Home › Guides › Loading and performance
Loading and performance
Load factor and stall speed: the bank angle math for the Part 107 test
Load factor is lift divided by weight, measured in Gs. In a coordinated level turn it grows with bank angle: 1.154 at 30 degrees, 1.414 at 45 and 2.0 at 60. Stall speed rises in proportion to the square root of load factor, so a 60 degree bank raises a 40 knot stall speed to about 57 knots.
What is load factor, and why does the FAA test it?
The Remote Pilot Study Guide defines the maximum load factor at a given bank angle as the proportion between lift and weight, measured in Gs. A load factor of 3 means the total load on the structure is three times the aircraft's weight. The guide gives two reasons pilots need the idea: it is possible to impose a dangerous overload on the structure, and a higher load factor raises the stalling speed, so a stall can happen at an airspeed that looks safe.
The test sits in the loading and performance area, which is a small slice of the exam. It rewards people who have the table in their head, because the question usually gives a bank angle and asks for a load factor, or gives a stall speed and asks what it becomes in a turn. The arithmetic is short once you know the pattern.
For the broader loading topics (the 55 lb limit, density altitude, overloading effects) see Part 107 loading and performance. This page goes deeper on the bank angle side.
Sources (checked 2026-11-14): FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22); FAA Pilot's Handbook of Aeronautical Knowledge.
What is the load factor at 30, 45 and 60 degrees of bank?
The FAA testing supplement (FAA-CT-8080-2H) prints the numbers as Figure 2, Load Factor Chart. In a coordinated, constant altitude turn the load factor equals 1 divided by the cosine of the bank angle, which reproduces the chart.
| Bank angle | Load factor (Figure 2) | Square root | Stall speed if 1 G stall is 40 kt |
|---|---|---|---|
| 0 degrees | 1.0 | 1.000 | 40.0 kt |
| 30 degrees | 1.154 | 1.074 | about 43.0 kt |
| 45 degrees | 1.414 | 1.189 | about 47.6 kt |
| 60 degrees | 2.000 | 1.414 | about 56.6 kt |
| 70 degrees | 2.923 | 1.710 | about 68.4 kt |
| 80 degrees | 5.747 | 2.397 | about 95.9 kt |
Two things stand out. The first is that the load factor barely moves below 30 degrees: shallow turns cost almost nothing. The second is how fast it climbs after 45 to 50 degrees. The PHAK says the load factor rises "at a terrific rate" past that point, puts a 60 degree bank at 2 Gs, and an 80 degree bank at 5.76 Gs. The supplement table shows 5.747 at 80 degrees, a small difference in the third digit that does not change which answer choice is closest.
Memorize three rows: 30 degrees is about 1.15 G, 45 degrees is about 1.4 G, and 60 degrees is exactly 2 G. Everything else on the test can be read off Figure 2.
Sources (checked 2026-11-14): FAA Pilot's Handbook of Aeronautical Knowledge; FAA airman testing supplements (FAA-CT-8080-2H); FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22).
How does load factor change stall speed?
The PHAK and the study guide give the same rule: the stalling speed increases in proportion to the square root of the load factor. Write it as
Vs in the turn = Vs at 1 G x the square root of the load factor
The handbook's own example is an aircraft with a normal, unaccelerated stall speed of 50 knots. At a load factor of 4 Gs the square root is 2, so it can stall at 100 knots. If the airframe could survive a load factor of 9, the square root is 3 and the stall speed would be 150 knots. The same handbook text warns about stalling an aircraft by increasing the load factor "in a steep turn or spiral", because the airspeed on the gauge can look comfortable while the wing is already at its limit.
The reason is lift. To hold altitude in a bank, the wing must produce lift equal to the weight times the load factor. More lift at a given speed means a higher angle of attack, and the wing stalls at the same critical angle of attack regardless of weight, bank or speed. The speed at which it reaches that angle is what changes.
Sources (checked 2026-11-14): FAA Pilot's Handbook of Aeronautical Knowledge; FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22).
How do I work a stall speed problem step by step?
Worked example
A 60 degree bank in a fixed-wing sUAS
Say a fixed-wing aircraft stalls at 36 knots in wings-level flight, and the pilot flies a coordinated, level turn at 60 degrees of bank.
- Read the load factor for 60 degrees from the chart: 2.000.
- Take the square root: 1.414.
- Multiply: 36 x 1.414 = 50.9 knots.
The stall speed has risen by about 41 percent. A pilot cruising at 45 knots, comfortable above 36, is now below the stall speed of the turn. Notice that the load factor of 2 doubled the lift demand, but the stall speed only rose by the square root, which is why the change is large without being doubled.
Worked example
Working backward from a limit
The PHAK uses a related example for design maneuvering speed. For older airplanes, this speed is roughly 1.7 times the normal stalling speed. A plane that normally stalls at 60 knots stalled at 102 knots (60 x 1.7) sees a load factor equal to the square of the speed increase: 1.7 x 1.7 = 2.89 Gs. The handbook adds that the figures are approximations to use as a guide, and that the true maneuvering speed comes from the aircraft's own limitations.
The step is useful because it shows the relation in both directions. Multiply by the square root to go from load factor to speed, square the ratio to go from speed to load factor.
Sources (checked 2026-11-14): FAA Pilot's Handbook of Aeronautical Knowledge.
How do I read Figure 2 on the test?
The supplement page has a small table on the left (bank angle and load factor) and a curve on the right with load factor in G units on the vertical axis and bank angle on the horizontal axis. The table lists 0, 10, 30, 45, 60, 70, 80, 85 and 90 degrees, and the load factor at 90 degrees is shown as infinity because a level turn at 90 degrees of bank is mathematically impossible.
- Find the bank angle in the table first. If it is listed, you have the load factor without reading the curve.
- If the question uses an angle between rows, such as 50 degrees, find where the curve sits between 45 degrees (1.414) and 60 degrees (2.0). The answer choices are usually far enough apart that a rough read is enough.
- Apply the square root with the built-in calculator. A stall speed question normally lists answer choices a few knots apart, so compute to one decimal.
- Check direction: the answer must be higher than the original stall speed, but lower than the load factor itself times that speed (unless the load factor is 1).
The figure is the same one used for other pilot tests, so it is labelled for airplanes. The test applies the same chart to the small aircraft in the question.
Sources (checked 2026-11-14): FAA airman testing supplements (FAA-CT-8080-2H).
Does this apply to a multirotor that cannot stall?
A quadcopter has no wing to stall, so the stall speed part is about fixed-wing and hybrid aircraft. The geometry still carries over. A multirotor holding altitude in a banked turn has to tilt its total thrust, and the vertical part of that thrust must still equal the weight. That means the total thrust required goes up by the same 1 divided by cosine factor. At 60 degrees of tilt it needs twice the weight in thrust, which leaves less margin for the motors and batteries. This is my own explanation of the physics, not a rule from the FAA documents, but it matches why aggressive maneuvers drain a battery faster and why the guides tell you to respect the manufacturer's limits.
The study guide frames load factor as something "for any aircraft", and the test does not ask you to distinguish airframe types. If the question says bank angle and load factor, use Figure 2.
Sources (checked 2026-11-14): FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22).
What are the common traps?
- Forgetting the square root. Doubling the load factor does not double the stall speed. A load factor of 4 doubles it, and a load factor of 2 raises it about 41 percent.
- Reading load factor as bank angle. The chart's horizontal axis is degrees, the vertical axis is Gs. A 45 degree bank is 1.414 G, not 45 anything.
- Assuming steeper is linear. From 30 to 60 degrees the bank doubles, but the load factor goes from 1.154 to 2.0. From 60 to 80 degrees it goes from 2 to about 5.75.
- Taking the study guide's rounded example literally. The guide says a bank of more than 72 degrees produces a load factor of 3 and, for a 45 knot aircraft, the airspeed must stay above 75 knots. Exact arithmetic gives a load factor of 3 near 70.5 degrees and a stall speed of about 78 knots (45 x 1.732). Treat the guide's numbers there as rounded and trust the supplement's table if an answer choice looks off.
- Mixing weight and load factor. Excess weight also raises stalling speed, but a bank angle question wants the Figure 2 value. The weight effects are on the weight and balance page.
Sources (checked 2026-11-14): FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22); FAA airman testing supplements (FAA-CT-8080-2H); FAA Pilot's Handbook of Aeronautical Knowledge.
What should I study next?
Load factor links to overloading, which the study guide lists as raising stalling speed, takeoff speed and landing speed. After this page, try the loading and performance guide and the Part 107 practice test.
Related guides
- Loading and performance for drone pilots
- Drone weight and balance: center of gravity, payloads and manufacturer limits
- Density altitude for drone pilots: what it is and how it hurts performance
- The FAA testing supplement for Part 107: figures, legends and the October 2026 change
- Free Part 107 practice questions
- All Part 107 guides
Study the charts on your phone
Sectional Cue has 1150+ original questions with explanations, 27 FAA figures you can tap to read, and timed 60-question rehearsals. About 152 questions and three chart lessons are free.
Sources
- FAA Pilot's Handbook of Aeronautical Knowledge, checked 2026-11-14
- FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22), checked 2026-11-14
- FAA airman testing supplements (FAA-CT-8080-2H), checked 2026-11-14
How this page was made: written by Certloom Learning from the sources above, with the rules checked against the current regulation text. Practice items are original questions from the app's reviewed bank. Spot an error? certloomlearning@gmail.com.