PAC Up and Go

Three easy steps to take the danger out of unpracticed low-and-slow operations such as go-arounds


Bewildered, I began filling out a Notice Of Disapproval – the proverbial pink slip – for a commercial pilot applicant. Up to the point of the final landing for the flight test it had been a picture perfect checkride. The applicant had performed all the maneuvers, including the go-around, quite well. His smoothness, accuracy and judgment were to be applauded. Surprisingly, it was the second performance of the go-around maneuver of the day that caused the unsatisfactory performance.

We were operating out of a non-towered airport the day of the test. While on short final for a landing, another airplane – with a flight instructor on board – pulled out onto the runway in front of us. We were forced into making a go-around. His response to this real-life situation was so out of sync that the execution of the go-around maneuver almost ended with us becoming part of the accident database.

In his attempt to avoid the conflict with the encroaching airplane, his flight control and power applications were out of sequence. Improper aircraft configuration changes aggravated the situation. He pitched-up and began to retract the flaps without applying power; then started reaching for the landing gear handle. I applied power, stopped the flap retraction, blocked his hand going towards the gear handle, and adjusted the pitch attitude – all the while yelling, I have it.

At this point you are probably wondering why an examiner would want to take control of an aircraft instead of letting the applicant discover his mistakes himself. In this case, the answer was really quite simple: examiners have the right to save their own lives. After climbing to a safe altitude I returned the controls to the applicant and we landed without further incident.

His poor performance under the unexpected conditions experienced late in the test negated the satisfactory performance he had previously demonstrated. The applicant got so caught up in a set of circumstances so different from any he had previously experienced that he simply forgot what to do when the chips were down.

He reverted to his survival instincts, but there are times when physical law contradicts logic. Understanding and applying these differences is implied in the term applied aeronautical knowledge. For reasons unexplained, and while under pressure, his thought processes reverted to survival instincts and logic, but failed to trigger his aeronautical knowledge.

When we talked about it afterward, it was clear that his improper reactions were the result of several misconceptions. His reasoning for immediately retracting the flaps was to reduce drag so the airplane could accelerate faster. Basic aerodynamics tells us that without power application and effect, flap retraction would reduce lift, increase stall speed, and allow the airplane to settle.

The airplanes nose was going down, so he immediately applied nose-up elevator pressure; forgetting that without power this would increase angle of attack, g-loading, and stall speed. To simultaneously induce a loss of lift and reduce the margin above stall speed of an airplane at low altitudes is something most pilots would never dream of doing, yet this pilot did just that.

In his attempt to flee the threat, he forgot power, the first item in the PAC sequence, and could not explain why. It was obvious that he had been properly taught how to execute a go-around maneuver; as he had demonstrated earlier in the test. It was also obvious he did not understand the elements of the maneuver; he had performed it mechanically.

It was also apparent that he did not fully appreciate the importance of performing each task in a specified sequence. Student pilots are great imitators, and it was evident that he had impressed his instructor by imitation and not by true performance. This explained the mechanical performance of the maneuver.

He also admitted money was tight, and he feared further questioning of the instructor might result in additional flight training costs. Unfortunately, he must now pay for not only additional training, but another testing fee.

A discussion with his instructor disclosed that the pilot had properly demonstrated the maneuver on a number of occasions. After observing his performance the instructor assumed the student understood the elements of the maneuver. The instructor truthfully admitted not giving any unannounced go-arounds during training to measure the pilots performance and reaction to the unexpected. The conversation ended on a positive note with a much wiser instructor.

The Maneuver
The go-around maneuver can go by several names, but is most often referred to simply as a go-around. For aircraft certification purposes, and in some government and industry flight handbooks, it is referred to as a balked landing. Its execution when performed under instrument conditions is called a missed approach. No matter what you label it, however, it remains a transition from landing configuration to climb configuration.

The secret of a successful go-around is to recognize the need as early as possible during the approach. Because of this, pilots must constantly be alert for the unexpected. An aircraft taxiing rapidly from the run-up block directly toward the departure runway, or an aircraft suddenly appearing below and in front of you in the traffic pattern are two examples of the unexpected.

Delayed recognition or response times can convert an unexpected but easily accommodated situation into one that has an almost frighteningly high accident potential. Awareness and anticipation of the possible need to go around are the keys to early recognition and shorter pilot reaction times.

Properly executing a successful go-around requires that the pilot follow a prescribed course of action. This planned method should be practiced by pilots until it becomes second nature. The PAC method of aircraft control is the most popular in use today and can be readily applied to the go-around maneuver.

The PAC method simply states that power + attitude + configuration = performance. Many pilots have been following this sequence for years but never realized it. The PAC method can accommodate all but a few flight situations when properly performed.

Operationally, the PAC sequence is extremely straightforward. Apply the necessary power for the performance desired, then establish a predetermined aircraft attitude, then change the configuration as required for the maneuver.

The PAC method can be used in a variety of maneuvers, not just go-arounds. It does not require that all three steps be performed for each maneuver; just that the correct sequence be followed; even if a step is omitted. An out-of-sequence step can disrupt a maneuver in all but a few situations.

One of the few exceptions in which the order can be changed is the level-off from a climb, where the attitude change (pitch) is followed by a configuration change (cowl flaps) and, as cruise airspeed is attained, the power is adjusted. Another would be when making a constant airspeed approach to a landing using configuration changes (flaps, spoilers, gear) to control the glide path, then adjusting airplane attitude to accommodate the configuration change and changing the power setting as required.

Executing a Go-Around
Execution of a go-around maneuver begins as soon as the pilot decides its needed. Before entering any phase of flight, mentally condition yourself for the abnormal and emergency situations likely to be encountered during that phase of flight. This conditions your recall in anticipation of executing a procedure – a practice commonly known as staying ahead of the airplane.

Proper mental conditioning in preparation for an emergency stimulates recall and aids the pilot in the decision-making process. With recall readily available, you are conditioned to act at the moment you decide to discontinue the approach. This avoids being caught in a swimming-in-glue situation.

In the swimming-in-glue situation, you are unaware of the unusual circumstances until you are caught-up in them. This requires that you acknowledge the emergency, make a hurried decision on how you are going to respond to it and then act. Such a process delays the response time, lends itself to a greater chance of error, and aids in the development of an accident chain. Any further compounding of the problem by an unintentional mistake could complete the chain and result in an accident.

To avoid being caught in a swimming-in-glue situation, stay ahead of the airplane by conditioning yourself to recognize and anticipate common errors associated with both the present and next phase of flight.

Once the decision is made to execute a go-around it is time to act: Immediately apply power.

As power takes effect, smoothly rotate to your predetermined climb attitude. With the airplane accelerating, retract the flaps to the initial setting recommended by the airplanes manufacturer. With flap retraction there will be a tendency for the airplane to settle.

To overcome this, apply enough nose-up elevator pressure to maintain the predetermined climb attitude. This will increase the angle of attack and lift coefficient, offsetting the loss of lift and settling caused by flap retraction. Verify a positive rate-of-climb, then retract the landing gear – unless the manufacturer recommends otherwise. Once the best rate-of-climb airspeed (Vy) is attained, retract the remaining flaps.

While climbing at Vy, maneuver to the side of the runway that allows the pilot full view of the runway. Since the pilot usually sits on the left side of the fuselage, keep the runway to the left of the airplane. This is true regardless of whether you are flying a left or right hand traffic pattern. The object is to provide the pilot full view of the runway environment and the conditions causing the go-around.

Maintain a straight climb path (correcting for wind effect), avoiding other aircraft and obstructions until altitude and circumstances permit safe maneuvering for a return to a landing. Remember to execute the Climb checklist when conditions permit.

Do not forget to complete the Before Landing checklist prior to landing. There have been many instances of gear-up landings following a go-around because the pilot remembered doing it during the first approach.

Common Errors
The most prevalent kinds of errors involve out-of-sequence PAC steps in the execution of a go-around. The most common mistake is to pitch-up to climb attitude before adding power.

The airplane is already in a high-drag landing configuration and the pitch-up increases the angle of attack, further increasing drag and reducing airspeed. Therefore, a greater portion of the power applied will be absorbed by this additional drag, resulting in less excess power being available for climb performance. Follow the PAC sequence using predetermined power settings and airplane attitudes to avoid this error.

Another common mistake is to apply power and then retract the flaps while the airplane is still descending. In a descent, your thrust vector has a downward component. With flap retraction you experience a reduction in lift and a settling of the airplane. These two conditions (thrust angle and settling) combine to increase your rate of descent.

The last thing you want to experience at low altitudes is an increased rate of descent. To avoid this, follow the PAC steps in their proper sequence.

Common mistake number three is to rotate to a climb attitude first, before applying power. Then, before power can take effect, the pilot retracts the flaps – increasing the stall speed – and raises the landing gear. This results in an uncommanded slight nose down pitch moment that the pilot tries to overcome by applying nose-up elevator.

The reduction in lift caused by raising the flaps, combined with increase in angle of attack and drag cause by the sudden application of nose-up elevator, serve to reduce airspeed. The configuration increases stall speed, and the airplane may begin to mush and the nose may start to pitch downward. Additional application of nose-up elevator to stop the nose down pitching moment further increases the angle of attack and drag and this whole attempt could possibly end with a power-on stall.

If caught in such a situation – in fact anytime an uncommanded nose down pitch moment is experienced – relax pressure on the elevator and lower the nose to the horizon. Then follow the PAC procedure. Lowering the nose when youre low and slow requires a great deal of discipline, but it must be done.

Follow the PAC method until your predetermined climb attitude is established. By this time you will have attained your best rate-of-climb airspeed and stabilized your climb. This entire situation could have been avoided had the pilot properly initiated the PAC procedure when first recognizing the need for a go-around.

Trim It Proper
Perhaps the most dangerous error of all, one that many pilots quite innocently get caught in, is the improper use of elevator trim. Some pilots have a habit of continuing to apply nose-up trim to a point just prior to touchdown.

During the landing phase the elevator pressure increases as the airspeed decreases. The nose gets heavier as greater control displacement is required to make the aircraft react. To reduce this pressure some pilots continue to apply nose-up elevator trim almost to the point of touchdown.

If they trim the airplane for an airspeed below 1.1 times Vx (or, if Vx is not given, 1.3 times Vso), they are setting themselves up for a serious control problem in the event of a go-around.

If the airplane is properly trimmed at 1.1 Vx or 1.3 Vso as appropriate, and maximum power is suddenly applied with no immediate flight control inputs, the pilot can expect the following:

• The nose will pitch up. This is a reaction caused by the increased power augmenting the dynamic pressure of the propeller slipstream as it passes over the horizontal tail surfaces. This, compounded by an increased upward vertical component of thrust, produces a pronounced nose-up pitch moment.

• As the nose pitches up there will be a tendency to yaw and roll to the left. This is due to conditions associated with torque and P factor.

• If the trim speed is improperly set, the nose-up pitch moment combined with the left-turning yaw and roll, will cause the airspeed to dissipate to the point of stall. The airplane could experience an elevator trim stall and possible spin. Fortunately, when the airplanes trim speed is properly set at 1.1 Vx or 1.3 Vso, a drop in airspeed will result in the nose lowering itself and the airspeed increasing to its trim speed. This discourages a stall from occurring and aids the pilot in the recovery.

If the trim speed is improperly set, the nose will continue to rise even if airspeed is below Vx. There is no reversal or lowering of the nose as the airspeed decreases below Vx, and a stall will occur without immediate flight control correction.

So by using improper trim technique (trimming below 1.1 Vx or 1.3 Vso) the pilot has unknowingly set up an elevator trim condition that could result in a stall should a go-around maneuver be required. To avoid this error, just remind yourself while on final approach not to use elevator trim at airspeeds less than 1.1 Vx or 1.3 Vso. From that point on its all muscle.

In a Nutshell
This entire experience emphasizes the need for constant vigilance and preplanning while airborne. It also emphasizes the importance of safe ground operation practices and clearing the final approach leg before taking the runway. In the experience cited earlier, the unexpected taxiing out of an airplane onto the runway while we were on short final, combined with the pilots incorrect reaction, placed the airplanes occupants in grave danger.

Pilots should expect the unexpected and be mentally conditioned to act. Some would say that you should approach each landing assuming youre going to be forced into a go-around until youre committed to land. Although that may be taking vigilance a bit far, always be alert for the development of events that may require a go-around before you enter the landing phase. This preparation will trigger your recall, decrease response time, and reduce the chance of error.

Once you decide to execute a go-around, you should rely on and follow your trained response. Do not delay the procedure by trying to convince yourself that a go-around is necessary and then mentally reviewing each step prior to taking action. This soggy state of mind can place the airplane and its occupants in a very dangerous position.

Unless the manufacturer provides a procedure contrary to its usage, the PAC procedure is a simple three-step method that will accommodate all but a few flight situations.

Once the PAC procedure is complete, maneuver to that side of the runway providing the pilot with a full view of the runway and the conditions that caused the go-around. Maneuver as necessary for a return to a landing.

The best way to maintain proficiency in this and any other maneuver is through practice.

Recurrent training and review should be given at intervals required to meet your individual requirements for safetys sake. Choose a personal training program and stick to it.

Also With This Article
Click here to view “What Goes Around Comes Around.”
Click here to view “PAC Up and Go-Around.”

-by Thomas L. Oneto

Thomas L. Oneto is a 13,000-hour ATP/CFII, Part 121 and corporate pilot and former Designated Pilot Examiner.


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