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Loading and performance

Drone weight and balance: center of gravity, payloads and manufacturer limits

Last updated 2026-11-14 · Published by Certloom Learning · Sources

Weight and balance means keeping the aircraft under its maximum weight and keeping its center of gravity (CG) inside the manufacturer's limits. The CG is not a fixed mark on the aircraft: it moves as you add, remove or shift items, and if it ends up outside limits you must relocate or shed weight before flight.

What is the center of gravity of a drone?

The Remote Pilot Study Guide describes the CG as the point at which all the weight of the aircraft may be considered concentrated. If you supported the aircraft at its exact CG it would balance in any attitude. The guide stresses that the CG is of major importance in a small UA because its position has a great bearing on stability.

It also says something people forget: the CG "is not a fixed point marked on the aircraft; its location depends on the distribution of aircraft weight." Add a gimbal camera on the front, swap a larger battery, hang a spotlight on the left arm, and the CG moves. AC 107-2A repeats the point in Appendix B (B.2.2), and both documents say limits for the CG location may be established by the manufacturer.

Sources (checked 2026-11-14): FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22); FAA Advisory Circular 107-2A.

Why does balance matter as much as weight?

The study guide says adverse balance conditions "may affect flight characteristics in much the same manner as those mentioned for an excess weight condition". The PHAK states it plainly in its weight and balance section: operation with the CG outside the approved limits results in control difficulty, and operating above the maximum weight compromises structural integrity and performance.

For a fixed-wing sUAS the study guide gives the pitching reason. Weight acts at the CG and lift acts at the center of pressure. When the CG is forward of the center of pressure the aircraft wants to pitch nose down, and when the center of pressure is forward of the CG there is a nose-up moment. Designers therefore fix the aft CG limit forward of the center of pressure, so the aircraft stays in equilibrium. Move the CG aft of that limit and the aircraft loses that margin.

A multirotor does not have that wing geometry, but an off-center payload still means some motors work harder than others to keep the aircraft level, which cuts into the control margin and flight time. That sentence is my plain-language reading, so check your manual for the limits that apply to your model.

Sources (checked 2026-11-14): FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22); FAA Pilot's Handbook of Aeronautical Knowledge; FAA Advisory Circular 107-2A.

What does overloading do to a small unmanned aircraft?

The study guide lists the most important deficiencies of an overloaded aircraft: higher takeoff speed, longer takeoff run, reduced rate and angle of climb, lower maximum altitude, shorter range, reduced cruising speed, reduced maneuverability, higher stalling speed, higher approach and landing speed, and a longer landing roll. It adds that if an aircraft is not properly loaded, the initial indication of poor performance usually appears during takeoff.

Both the study guide and AC 107-2A tell you the maximum gross takeoff weight on paper may not be safe in every condition. High elevation, high air temperature and high humidity, which add up to high density altitude, may require less weight before you launch. The same text lists launch area length, surface, slope, surface wind and obstacles as reasons to reduce the load. See the density altitude guide for the weather side of this.

Then there is the regulatory ceiling. Under 14 CFR 107.3 a small unmanned aircraft weighs less than 55 pounds on takeoff, including everything on board or attached. Exactly 55 pounds is over the line.

Sources (checked 2026-11-14): FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22); FAA Advisory Circular 107-2A; 14 CFR 107.3 (eCFR).

How do payload changes move the CG?

The study guide spells out two cases. If variable load items are shifted or expended, there may be a resultant shift in CG location, and the remote PIC should determine how it will shift and what effect that has on the aircraft. In small UA operations, weight can change during flight when expendable items are used on board, for example a jettisonable load. Dropping a payload makes the aircraft lighter and can improve performance, yet it can have a negative effect on balance.

The same paragraph tells you what to do if the CG is out of limits: relocate or shed some weight before flight is attempted. Do not rely on trim or software to make up for it. The preflight rule in 14 CFR 107.49(e) also applies: any object attached or carried must be secure and must not adversely affect flight characteristics or controllability.

• A heavier camera mounted forward moves the CG forward.
• A larger battery slid back in its tray moves it aft.
• A payload released mid-flight changes both weight and CG at once.
• A loose item that slides in flight can move the CG while you are airborne.

Sources (checked 2026-11-14): FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22); 14 CFR 107.49 (eCFR).

How do I calculate the CG with moments?

The PHAK (chapter 10) uses weight, arm and moment. The arm is the distance from the datum (a reference line chosen by the manufacturer) to an item. The moment is the weight times the arm. The CG location is the total moment divided by the total weight. The handbook's own airplane example divides 281,430 in-lb by 3,320 lb to get 84.8 inches.

The FAA testing supplement includes weight and balance figures with datum and arm markings (for example Figure 61, Weight and Balance Diagram), so the layout of a datum, arms and a CG location will look familiar if one comes up. Always use the figure's own numbers and the question's own definitions.

Sources (checked 2026-11-14): FAA Pilot's Handbook of Aeronautical Knowledge; FAA airman testing supplements (FAA-CT-8080-2H).

What do the manufacturer and AC 107-2A expect from me?

Both the study guide and AC 107-2A say the weight and balance restrictions established by the manufacturer or builder should be closely followed, and that compliance with the manufacturer's limits is critical to flight safety. Before any flight the remote PIC should verify the aircraft is correctly loaded by determining its weight and balance condition, and should consider the consequences of an overweight aircraft if an emergency happens.

For aircraft without published data, AC 107-2A notes that manufacturer performance data is not standardized. If none is available, it suggests looking at data other users of the same model have published and using it as a starting point. For everyday flying that means:

1. Find the maximum takeoff weight and any CG or payload limits in the manual.
2. Weigh the aircraft with the exact payload, batteries and accessories you will carry.
3. Check that the aircraft stays under 55 lb including everything attached.
4. Secure every item (107.49(e)).
5. Reduce the load for hot, high or humid conditions, short launch areas or obstacles.
6. If you carry something that will be released or used up, work the CG for the loaded and unloaded cases.

The AC also lists proper aircraft loading and performance planning among the actions that mitigate risk in the risk assessment process, so it belongs in your preflight briefing as well as on paper.

Sources (checked 2026-11-14): FAA Advisory Circular 107-2A; FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22); 14 CFR 107.49 (eCFR).

What are the common traps on the test?

• Weight versus balance. A correct total weight does not prove the CG is inside limits.
• CG as a fixed point. The correct statement is that the location depends on the distribution of weight and moves when items are shifted or expended.
• Fuel or payload use. Using up an expendable item makes the aircraft lighter, which improves performance, and can still harm balance.
• The 55 lb rule. It counts everything on board or attached at takeoff.
• Fix for an out-of-limit CG. The answer is to relocate or shed weight, not to fly with a lower speed.

Related reading: load factor and stall speed, preflight and maintenance and loading and performance.

Sources (checked 2026-11-14): FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22); FAA Advisory Circular 107-2A; 14 CFR 107.3 (eCFR).

Related guides

• Loading and performance for drone pilots
• Load factor and stall speed: the bank angle math for the Part 107 test
• Preflight and maintenance for Part 107 flights
• Density altitude for drone pilots: what it is and how it hurts performance
• All Part 107 guides

Sources

• FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22), checked 2026-11-14
• FAA Advisory Circular 107-2A, checked 2026-11-14
• FAA Pilot's Handbook of Aeronautical Knowledge, checked 2026-11-14
• FAA airman testing supplements (FAA-CT-8080-2H), checked 2026-11-14
• 14 CFR 107.3 (eCFR), checked 2026-11-14
• 14 CFR 107.49 (eCFR), 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.