Navigating a KC-135 from Alaska to Thule, Greenland by Gerald Hanner

In the very early sixties, when the Evil Empire was actively testing the limits of its power, I joined the Air Force. There was no particular patriotic sense involve. My chief aim at that early point in what turned out to be a 25 year career was to fly airplanes, particularly military jets. Circumstances conspired to prevent me from being a pilot, so I took the next best offer and enlisted into something called the Aviation Cadet program and went through a year of intensive training as a navigator. When I came out the other end of that program, I was a Second Lieutenant in the Air Force Reserve and had a shiny new pair of Navigator/Observer wings.

At that point computers able to reliably and accurately solve the basic navigation problem did not exist in any quantity, so most of us newly minted navigators were destined for either Military Air Transport Service (later to become Military Airlift Command) or Strategic Air Command. Like so many others, I ended up in SAC, and by virtue of the rapid build-up in military strength going on at the time, I was lucky enough to fulfill at least part of my original objectives: I was going to fly a military jet. I was assigned to a squadron of KC-135s.

For those who don’t know, the KC-135A is the proto-type for the Boeing 707 series, and it was just starting a long service career that is still in progress as 1996 approaches its conclusion. The bird is designed as an aerial tanker, i.e., it has the capability to refuel other aircraft in flight. At its inception, the KC-135 was the replacement for the Boeing KC-97, which was a piston engine designed based on the B-29. It was sorely lacking in capability.

Since the KC-135 has a lot of capability, SAC immediately put its capability to use. To reiterate, the Evil Empire was flexing its military muscle, and the United States was doing some muscle flexing of its own. One mission was airborne alert. The idea behind airborne alert was to have a small number of B-52s instantly ready to retaliate, in the event of a Pearl Harbor-style attack by the Evil Empire. That’s where the KC-135 came in.

In order to sustain airborne alert, the B-52s had to be refueled in-flight, and the KC-135 was the only tanker capable of going where the B-52s went. The B-52s went north. The crux of our mission was to fly from bases in Alaska and rendezvous with B-52s out over the Arctic wilderness; sometimes over Alaska, and sometimes over the water (ice) between Greenland and the Canadian Arctic.

The jaunt from Alaska to the vicinity of Thule Greenland was not a particularly difficult in the Arctic summer. Daylight was a 24-hour phenomenon, and the pack ice receded from the Canadian Arctic islands so that they could be easily identified on the route to Thule and back. We had to steer by unslaved gyro all the time, since we flew very close to the north magnetic pole; mag compasses were useless where we flew. The Arctic winter was another story. Winter on the ground and in the air made the mission much more hazardous. Of course the cold and snow interfered with the maintenance and operation of our aircraft. In addition, darkness was the 24-hour phenomenon and the combination of pack ice and heavy snowfall rendered our navigational way points (those Arctic islands) nearly invisible — even to radar. The problem was that radar could not easily distinguish between the twisted pack ice and the snow-covered iislands it surrounded. It took considerable imagination to look at a radar scope and see those ice shrouded islands — especially the craggier ones. The Arctic winter also created an odd phenomenon: “return reversal.” Return reversal occurs when the normally smooth water (which presents a extremely weak radar return) freezes into pack ice and gives a strong return. Some of the flatter, smoother islands, now covered with even smoother blankets of snow, give radar returns nearly as weak as water. The effect is to see an outline of an island as a “hole” in an otherwise very strong radar return. The navigation problem becomes very challenging under those conditions, but SAC trained its navigators to operate in that kind of environment.

I had flown the route to Thule during the summer months. Later, after a long interlude flying other missions, I returned to the Arctic winter to fly the route to Thule again. What a change! Climbing out over the Alaskan interior, the radar landmarks were much less distinct than they had been during the summer. Well before we got to the Canadian coastline, we were level at flight level 250 and I studied the radar scope trying to get used to the unfamiliar images I was seeing. As we approached our “coast out” point, I could barely distinguish the shoreline it was obscured so badly by pack ice pushing up on the beaches. I decided to do a bit of celestial navigation to keep track of our position until we came up on Banks Island, our first way point on the trip to Thule. Since I was still relatively new at the navigation game, I planned a celestial “fix” for about 40 minutes after coast out. That would give me a reference point from which to get oriented to pick Banks Island out of the jumble of ice that surrounded it. Unfortunately, a phenomenon not widely know at the time was about to make the day difficult for me: something called land-water contrast. The KC-135’s Doppler radar usually gave reliable ground speed and drift information to navigate by. However, when the Doppler radar beams were in the process of going to relatively rough to relatively smooth surfaces (and vice versa) the ground speed and drift indications would discretely “go mad” for a while until the system adapted to the new conditions.

So, new guy that I was, I fell for the, temporarily, “mad” indications coming from the Doppler system and used them to dead reckon out to my intended celestial position. The Arctic winter conspired against me again. As we approached the time I had planned for my celestial fix, turbulence and cloud conditions prevented me from getting more than a “speed line.” I knew pretty well how fast we were going, but had no information as to how close to course we were. No matter, I thought, in another 15 minutes I’ll be able to fix off of Banks Island. As my ETA for Banks Island approached, I searched the radar returns for a hint of an outline to tell me where the island was. Nothing. Banks Island is a pretty large island, and our course took across its wider part, so I had quite a bit of time to search for something familiar, but nothing familiar appeared on the scope.

Disconcerted, I sat back in my seat and thought for a minute. Maybe I’m not where I think I am. After all I only got a speed check with that celestial position; maybe I’m off course. But where? I went back to my last known position, which was an hour or so earlier at coast out. I simple assumed that I could be 10 degrees left or right of my intended course and drew out rays from that last known position. And then I studied the chart of the islands I knew were down there in the dark and the ice. Then I looked back at the scene in the radar scope. A few things gave the hint of islands, but still nothing recognizable. Back to the chart for another look; then to the radar scope to try again for a comparison. Still nothing I could swear to. Back and forth. Chart to scope. My level of unease was rising rapidly. Then the crisis was over. I looked from the chart to scope and saw the unmistakable outline of Emerald Isle. A perfect example of return reversal: it looked like a hole in the scope. A quick radar fix confirmed what I had suspected about an hour and a half back: we were way off course, about 40 miles north of course to be reasonably precise.

After doing a bit more radar scope study, I satisfied myself that I really knew where we were and discretely changed our heading a few degrees to the right. I let a few more minutes pass then changed the heading again to the right. The aircraft commander was beginning to wonder what I was up to, but simply told him we were encountering a wind shift. Of course the wind shift had occurred about an hour and a half earlier, and it had been an erroneous one from a Doppler radar temporarily gone mad.

The rest of the mission went smoothly. We refueled our B-52 and returned to our Alaskan base safely.

In retrospect, it wasn’t much of a crisis, but it tested my skills none the less. I was faced with a situation that I hadn’t expected and had to come up with a solution. Three other people on that KC-135 depended on me to get them to where we had to go. I learned a lot from that little episode; and it was one of the first of several episodes I would learn from over the next decade or so. We didn’t have all the answers, and some of the book solutions turned out to be inappropriate. I learned and adapted, and others did the same. We taught each other.

Gerald P Hanner