ANAC CEL Theoretical Exam (Airframe Group) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Rivet pitch rule

Rivet pitch is the center-to-center distance between rivets, typically 3D to 4D for single-row joints, where D is the rivet shank diameter.

Edge distance

Edge distance is the distance from the rivet hole center to the edge of the sheet, normally at least 2D to prevent tear-out under load.

Bend allowance

Bend allowance is the length of the neutral axis in a bend, calculated as bend angle in radians times the sum of inside radius and K times thickness.

Setback formula

Setback equals (radius plus thickness) times the tangent of half the bend angle, measured from the mold point to the bend line.

Alclad protection

Alclad is a thin layer of pure aluminum bonded to a stronger aluminum alloy core, providing sacrificial corrosion protection to the core.

Galvanic corrosion

Galvanic corrosion occurs when two dissimilar metals contact in an electrolyte; the more anodic metal corrodes while the cathodic metal is protected.

Intergranular corrosion

Intergranular corrosion attacks along grain boundaries, often in 2024 and 7075 alloys, causing loss of strength without visible surface evidence.

AN bolt dash number

The dash number after an AN bolt size indicates grip length in eighths of an inch, so a dash 5 bolt has a grip of five-eighths inch.

Torque and lubrication

Lubricated threads reach the same clamp load at lower torque than dry threads, so applying lubricant without adjusting torque can overstress the fastener.

Anodizing

Anodizing builds a controlled oxide layer on aluminum for corrosion resistance and paint adhesion; the finish is non-conductive, so bonding points must be masked.

Pitot-static function

The pitot tube supplies total pressure and the static port supplies ambient pressure; the airspeed indicator uses the difference, while the altimeter and VSI use static pressure.

Blocked static source

A blocked static source causes the VSI to freeze at zero after a momentary indication, the altimeter to freeze, and the airspeed indicator to act like an altimeter.

Outflow valve

The outflow valve controls cabin pressurization by regulating the rate at which cabin air leaves the aircraft, thereby controlling cabin altitude.

Oleo strut

An oleo strut absorbs landing loads using compressed nitrogen as a spring and hydraulic fluid forced through an orifice for damping.

Ohm's law

Ohm's law states that voltage equals current times resistance, and power equals voltage times current, or current squared times resistance.

Series versus parallel

In a series circuit the current is the same through all components and voltages add; in a parallel circuit the voltage is the same and currents add.

Bonding purpose

Bonding provides a low-resistance electrical path between aircraft structures to carry return current and discharge static electricity safely.

Battery capacity

Battery capacity is rated in ampere-hours, the product of current and time; a 24 V lead-acid battery contains 12 cells of about 2.1 V each.

Wire gauge

Wire gauge uses the AWG system, in which a smaller number indicates a larger wire; 10 AWG is larger than 20 AWG.

Differential ailerons

Differential ailerons deflect the up-going aileron more than the down-going one, reducing adverse yaw during roll.

Hydraulic accumulator

A hydraulic accumulator stores pressurized fluid to supply peak demands, dampen pressure pulses, and provide emergency actuation if the pump fails.

Phosphate ester fluid

Phosphate ester hydraulic fluid, such as Skydrol, is fire resistant but attacks natural rubber seals and many paints, requiring compatible seals.

Squat switch

A squat switch senses weight on the wheels and prevents landing gear retraction on the ground while enabling gear warning logic in flight.

Trim tab function

A trim tab moves opposite the control surface to hold a trimmed condition, while an anti-servo tab moves with the surface to increase control feel.

Dye penetrant inspection

Dye penetrant inspection reveals surface-breaking defects in non-porous materials by applying penetrant, removing excess, and developing the indication.

Magnetic particle inspection

Magnetic particle inspection uses a magnetic field and iron particles to reveal surface and near-surface discontinuities in ferromagnetic materials only.

Eddy current inspection

Eddy current inspection uses induced electrical currents to detect surface and near-surface defects in conductive materials such as aluminum.

Weight and balance

Moment equals weight times arm, and center of gravity equals total moment divided by total weight; the result must lie within the CG limits.

Empty weight definition

Empty weight includes the airframe, engines, equipment, unusable fuel, and full oil; useful load is maximum takeoff weight minus empty weight.

ANAC role

ANAC is the Brazilian civil aviation authority that regulates civil aviation, issues certificates and licenses, and enforces the RBAC regulations.

RBAC 145

RBAC 145 is the Brazilian regulation governing maintenance organizations, requiring an approved quality system and qualified personnel.

Dirty Dozen

The Dirty Dozen human factors include fatigue, complacency, lack of communication, distraction, lack of resources, pressure, and lack of teamwork.