Load Factor on the Part 107 Test

Loading and Performance is the smallest area on the Part 107 test, but it contains one of the few questions that needs arithmetic: load factor. The FAA's Pilot's Handbook of Aeronautical Knowledge defines it as the force on the structure as a multiple of the aircraft's weight, measured in Gs. A load factor of 2 means the wing, or the rotors, must carry twice the aircraft's weight.

How does bank angle change load factor?

In a level, coordinated turn, the wing has to hold the aircraft up and pull it around the turn at the same time, so it has to make more lift than in straight flight. The load factor is 1 divided by the cosine of the bank angle.

The handbook gives the 60° and 80° values and points out that the load factor "increases at a terrific rate" after 45° or 50°. A level turn at 90° is not possible at all, because no amount of lift can hold altitude with the wing vertical.

How do you use Figure 2 on the test?

The testing supplement's Figure 2 is a load factor chart: bank angle along the bottom, load factor up the side. The FAA's own sample question asks what load a 33-pound unmanned airplane's structure must support in a 30° banked turn at constant altitude. Read about 1.154 off the chart and multiply:

33 lb × 1.154 ≈ 38 lb

The answer choices are 34, 38 and 47 pounds. The wrong ones come from adding instead of multiplying, or from reading the wrong bank angle. The load factor calculator does this for any angle and weight, and the sample questions post covers the other loading questions in the FAA set.

Why does stall speed rise in a turn?

A stall happens when the wing exceeds its critical angle of attack, at any airspeed. In a turn the wing needs more lift, so it flies at a higher angle of attack and reaches the critical angle at a higher speed. The handbook says stall speed increases in proportion to the square root of the load factor.

At 60°, the load factor is 2, and the square root of 2 is about 1.41, so stall speed is about 41% higher than in level flight. An unmanned airplane that stalls at 25 knots straight and level stalls at about 35 knots in that turn.

Does load factor matter for a multirotor?

The test's load factor questions are about airplanes, but the geometry carries over. A multirotor that tilts to hold altitude in a turn or in fast forward flight needs total thrust equal to its weight divided by the cosine of the tilt angle. At a 30° tilt that is about 15% more thrust than a hover, and at 45° about 41% more.

That extra thrust comes out of the same margin that a hot, high or humid day already shrinks, and that a heavier payload uses up. The manufacturer's limits, not a calculator, decide how much is left.

What the exam asks about loading and performance

The ACS element is UA.IV.A.K1: general loading and performance, with sub-elements for the effects of loading changes and for balance, stability and center of gravity. Expect the Figure 2 calculation, a stall question, and a question on where loading instructions come from, which the FAA answers as the Pilot's Operating Handbook or UAS flight manual. The exam mistakes post explains why this small area still deserves an hour of practice.