Hazmat & External Loads
~9 min read · Apply the hazardous-materials ban and the securing rules for carried loads.
Part 107 lets you carry things for hire — external load and even package delivery inside strict fences — but hazardous materials are an absolute stop. The exam tests the hazmat ban, the securing rules, and the interstate line that grounds drone delivery businesses.
The hazmat prohibition
107.36: an sUAS may not carry hazardous materials as defined in the DOT regulations (49 CFR) — flammables, explosives, corrosives, compressed gases, and the rest of the hazard classes. This prohibition is not waivable. Note the boundary: the aircraft's OWN lithium batteries installed for propulsion are equipment, not carried hazmat — but transporting spare lithium batteries as cargo crosses the line.
- No hazmat carriage, ever — unwaivable
- Defined by DOT 49 CFR hazard classes
- Installed propulsion batteries: fine. Batteries as cargo: hazmat.
External loads and towing
External-load operations are allowed if the load is securely attached and does not adversely affect the flight characteristics or controllability of the aircraft. The pilot must account for the load in weight-and-balance and performance planning (total under 55 lbs, CG in limits, endurance derated). Dropped objects remain governed by 107.23 — no undue hazard to people or property below.
- Secure attachment + no adverse effect on controllability
- Total weight with load stays under 55 lbs
- Any release/drop must create no undue hazard
Transport for hire and the interstate line
Carrying property for compensation or hire is legal under Part 107 with limits: total weight under 55 lbs, the flight within VLOS, and — critically — not across state lines (transportation of property for hire must occur wholly within the boundaries of a single state; interstate air carriage requires DOT/FAA air-carrier authority, the Part 135 route). Also barred: carriage for hire from a moving vehicle, and operations in Hawaii/DC have their own special constraints under the rule.
- Intrastate only: origin and destination in the same state
- VLOS applies — no BVLOS delivery under bare Part 107
- Interstate or beyond-VLOS delivery = Part 135 territory
Worked example
A courier startup asks you to fly (a) medication 3 miles across town, (b) a spare phone battery pack to a job site, and (c) a document pouch across the river — which is the state line. All loads under 2 lbs. Which flights are legal under Part 107?
(a) Medication across town: property for hire, intrastate, light, and — if you can genuinely maintain VLOS across 3 miles (doubtful without relay pilots; assume a route flown in VLOS segments or a closer mission) — the category is legal; the practical barrier is VLOS, not the cargo. (b) Spare lithium battery pack as cargo: that is hazardous material under DOT rules — prohibited outright, not waivable, regardless of size. (c) The document pouch crossing the state line: interstate carriage of property for hire — outside Part 107, requires air-carrier (Part 135) authority. Score: (a) legal in principle within VLOS; (b) never; (c) not under 107.
Common exam pitfalls
Treating small quantities of hazmat as de minimis.
The prohibition has no quantity threshold — a single spare lithium pack as cargo is carried hazmat.
Confusing installed batteries with battery cargo.
Propulsion batteries powering the aircraft are equipment. The same battery in the cargo hook is hazmat.
Planning delivery routes that cross state lines 'briefly'.
For-hire property transport must be wholly intrastate under 107 — any interstate leg needs Part 135 authority.
Carry it tight, keep it light, stay in-state, nothing that burns.
Recap
- Hazmat carriage prohibited and unwaivable (DOT 49 CFR classes)
- Installed propulsion batteries are equipment; spare batteries as cargo are hazmat
- External loads: secured, no adverse effect on controllability
- Property for hire: under 55 lbs total, VLOS, wholly intrastate
- Interstate or BVLOS delivery requires Part 135 air-carrier authority
- Object drops still answer to the no-undue-hazard rule
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