KCAA ATC common mistakes
KCAA ATC · Understand the traps and how to avoid them.
When asked to separate aircraft using surveillance-derived positions, the candidate treats a Mode S or ADS-B reported level as automatically equal to a verified pressure altitude and clears aircraft without confirming altimeter setting source and transition level.
Study material often presents surveillance data as a single 'position and height' feed, so candidates memorise separation minima numerically but never learn that Mode C/ADS-B level is pressure altitude referenced to QNE above the transition level and to QNH below it; they also forget that a pilot-reported level differs from a controller-displayed level when the altimeter setting is wrong.
What to do instead
For every surveillance separation question, state the source of the level (Mode C, ADS-B, pilot report), the reference datum (QNH or standard), and the transition level in force. Drill conversion between QNH-referenced and standard-pressure levels with worked examples, and practise writing the phrase 'verified level' only after confirming the datum.
The candidate applies the full radar separation minimum between two aircraft on the same route without checking whether both are within surveillance coverage and identified, and without considering whether the minimum is reduced for aircraft in the same or adjacent flight levels.
Candidates memorise a single headline figure (for example 5 NM or 10 NM) and apply it universally, missing that reduced minima depend on radar performance, position accuracy, and whether identification has been positively established and maintained.
What to do instead
Build a decision table: coverage confirmed or not, both identified or not, same level or vertical separation applied, and read the applicable minimum from that table. For each practice scenario, write one sentence justifying the chosen minimum against coverage and identification status before computing the distance.
In questions about SSR codes and Mode S, the candidate confuses the purpose of a discrete code with that of a conspicuity code, or assigns a special-purpose code (for example 7500, 7600, 7700) as a routine identification squawk.
Codes are taught as a list to memorise rather than as categories with operational meanings, so the candidate recalls the digits but not the rule that emergency codes are never assigned for identification and that conspicuity codes have defined applicability.
What to do instead
Group codes by function: emergency, radio failure, unlawful interference, conspicuity, and discrete allocation. For each practice item, first classify the operational situation, then select the code category, then the digits. Write out why a routine identification squawk must be discrete and not a special code.
When computing or applying separation in the air traffic control service domain, the candidate mixes time-based and distance-based minima, or applies a lateral minimum without first establishing that the required vertical separation has been lost.
The order of precedence (vertical before horizontal) is stated in documents but rarely practised, so under time pressure candidates jump to the horizontal figure they remember and ignore whether vertical separation still exists.
What to do instead
Adopt a fixed checklist for every separation question: establish vertical separation status, then choose lateral or longitudinal method, then state the minimum and the condition for it. Practise with scenarios where vertical separation is lost mid-flight and the candidate must state the exact moment horizontal separation must be assured.
The candidate answers wake turbulence separation questions using aircraft categories from memory without checking the weight category of the leading and following aircraft, and applies the same interval regardless of whether the following aircraft is heavier or lighter.
Wake categories are learned as labels (light, medium, heavy, super) but the intervals depend on the specific leader-follower pair, and candidates often reverse the pair or apply the leader's category to the follower.
What to do instead
For every wake turbulence item, write the leader category and the follower category explicitly before selecting an interval, and state the phase of flight (departure, arrival, crossing) because intervals differ. Use paired drills that deliberately swap leader and follower to expose reversal errors.
In SAR questions, the candidate describes the controller's role as directly tasking rescue assets, rather than describing notification, coordination, and the boundary between the ATS unit and the rescue coordination centre.
Candidates conflate the ATS responsibility to alert with the RCC responsibility to conduct the search and rescue operation, because study notes list both under 'SAR' without drawing the organisational boundary.
What to do instead
Draw a two-column diagram: ATS unit actions (detect emergency phase, declare uncertainty, alert, provide communications, plot last known position) versus RCC actions (assume responsibility, task assets, conduct search). Answer each SAR item by naming which column the action belongs to before writing the response.
The candidate cannot distinguish the emergency phases (uncertainty, alert, distress) and applies the wrong phase to a described situation, or skips the intermediate phase and jumps straight to distress.
The phases are defined by specific conditions (position uncertainty, fuel or communication concerns, imminent danger) that candidates memorise as three words without the triggering criteria, so borderline scenarios are misclassified.
What to do instead
Write the trigger criteria for each phase in your own words and test them against short scenarios: overdue position report, no communication after a specified interval, and a reported forced landing. For each, state the phase, who is notified, and what changes in the ATS response.
In aeronautical information management items, the candidate treats NOTAM and AIP amendments as interchangeable and does not state the criterion (temporary versus permanent, or short-notice versus scheduled) that determines which publication is used.
Both are 'information about the aerodrome', so candidates select by topic rather than by duration and notice period, missing that a permanent change belongs in the AIP cycle while a temporary or short-notice condition belongs in a NOTAM.
What to do instead
For each item, answer three questions first: is the change temporary or permanent, is the effective date within the AIP amendment cycle, and is the information safety-critical at short notice? Only then choose the publication. Practise with paired examples of the same change expressed as temporary and as permanent.
The candidate confuses the validity, trigger, and cancellation rules for NOTAMs, for example assuming a NOTAM remains valid until an AIP amendment is published, or that a NOTAM series can be replaced without a cancellation notice.
Validity periods and the relationship between NOTAM and AIP are administrative details that are skimmed, so candidates remember that NOTAMs are 'short notice' but not the rules for estimating duration, replacement, or cancellation.
What to do instead
Build a timeline for a sample change: origin, NOTAM issue, AIP amendment effective date, NOTAM cancellation. For each step, write who issues it, what triggers it, and what the recipient must do. Test yourself by predicting which document is in force on a given date.
The candidate answers coordination and handover questions in the ATC service domain by describing the communication act only, omitting the conditions that must be satisfied before transfer of control (identification, separation assured, and acceptance by the receiving unit).
Coordination is taught as a phraseology exercise, so candidates reproduce the words of a handover without the underlying conditions, and lose marks on items that ask what must be true before the transfer.
What to do instead
For every coordination item, list the pre-conditions in order: separation assured at the transfer point, the receiving unit has accepted, and the aircraft has been instructed as required. Then write the phraseology that matches. Practise scenarios where a condition fails and state what the transferring controller must do instead of handing over.