TSA Computer-Based Test (TSA CBT) Prohibited Items and Threat Recognition Syllabus

What is a command initiation device and how does it differ from a time device?

It is detonated on demand by an operator via a remote signal (cell phone, radio, wire) rather than a preset delay, giving the attacker control over timing.

Name three common types of IED initiation (triggering) methods.

Time/timer initiation, command/remote initiation, and victim-operated (e.g., trip-wire, pressure, or movement-activated) initiation.

What is the key visual difference between a knife and a box cutter on X-ray?

A knife shows a single solid dense blade with a handle; a box cutter/utility knife shows a small dense blade often within a slim rectangular metal/plastic housing with a slide mechanism.

Why are razor blades especially challenging to detect on X-ray?

They are very thin and flat, so when laid edge-on to the beam they present minimal density and may nearly disappear; orientation can hide them in paper, cardboard, or clothing.

What everyday objects are commonly used to conceal blades?

Belt buckles, combs, pens, lipstick tubes, credit-card knives, hairbrushes, canes, and the soles or heels of shoes.

What is a 'credit card knife' and why is it a screening concern?

A flat folding blade disguised as a credit card that fits in a wallet; on X-ray its thin blade can blend with cards, requiring careful inspection of wallet contents.

Give examples of martial arts / self-defense weapons that are prohibited and recognizable on X-ray.

Throwing stars (shuriken), nunchaku, brass/metal knuckles, kubotans, expandable batons, and push daggers - typically dense metal with distinctive shapes.

How do brass knuckles typically appear on X-ray?

As a dense (dark) metal piece with a row of finger holes - a recognizable pattern of four connected loops with a flat striking surface.

What categories of blunt instruments and clubs are prohibited in a cabin?

Baseball/cricket bats, billy clubs, blackjacks, nightsticks, expandable batons, hockey/lacrosse sticks, and heavy tools usable as bludgeons.

On X-ray, what makes an expandable (telescoping) baton identifiable?

A dense metal cylinder with concentric nested tubes of decreasing diameter, often with a weighted tip - distinctive collapsible segmented shape.

What general property defines a 'flammable liquid' as a hazardous material?

A liquid with a low flash point that gives off ignitable vapor at relatively low temperatures (generally flash point below 140 F / 60 C), e.g., gasoline, lighter fluid, acetone.

Why are flammable gases (e.g., butane, propane) prohibited and how might they appear?

They are pressurized and ignitable; canisters appear as dense sealed cylinders with thick walls and a valve, often a hazmat threat for fire/explosion.

What is the difference between a corrosive and an oxidizer as hazardous materials?

A corrosive (acid/base) chemically destroys living tissue and materials on contact; an oxidizer supplies oxygen that intensifies combustion of other materials even without air.

Why are reactive chemicals and oxidizers dangerous when combined with other items in luggage?

They can react violently, ignite, or explode when mixed with fuels, organics, or each other; oxidizers can turn an otherwise inert flammable into a fire/bomb hazard.

Why are lithium batteries restricted from checked baggage and limited in carry-on?

They can undergo thermal runaway causing intense, hard-to-extinguish fires; spares/power banks must be carried in the cabin where a fire can be detected and addressed quickly.

What is 'thermal runaway' in a lithium battery?

A self-sustaining chain reaction where a damaged or shorted cell rapidly overheats, igniting adjacent cells and producing fire that reignites and is difficult to extinguish.

What is the TSA 3-1-1 LAGs rule for carry-on liquids, aerosols, and gels?

Containers must be 3.4 oz (100 mL) or less, all fitting in 1 quart-sized clear resealable bag, 1 bag per passenger.

What common items count as 'gels or aerosols' under the LAGs rule?

Toothpaste, gel deodorant, shaving cream, hair gel, lotions, perfumes, sprays, and similar pourable/spreadable/pressurized substances.

Name common exemptions to the 3-1-1 LAGs rule.

Medically necessary liquids/medications, baby formula/breast milk, and required liquid items - allowed in reasonable quantities but must be declared for separate screening.

What is a 'false compartment' in modified luggage?

A hidden, often sealed cavity built into a bag (false bottom, double wall, or lining) used to conceal contraband, weapons, or explosives from view.

What X-ray clues indicate a possible false compartment in a bag?

Unexplained dark/opaque areas, thicker-than-normal walls or bottoms, areas the beam cannot penetrate, and internal dimensions that don't match the bag's exterior size.

What is 'shielding' in the context of X-ray threat concealment?

Deliberately surrounding a threat item with dense material (lead, thick metal, stacked dense objects) to block X-ray penetration and hide what is behind it.

What should a screener do when an opaque/un-penetrable dark mass blocks the X-ray image?

Treat it as a potential deliberate shield, do not clear the bag - require a physical search or rescan at a different angle/energy since a threat may be hidden behind it.

What is 'artful concealment' in screening?

Hiding a prohibited item inside a legitimate object so it blends with normal contents - e.g., a knife inside a hollowed book or a weapon disguised as part of an electronic device.

Why are electronic devices like laptops a common concealment method, and how is it countered?

Their dense, cluttered internals can hide blades, drugs, or explosives; countered by removing large electronics for separate screening and looking for missing/altered components or anomalous masses.

How can shoes be used for artful concealment and what should screeners watch for?

Threats can be hidden in hollowed heels, soles, or layered insoles; watch for unusually thick soles, dense regions in the heel, or organic masses inconsistent with footwear.

What is 'bulk concealment' of contraband?

Hiding large quantities of an item (drugs, undeclared currency, contraband) packed densely in a bag, lining, or body of luggage to evade detection.

On X-ray, how does bulk concealed currency or drugs often appear?

As uniform, tightly-packed organic (orange) blocks or bricks with a consistent rectangular shape, often layered to look like clothing but with a dense, even mass.

What general procedure follows when an operator cannot identify an item or clear a bag on X-ray?

The bag is referred for additional screening - a physical hand search, explosive trace detection (ETD), or rescan at another angle - and is never cleared while doubt remains.

What is the threat-recognition principle behind looking for IED 'components together' rather than one item?

Individual parts (battery, wire, switch, mass) may look innocuous alone, but their combination forming a complete circuit/charge is what signals an assembled device; recognizing the relationship is key.