GCAA CAR-66 B1 Exam common mistakes
GCAA CAR-66 B1 Exam · Understand the traps and how to avoid them.
When a defect is found on a component, selecting the maintenance action from memory of a similar task rather than confirming whether the task is classified as a repair, an inspection, or a replacement under the applicable approved data, and whether it requires a specific authorisation.
Candidates study systems technically but skim the procedural classification of tasks, so they default to 'fix it' answers instead of identifying the correct category of work and who may certify it.
What to do instead
For every maintenance scenario, first classify the work (inspection, repair, replacement, modification) and ask which approval status and which certifying staff category covers it, before choosing the technical action.
Treating 'human error' and 'violation' as interchangeable, and selecting an outcome that blames the individual when the scenario describes a systemic pressure (time, tooling, documentation), or vice versa.
The distinction between error types, violations, and organisational factors is learned as vocabulary rather than as a decision rule, so the terms blur under exam pressure.
What to do instead
Practise sorting scenarios into a two-step decision: was the action intended (violation) or unintended (error), and if unintended was it a slip/lapse or a mistake? Then check whether organisational factors are the root cause.
Mixing up the roles of ICAO, the national authority, and the operator, and answering questions about who issues, approves, or accepts a document with the wrong body.
Candidates memorise document names without mapping each document to the body that produces it, so 'who does what' questions collapse.
What to do instead
Build a one-page matrix of body versus instrument (standards, recommended practices, national requirements, approvals, certificates) and test yourself by covering columns, not by re-reading.
Calculating electrical quantities with inconsistent units or ignoring whether the circuit is series or parallel before applying a formula.
Candidates reach for a familiar formula immediately instead of first drawing the circuit and stating known and unknown quantities with units.
What to do instead
For every numerical question, sketch the circuit, label each element as series or parallel, convert all values to base units, then select the formula. Check the answer's order of magnitude before committing.
Confusing semiconductor behaviour terms (forward/reverse bias, doping type, majority carrier) and applying them to the wrong device terminal.
The topic is taught descriptively, so candidates recognise terms but cannot apply them to a described circuit state.
What to do instead
Learn each device by a small table: terminal names, condition for conduction, and what blocks it. Then answer by matching the described condition to the table rather than to a remembered sentence.
Answering material and hardware questions by hardness or appearance rather than by the specified property being tested (strength, fatigue, corrosion resistance, temperature capability).
Candidates learn material names with a single adjective ('strong', 'light') and cannot discriminate between options that are all plausible.
What to do instead
For each material family, memorise the property that drives its selection and one typical aircraft application. Answer by identifying which property the question is actually asking about.
Applying a torque or fastener rule without first identifying the fastener type, thread condition, and whether the value is dry or lubricated.
Torque values are memorised as numbers, detached from the conditions that make them valid.
What to do instead
Treat every torque question as conditional: state fastener type, thread and surface condition, then the value. If the conditions in the stem differ from the memorised case, the memorised number is wrong.
Confusing the four forces and their balance across phases of flight, or attributing a change in one force to the wrong cause (for example, induced versus parasite drag at low speed).
Candidates learn definitions in isolation and do not rehearse how the balance shifts between climb, cruise, and descent.
What to do instead
For each phase of flight, write the force balance and identify which drag component dominates. Answer by locating the phase first, then the dominant effect.
Describing a system's function without tracing its flow path, so questions about what happens downstream of a failed component are answered by guesswork.
Systems are revised as component lists rather than as connected flows (hydraulic, pneumatic, fuel, electrical).
What to do instead
Draw each system as a flow diagram from source to consumer with the failure point marked, then trace the consequence forward and backward. Revise by redrawing from memory.
Mixing up engine station numbering and the relationship between pressure, temperature, and velocity through each section, leading to wrong conclusions about thrust or surge.
Station numbers are memorised as a sequence without attaching the thermodynamic change at each station.
What to do instead
Build a station-by-station table (pressure, temperature, velocity trend) and answer engine questions by locating the station and reading the trend, not by recalling a phrase.