ANAC CEL Theoretical Exam (Airframe Group) key terms

A mandatory instruction issued by the aviation authority requiring inspection, repair, or modification of an aircraft or component to correct an unsafe condition. Compliance is compulsory and must be recorded in maintenance records.

A document from the manufacturer recommending or describing inspections, modifications, or part replacements for a product. Unlike an airworthiness directive, an SB is advisory unless the authority mandates it.

A certification signed by authorized personnel confirming that specified maintenance has been completed and the aircraft or component is returned to service in an airworthy condition.

A dated and signed record in an aircraft or component log describing work performed, defects found, parts installed, and references to approved data used, providing traceability of maintenance history.

Technical information accepted by the aviation authority for performing maintenance, such as type certificate data sheets, manufacturer manuals, or approved engineering documents. Unapproved data may not be used for return to service.

The set of regulations issued by ANAC governing civil aviation in Brazil, covering aircraft certification, maintenance organizations, licensing, and operations. Compliance with applicable RAB requirements is legally mandatory.

The Brazilian National Civil Aviation Agency, responsible for regulating and supervising civil aviation safety, issuing airworthiness directives, certifying organizations, and licensing maintenance personnel in Brazil.

The distance between the centers of adjacent rivets in a row. Pitch influences joint strength and must follow the approved repair data; too large a pitch reduces load capacity, too small a pitch weakens the sheet.

The distance from the center of a rivet hole to the nearest edge of the sheet. Insufficient edge distance causes tear-out failure; typical minimums are expressed as a multiple of rivet diameter.

A joint formed by overlapping two sheet edges and fastening them with rivets or other hardware. It is simple to produce but creates eccentric loading and requires sealing against moisture ingress.

A fastening condition in which the fastener diameter is slightly larger than the hole, producing radial pressure that improves fatigue life and load transfer. It requires controlled hole sizing and installation force.

A two-piece threaded fastener consisting of a pin with a collapsible collar, installed with a controlled torque tool. It provides consistent clamp-up and is common in aircraft structural assemblies.

A temporary spring-loaded pin used to align and hold sheet metal parts together during drilling and riveting. It is removed after permanent fasteners are installed.

A compound applied to joints, seams, or fasteners to prevent fuel, water, or air leakage and to protect against corrosion. Proper surface preparation and cure time are essential for effectiveness.

The electrochemical deterioration of metal caused by environmental exposure and dissimilar metal contact. Common forms include surface, galvanic, pitting, and stress corrosion, each requiring specific inspection and treatment.

Corrosion accelerated when two dissimilar metals are joined in the presence of an electrolyte, causing the more active metal to deteriorate. Prevention includes isolation, sealants, and compatible material selection.

Cracking that results from the combined action of sustained tensile stress and a corrosive environment. It often appears in high-strength alloys and can propagate rapidly with little visible warning.

A non-destructive method using electromagnetic induction to detect surface and near-surface defects in conductive materials. It is widely used to find cracks and corrosion in aircraft structures.

A non-destructive test in which a colored penetrant is applied to a cleaned surface and drawn out of surface-breaking defects by a developer, revealing cracks and porosity.

A calibrated tool that applies a measured twisting force to a fastener. It must be checked regularly and used within its specified range to ensure correct fastener preload and joint integrity.

A locking method in which twisted wire is threaded through fastener heads to prevent loosening from vibration. Correct direction and tension are required for it to be effective.

A split metal pin inserted through a hole in a bolt or shaft and bent to secure a nut or component against rotation. It is a positive locking device used in many aircraft assemblies.

A system that transmits force through pressurized fluid to actuate components such as landing gear, brakes, and flight controls. It includes reservoirs, pumps, valves, accumulators, and actuators.

A pressure vessel containing fluid and a gas charge that stores hydraulic energy, dampens pressure surges, and supplies emergency pressure for limited operation after pump failure.

The liquid medium that transmits pressure in a hydraulic system. Its type, viscosity, and compatibility with seals and system materials must match the aircraft manufacturer's specification.

The sequence in which the landing gear is folded into the aircraft structure after takeoff, usually powered hydraulically or electrically and secured by uplocks with position indications to the flight deck.

A mechanical device that holds landing gear in the extended position, often with an over-center linkage or pin, preventing collapse under landing loads. It is verified by cockpit and visual indicators.

A movable aerodynamic surface such as an aileron, elevator, rudder, or flap that changes the lift or moment on the aircraft. Each surface is connected to cockpit controls by mechanical or hydraulic linkages.

The measured tightness of a flight control cable, set with a tensiometer according to approved data. Incorrect tension can cause flutter, excessive friction, or control lag.

The process of adjusting control linkages and stops so that surfaces move through the correct range and neutral position as specified in approved data.

A system of probes and ports that supplies total pressure and static pressure to flight instruments. Blockages or leaks cause erroneous airspeed, altitude, and vertical speed indications.

An opening on the aircraft exterior that senses ambient static pressure for the altimeter, airspeed indicator, and vertical speed indicator. It must be kept clear and leak-free.

The electrical conductors and connectors that carry power and signals through the aircraft. Proper routing, support, and identification are required to prevent chafing, arcing, and interference.

The electrical connection of aircraft structure and components to provide a low-resistance path for current, reducing static buildup, lightning damage, and radio interference.

A resettable protective device that opens an electrical circuit when current exceeds a set value, preventing overheating and fire. Reset procedures must follow approved maintenance data.

A structural material made of reinforcing fibers embedded in a resin matrix, offering high strength-to-weight ratio. Inspection focuses on delamination, fiber damage, and moisture ingress rather than metal corrosion.

Separation between layers of a composite laminate, often caused by impact, manufacturing defects, or moisture. It may be invisible externally and requires tap testing or ultrasonic inspection.