DGAC Bolivia Air Traffic Controller (CTA) common mistakes
DGAC Bolivia Air Traffic Controller (CTA) · Understand the traps and how to avoid them.
When asked to classify a Bolivian airspace or ATS route, the candidate answers from generic ICAO memory (e.g., labels a control area as Class D or assigns Class F to an airway) without checking the DGAC Bolivia classification scheme and the specific lateral/vertical limits published in the national AIP.
Most study material is built from ICAO Annex 11 and foreign syllabi, so candidates memorize the seven ICAO classes abstractly and never anchor them to Bolivian designations, where the letter classes, the naming of FIR/CTA/CTR/TMA and the route designators follow national publication. Under exam pressure the generic answer feels correct.
What to do instead
Build a one-page mapping table from the Bolivian AIP (ENR sections) listing each airspace type, its class letter, vertical limits and the services provided, and recite it before every practice session. For each route or area you study, write the class, limits and controlling unit side by side, and practise converting a described scenario into the Bolivian label rather than the ICAO generic one.
Applying a single separation minimum everywhere: the candidate quotes 5 NM or 1000 ft for every pair of aircraft regardless of surveillance environment, airspace class, or whether the traffic is in a radar or procedural environment, and forgets to state the condition under which the minimum applies.
Separation minima are learned as isolated numbers rather than as a decision tree. Candidates recall the most frequently repeated figure from training and skip the qualifying conditions (surveillance coverage, controller intervention capability, aircraft category), so the answer is numerically plausible but operationally wrong.
What to do instead
Rewrite separation as conditional statements: 'In [environment], between [aircraft], the minimum is [value], provided [condition].' Drill ten scenarios where the environment changes (radar, procedural, direct controller-pilot communication absent) and require yourself to state the condition aloud before the number. Mark every minimum you cannot attach a condition to as unknown and look it up.
Using the wrong wake turbulence category or applying the wrong time/distance interval behind a heavy or a super-heavy aircraft, including failing to distinguish the leader and follower categories and forgetting that the interval changes for crossing runways or for departures behind arrivals.
Wake categories are memorized by aircraft type name rather than by maximum certificated take-off mass and the current category definitions, and interval tables are recalled as one flat list. Candidates also confuse the interval for a following departure with the interval for a following arrival on the same runway.
What to do instead
Memorize the category definitions by mass thresholds first, then attach example types to each category. Draw the interval table yourself from the regulation, with separate rows for arrival-arrival, arrival-departure and departure-departure, and for parallel runways with and without displaced thresholds. Test yourself by naming a leader type and a follower type and stating the interval plus its unit.
Producing a flight plan or flight-plan-related answer that mixes VFR and IFR requirements: for example, giving IFR alternate minima for a VFR flight, omitting the VFR visibility/cloud requirement, or accepting an IFR flight plan without the required endurance, alternate or equipment entries.
Flight rules are studied as two parallel lists and candidates blend them under time pressure, especially where the same form field (alternate aerodrome, endurance, level) appears in both. The Bolivian differences for VFR at night or in controlled airspace are also frequently skipped.
What to do instead
Create a two-column comparison sheet for every flight-plan field and for every meteorological minimum, with columns for VFR and IFR and a third column for Bolivian national differences. Practise by taking a completed flight plan and auditing it field by field against the correct column, saying out loud which rule set applies and why.
Answering meteorology questions with the general weather outcome instead of the ATC-relevant operational consequence: the candidate describes what a cumulonimbus or a wind shear event is, but does not state what the controller must do, what information must be passed, or which minima or separation change as a result.
Meteorology is revised as a physical-science subject, so answers are descriptive. The exam expects operational judgement, and candidates do not rehearse the link between a phenomenon and a controller action, so the operational half of the answer is missing.
What to do instead
For each phenomenon on the syllabus (thunderstorm, icing, wind shear, low visibility, mountain wave, turbulence), write three lines: what the pilot reports, what the controller passes, and what changes in the clearance or separation. Rehearse the phrasing of significant weather information as actual radiotelephony, not as a definition.
Giving a clearance or instruction that is not read back correctly, or answering a phraseology question with non-standard wording: the candidate uses plain-language paraphrases, omits the callsign or the readback requirement, or fails to correct an incomplete readback before the aircraft proceeds.
Candidates translate from their native phrasing into English or into standard Spanish radiotelephony and produce grammatically sensible but non-standard transmissions. Readback is treated as a formality rather than as a required verification step with a defined action when it is wrong.
What to do instead
Practise scripted exchanges aloud with a partner, and treat any deviation in the readback as a trigger to say 'negative, I say again' and re-issue. Keep a personal list of the twenty most-used standard phrases and test yourself by converting a plain-language instruction into the standard form, then back again, until the standard form is automatic.
Mixing units or reference systems: the candidate gives a level in metres when feet are required, a distance in kilometres when nautical miles are required, a QFE-based altitude when QNH is the reference, or a bearing that is magnetic in one part of the answer and true in another.
Bolivia uses metric units in some national contexts while international ATS uses feet and nautical miles, and candidates carry the metric habit into questions that expect the international convention. Unit conversion is done silently in the head and the wrong reference is never stated.
What to do instead
Adopt a habit of always writing the unit and the reference after every number in practice answers (e.g., 'FL 240', '8 000 ft AMSL', '12 NM', 'magnetic'). Do conversion drills in both directions and, for each question type, decide in advance which unit system the answer requires.
Describing aerodrome and approach control as one undifferentiated service: the candidate cannot state where tower responsibility ends and approach responsibility begins, who issues the landing clearance, who owns the missed-approach instruction, or how coordination between the two positions is effected.
The two positions are studied from the same chapter and candidates learn the services rather than the boundaries. The handover point, the transfer of control and the coordination phraseology are the parts most often omitted from study notes.
What to do instead
Draw the aerodrome as a diagram with the zones of responsibility marked, and annotate each boundary with the exact coordination action and phrase. For a complete arrival, write the sequence of clearances from first approach contact to runway vacation, naming the issuing unit for each. Repeat for a departure and for a missed approach.
Treating CNS and surveillance as equipment identification only: the candidate can name a radar or a navigation aid but cannot explain its coverage limitations, failure modes, or what the controller does when the service degrades (e.g., loss of radar, loss of communication, GNSS interference).
Systems are revised as hardware lists because the technical chapters are dense, and the contingency procedures are read once and not rehearsed. Under questioning the candidate describes the box rather than the operational consequence of losing it.
What to do instead
For each system on the syllabus, write a three-part card: what it provides, its principal limitation, and the controller's fallback when it fails. Practise stating the change in separation or procedure that follows each failure, and rehearse the contingency phraseology for loss of communication and for degraded surveillance.
Answering aircraft performance questions with a memorized type characteristic rather than with the performance implication for the controller: the candidate quotes a climb rate or a speed but does not connect it to a required climb gradient, a departure obstacle limit, or a sequencing decision.
Performance is learned from aircraft data rather than from procedure design, so the numbers are disconnected from the ATS decision they feed. Candidates also forget that published departure procedures carry a minimum climb gradient that must be checked, not assumed.
What to do instead
For each performance topic, write the controller's question it answers (can this aircraft make the departure? how much room do I need behind it? what speed will it hold on final?). Work through departure scenarios where the required gradient is stated and the aircraft's capability must be compared with it, and state the decision that follows the comparison.