The recent tragic midair collision between an Army Blackhawk helicopter and an American Airlines jet over the Potomac River in Washington D.C. bright back memories of flying, specifically some of the near- midair collisions I experienced during my 33-year flying career.
We had a saying, “big sky, little bullet” which was meant to communicate that the odds of two aircraft colliding were very small. My guess is that this came from combat flying in Vietnam where helicopter pilots were under constant threat from small arms fire, but was later adapted to aircraft. In theory, this idea is true. When you take the vastness and three dimensionality of the sky, the chance of a collision is very, very slim.
But when you factor in such things as aircraft typically flying at cardinal altitudes (1,000 feet, 2,000 feet, etc.) instead of random altitudes and operations in congested airspace where all aircraft are converging on a single point (an airport), the odds of a midair collision increase dramatically. In fact, another common saying in the aviation world is “keep your head on a swivel” which meant maintaining a constant, 360-degree scan for other aircraft. Such vigilance was difficult to sustain, however, and distractions (some necessary, like navigating, radio tuning, troubleshooting problems, etc.) and complacency would inevitably detract from that constant scan.
When you add in flying at night and things like confusing ground lights with aircraft lights, the odds increase even more. Flying with night vision goggles (NVGs) adds even more danger as they turn the white lights on the ground, red lights on obstacles (e.g. towers and tall buildings), and red/green/white aircraft position lights all into various shades of green.1
My earliest near-midair collision occured during my first winter in Germany when I was still a copilot flying Hueys. Looking back on it now, the rules allowed us to fly in some incredibly bad weather—especially on training flights. If memory serves, we were allowed to fly under visual flight rules (VFR) in 300 feet ceilings and ¼ mile visibility during the day! This was because as a helicopter, as the weather got worse, we could get slower and slower or hover or even land in a field to wait out a snow storm or other bad weather.
On this particular winter day, we were returning from a deployment at Hohenfels back to our base in Grafenwoehr. During the winter in Bavaria, the weather could be clear one minute then drop to zero/zero2 in a snow shower the next. When these snow showers would be passing through and visibility dropping to almost nothing, we would either find a field to land in until it passed, or if we were confident is was a small one, we would just find some trees to hover right above (for a visual reference) until the snow shower passed by.
We had just run into one of these scattered snow showers and elected the latter tactic. We had been hovering a few feet above a small grove of trees for a only a minute when suddenly, out of the mist of the snow shower, at only 100 feet altitude a Blackhawk appeared, heading in opposite direction. Just as quickly as it appeared, it was engulfed again in the thick, falling snow, too quickly for us to even get its tail number! They must have been doing at least 100 knots! Crazy, and completely irresponsible flying. The other pilot and I just looked at each other and shook our heads. Had we not elected to pause and wait for the visibility to improve, we and that Blackhawk would have passed extremely close to each other, if not collided head on. We couldn’t understand those pilots’ thought process to be going so fast in such conditions. I guess they were adhering to that “big sky, little bullet” philosophy.
A second, similar situation occurred a couple of years later at the Hohenfels training range during a completely clear, beautiful summer day. (We had Blackhawks by then.) We were there for a typical two-week deployment to provide medevac support for the ground troops who were at Hohenfels for maneuvers training. One of the major differences between the Grafenwoehr training area and the Hohenfels training area was that the first was all live-fire, while the latter was just maneuvers. In the case of Grafenwoehr, all the ranges were considered “hot”, meaning we couldn’t fly over them without permission (and a very good reason, like a medevac). At Hohenfels, we could fly how and where we wanted, with the comfort of knowing that there were no obstacles to threaten us except the ground and trees, i.e., there were no high-tension wires (a constant hazard in Germany) and no other aircraft except us.
Usually.
On this particular morning, we had decided to conduct a training flight (which really meant just flying around having fun). Hohenfels was like a flying playground for us for all the reasons mentioned above, but also because the terrain was very fun to fly over and around. Lots of rolling hills, places to practice slow, nap-of-the-earth flying, and high-speed, low-level flying. After contacting range control to let them know we’d be airborne and flying around the range for a couple of hours (in case they needed to get a hold of us for a medevac), we started having fun: up and over the hills, around the trees, toying with some of the crews of the M-1 tanks and Bradley fighting vehicles out on maneuvers, etc.
At one point, we had made a dash across a small valley, reached the hill on the other side, did a high speed cyclic-climb up and over the hill–when at that exact moment we crested the hill-seemingly out of nowhere appeared another Blackhawk, at speed like us, topping the hill just as we were, but going the opposite direction! Before either of us could react, we passed right next to each other—at most, two rotor diameters apart! Holy shit! Where did those guys come from? We were supposed to be the only aircraft out here. A quick call to range control confirmed that. “Oh, yeah! Didn’t we tell you? There’s going to be another Blackhawk out on the range today!” No you didn’t. And no thank you. Barry don’t play that game. That near miss had done it for us. We headed back to the clinic and shut down, choosing to wait for another day to go back out and play—meaning after the other Blackhawk had left town!
There is another axiom that I learned in the Army about avoiding other aircraft: “Decreasing range, constant azimuth.” In this case, range means distance and azimuth means direction. The saying basically means that if you’re looking at another aircraft (or any object for that matter) and its distance to you is getting smaller, but it is staying at exactly the same relative bearing to you, you are going to collide with it.
Checking this is typically accomplished by comparing the other object’s relationship to some physical components on your own aircraft, e.g., a window support, an antenna—anything that allows you to see the other objects relative motion, forward or backwards, from that fixed object on your aircraft. If, say, another aircraft is sighted at what appears to be an inch aft of a vertical antenna, if over time, it slowly creeps forward of that antenna (assuming your aircraft has maintained a constant heading), it means that that other aircraft will pass in front of you. Similarly, if the other aircraft’s relative position seems to move aft from the antenna, it will pass behind you. If it stays exactly 1” behind the antenna as it gets closer (decreasing range), it is going to collide with you (in fact hitting you exactly 1” behind your antenna!) Makes sense, right?3
Another very close call was during a commercial Bayflite medevac flight one beautiful summer night. We were returning from St. Joseph’s hospital in Tampa where we had just dropped off a patient, heading to our base 30 miles north in Brooksville. After clearing Tampa’s airspace and terminating contact with approach control, we settled down for what would typically be an uneventful 15-minute flight back home above rural Florida. As usual when we didn’t have a patient on board, the paramedic sat in the copilot seat on the left side of the cockpit to help with radios and navigation and to keep a second set of eyes out front for aircraft and obstacles. We were cruising at about 800 feet, and I was on NVGs. Also as usual, we had started a discussion about something—this time about the Call of Duty game we had been playing before being rudely interrupted by a scene call and which we were all anxious to jump back into.
As was my practice when flying with NVGs, every once in awhile I would tilt my head up to look under them so that I might notice any red or green lights in the area. As mentioned, one of the few disadvantages of using NVGs is the inability to distinguish colors; everything looks green. So towers, street lights, other aircraft, car headlights, antennae hazard lights, strobe lights, red obstacle lights—all green. Being able to distinguish the color of lights made aircraft, with their red and green position lights (red on the left side, green on the right) stand out from the ground lights most of the time. (Except that the hazard lights on towers and buildings were also red for some inexplicable reason, and it wasn’t difficult in the right circumstances to confuse them with aircraft and vice versa.) Thus, a check with my naked eyes underneath the goggles every few minutes increased my chances of seeing other aircraft in the area.
During one of these glances, I noticed far out at our 10 o’clock a red light on the horizon. It seemed to be at least five miles away, so I figured it was one of the antennae to our northwest and didn’t think much more about it. We continued discussing our favorite Call of Duty weapons and tactics.
A few minutes later, another underneath-my-goggles scan revealed the light right where it had been before—no worries.4 “It must be much further way than I initially figured,” I thought to myself, since we hadn’t really moved past it much, if at all. Back to Call of Duty arguments.
The next glance under the goggles a few minutes later confused me. The light was still exactly where it had been—the same spot on the copilot’s windshield–but it was now much brighter. The paramedic had noticed the light by now, and we actually discussed how strangely the light was acting and why a tower light would be getting brighter and brighter. (Yes, such is human fallibility and why the vast majority of aircraft crashes are pilot error.)
My brain was truly confused…until I felt a chill run down my spine as I realized in an instance that it must be another aircraft which had been converging with us this entire time and judging by the brightness of the light, it must be very close! My brain somehow also processed that since it appeared to be exactly on the horizon it was also at our altitude! “Decreasing range/constant azimuth!” blared through my head.
I immediately pulled an armload of collective and yanked back on the cyclic, initiating an emergency climb while glancing down at the power gauge to ensure I hadn’t overtorqued the engine. As I did, I announced to the crew so they would understand my erratic maneuver, “I think that’s an aircraft at our 10 o’clock!” Sure enough, about three seconds later, an aircraft of some sort passed directly underneath us, moving from our 10 o’clock to our 4 o’clock. We couldn’t tell exactly how far beneath us it was, or even what type of aircraft that it was. But it was very, very close. It was obvious that pilot had never seen us. Had my brain not finally realized what I had been seeing the previous 10 minutes, there is no doubt that the next time anyone would have seen us would have been when they were pulling our charred remains out of a smoking hole in the ground—with the other aircraft’s smoking hole not far away.
I would imagine that all career pilots have similar stories, probably more than most would admit. A final axiom in aviation is: Flying is hours of boredom punctuated by moments of shear terror. I found it to be very accurate.
- NVGs are great for seeing objects in the dark, like trees and buildings and telephone poles, but make lights very confusing because of their monochromatic nature. Around cities, to be able to see the different colored lights, it was necessary to either momentarily look under the NVG tubes (by tilting one’s head) or just swing them out and lock them out of the way unless needed. The latter is what most pilots would do when flying over big cities because the vast amount of artificially lighting blinded (whited-out) the hyper-sensitive NVGs, anyway. But, in my experience, Army-trained pilots—especially those fresh out of the Army—were reluctant to relinquish their use of the NVGs—even around big urban areas–and would sometimes use them well past the point where they had gone from being helpful to being a hinderance. Army training, I guess. ↩︎
- Short for zero ceiling/zero visibility ↩︎
- This same technique is also used in the nautical world, but I have found it much more difficult to use on a boat than in an aircraft because boats tend to wobble back and forth a lot more than an aircraft. If my boat’s heading is moving left and right with each wave, it’s hard to determine whether the azimuth relative to a specific part of the boat is changing over time since it is swinging back and forth past that part with each wave. ↩︎
- It is easy to think–subconsciously at least–that only obstacles in front of the aircraft pose a hazard since those are the things we would “run into.” ↩︎