An F-16 like one of these ran into a little civilian Cessna 150 near Charleston, South Carolina this month. Why?Ints Kalnins / Reuters

Earlier this month an Air Force F-16 and a little single-engine Cessna 150 collided at low altitude near Charleston, South Carolina. The Air Force pilot ejected to safety; the two people aboard the Cessna both died. I wrote about the original episode here, and yesterday I mentioned the “preliminary information” from the National Transportation Safety Board.

Although it takes the NTSB months or years to come up with its definitive analyses, I said that this preliminary report included a chronicle of the Charleston air-traffic controller telling the Air Force pilot “turn left,” and then “turn left immediately” if he didn’t have the little Cessna in sight. “For whatever reason,” I said, that didn’t avert the crash. Exactly what the reasons were is what the NTSB will investigate.

A retired Air Force fighter-plane pilot who still lives in South Carolina seriously disagrees with the way I presented this information. As I’ll explain below, I disagree with him in return. But first here is his response, in original form:

I read, with interest, your conviction of the Shaw AFB F-16 pilot in the Atlantic Magazine article. As a former F-15 pilot who investigated several AF mishaps during my career I wanted to give you my views on the matter given the limited information that has been disseminated.

First of all your decision that the cut-and-dry cause of the midair was the F-16 pilot’s failure to turn immediately is unfair and unrealistic.  No doubt, the faster and more maneuverable aircraft has a duty to avoid and yield right-of-way to slower, less maneuverable aircraft.  There were, as in most cases leading to an aircraft mishap, many factors leading up to this midair.

Consider, first, the mission that this aircraft was flying. It was an instrument mission which is one designed purely for the pilot to go to a foreign airfield and practice instrument approaches. That, by its very nature requires the pilot to fly his or her instruments with his main focus being inside the cockpit as opposed the eyes outside, “head on a swivel”. According to the report he had flown two approaches at Myrtle Beach and was proceeding to Charleston for another and was under control of Charleston approach.

Second,  the air traffic controller continually transmits altitudes of the traffic to the F-16 pilot. At 19 seconds after the hour the traffic was at an “indicated” altitude of 1,200 feet  well separated vertically from the F-16 and then 30 seconds later the traffic was called at 1,400 feet.  Still, sufficient, normal and acceptable vertical separation for VFR flying in the US.

Finally, the preliminary report which you quote states that the F-16 was not heading 180 as directed but was heading 215. I recall that an aircraft flying instruments normally makes standard rate turns at 30 degrees of bank and at that bank angle any aircraft turns at 3 degrees per second or 360 degrees in two minutes. You crucify the pilot for not instantly being established on a 180 heading. The report said the pilot was on a heading of 215 and was being told to turn left [the long way around] to a heading of 180;  a 325 degree turn  to establish a 180 heading. That turn would have taken at least 90 seconds.  

Yes the F-16 could have turned to 180 in 30 seconds by establishing a turn over 60 degrees at high G rate, but that is unrealistic given the situation. Should the F-16 pilot seen the Cessna? Yes, both on radar and visually, but I would guess, given almost 3,000 hours in F-15s myself, that he thought there was sufficient vertical separation and that he was turning at a standard rate turn sufficient to maintain separation…as he was instructed to do. Unfortunately, he may not able to turn 325 degrees instantly as the controller desperately wanted.   

The Air Force will get to the bottom of this accident. One of its top priorities is to preserve the men and women and equipment required to perform its war time job. The Air Force is safer than it has ever been. If you compare accident rates per million hours flown over the years, you will see that those rates have dropped significantly.

The Major flying his F-16 out of Shaw did not go out to kill the two civilians in the Cessna that day and I am sure he regrets everything that happened, but this was not a cavalier fighter jock “doing his own thing” or joy riding through the skies of SC. Your USAF pilots are professionally trained and are the best pilots in the world. Next time you step on to an airliner I will bet you have at least one in the two front seats that have military experience. Airlines value that experience and they value fighter experience above all.  If your pilots don’t have that experience, then you need to start worrying.

***

I thank this reader for his response, because the outlook it illustrates is worth noting. Here’s why I disagree with what he says:

Withholding Judgment. No one is “convicting” or “crucifying” the Air Force pilot in “cut-and-dry” terms. I relayed what was in the NTSB finding—that the controller gave increasingly insistent instructions to turn—and the reality that, “for whatever reason,” the instructions did not avert the crash. Figuring out the “accident chain” that leads to aviation disasters is a long and complex process, with the originally apparent cause often proving to be misleading.

Right- Versus Left-Hand Turns. As many readers will already have noticed, the Air Force veteran apparently misread a very important detail in the NTSB report. When the controller first alerted the F-16 pilot to a possible traffic-conflict, the F-16 was on a heading of 260 degrees. That is almost due west, straight west being 270 degrees. (Aviation readers will want to know that this was a heading to intercept the inbound course for the TACAN approach to Runway 15 at KCHS.)

The controller’s instruction, so as to avoid the traffic, was to turn left to a heading of due south, or 180 degrees. If you are turning from west to south, a left-hand turn is the short way around the circle, in this case involving a total distance of 80 degrees. A right-hand turn would be the long way around, a total of 280 degrees.

What you see below is my very crude, explicitly non-accurate rendering of the general directions of flight. The original 260 heading for the F-16 is in bright blue; the controller’s requested due-south heading is in green; and the 215 heading, which the F-16 reached 23 seconds after the first request to turn (and not long before the crash), is in magenta. The general idea of the Cessna’s course is in orange, with the collision area more or less in the vivid pink circle. The fainter red oval above is the small airport from which the Cessna departed.

An FAA VFR Sectional Chart, with a rough idea of the paths of the affected airplanes.

I am sure the pilot-reader knows from his flying experience that “turn left” was the correct instruction for heading south. But for whatever reason he exactly misread the report and mixed up left and right. I imagine that the misreading aggravated his sense that the controller was placing unreasonable demands on the F-16 pilot.

IFR in VMC. As aviation-world readers will already have noticed, the F-16 was indeed flying a “practice instrument approach,” but he was doing so in visual flight conditions. This is a very, very important distinction to recognize.

When you are flying “IFR in IMC”—flying under Instrument Flight Rules and during Instrument Meteorological Conditions—you are supposed to be strictly heads-down looking at the instruments. There is nothing to see outside the airplane, and any visual cues you do see could be misleading. Since other airplanes cannot safely or legally be in the air in these conditions except under IFR and under a controller’s instruction, you rely on the controller to keep traffic separated.

It’s different when you are flying “IFR in VMC”—instrument flight rules but under Visual Meteorological Conditions. VMC means the relatively clear-sky conditions in which pilots can see where they are going and have primary responsibility to avoid hitting hillsides, towers, or other planes. In those circumstances (and outside certain controlled airspace near airports), you may be sharing the sky with other aircraft that are flying around perfectly legally without talking with the controller. That is what the Cessna was doing.

I don’t know about the military’s rules, but in civilian aviation if you are flying “IFR in VMC” and intend to have your head down looking at the instruments, you are supposed—in fact, required—to have a “safety pilot” aboard. That is precisely so that safety pilot can have his “head on a swivel” to see and avoid other VFR traffic. Moreover, when you’re being directed by a controller (as the F-16 was) you’re supposed to comply with instructions.

None of that proves what happened in this case. But I belabor it to emphasize a possible disconnect between military and civilian flying cultures suggested by this reader’s letter. This highly experienced Air Force pilot seems to assume that since the F-16 pilot was on a practice-instrument approach, the legal, normal civilian traffic sharing the space wasn’t his concern, and he didn’t have to be on the lookout for it. Civilian aviators, by contrast, would assume that in visual conditions, everyone shared the responsibility to “see and avoid.”

Intentions. The pilot-reader says that the F-16 pilot in this tragedy did not go out intending to kill anyone. Of course he didn’t. When he headed off for Martha’s Vineyard, John F. Kennedy Jr. did not intend to kill himself and his family members. No one involved in a genuine accident (as opposed to a disguised suicide) in a car, boat, airplane, climbing expedition, or other circumstance started the day intending to do harm. But when harm gets done, we try to understand why.

My heart goes out to this skilled Air Force pilot and all affected by this tragedy, as well as to the families of the people in the Cessna. Without concluding anything about the cause of this tragedy, the point of the investigation is to understand how it could have come about. And it respects rather than impugns the professionalism of the Air Force to want to understand what went wrong.

***

Just as I was about to post this, a note came in from another reader. It bears on a possible civilian-military difference in outlook

As a private pilot with 50 years experience, may I offer a comment on this tragedy?

This F16 pilot was practicing instrument approaches, which means he likely had his head down to follow the instruments on the panel. Yet he was doing this in visual conditions, in which other aircraft would likely be flying without contact with ATC (air traffic control), nor would that contact be required.

I have done this many times, always with a qualified safety safety pilot along, to keep his head outside to spot other aircraft while I concentrated on the instruments. The F16 only has ONE SEAT.  

What's wrong with this picture?  Why is this never mentioned in the news accounts?  

You may refer to an excerpt from the FAA AIM (airman's information manual). See the parts in bold.
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Practice Instrument Approaches 4-3-21.

  1. Various air traffic incidents have indicated the necessity for adoption of measures to achieve more organized and controlled operations where practice instrument approaches are conducted. Practice instrument approaches are considered to be instrument approaches made by either a VFR aircraft not on an IFR flight plan or an aircraft on an IFR flight plan. To achieve this and thereby enhance air safety, it is Air Traffic's policy to provide for separation of such operations at locations where approach control facilities are located and, as resources permit, at certain other locations served by ARTCCs or parent approach control facilities. Pilot requests to practice instrument approaches may be approved by ATC subject to traffic and workload conditions. Pilots should anticipate that in some instances the controller may find it necessary to deny approval or withdraw previous approval when traffic conditions warrant. It must be clearly understood, however, that even though the controller may be providing separation, pilots on VFR flight plans are required to comply with basic VFR weather minimums (14 CFR Section 91.155). Application of ATC procedures or any action taken by the controller to avoid traffic conflictions does not relieve IFR and VFR pilots of their responsibility to see-and-avoid other traffic while operating in VFR conditions (14 CFR Section 91.113)...
  1. Pilots conducting practice instrument approaches should be particularly alert for other aircraft operating in the local traffic pattern or in proximity to the airport.

This was a tragedy, and eventually the NTSB will do its best to explain why and how it happened. It’s possible that a factor I mentioned in the initial dispatch, a gap between military and civilian understandings of how they share the sky, will play its part. It’s also possible that the investigation will rule this out. We await the findings and lessons.

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