What is the NOTOC and when must the pilot in command receive it?

The NOTOC (Notification to the Captain) is a written document the air carrier must provide to the PIC before departure, listing every dangerous goods shipment on board including the proper shipping name, hazard class, UN number, quantity, and hold location. This requirement comes from 14 CFR §175.33. The PIC uses the NOTOC to guide emergency decisions and has the authority to refuse any dangerous goods shipment regardless of documentation.

Can passengers bring lithium batteries in checked baggage on an airline flight?

Spare lithium-ion and lithium metal batteries—including external battery packs—must be carried in carry-on baggage only and are prohibited in checked baggage under 14 CFR Part 175 and ICAO Technical Instructions. The reason is that a lithium battery fire in the cabin can be identified and fought by the crew, while a fire in the cargo hold may go undetected. Batteries installed in devices may generally be checked, but spares cannot.

How often must airline employees complete hazardous materials training?

Under 49 CFR §172.704(c)(2), employees who perform functions covered by the hazardous materials regulations—including flight crew, cargo acceptance personnel, and check-in agents—must complete recurrent hazmat training at least once every three years (36 calendar months). Initial training must be completed before an employee independently performs covered functions, and training records must be kept for two years after the employee leaves the covered role.

Carriage of Dangerous Goods and Hazardous Materials on Air Carriers

Dangerous goods and hazardous materials represent one of the most consequential compliance areas for air carrier operations. An improperly declared shipment of lithium batteries, undisclosed flammables, or mislabeled oxidizers has the potential to cause an in-flight fire, explosion, or toxic exposure that no crew can fully mitigate at altitude. For that reason, 14 CFR Part 175—along with the broader DOT hazardous materials regulations in 49 CFR Parts 171–180 that Part 175 references—establishes a comprehensive framework governing how dangerous goods move through the commercial aviation system. Airline transport pilot candidates must understand this framework not just to pass the ATP written exam, but because captains bear direct legal and safety responsibility for what is carried aboard their aircraft.

The term dangerous goods is the international ICAO/IATA term; U.S. domestic regulations use the parallel term hazardous materials (hazmat). In practice the two phrases are used interchangeably in airline operations. Nine hazard classes—from explosives (Class 1) to miscellaneous dangerous goods (Class 9)—organize every regulated substance and article, and air carriers must train their employees to recognize, accept, refuse, or properly handle each class.

Regulatory Framework and Authority

14 CFR Part 175 is titled "Carriage by Aircraft" and appears within Subchapter C of the DOT's hazardous materials regulations. It does not stand alone: it works in concert with 49 CFR Parts 171 (general information and definitions), 172 (hazardous materials table, communication requirements, and training), 173 (shippers' requirements for packaging), and 174–177 (carrier-specific requirements by mode). For air transportation specifically, Part 175 governs the operator's responsibilities—what the airline itself must do once a shipment is tendered for carriage.

ICAO's Technical Instructions for the Safe Transport of Dangerous Goods by Air (ICAO TI) are incorporated by reference through 49 CFR Part 171.7. IATA's Dangerous Goods Regulations (IATA DGR) are accepted as an equivalent alternative. This matters operationally because most international shipments are documented under IATA DGR standards, and U.S. carriers routinely accept such documentation as compliant.

How the System Works: From Shipper to Flight Deck

Responsibility for safe carriage is layered. The shipper (offeror) must classify, package, mark, label, and document the dangerous goods correctly before tendering them to the carrier. The air carrier then has an independent duty to inspect, verify, and accept or reject the shipment. This dual-responsibility structure is deliberate: it prevents a single point of failure.

When a shipper tenders dangerous goods, they must provide a Shipper's Declaration for Dangerous Goods (or the equivalent air waybill notation for certain limited-quantity and excepted-quantity articles). The declaration identifies the proper shipping name, UN identification number, hazard class and division, packing group, quantity, and packing type. The carrier's acceptance check—performed by trained cargo acceptance personnel—must confirm that the documentation matches the physical package, that labels and markings are correct, that the package is not damaged or leaking, and that the goods are not forbidden aboard aircraft.

Forbidden vs. Acceptable Dangerous Goods

14 CFR Part 175 and the ICAO TI draw a critical distinction between articles and substances that are absolutely forbidden by air under any circumstance, those forbidden on passenger aircraft but permitted on cargo-only aircraft, and those that may move on passenger aircraft under specific conditions. Examples of absolute forbidden items include certain explosives, infectious substances of extreme hazard, and materials that are too reactive to be safely packaged for air transport. Radioactive material in certain categories, certain flammable gases, and organic peroxides may be acceptable on cargo aircraft but prohibited from passenger-carrying operations. Operators must train staff on these distinctions and maintain current forbidden-articles references.

Notification to the Pilot in Command

One of the most directly pilot-relevant requirements in Part 175 is the mandate for notification to the pilot in command (NOTOC). Under 14 CFR §175.33, the air carrier must provide the PIC with written information about any dangerous goods on board before departure. This notification must include the proper shipping name, class or division, UN number, quantity, and location (aircraft hold position) of each dangerous goods shipment. The PIC uses this information to make emergency decisions—for example, knowing that a leaking package in position 4L contains a corrosive liquid versus a flammable liquid changes the emergency response entirely.

The NOTOC must be kept accessible to the crew during flight and delivered to the next operator if the shipment transfers to a connecting carrier. The PIC has the authority to refuse or remove any dangerous goods shipment if in their judgment it poses a safety risk, even if the documentation appears correct. This authority is absolute and non-negotiable under Part 91's general PIC authority as well as Part 121 operations specifications.

Training Requirements

14 CFR §175.20 and the broader requirements of 49 CFR Part 172 Subpart H mandate that all air carrier employees who could encounter dangerous goods—cargo agents, flight dispatchers, passenger service agents at check-in, and flight crewmembers—receive initial and recurrent hazmat training. For crewmembers, the training focuses on recognition of undeclared hazardous materials, passenger carry-on and checked baggage restrictions, and emergency response procedures. Recurrent training for most personnel is required at least once every three years (36 calendar months) under 49 CFR §172.704(c)(2). Training records must be maintained for two years after the employee no longer performs the covered functions.

A key concept in training is undeclared dangerous goods—shipments tendered without disclosure. Shippers sometimes mislabel or omit dangerous goods declarations intentionally or through ignorance. Crew members are trained to recognize clues: shipping names that suggest chemical content, packages from laboratory or industrial shippers, strong odors, damaged or leaking packages, or passenger declarations of items such as camping equipment, car parts, or medical supplies that may contain regulated substances.

Passenger Carry-On and Checked Baggage Rules

Part 175 directly governs what passengers may carry aboard or check. Many items dangerous goods that would be forbidden as cargo may be carried by passengers in limited quantities for personal use. For example, passengers may carry medically necessary lithium-ion batteries exceeding the standard 100 Wh limit with airline approval. Spare lithium-ion batteries and power banks must be in carry-on baggage only—not checked—because lithium battery fires in the cabin can be fought by the crew, while fires in the hold may not be detected quickly enough. Fuel cells, matches, and lighters also fall under specific Part 175 restrictions.

Items absolutely prohibited in both checked and carry-on baggage include replica or inert explosives (regardless of their actual danger), strike-anywhere matches, and certain compressed gases. Passengers discovered attempting to carry forbidden items face civil penalties and potential criminal prosecution.

Key Numbers and Rules

9 Hazard Classes: Explosives (1), Gases (2), Flammable Liquids (3), Flammable Solids/Pyrophorics/Water-reactives (4), Oxidizers/Organic Peroxides (5), Toxic/Infectious (6), Radioactive (7), Corrosives (8), Miscellaneous (9).
NOTOC required before departure for all dangerous goods on board per 14 CFR §175.33.
Recurrent hazmat training: at least once every three years (36 calendar months) for covered employees (49 CFR §172.704(c)(2)).
Lithium-ion battery thresholds: up to 100 Wh permitted without airline approval; 101–160 Wh permitted with airline approval (carry-on only); above 160 Wh generally forbidden on passenger aircraft.
Lithium metal battery thresholds: up to 2 g lithium content without approval; 2–8 g with airline approval; above 8 g forbidden on passenger aircraft.
Spare lithium batteries: must be in carry-on baggage only—never checked.
PIC authority: absolute right to refuse or remove dangerous goods under 14 CFR §175.75 and general PIC authority.
Air waybill retention: records of dangerous goods shipments must be retained for specific periods per 49 CFR Part 172 requirements.

Why It Matters: Safety and Legal Consequences

Undeclared or improperly handled dangerous goods have been implicated in major aviation accidents worldwide. The combination of pressurization changes, temperature extremes, vibration, and the inability to stop and unload mid-flight makes air transport uniquely hazardous for goods that might be moved safely by ground transport with a minor error. In-flight fires are among the most rapidly incapacitating emergencies a crew can face.

From a legal standpoint, violations of 14 CFR Part 175 and 49 CFR hazmat regulations carry civil penalties of up to tens of thousands of dollars per violation per day. Willful violations can result in criminal prosecution. Carriers operating under 14 CFR Parts 121 and 135 must include hazmat compliance in their operations specifications (OpSpecs), and FAA inspectors review dangerous goods programs during surveillance. An air carrier that repeatedly accepts undeclared or improperly documented dangerous goods risks suspension or revocation of its operating certificate.

Common Test Traps

Confusing shipper and carrier responsibility: The shipper packages and declares; the carrier inspects and accepts. Both bear legal responsibility, but they are distinct duties. Exam questions sometimes blur this line.
NOTOC timing: The PIC must receive the NOTOC before departure, not simply before loading. A last-minute addition of dangerous goods after NOTOC issuance requires an updated notification.
Lithium battery location rules: Spare batteries in checked baggage is a common wrong answer. Spare lithium batteries—both lithium-ion and lithium metal—must travel in the cabin (carry-on) only.
36-month recurrence vs. annual: Hazmat training recurrence is at least once every three years (36 calendar months), not annually. Don't confuse with the 12-month currency requirements found elsewhere in the FARs.
Cargo-only vs. passenger aircraft distinctions: Many dangerous goods forbidden on passenger aircraft are permitted on all-cargo aircraft under more permissive quantity limits. Test items may ask about a specific class without specifying aircraft type—read carefully.