Flight Patterns and Descent: Insights From Microsoft Flight Sim

Exigence

The article was commissioned by Dr. Peter Tong as a part of his AL Aerospace Engineering class. Our final exam tomorrow is about basic skills in Microsoft Flight Simulator (MSFS) 2020 and 2024. This article is a dive into one of the guiding questions I encountered during my time spent practicing.

How I Practice On Flight Sim

Our course requires us to be fully competent in the skills pertaining to takeoff and landing. Thus, instead of spending most of my time cruising, I wanted to maximize the amount of time I spent leaving and arriving at a runway instead of being in the air. There were two ways by which I practiced this. To practice both skills, I could choose to take off from one airport and land in another. To purely practice landing (the harder part for me) I could set a departure point in the air and descend toward an airport.

However, there were problems with each of these approaches. For the takeoff + landing strategy, I would often spend too much time on cruising (if I arrive in a different airport) or struggle with turning properly (if I land at the same airport as my departure.) When I depart from the air, my altitude was often too high, and descending rapidly would overstress my plane structure and cause permanent damage, while descending slowly would often see me being at a very high altitude as I approach the airport.

In short, I had no idea about what I was doing. I could understand the strategies surrounding throttle, flaps, landing gear, parking brake, pedals and yoke, but not what path my plane should take when approaching/leaving an airport. (As seen in Fig. 1) Thus, I departed on a journey of curiosity to discover what I could do to better manage by training and practice.

Fig. 1 Inspecting Flight Instruments In Microsoft Flight Sim

Traffic Patterns

When landing at an airport in MSFS, there is a guided route which encourages the pilot to approach the runway parallel on the yet opposite to the runway direction, so that the pilot “U-turns” left. (As seen in Fig. 2)

Fig. 2 Recommended Descent Pattern in MSFS

This reflects a real-world standard practice adopted by pilots and airports across the world known as a traffic pattern. It was implemented and is encouraged by the FAA (Federal Aviation Administration) for three primary reasons.

1. Standardization
2. Position of pilot/captian
3. P-factor

Allowing all planes to turn in the same direction greatly increases safety because traffic controllers will not have to specify direction to pilots. The more information is understood without speaking, the less likely it is for miscommunication to happen.

The position of the captain also plays a role in this decision: because the pilot generally sits on the left side, turning left is more safe since they are closer the the left-hand window. This allows pilots to monitor the runway and keep a sense of its position relative to the aircraft.

Finally, the left turning tendencies of aircraft due to P-factor make turning left easier. If the aircraft were to turn right, pilots would have to use the right rudder significantly more. This effect was explained earlier in my article on propeller aircraft.

A traffic pattern consists of several legs as seen in Fig. 3: upwind, crosswind, downwind, base, and final. After takeoff, I fly straight ahead (upwind), then turn left to crosswind, then left again to downwind (parallel to the runway), followed by base and final to line up for landing. This allows me to repeatedly practice takeoff and landing at the same airport.

Fig. 3 Different Legs of a Traffic Pattern

Not only is this method advantageous in the real world for safety and other practical reasons, but it is also just easier for pilots to fly. After departing the runway in a straight line (using the right rudder to go straight for a distance,) we must turn right ninety degrees. In order to do this, there are two methods which we can use. The angle between each leg in this pattern is exactly 90 degrees, allowing for the easy implementation of both visual and instrument aids.

Our first method for turning uses the compass instrument which tells us which heading we have, as seen in Fig. 4. If the runway goes directly west, for example, we turn the plane until it faces south.

Fig. 4 Compass Mounted in a Cockpit

Our second method is more intuitive and easy to use, because it does not require flight instruments. When preparing to turn, track a reference point with relation to the wing tip. For example, a specific building or hill would be a good reference. Then, turn right until the nose of the plane is aligned with that landmark. Obviously, the angle between the tip of the wing and the nose is 90 degrees, which is how much we want to turn. This is useful when the heading of the plane is not one of the cardinal directions. Even though this method is more “primitive,” it is also more reliable because sometimes magnetic compasses can fail or be inaccurate. Pilots use the acronym UNOS for the Northern hemisphere: Undershoot North Overshoot South. This means that when turning from a northerly heading, the compass briefly turns in the opposite direction and undershoots. The requirement for this acronym to exist demonstrates the unreliability of the instruments in our cockpit and the need to compensate for their errors. Furthermore, because of the role of the hemisphere in determining these tendencies of compasses, pilots also have to factor in whether they are in correct hemisphere when applying this rule of thumb.

By using these skills to fly the traffic pattern, pilots will be able to practice take off, landing, and turning with precision without spending too much time or fuel on cruising. However, I still wanted to explore how pilots descend from high altitudes safely and reliably to approach a landing.

Along with the pattern itself, pattern altitude is also a standard adopted by airports around the world. Each airport has a designated pattern altitude, which is the altitude pilots must reach before entering the traffic pattern. This also ensures that all aircraft in the vicinity operate at a consistent height, reducing collision risk and improving predictability.

Descent Planning

When flying from farther distances (for example, an airport 70 miles away), proper descent planning becomes essential. This is because airplanes simply cannot have rates of descent which are too high. From my experience in the simulator, this is primarily due to two reasons:

1. Structural limits
2. Keeping clear of the ground

When descending rapidly, the speed of the plane can easily exceed the maximum speed of the plane. This limit, also called the Never Exceed Speed (VNE), is 158 KIAS (Knot-Indicated Air Speed) for the Cessna 172.This is because as the aircraft accelerates, aerodynamic forces acting on the airframe increase significantly, especially on control surfaces such as the elevators and ailerons. Beyond VNE, these forces can become strong enough to cause structural damage or even catastrophic failure.

In a descent, gravity contributes to acceleration, meaning that even with low or zero throttle, the aircraft can still gain speed quickly if the nose is pitched too far down. This makes steep descents dangerous. Descent additionally introduces a significant force which must be accounted for.

To manage this, pilots must moderate pitch. Reducing throttle alone is not sufficient reduction of speed. Thus, the angle of descent must also be controlled. Generally, a shallow, controlled descent such as a standard 3-degree glide path can maintain a safe airspeed while gradually losing altitude.

Flaps can also be used to help manage descent. Deploying flaps increases drag, which allows the aircraft to descend more steeply without gaining excessive speed. However, flaps have their own speed limitations (VFE, meaning maximum flap extended speed.) Thus, they can only be deployed gradually and within safe airspeed ranges.

Losing altitude as quickly as possible results in excess stress on the plane so pilots must plan to lose altitude slowly over a long distance of time. In order to do this, pilots do not eyeball the distance and start descending when they feel like it as I did in my first couple of flights. They must calculate the Top of Descent (TOD) and a descent airspeed and angle.

The “top of descent” is the point at which a pilot should begin descending to reach the correct altitude before entering the traffic pattern (process of landing.)

To estimate the TOD, we can use a standard 3-degree descent path. The rule of thumb proposed by FlightInsight of YouTube is:

Change in altitude (current altitude minus pattern altitude), divided by 1,000, then multiplied by 3, gives the distance in nautical miles from the airport where descent should begin.

For example, if I need to descend 5,000 feet, I should start descending approximately 15 NM (nautical miles) from the airport by plugging the required altitude change into the equation.

It is also important to arrive at pattern altitude several miles before reaching the airport to allow for adjustments and proper alignment with the traffic pattern. Thus, if the equation tells us to start descending 15 NM away from the runway, it is safer to start descending when 18 NM away, so that the plane will arrive at the desired altitude 3 NM in advance.

This rule of thumb can be verified via trigonometry as seen in Fig. 5, where we can use the cotangent function to determine the side adjacent to the angle of descent.

Fig. 5 A descent pattern visualized via trigonometry

Using The Altitude Intercept Arc

A way to use technology to more precisely predict the TOD is via the computer on planes. Electronic flight instrument systems (EFIS) like the Garmin G1000 (Fig. 6) can tell you at what position will you meet the desired pattern altitude using the current speed and degree of descent. Each airport will have a set pattern altitude which they require planes preparing for landing to reach before they start their final approach.

Fig. 6, The Garmin G1000, a standard EFIS used in many planes

Modern aircraft systems can assist with this. Navigation systems such as the Garmin G1000 display an altitude intercept arc, showing where the aircraft will reach the selected altitude based on current speed and descent rate. These tools can automatically compute and update the top of descent as needed.

Several explanations of what is going on in Fig. 7 below:

1. ALT 5800 FT means the system is working with a target altitude of 5,800 feet at that waypoint.
2. BRG 245° is the bearing from your current position to the waypoint.
3. CRS 244° is the desired bearing to the waypoint.
4. DIS 59.3 NM is the remaining distance to that point.
5. Offset -3 NM means the computed descent point is shifted 3 nautical miles before the waypoint, so you start descending early enough to arrive at the desired altitude.

Fig. 7, Interface on a G1000

For more manual control, we can also set a target altitude and adjust vertical speed accordingly, and the computer will help compute the desired TOD.

Under the VNV (Vertical Navigation) tab in Fig. 8, setting the speed target (VS TGT) and flight path angle (FPA) can also adjust the TOD as required. We can see that the hollow dot in front of the plane is the calculated TOD, given the VS TGT and FPA.

Fig. 8, VNV Profile on a G1000

Conclusions

Prior to being aware of traffic patterns and the concept of calculating a TOD point, my strategy toward landing and takeoff was extremely random and unpredictable. I often overstressed my aircraft to the degree which my flight ended in a crash. After learning about these strategies, I found it way easier to practice takeoffs and landings.

References

Airplane Flying Handbook (FAA-H-8083–3C) Chapter 8: Airport Traffic Patterns. (n.d.). https://www.faa.gov/sites/faa.gov/files/regulations_policies/handbooks_manuals/aviation/airplane_handbook/09_afh_ch8.pdf

Burton, R. B. (2022, October 13). G1000 Flight Plan Tips & Tricks — Online Pilot Training | AviatorsAcademy.com. Online Pilot Training | AviatorsAcademy.com. https://aviatorsacademy.com/glass-panel/g1000-flight-plan-tips-tricks/

FlightInsight. (2022, July 19). Calculating Top of Descent Point | Descent Planning Rules of Thumb. YouTube. https://www.youtube.com/watch?v=k-AiOWy0CBU

Hardiman, J. (2021, May 16). Why Do Airline Captains Sit On The Left-Hand Side? Simple Flying. https://simpleflying.com/why-do-airline-captains-sit-on-the-left-hand-side/

Kitplanes. (2019, May 31). Garmin adds latest FIS-B weather products to the GTN 650/750 series — KITPLANES. Kitplanes. https://www.kitplanes.com/garmin-adds-latest-fis-b-weather-products-to-the-gtn-650-750-series/

Magnetic Compass Errors: Identify and Correct for Safety. (2026). PilotMall.com. https://www.pilotmall.com/blogs/news/magnetic-compass-errors-how-pilots-identify-correct-them?srsltid=AfmBOoob2JxfN9TLtm5SHD5d8y0Wc64NRE9QWlFaWio5JaeXWU0Y8hiB

Purdue Aviation. (n.d.). Www.purdueaviationllc.com. https://www.purdueaviationllc.com/aircraft-rental/cessna-172

US Department of Commerce, N. O. and A. A. (n.d.). What is the difference between a nautical mile and a knot? Oceanservice.noaa.gov. https://oceanservice.noaa.gov/facts/nautical-mile-knot.html