Arctic tankers

Mark Ayton tells the fascinating story of the only US Air Force KC-135 unit located in an arctic region, the 168th Wing at Eielson Air Force Base, Alaska


Standing on the vast Eielson Air Force Base flight line looking at six of the nine KC-135Rs assigned to the Alaska Air National Guard’s 168th Wing, there is nothing much different from any other tanker ramp in the Air Force. In early June the biggest challenge to endure is the mosquito; the species comes alive in Alaska in the early summer. Basking in sunshine and a pleasant 75 degrees, with an outlook on the snow covered Alaska range mountains, Eielson Air Force Base is a pleasant location. The base is vast; so big, in fact, that a flight line with a dozen KC-135Rs parked occupies just a fractions of the real estate owned by the Air Force. Return to Eielson in January and it’s a different place entirely: darkness for much of the day, and sub-zero temperatures that endanger life and aircraft alike.

The men and women assigned to the 168th operate its KC-135Rs throughout the year in support of state, federal and overseas operations. Tasking includes an alert mission held at Eielson, 24/7, 365 days of the year, with a KC-135R aircraft and a crew ready to go at a moment’s notice in support of North American Aerospace Defense Command. When launched, the alert tanker provides aerial refuelling to US Air Force F-22 Raptors and E-3 AWACS scrambled from Elmendorf Air Force Base at Anchorage to intercept and monitor unknown aircraft approaching US airspace. Usually the aircraft involved are Russian long-range bombers flying in international airspace, but near to that of the United States or Canada. One day before the author visited the 168th, two Russian Tu-95 Bear bombers had tested the American air policing capability during a long-range mission from Russia’s far east. Intercepts where made by F-22 Raptors supported by an E-3 AWACS and a 168th Wing KC-135R. All aircraft involved, including the Russian Bears, returned to their respective bases without incident, thankfully the standard outcome from such encounters in the arctic north. Russia has a number of arctic bases, the main one in the Russian far east is Ukrainka in Amur Oblast from where long-range bombers fly against Canadian and US airspace, on what Russian authorities called combat patrols. Alaska and Russia are separated by just 50 miles across the Bering Strait, which is where Russian bombers often fly and then run either the Alaskan or Canadian northwest polar coastlines or the Alaskan Pacific coastline.

An F-16C assigned to the 18th Aggressor Squadron, refuels from an Alaska Air National Guard KC-135R Stratotanker. SSgt Paul Labbe/US Air Force

Lt Col Ben Doyle, 168th Operational Support Squadron Commander, said a typical Bear mission involves the Russian aircraft flying from the north against the north slope of Canada or flying south between Russia and Alaska and then following the Air Defense Interception Zone.


“We are flying warbirds, but they are great aeroplanes,” said 168th Operational Support Squadron Commander Lt Col Ben Doyle. The nine KC-135Rs assigned to Alaska Air Guard’s tanker unit were built between 1959 and 1963. None of the guardsmen that hosted the author at the squadron’s billets was born when their magnificent jets were built. However, the aircrafts’ age is not given away by their state of repair and appearance. Sixty years old maybe, but these Alaskan birds are all in tremendous condition thanks to the dedication of the maintainers and other guardsmen that work in all of the back shops, often seven days a week, to generate aircraft ready to fly and support the wing’s various missions.

Air National Guard units are always rewarding to visit for so many reasons. Personnel are always fantastic hosts, highly experienced, know their aircraft rivet by rivet, and of course are true patriots of their nation. Master Sergeants, Tech Sergeants and Senior Master Sergeants provide so much insight into any aspect of a mission, which in conversation always tends to flow eloquently and easily; experience is priceless. The wing has 826 authorised personnel of whom 350 are full time; the balance comprises traditional guardsmen. The predominance of personnel lives in Fairbanks, the main city close to Eielson, and Anchorage 350 miles to the south. Explaining the wing’s articulation, Lt Col Doyle said it’s a tenant unit at Eielson that undertakes federally funded operations in Title 10 of the US Code. He said: “When we work for the federal government, the President, we conduct wartime tasking, the so-called o plans. Guardsmen can either be called up involuntarily and brought to active duty status or they can volunteer for active-duty service. Our everyday training lines are undertaken when working for the state governor, most of which is supporting the active-duty Air Force and its training missions, which helps to accomplish our training to keep us ready. “Our war tasking is primarily to support an air bridge to the Pacific theatre from Alaska, a very strategic region. Eielson is located at roughly an equal distance to Norfolk, Virginia as it is to Tokyo. We can get to any destination in the northern hemisphere in roughly 12 hours from base.

Does the wing, then, as a matter of standard procedure, fly across the pole to reach destinations in the northern hemisphere? “We could,” replied Lt Col Doyle, “but most of the places we head to do not require us to go that far north. When we deploy to Germany we only go to 75° North, on the great circle routing. We call this a polar route, and tend to take such a route to get to places as RAF Mildenhall in the UK, which is about an eight-hour flight. Iceland is about six hours, Germany nine hours. Each route takes us pretty far north.” Discussing some of the air refuelling tracks used by the Alaska guard tankers, Lt Col Doyle explained that one track called 508 runs past Alaska from the lower 48 and straight towards Japan. Another, designated 505, is route that runs between Europe and Asia. Each track, tracks both ways. Located over cold, choppy northern ocean, when using the 508 track, mission planners must consider the water temperature and the sea state. There are occasions when the route cannot be used to drag fighters, because in the event of an emergency and the crew having to eject the odds of survival are much lower. Under such conditions the tracks used are much further south to Hawaii. Doyle said: “In peace time, depending on where aircraft are transiting to, Eielson serves as the primary staging airfield between the lower 48 and Asia, because of the great circle route which passes right by Alaska. Generally, the 168th handles aircraft going to or from Japan and the Korean peninsula.

“We deploy to the CENTCOM and PACOM areas of responsibility, for which, primarily our DSGs [drill status guardsmen] are activated to support operations on an as-needed basis. In addition to that tasking we conduct voluntary missions for either Air Mobility Command, Pacific Air Forces or the National Guard Bureau usually to meet the needs of whatever receivers need aerial refuelling.” Once a year, the 168th deploys to Geilenkirchen Air Base, Germany to support the NATO Airborne Early Warning Force providing the aircrews with good training in European airspace, which is a lot different from Alaska. The 168th is the only tanker unit based in Alaska, and is primarily a part-time force, yet it is able to fulfil between 40 and 50% of the requirements for aerial refuelling in Alaska and the northern Pacific. The balance of requirements is met by other units deploying to Eielson on TDY, which means the Alaskan guardsmen can train cooperatively with the visiting units. As arctic experts on the KC-135, the wing receives lots of questions about operating in the extreme cold conditions of Alaska during the winter months.

A 168th Wing KC-135R Stratotanker parked on the ramp at Eielson Air Force Base, de-iced and with heaters running, awaiting the arrival of its crew. SMSgt Paul Mann/Alaska Air National Guard
An Alaska Air National Guard KC-135R flies over its home station, Eielson Air Force Base during typical winter conditions found at the base in the month of December. Captain Kay Nissen/US Air Force

You can have a Tech Sergeant or a Master Sergeant out on an aircraft who has maintained and looked after that particular aeroplane for years. They know every nut and bolt, every rivet and often know what needs to be done to make the aeroplane ready to fly.

Primary customers of the 168th are its sister air guard unit, the 176th Wing, and the two active-duty wings based in Alaska; the 3rd Wing at Elmendorf, and the 354th Fighter Wing, co-located at Eielson. According to Lt Col Doyle, the two activeduty wings have the greatest preponderance of aircraft so many of the 168th’s aerial refuelling missions supporting both activeduty wings. Support is also provided to the various exercises held in Alaska, Red Flag, Northern Edge and Distant Frontier are three primary examples. The wing also supports Pacific Angel, an annual US-led joint and combined humanitarian assistance and disaster relief engagement that includes general health, dental, optometry, paediatrics and engineering programmes throughout the Pacific theatre. Lt Col Doyle said this year’s mission was in Mongolia. Another facility manned by 168th personnel is a radar site located 60 miles (95km) to the west of Eielson that conducts space surveillance, detecting information after a missile launch and cataloguing satellites and space junk, to retain a map based on time and how much junk is present. There are two future missions that the 168th Wing is bidding to assume involving classic associations with active-duty KC-46 and F-35 units.

Sub-zero maintenance

According to SMSgt Haines, a maintenance chief with the 168th, the conditions for maintenance during the winter at Eielson are very hard to grasp until you are actually trying to do the work. He said: “I’ve served in many warm locations during my Air Force career, then most recently joined the aircraft maintenance squadron as a flight chief working on the flight line. When the temperature first started to drop and reached 40° below with driving snow when trying to get an aircraft airborne, with de-icing trucks waiting the nod from the crew to get the aircraft de-iced, it’s hard to paint the picture of what conditions are really like when it’s -50°C outside. “Frostbite is a concern and we take rest cycles in our building to warm up, and use trucks that are running all day to keep them warm, to get back and forth to the building. Specialised clothing is essential and include thick coveralls, bibs, jackets, gloves, hats and winter boots.” Use of metal tools must also be managed closely. Crew chiefs keep the tools on board the warmed-up aircraft, while specialists from any of the squadron’s back shops coming out to an aircraft bring their tools with them. SMSgt Haines stressed, however, that people are careful when working in such extreme low temperatures, wearing gloves as much as they can and always working as quickly as possible to protect themselves, while avoiding as much exposure to the conditions that can also affect a person’s dexterity. As for the aircraft, these require preheating for three hours before engine start to prevent failures capable of preventing the jet from taking off. Consequently, the aircraft maintenance squadron operates a mid-shift whose personnel preheat the aeroplane on the flight line. This involves placing 16 heaters on the undercarriage struts, the crew ladder, the nose to keep the electronics warm, and the aft hatch to keep the cargo area warm. As a result of this procedure, personnel working the subsequent day shift arrive to launch a warmed-up aircraft.

Heaters used are AGE or aerospace ground equipment heaters fitted with 12- inch (305mm) diameter hoses that supply the warm air to the required position on the aircraft. SMSgt Haines said that if heat is not placed on the aircraft a couple of hours before takeoff, when the flight crew arrives at the aircraft and steps on the ladder they will crack the windows. SMSgt Phillip Newton, a maintenance chief with the 168th, explained the reason why boom windows crack at the aft of the aircraft when someone steps on the ladder at the front is the stiffness of the fuselage. He also said the diesel-powered heaters generate so much exhaust, fog is created around the aircraft such that it’s shrouded from view. He said: “Because the aircraft flies at altitude in sub-zero temperatures, the aircraft itself can handle the cold. The challenge is keeping people and support equipment warm and initially getting the aircraft thawed so that you have at least enough air friction keeping it warm, so the heat provided, is completely wrapped around the aircraft. As the exhaust emissions meet the very cold air they start to freeze and crystallise so they just hang in the air. Effectively, we create our own fog.”

A crew chief assigned to the 168th Wing prepares KC-135R 62-3524 for a mission from a snow-packed Eielson. MSgt Scott Thompson/Alaska Air National Guard

SMSgt Haines said: “In addition to that, if the crew taxis the aircraft out without heat having been applied on the struts, seals within the struts will blow, caused when they roll up on the strut as the strut moves and leaks, which for flight safety reasons prevents the aircraft from taking off. Even with those best plans and procedures, we will still crack windows and blow struts in the winter, meaning the aircraft has to be put into a hangar so the blown strut can be removed, taken apart, repacked, refitted on the jet, and then returned to the flight line.” Explaining the way struts function, SMSgt Newton said they contain fluid to provide a cushion when the aircraft lands and internal rings hold the fluid in the strut. He said: “Seals Will blow out in extremely cold temperatures, so not only do we have to heat the jet before we move it, but if it is super heavy and we sway too far in one direction the seals will blow, hydraulic fluid will start leaking creating a three-day maintenance turnaround an almost $10,000 in damage. So that is one of the first components we heat all the time. We put heat on all three struts for the nose gear in the main gear, and we pipe hot air into the wheel well, with the doors closed, so that heat starts to rise through the hydraulic system, and then by convection, starts to warm up the entire aircraft.

“Elsewhere, the aircraft is equipped with several flight management computers. The lower nose bay houses a lot of the avionics and electronics, so before an aircrew ever arrives at the aeroplane to avoid computers going down or popping circuit breakers, we pump heat into the lower nose area for about two hours before we engine start to prevent a computer from crashing. We have to be careful with the cables and pulleys, because if we overheat the area the cables will slacken, creating flight control problems. Just based on our experience of being in Alaska, we have learned that we have to pipe heat up into this area, but if the heat is directed directly at the flight control cables they fall off the pulleys and the aircraft is unserviceable for that reason. Heat it is good, but too much in one direction and you are almost as bad off as you would be without putting any on the aeroplane. If the weather is super cold and we are handling an alert launch, then the engines will have covers applied. We pipe heat to the front of the engine with large hoses and use smaller hoses to pump heat into the aft of the engine.” Reducing the fuel load uploaded on an aircraft during winter is another procedure used to combat strut issues. In the summer, the fuel load can be as high as 177,000lb, during the winter months it’s down to 65,000lb. SMSgt Haines noted that on long weekends the aircraft sit frozen with formations of icicles for periods over 48 hours presenting problems for aircraft generation to meet the flight schedule on Monday morning. He said: “On Sunday evening we preheat the ones required for flying on Monday morning, get them ready and do the pre-flight inspections ensuring the tyres, struts and fuel load are in order, so when the crew steps out they have an aeroplane that is ready to fly.” SMSgt Haines said the maintenance squadron’s workshops have fabricated attachments for the aft hatch and crew ladder from which to hang the hoses, and have shared the blueprints with other tanker units based in the lower 48.

Fuel, fluids and engine oil

Sub-zero conditions affect aviation fuel, such that the maintainers become concerned when the temperature drops to -45ºC, which is close to the gel freeze point of the fuel. At Eielson, negative temperatures occur throughout the winter, but tend to be lowest in January and February when it drops to as low as -50ºC for periods up to two weeks. SMSgt Haines said that winter weather at Eielson can change no matter what the month, varying from 0 to -40ºC depending on the weather pattern. Servicing the aeroplane before and after a flight in such temperatures also presents physical challenges. Standard engine oil used on the KC-135R will solidify to varying states from semi-fluid, sticky and thick viscosity depending on the ambient temperature, so the 168th runs with a different grade of engine oil that retains the required viscosity.different in this example means different from the standard engine oil used by all other KC- 135 units. Explaining some of the physics, SMSgt Newton said: “The oil gets so thick at those temperatures that if you tried to pour it out of a can it would form in a pyramid, because it’s like a sludge. Until the engine is fully spooled up, the crew will receive a low-pressure warning light on the flight deck, so the engines get a 15-minute warm-up before take-off.

Lt Col Ben Doyle, 168th Operational Support Squadron Commander

We are flying warbirds, but they are great aeroplanes.

”Fuel quantity indication is built of resistance. Probes within the tanks measure resistance and feed the data to the main flight management computer and then to the flight deck as the fuel quantity. That system is only rated down to 40 below, so once the fuel temperature dips lower, the entire system dashes out, because the computer can no longer calculate fuel density.” In general, fluids and hydraulic fluid thicken up because of the extreme cold, but according to SMSgt Haines the squadron’s procedures have been fine-tuned over the years to help in such situations. He said the squadron typically does not encounter issues when servicing the aeroplane in the extreme cold, but should a problem arise, the engineers can contact their counterparts at Oklahoma City Air Logistics Center, the KC-135R depot for help and guidance is the problem is not covered in the technical data. He said: “Typically, we get more fuel leaks in the winter than we do in the summer. In such a case we tow the aircraft into the fuel barn to fix it. A fuel leak is our biggest issue because it means the aircraft will be down [grounded] for a while. It is not a quick fix. We have to defuel the jet maybe change a bladder. If we cannot source a replacement bladder on base, we have to order one, which often takes several days to arrive at Eielson.”

Snow and darkness

Consider the winter environment at Eielson with lots of snow laying on the ground. Then consider the challenges of launching a KC-135R weighing up to 300,000lb from a frozen flight line surrounded by 2ft (600mm) of snow. A scenario that’s common place at Eielson, and one that requires more people to move snow and carefully position all the equipment around the jet. This is another limiting factor for the crews as SMSgt Newton explained: “In such a scenario, we can no longer do launch and recovery without bringing in snow removal vehicles and trucks because we have to be able to pull equipment, all of which has to be somewhat precise so we do not run into the aircraft. Then there’s de-icing. In a dry climate like this, we do not get a lot of ice build-up on the aircraft so we just use deicing fluid and not an anti-icing fluid. We have to blow snow off the aircraft before we start any heating. Otherwise icicles would form as the snow melted on the warm aircraft. We de-ice the aircraft once it’s heated.” Cold is not the only adverse condition at Eielson; maintenance crews also have the additional burden of extended darkness throughout the winter months. To counter the darkness, every maintainer uses headlamps and flashlights, and if required mobile lights are used to illuminate the aircraft. SMSgt Haines reckons headlamps are a maintainer’s best friends and they get very proficient at night operations.

Maintenance types

Despite the strategic aerial refuelling mission held by the 168th, and the distance from Oklahoma City Air Logistics Center, the maintenance group is not given any additional leeway in the kinds of maintenance activities it is allowed to carry out on its aircraft compared to other tanker units based elsewhere. However, KC-135 engineers at the Air Logistics Center allow the Eielson-based maintenance group to overhaul some parts that fail. SMSgt Haines said the hydraulic shop has overhauled actuators in such a situation.

Most of the nine KC-135Rs assigned to the 168th have between 19,000 and 24,000 hours on their clocks, which are pretty typical figures of the KC-135 fleet. The bigger problem is the chronological age of the jet, corrosion being the biggest associated issue in the fleet, particularly on the keel beam and in the wheel wells. Consider 50 to 60-year-old aluminium enduring desert and saline environments, and it adds up over time. The Oklahoma City depot is also encountering more structural issues on aeroplanes entering their six-year programmed depot maintenance (PDM) to the point where engineering teams visit a unit to inspect an aircraft during a standard isochronal (ISO) inspection to get an early look at the aeroplane to determine if anything significant is evident before that aircraft goes into the PDM cycle. ISO inspections are conducted by the operating unit every 24 months and are a major maintenance event that take between six and eight weeks to complete, and involved stripping the aircraft down to allow inspection of numerous essential aircraft systems. According to SMSgt Newton, inspection crews continually discover faults and conditions that have not been seen before. He said: “We recently completed a TCTO [time compliance technical order] that increased the number of inspections to a spar. One of our crew chiefs found corrosion of the wing strut which was cracked all the way through. The relays fitted on KC-135s came off the assembly line in the 1950s and are starting to fail, but they have been rock solid for all those years.

The pilot of KC-135R 62-3524 looks out the cockpit while conducting pre-flight checks. This aircraft wears nose art featuring the legend ‘Ice Dogs’, the name of the Fairbanks ice hockey team. Senior Airman Daniel Snider/US Air Force

We have to blow snow off the aircraft before we start any heating. Otherwise icicles would form as the snow melted on the warm aircraft.

Fortunately, the 168th has not encountered as many corrosion issues on its aircraft like other KC-135R aircraft in the fleet assigned to units in the lower 48, which is attributed to the drier Alaskan environment. Most of maintenance activity is scheduled, but of course unscheduled events occur, such as popped rivet, cracks or boom functionality post-flight. During the author’s visit to the 168th, the maintenance group was working through a series of TCTOs for servicing hydraulic systems. The 168th Maintenance Group has also adopted predictive maintenance procedures using a system called CDM plus, issued by the Oklahoma City depot. The process, originally used by Delta Airlines, involves using historical data of specific components to try and predict when each will fail and to change a component before it does fail, all in an effort to increase the aircraft’s availability and mission capable rate. Most unscheduled maintenance requirements on the KC-135R involve hydraulic and fuel leaks and avionics systems, particularly communication control modules. The scheduling office tracks the maintenance requirements for each aircraft, which include things as different as battery changes and the lap belts used by the flight crew. SMSgt Haines summed up saying: “The KC-135, for as old as it is, given the climate we endure during the winter, holds up really, really well. If an aircraft is down, it is not down for long, and if we are waiting to return it to the flight line, we are waiting for parts to arrive.”

Devotion to duty

Meeting guardsmen assigned to the 168th Wing, it’s abundantly clear of the pride they hold for the wing and its various missions. As an example of the level of experience held by guardsmen across the wing, in this case those assigned to the maintenance squadron, SMSgt Haines said: “You can have a Tech Sergeant or a Master Sergeant out on an aircraft who has maintained and looked after that particular aeroplane for years. They know every nut and bolt, every rivet and often know what needs to be done to make the aeroplane ready to fly. We have had personnel from other units that see our aeroplanes, and comment on how clean, how well they fly, and how well they are maintained. Everyone assigned to the wing contributes to the aircraft status in whichever trade they practise.” The 168th’s aircraft do look immaculate, a fact that did not escape the author’s attention, which SMSgt Haines attributed to the devotion of the crew chiefs and maintenance teams who look after the aircraft. “Remember,” he said, “there are six years between depot cycles [when the aircraft enters programed depot maintenance at Oklahoma City] when the aircraft gets repainted. Well, we take pride in the fact that our aircraft always look like they came from the depot just yesterday, even though they’ve been sitting out on the ramp in all weathers for years. Never forget that the aircraft we sign over to the pilots need to be A1 because their lives depend on what we as maintainers do. That fact is taken to heart every time a maintainer goes out to work on the aeroplane; we have people’s lives in our hands every day. AI