Today On Basic Fighter Maneuvers

Basic fighter maneuvers (BFM) are tactical movements performed by fighter aircraft during air combat maneuvering (ACM). They are generally grouped into two categories:

Primary BFM

Relative BFM

Primary maneuvers are those which are performed without respect to an enemy's position. These are often simple maneuvers, such as climbs, turns and rolls. Relative maneuvers are performed in relation to the motion of another aircraft. These are often more complex, including energy saving maneuvers, such as the high and low Yo-Yos, and repositioning maneuvers such as displacement rolls. It is easy to fall into the trap of considering BFM to be a series of set maneuvers providing a foolproof recipe for a dominant position. The reality is that BFM is a series of fluid and often improvised proactive and reactive actions, varying infinitely according to range, altitude, speed, aircraft type, weapons system type and any of an enormous range of other factors. An extremely successful tactic one day may yield unfortunate results if repeated the next day, and pilots often credit luck as a major factor.

BFM is normally considered to be individual maneuvers, where ACM is applied to the tactics behind dog-fighting as a whole. In military training, BFM is often conducted against an adversary in the same type of aircraft. This allows the pilot to fly against a machine with known performance values and allows aircrew to build their awareness of important concepts such as sight picture, rates of closure and line of sight rates that are cues to being successful in the visual arena.

Dissimilar BFM, is BFM performed by aircraft of two separate types (such as F-16 vs F/A-18). This training is valuable in that both pilots are not as aware of the performance capabilities and characteristics of the other aircraft and, therefore, must rely on the fundamental BFM principles and evaluation/decision making skills to maneuver to an advantageous position versus their opponent. This type of training, while less common, is the most beneficial for aircrew once basic BFM skills are mastered.

BFM principles

In combat a pilot is faced with a variety of limiting factors. Some limitations are constant, such as gravity, drag, and thrust-to-weight ratio. Other limitations vary with speed and altitude, such as turn radius, turn rate, and the specific energy of the aircraft. The fighter pilot uses BFM to turn these limitations into tactical advantages. A faster, heavier aircraft may not be able to evade a more maneuverable aircraft in a turning battle, but can often choose to break off the fight and escape by diving or using its thrust to provide a speed advantage. A lighter, more maneuverable aircraft can not usually choose to escape, but must use its smaller turning radius at higher speeds to evade the attacker's guns, and to try and circle around behind the attacker.

BFM is a constant series of trade-offs between these limitations to conserve the specific energy state of the aircraft. A pilot may use gravity to provide a sudden increase in speed, by diving, at a cost in the potential energy that was stored in the form of altitude. Similarly, by climbing the pilot can use gravity to provide a decrease in speed, conserving the aircraft's kinetic energy by changing it into altitude.

Both turn rate, (degrees per second), and turn radius, (diameter of the turn), increase with speed, until the "corner speed" is reached. At this point, the growing turn radius begins to decrease the turn rate, so the aircraft will reach its best turn performance at its particular corner speed. The corner speed of an aircraft is the minimum speed at which it can sustain the maximum g-force load, and varies with its structural design, weight, and thrust capabilities. It often falls in the area of 250 to 400 knots.

Instantaneous turn rate describes maximum g turns which cause a loss in energy, but may be compensated for, to a degree, by adding thrust, known as "excess specific power." This often occurs during hard turns or even harder breaks. Only by turning the aircraft at its best "sustained turn rate" can the aircraft maintain its specific energy. However, situations in combat may require a change in energy, and energy may also be increased by pulling less than the maximum sustained g-force.

Successful BFM requires geometry as much as it does skill and stamina. Pilots must know their aircraft's corner speed, as well as optimum angles of bank (AOB) and angles of attack (AOA), without consciously thinking about them. At the same time, pilots must remain conscious of the angle between the opponent's velocity vector and their own, called the angle off tail (AOT).

A high AOT causes a high rate of closure, but makes achieving a suitable guns solution nearly impossible. Acquiring a low AOT, (getting on the enemies tail), is usually the primary goal before an overshoot occurs, which can decrease or even reverse closure rate. However, an uncooperative defender may try to take advantage of the high closure rate by turning to increase AOT, forcing an overshoot.

One tactic used to decrease AOT is to use various barrel rolls called displacement rolls, in order to shift the aircraft laterally from its projected flight path onto a new flight path. By controlling the roll rate the pilot can control the degree of displacement. An attacker following a more maneuverable opponent may become stuck in lag pursuit, (outside the defender's turn radius), unable to achieve a guns solution. By displacing the turn, the two aircraft's flight paths will eventually cross. The AOT will then decrease until the nose of the attacker's aircraft points momentarily at the defender, (pure pursuit), and then ahead of the defender, (lead pursuit).

There are three basic situations in air combat maneuvering requiring BFM to convert to a favorable result. The three situations, and the primary goals of a pilot in that situation are:

Defensive - the pilot is in a weak position, primarily concerned with denying a shot to the opponent rather than achieving a dominant position. The goal in this situation should be to convert to a neutral situation or extend to escape the unfavorable position.

Neutral - neither the pilot nor their opponent have a particular advantage, nominally defined as the ability to "point" the nose of his/her aircraft at the opponent with sufficient range to employ forward firing ordnance (missiles/gun) prior to their opponent threatening in a similar manner. Each is focused on converting to an offensive situation whilst forcing their opponent defensive.

Offensive - the pilot is in a dominant position, primarily concerned with prosecuting their advantage for a kill.

Maneuvers

Combat Spread

The combat spread is the most basic of maneuvers used prior to engagement. A pair of attacking aircraft will separate, often by a distance of one mile horizontal by 1500 feet vertical. The fighter with the lower altitude becomes the defender, while his wingman flies above in "the perch" position. The defender will then attempt to lure his opponents into a good position to be attacked by his wingman.

Defensive Split

A pair of fighters encountering one or two attackers will often use a defensive split. The maneuver consists of both defenders making turns in opposite directions, forcing the attackers to follow only one aircraft. This allows the other defender to circle around, and maneuver behind the attackers.

Break

Spotting an attacker approaching from behind, the defender will usually break. The maneuver consists of turning sharply across the attacker's flight path. The defender exposes the aircraft to the attacker's guns for only a brief instant. The maneuver works well because the slower moving defender has a much smaller turn radius, and an aircraft moving in such a direction is very difficult to shoot. This can also help to force the attacker into "lag pursuit" (outside the defender's turn radius), which may not be true had the turn been made away from the attacker's flight path.

Barrel Roll Attack

The counter to a break is often a barrel roll attack. A barrel roll consists of performing a roll and a loop, completing both at the same time. The result is a helical roll around a straight flight path. The barrel roll attack uses a much tighter loop than the roll, completing a full loop while only executing 3/4 of a roll. The result is a virtual 90 degree turn, using all three dimensions, in the direction opposite of the roll. Rolling away from the defender's break, the attacker completes the roll with the aircraft's nose pointed directly at the defender (pure pursuit), or inside the defender's turn radius (lead pursuit).

Immelmann

An Immelmann trades airspeed for altitude during a 180 degree change in direction. The aircraft performs the first half of a loop, and when completely inverted, rolls to the upright position. The Immelmann is a good offensive maneuver, for setting up an attack, but is a poor defensive maneuver, turning the defender into a slow moving target.

Split-S

The opposite of an Immelmann is the split-s. This maneuver consists of rolling inverted and pulling back on the stick, diving the aircraft into a half loop, which changes the aircraft's direction 180 degrees. The split-s is rarely a viable option in combat as it depletes kinetic energy in a turn and potential energy in a dive. It is most often used to set up an attack, although it is sometimes used as a disengagement tactic.

Pitchback

A pitchback is an Immelmann that is executed in some plane other than the vertical. The fighter will be at some angle of bank before performing the half loop and roll. Unlike the Immelmann, a pitchback depletes less energy and is harder for an adversary to track.

Low Yo-Yo

The low yo-yo is one of the most useful maneuvers, which sacrifices altitude for an instantaneous increase in speed. This maneuver is accomplished by rolling with the nose low into the turn, and dropping into a quick dive. By utilizing some energy that was stored in the vertical plane, the attacker can quickly decrease range and improve the angle of the attack, literally cutting the corner on his opponent's turn. The pilot pulls back on the stick, climbing back to the defender's height, slowing the aircraft and placing the energy back into altitude.

High Yo-Yo

The high yo-yo is a very effective maneuver, and very difficult to counter. The maneuver is used to slow the approach of a fast moving attacker while conserving his airspeed energy. The maneuver is performed by reducing the angle at which the aircraft is banking during a turn, and pulling back on the stick, bringing the fighter up and over his enemy. The trade off between airspeed and altitude provides the fighter with a better angle from which to attack, and a burst of increased maneuverability.

Lag Displacement Roll

A lag displacement roll, also called a "high-g barrel roll", is a maneuver used to reduce the angle off tail, (the angle between the flight paths), by bringing the attacker from lag pursuit to pure, or even lead pursuit. The maneuver is performed by rolling up and away from the turn, then, when the aircraft's lift vector is aligned with the defender, pulling back on the stick, bringing the fighter back into the turn. This maneuver can also be used to increase the distance between aircraft.

Scissors

The Scissors are a series of turn reversals and overshoots intended to slow the relative forward motion of the aircraft in an attempt to either force an overshoot, on the part of the defender, and prevent an overshoot on the attacker's part. The defender's goal is to stay out of phase with the attacker, trying to prevent a guns solution, while the attacker tries to get in phase with the defender. The advantage usually goes to the more maneuverable aircraft. There are two types of scissor maneuvers, called flat scissors and rolling scissors.

Flat scissors

Flat scissors, also called horizontal scissors, usually occur after a low speed overshoot in a horizontal direction. The defender reverses the turn, attempting to force the attacker to fly out in front and to spoil aim. The attacker then reverses, trying to remain behind the defender, and the two aircraft begin a weaving flight pattern.

Rolling scissors

Rolling scissors, also called vertical scissors, tend to happen after a high speed overshoot from above. The defender reverses into a vertical climb and into a barrel roll over the top, forcing the attacker to attempt to follow. The advantage lies in the aircraft that can pull its nose through the top or bottom of the turn faster. In battles with aircraft that have a thrust-to-weight ratio of less than one the aircraft will quickly lose altitude, and crashing into the ground becomes a possibility. According to author Mike Spick, "Disengagement from a vertical rolling scissors is best made with a split-s and a lot of hope."

Guns Defense

Guns defense maneuvering, or "guns-D," is the last resort for a defender that fails to out-maneuver the attacker. Guns-D is a series of random changes in the defenders flight path, intended to spoil the attacker's aim by presenting a constantly shifting target, and, hopefully, to maneuver out of the bullet stream. It consists of arbitrary speed changes, yaws, skids, pitch-ups, and rolls, often referred to as "junking," and is very effective at preventing the attacker from achieving a suitable guns solution. However, guns-D maneuvering leaves the defender susceptible to stray bullets and "lucky shot" hits, and is only employed when nothing else works.