introduced the world to the tail-rotor helicopter in 1940 with his VS-300 design, he did not create all types of rotorcraft. There was also Frank Piasecki, born in 1919 in Pennsylvania as the sole child of Polish immigrants, who created rotary-wing aircraft of a different design in 1945.

  Piasecki focused on a tandem design comprising two counter-rotating rotor systems, one mounted at the head of a helicopter’s fuselage and the other at its tail. “With a tandem helicopter,” explained Major Tom Renfroe, “all of the aircraft’s available power goes to thrust. There is no need for a tail rotor, as the counter-rotation of the two rotor systems cancels out each rotor’s torque.” Tandem-rotor helicopters operate by the same principles as tail-rotor helicopters, and pilots of each type have similar considerations, but there are a few differences, including the name of the collective pitch control. In a tandem craft, it is known as the thrust controller. While tandem rotorcraft do not require an anti-torque tail rotor, they have pedals to yaw the craft, rotating it on a level plane without banking the aircraft. While requiring more complex engineering in the rotor head, tandem-rotor helicopters provide pilots with incredibly precise control over the aircraft, making them ideal for lifting and depositing complex and heavy loads. The design also negates the need for a variety of anti-torque compensation control inputs required for pilots of tail-rotor helicopters. In a Chinook, one of only a handful of tandem-rotor helicopters built, pilots can rotate the aircraft about the forward rotor system, about the aft rotor system, or about the center of the helicopter.

  Piasecki noted tail-rotor helicopters’ limited cargo capacities and ultimately focused on what he felt to be the superior tandem-rotor configuration. His company, Piasecki Helicopter, manufactured the HRP Rescuer in 1945, delivered to the U.S. Navy, Marine Corps, and Coast Guard, and the H-25 Mule, used by the Army and Navy. His company then produced the powerful H-21 in 1949, which the Army designated the Shawnee following a naming convention based on Native American references that had started with the Bell Helicopter H-13, which the Army called the Sioux. Both the Army and the Air Force used the Shawnee, which could lift 4,000 pounds of cargo, for a variety of missions. The Air Force set two helicopter world records with the aircraft, one for speed (146.7 mph) and one for altitude (22,110 feet above sea level), proving the tandem-rotor configuration to be fast, powerful, and a great performer at high altitudes. During the early days of the Vietnam conflict, the Army relied heavily on the Shawnee due to its performance and cargo capacity.

  In 1956, the Piasecki board of directors forced Frank Piasecki out of his company and renamed it Vertol. That same year, the company reached out to the Army, Navy, and Marine Corps to determine their specific needs for a next-generation rotorcraft. Ultimately, the company, purchased by Boeing in 1960 and renamed Boeing Vertol, finalized two similar tandem-rotor models, the CH-46 Sea Knight in 1960 for the Navy and Marine Corps and the larger, more powerful CH-47 in 1961, which would soar to legendary status.

  “It’s the fastest helicopter in the Department of Defense,” explained Buddy Lee, adding that people unfamiliar with military aviation in general and the Chinook in particular often erroneously believe that it is a big “barn door” that lumbers sluggishly through the air and presents an easy target for enemy forces—an unfortunate stereotype. Considered a heavy-lift helicopter, with an impressive cargo capacity of more than 25,000 pounds for the D model, the CH-47 appears almost puny next to a CH-53D or CH-53E but ranks as the best high-altitude cargo aircraft ever developed.

  The Army-designated name for the CH-47, Chinook, comes from the anglicized form of the place name Tsinuk, which is associated with a group of Native Americans in the lower Columbia River region and adjacent areas of coastal Oregon and Washington. Ch
inook, which some pronounce with a soft “ch” sound, as in chef, and others with a hard “ch,” as in chase, is also the name of a strong, warm, dry wind—appropriate for the fast CH-47.

  Four years after its first flight tests in 1962, the Chinook arrived in Vietnam. “A lot of the techniques we use today were proven in Vietnam,” explained Kirk Kuykendall. Under the careful guidance of FEs, pilots would back Chinooks onto the sides of steep mountains, where crews would offload ammunition, food, and supplies to soldiers and Marines in desperate need. They would sling-load howitzers to positions no truck could ever navigate, and they offloaded platoons of soldiers and Marines and picked up the dead, wounded, and exhausted. After Vietnam, the Chinook continued to be an invaluable cog in the American war machine, one with evolving uses, notably the support of special operations.

  During the 1991 Gulf War, the Chinook was used extensively for a variety of needs. As part of the 6th Cavalry Regiment, Kirk recalls living in a tent city for weeks as he waited for his Chinook unit’s helicopters to arrive by boat at the Saudi Arabian port city of Dhahran. Once they were offloaded, he and other crewmen and pilots immediately reassembled the helicopters, just as he would do at Bagram Airfield years later in the Pakistan earthquake humanitarian relief mission, and readied them to charge into Iraq. But plans abruptly changed on January 14, the night before the air war began, due to a threat of Iraqi Scud missile attacks, forcing them to move earlier than expected. “They bugged out our entire battalion,” Kirk recalled. Under orders, 48 Chinooks lifted into the dark sky, pilots and crew without NVGs, and flew over the dunes of Saudi Arabia. At dawn, they saw that none of the enemy soldiers detected the night before were there.