Check Your Six

Top Gun. Iron Eagle. Rescue Dawn. All major films that feature military aircraft in combat. As with any highly specialized career field, there is jargon, lingo, and mission-specific slang that accompanies the more formal language required to teach flight science. One of those slang terms is “check your six” or “watch your six.”

Watching your six has become a bit of a national pastime. Hollywood movies like Top Gun and Top Gun: Maverick have had people talking in fighter pilot lingo (though military culture has been around in Hollywood a LOT longer than the Top Gun movies) for decades. There is a book called Check Your Six!, written by Jeffery Lee.

A video game available on the Steam platform called Check Your Six is just one type of game available that uses the term and the concept as it applies in a military sense; another game by the same name combines the rules of air combat with tabletop gaming complete with dice, the use of miniatures in game play, and a set of rules that apply to a specific era of aerial combat.

But what does “check your six” mean? And how did it trickle down from military jargon into popular culture?

Check Your Six: Air Combat Lingo

“Check Your Six” is simple, but complicated if you actually need to use the phrase professionally. The term refers to the use of the analog clock face as a way to give universal directions to one or more people at the same time. How does this work?

Pilots who have an aircraft or object in front of them, “dead ahead” as you might hear on board a seagoing vessel, have an object at “12 o’clock.” An aircraft to the immediate right of the pilot is said to be in the “3 o’clock” position, ditto for objects to the immediate left (9 o’clock).

The “six” position, 6 o’clock, is to the rear of the pilot–the most vulnerable position an enemy can use to try to shoot down your aircraft.

The phrase “check your six” refers to the need to visually identify an enemy pilot lining up behind the aircraft to bring it down. “Watch your six” could refer to an imminent attack that needs evading, or it could be a reminder not to get caught up in the heat of an air battle if a pilot is at a disadvantage. Two-dimensional thinking is the kiss of death when you’re flying at top speed, and that’s why “check your six” gets complicated in real life.

The Earliest Need To Check Your Six

What were some of the earliest examples of air-to-air combat? Some are surprised when they learn that dogfighting’s earliest history includes intercepts and combat in the air during the Mexican Revolution. Stranger still (to some), this history-making era is said to have started when two American mercenaries hired to fight on opposing sides of the war met one another in the air.

Pilots Phil Rader and Dean Ivan Lamb were both ordered to shoot one another down; the story goes that neither American wanted to harm the other; the two opponents opened fire but missed deliberately. Air And Space Magazine covered this, and Author Kenneth Baxter Ragsdale discusses this in his book Wings over the Mexican Border: Pioneer Military Aviation in the Big Bend.  

It may be surprising to some to learn that this chapter in military aviation history wasn’t necessarily associated with the Wright Brothers, the U.S. Army and Signal Corps, or the American military establishment in general.

Technical Origins of “Check Your Six”

When it’s necessary to watch your six in the real world, there is much science involved. What kind of science? Thrust-to-weight ratios, turn radius, even something called aircraft specific energy (described by some sources as the combination of the aircraft’s “potential energy” and its kinetic energy at any time.

Aircraft targeting other flying objects for attack need advantages in speed, the ability to turn quickly, the ability to quickly gain or lose altitude, and the ability to take an enemy pilot by surprise.

Among the most important factors a pilot must contend with once an air combat engagement actually begins? Keeping the enemy aircraft within the line of sight, and minimizing opportunities for the other aircraft to take advantage of a technical problem, mistake, or miscalculation by the other side.

Targeting The Six

Why target the six o’clock position? It is the most vulnerable spot of the target aircraft. The engines face the attacker’s weapons array, the pilot is forced to immediately deal with an imminent threat rather than continue an attack on some other target, and there is enhanced ability to score a “kill” on the other aircraft.

To put it in another way, some guitar players will road a live stage looking for a “sweet spot” where they can get controlled guitar feedback when they want it. The fighter pilot’s sweet spot is “the six.”

Some aircraft are equipped with countermeasures that can throw a heat-seeking missile off course. Military refueler aircraft, for example, may carry such countermeasures (flares and chaff) into a potential combat zone. Refuelers fly much slower than fighters, the countermeasures are definitely necessary.

The pilot who encounters a comparatively slower-moving airplane has the advantage–it can engage and retreat quickly, while a slower moving plane (like an Air Force refueler) must rely on countermeasures and evasive actions it is capable of at the slower speeds.

When approaching a slower plane, it’s easier to gain the upper hand and score a kill. When two jets of relatively equal size and speed engage, it’s a matter of taking full advantage of your own jet’s maneuverability and the opponent’s lack of it depending on the make and model of the plane.

All aircraft have shortcomings in one form or another; there are variances in the turning radius, weapons range, thrust, etc. The skill of the pilot is also key; there are many factors to remember in the heat of battle. Just one of those is called “nose-tail separation,” which is a factor fighter pilots must respect when lining up for a kill.

When the fighter is in weapons range, the pilot needs to maintain enough distance between the nose of the attacking aircraft and the tail of the defender to maintain good aim at top speed while simultaneously not overtaking the plane. The target aircraft will ideally maneuver to encourage an overshoot and keep the attacker from firing a shot.

A Brief History Of Air Combat

We discussed the first instance (or one of them) of air combat, recorded during the Mexican Revolution. But there have been plenty of other notable uses of air combat from the obvious (World War Two and the Vietnam War) to the relatively unsung.

World War I

This is the war that many associate specifically with the kind of early 20th century dogfighting made popular in movies and games decades later. World War One is the era of the Red Baron, of German fighter pilots shooting at their enemies with hand guns while flying combat missions, and of combat in prop-driven aircraft that seem hopelessly outdated by modern avionics standards.

1914 was a banner year for air combat. It was the year the first recorded intentional air collision happened; a Russian pilot rammed his plane into an enemy reconnaissance plane. 1914 also happens to be the year that the first aircraft was shot down by another pilot using a handgun; it wouldn’t be much longer in the grand scheme of things before machine guns were mounted on combat aircraft.

Spanish Civil War

What was known back then as dogfighting soon fell out of vogue after World War One due to innovations in aircraft propulsion. Some planes were hitting speeds at or over 250 miles per hour, were dogfights even possible?

New air combat tactics proved that even at top speeds, air-to-air warfare was definitely not a thing of the past. German pilots had developed a new buddy system for flying missions, dropping an older “flying V” tactic in favor of sending fighters up in pairs.

This is the origin of the “wingman” approach to air combat. Another innovation German pilots were subject to? Flying at night using instruments only as standard operating procedure. Using these tactics, some sources report successes including a five day streak of German kills on Spanish Republican aircraft; 22 aircraft shot down in five days with no German losses.

World War II

World War Two air combat was happening in two zones at once, and the Pacific air war had vastly different considerations than the air war over Europe. The Pacific campaign relied on aircraft carriers and the range of the aircraft on both sides would be instrumental in developing tactics and counterattacks.

Your concerns as a pilot in World War Two over the Pacific Ocean included not only whether or not you had the fuel and the aircraft integrity to make it back home in once piece, it also depended on whether or not the carrier you launched from had been sunk or not.

Over Europe, the concerns included anti-aircraft guns, enemy radar arrays, and comparatively crowded airspace compared to battles over the Pacific. And note that we haven’t even discussed the skill levels of the German pilots Allied forces would face while trying to liberate Europe.

One after-effect of World War Two was a tendency to over-rely on air to ground bombing campaigns and against aircraft engaged in bombing. The United States would come to view strategic bombing campaigns as the future of warfare or at least an important aspect of it.

The aftermath of the Vietnam War gave military planners a great deal to think about in that respect since the large-scale bombing there did little (in the long run) to prevent the fall of Hanoi or any of the other events that led to the American withdrawal from Vietnam.

Korean War, Vietnam

American pilots faced Chinese-piloted MiG fighters during the Korean War, but this was complicated by then-inferior aircraft weaponry on the American side; Korea had Americans flying prop-driven aircraft such as the P-51 Mustang (often used for close air support) but later the F-86 Sabre was put into service.

Vietnam is referred to in some circles as the first modern air war. During this conflict, the rise of the air-to-air missile combined with the installation of 20 millimeter cannon on some Air Force and Navy planes brought the United States Air Force into a whole new world of air combat and weapons tactics.

The addition of the upgrades to a pilot’s weapons array weren’t the only changes, but overall the modifications proved effective. More than 200 MiG had been brought down during the Vietnam War with at least 40 kills attributed to Air Force guns, and another eight kills attributed to Navy cannons.

The Gulf War And Beyond

The Persian Gulf has seen its share of dogfights. In spite of the press reports and news releases from official sources touting the Iraqi Air Force as being the “fifth largest in the world,” coalition forces decimated the Iraq air force within two days of the shooting. Size isn’t the only factor when trying to determine what a threat an enemy really is; between 1990 and 1991 U.S. forces lost a single F/A 18 aircraft to 39 Iraqi Air Force planes. 36 of the kills during this time can be attributed to the F-15 Eagle.

One interesting footnote to our account of air combat in this region (which technically should be considered a foreword since it actually happened before the Gulf War) is an incident that happened during the Iran-Iraq War which ran between 1980 and 1988.

This conflict had many dogfights, which Iran began to lose later in the conflict due to lack of replacement parts, obsolete gear, and other technical issues. But this war stands out among the others that we’ve discussed here for one reason: it’s the first (or among the first) confirmed dogfights between two helicopters.

This combat was performed by Iranian pilots flying AH-1J Internationals against Iraqi Army Air Corps pilots flying Hind helicopter gunships, or the helicopters known as Aerospatiale Gazelles. The outcomes of these battles? Indeterminate. But they happened, and even in airframes so different than the fighter jets we’ve been discussing for most of this article, chopper pilots still have to watch their six.

Joe Wallace is a 13-year veteran of the United States Air Force and a former reporter for Air Force Television News