GCAA CAR-66 B2 Exam common mistakes
GCAA CAR-66 B2 Exam · Understand the traps and how to avoid them.
Confusing the order of magnitude prefixes (mega, kilo, milli, micro) when converting units, e.g. writing 1 MHz as 1000 Hz or dropping a factor of 1000 in a multi-step conversion.
Candidates memorise the prefix names but not the powers of ten, and under time pressure they apply the wrong exponent or lose track of the sign of the exponent.
What to do instead
Write every conversion as an explicit power-of-ten multiplication (e.g. 1 MHz = 1 × 10^6 Hz) and carry the exponent through each step rather than doing it mentally; practise mixed-prefix conversions until the table is automatic.
Using the wrong sign convention or direction for vectors and forces, such as treating a deceleration as a negative acceleration inconsistently, or resolving a force into components with sine and cosine swapped.
Candidates apply formulas by rote without sketching the geometry, so they pick the wrong trigonometric ratio for the angle given.
What to do instead
Always draw a free-body or vector diagram, label the angle relative to the axis, and confirm which component is adjacent (cosine) and which is opposite (sine) before substituting numbers.
Misapplying Ohm's law and series/parallel rules, for example adding parallel resistances directly or assuming current is the same through parallel branches.
Candidates conflate the series and parallel rules and do not check the physical meaning of the answer.
What to do instead
State the rule aloud before calculating (parallel: reciprocal sum; series: direct sum) and sanity-check the result - total parallel resistance must be less than the smallest branch, and total series resistance must exceed the largest.
Mixing up the characteristics and operating regions of bipolar transistors and FETs, e.g. stating that a bipolar transistor is voltage-controlled or that a FET draws significant gate current.
Symbols and terminal names look similar, and candidates learn the devices superficially without a mental model of the control mechanism.
What to do instead
Build a comparison table (control variable, terminals, typical input impedance, saturation/cut-off conditions) and recall the physical mechanism - base current controls collector current; gate voltage controls channel.
Treating analogue and digital representations as interchangeable, e.g. claiming a higher sampling rate increases the number of quantisation levels, or confusing resolution with sampling frequency.
Candidates memorise definitions of sampling and quantisation separately but never link them to the same conversion process.
What to do instead
Sketch the ADC chain (sample → quantise → encode) and label which parameter controls which error: sampling rate controls bandwidth/aliasing, bit depth controls quantisation step size.
Confusing heat treatment processes and their effects, such as swapping the purposes of annealing, normalising, hardening and tempering, or misidentifying which materials respond to precipitation hardening.
Process names are learned as a list without the underlying microstructural change, so similar-sounding treatments blur together.
What to do instead
Link each process to its purpose and cooling method (annealing: soften, slow cool; normalising: refine grain, air cool; hardening: martensite, rapid quench; tempering: reduce brittleness after hardening) and note which apply to aluminium alloys.
Quoting torque values or fastener practices from memory without the correct units or the correct source, e.g. mixing lbf·in and N·m or ignoring the difference between torque and friction drag torque.
Candidates recall a number but not the associated unit or standard, and unit conversion errors go unchecked.
What to do instead
Always write the unit with the number and convert explicitly; when a question specifies a standard or manual, answer from that source rather than from memory, and check that the magnitude is physically sensible.
Reversing the relationship between angle of attack, lift and stall, e.g. saying lift increases with angle of attack up to and beyond the stall, or that a heavier aircraft stalls at a higher angle of attack.
The lift curve is remembered as a straight line without the critical angle, and candidates confuse stall angle with stall speed.
What to do instead
Memorise the lift curve shape with the critical angle marked: lift rises to CLmax at the critical angle then falls; weight changes stall speed, not the stall angle (for a given configuration).
Ignoring the influence of the pressurisation and environmental factors on human performance, e.g. attributing hypoxia symptoms to fatigue, or underestimating time of useful consciousness at altitude.
Symptoms are non-specific and candidates learn them as a list rather than as a recognisable pattern that must be acted on quickly.
What to do instead
Learn the hypoxia symptom cluster and the time-of-useful-consciousness table by altitude, and practise scenario questions that require identifying the onset before incapacitation.
Confusing the roles and applicability of the various continuing airworthiness and maintenance regulations, e.g. mixing Part-66 licence categories with Part-145 organisation approvals or misstating certification privileges.
The regulatory structure is learned as isolated facts without the relationships between the parts.
What to do instead
Draw a simple map of who does what (Part-66: individual licence; Part-145: maintenance organisation; Part-M/CAMO: continuing airworthiness management) and for each, note the privileges and limits; test yourself by classifying scenarios into the correct part.