Ente Nazionale per l’Aviazione
Civile Part-66 Basic Knowledge
Examination – Module 14:
Propulsion Exam
,Ente Nazionale per l’Aviazione Civile Part-66 Basic Knowledge Examination – Module 14: Propulsion Exam
Question 1
Which description best matches “Modular construction concepts”?
A. Low-bypass and high-bypass configurations, fan ducting, and bypass ratio mechanics
B. Reduction gearboxes, shaft power extraction, and combined jet/propeller thrust
C. Design, airflow path, core components, and operation
D. Major assembly breakdown, interchangeability, and field replacement guidelines
Correct Answer: D
Full Explanation: The relevant association for Modular construction concepts is major assembly
breakdown, interchangeability, and field replacement guidelines. This identifies the content of the
named concept rather than substituting the description of another concept. The alternatives describe
different associations.
Question 2
A stated case rule makes satisfactory “Temperature Indication Systems” necessary, but
not sufficient, for accepting “Fluid, Torque, and Mechanical Indication”. The necessary
condition is satisfied. What follows?
A. Acceptance is established because every necessary condition is also sufficient on its own.
B. One required condition is met, but acceptance still depends on the remaining conditions.
C. Acceptance is impossible because a necessary condition has now been satisfied.
D. The rule becomes irrelevant once evidence of the necessary condition is available.
Correct Answer: B
Full Explanation: A necessary condition must be met, but meeting it does not establish every
requirement. The phrase 'not sufficient' explicitly rules out automatic acceptance. The remaining
conditions must therefore be evaluated before a final decision is made.
Question 3
An earlier evaluation of “igniter plugs (surface-gap and constrained-gap plugs)” was
valid only under a stated condition involving “ignition activation”. That condition has now
changed. How should the earlier conclusion be treated?
A. Carry it over unchanged because the name of the evaluated topic is unchanged.
B. Treat the previous evaluation as proof that every later condition has already been examined.
C. Reverse the conclusion automatically, without considering the nature of the condition change.
D. Reassess its applicability under the new condition rather than carry it over automatically.
Correct Answer: D
Full Explanation: The earlier conclusion was conditional. Changing the condition can affect its
applicability, but does not by itself prove the opposite conclusion. A fresh comparison with the
conditions of validity is needed before the previous result is reused.
2902 Page 2
,Ente Nazionale per l’Aviazione Civile Part-66 Basic Knowledge Examination – Module 14: Propulsion Exam
Question 4
A case involving “Thermocouple principles” requires a result that distinguishes two
stated possibilities about “Engine Speed Measurement”. Which observation is insufficient
for making that distinction?
A. An observation that directly contradicts a necessary prediction of one of the two possibilities.
B. An observation predicted by one possibility and excluded by the other under the stated conditions.
C. An observation that both possibilities predict equally under the stated conditions.
D. An observation obtained by a valid check specifically separating the two competing predictions.
Correct Answer: C
Full Explanation: An outcome compatible with both possibilities does not discriminate between them.
By contrast, a valid observation that separates their predictions can help resolve the distinction. The
usefulness of evidence depends on its relationship to the competing possibilities.
Question 5
A case review treats “Turbojet engines: Design, airflow path, core components, and
operation” and “airflow path” as separate requirements. The first is confirmed; the
second has no recorded result. What conclusion is justified?
A. Both requirements are confirmed because they belong to the same review.
B. Neither requirement can be confirmed because one result is still missing.
C. The second requirement has failed because no result was recorded.
D. Only the first requirement is confirmed; the other still needs evidence.
Correct Answer: D
Full Explanation: Separate requirements need their own supporting results. A confirmed first result
does not establish the second, while a missing result is not itself a failure. The conclusion must preserve
the distinction between confirmed and unknown.
Question 6
A claim about “Gas laws, thermodynamics principles, heat transfer, and Bernoulli's
theorem in gas flow paths” is intended to hold across several conditions involving
“thermodynamics principles”. All existing observations come from only one of those
conditions. Which evidence would most strengthen the broader claim?
A. Relevant observations from the additional conditions to which the claim is being extended.
B. More copies of the existing observations, all still limited to the same condition.
C. A broader wording of the claim without extending the range of observations.
D. A list of the unexamined conditions that assumes their outcomes match the examined one.
Correct Answer: A
Full Explanation: The limitation is the range of conditions represented in the evidence. Observations
from the additional conditions address that limitation directly. Duplication or broader wording increases
neither coverage nor the basis for generalization.
2902 Page 3
, Ente Nazionale per l’Aviazione Civile Part-66 Basic Knowledge Examination – Module 14: Propulsion Exam
Question 7
A review of “Exhaust Gas Temperature (EGT) and Interstage Turbine Temperature (ITT)
systems” requires evidence for two distinct aspects of “material selection”: the stated
method and its observed result. Which submission is complete for this purpose?
A. Two descriptions of the intended method, both written before any result was observed.
B. An outcome claim with no description of how the relevant result was obtained.
C. A detailed description of the method with no record of any observed result.
D. A description of the method together with the observed result obtained by applying it.
Correct Answer: D
Full Explanation: The requirement has two parts: method and outcome evidence. Providing only one
part, even in detail or in duplicate, leaves the other unaddressed. A complete submission includes both
and connects the observed result to the method used.
Question 8
An exercise on “Stagnation thermocouples, rapid-response immersion probes, and signal
amplifiers” shows an issue only when a particular condition involving “Temperature
Indication Systems” occurs. Which follow-up best investigates that observation?
A. Examine the stated condition and compare results when it is present and absent.
B. Repeat only the condition under which the issue has never been observed.
C. Ignore the issue because it does not occur under every possible condition.
D. Assume the condition is the sole cause without making any relevant comparison.
Correct Answer: A
Full Explanation: The observation identifies a condition worth investigating, not yet a proven sole
cause. Comparing relevant conditions helps test the association and possible explanation. Avoiding the
condition or dismissing intermittent findings does not investigate the reported issue.
Question 9
In a review concerning “Pulse-type speed probes”, the stated aim is to distinguish an
observation about “Engine Pressure Ratio (EPR) measurement systems, total pressure
probes (inlet and turbine discharge)” from an assumption used to interpret it. Which note
best does so?
A. State what was observed, identify the assumption, and mark the conclusion as dependent on that
assumption.
B. Treat every assumption as verified simply because it appears in a formal report.
C. Omit the observation and state only the conclusion without identifying its dependence.
D. Present the assumption as though it had been directly observed in the same check.
Correct Answer: A
Full Explanation: The note should preserve the chain from observation through assumption to
conclusion. Making the dependence explicit enables the reader to examine it. A formal presentation
does not turn an assumption into an observed or verified fact.
2902 Page 4
Civile Part-66 Basic Knowledge
Examination – Module 14:
Propulsion Exam
,Ente Nazionale per l’Aviazione Civile Part-66 Basic Knowledge Examination – Module 14: Propulsion Exam
Question 1
Which description best matches “Modular construction concepts”?
A. Low-bypass and high-bypass configurations, fan ducting, and bypass ratio mechanics
B. Reduction gearboxes, shaft power extraction, and combined jet/propeller thrust
C. Design, airflow path, core components, and operation
D. Major assembly breakdown, interchangeability, and field replacement guidelines
Correct Answer: D
Full Explanation: The relevant association for Modular construction concepts is major assembly
breakdown, interchangeability, and field replacement guidelines. This identifies the content of the
named concept rather than substituting the description of another concept. The alternatives describe
different associations.
Question 2
A stated case rule makes satisfactory “Temperature Indication Systems” necessary, but
not sufficient, for accepting “Fluid, Torque, and Mechanical Indication”. The necessary
condition is satisfied. What follows?
A. Acceptance is established because every necessary condition is also sufficient on its own.
B. One required condition is met, but acceptance still depends on the remaining conditions.
C. Acceptance is impossible because a necessary condition has now been satisfied.
D. The rule becomes irrelevant once evidence of the necessary condition is available.
Correct Answer: B
Full Explanation: A necessary condition must be met, but meeting it does not establish every
requirement. The phrase 'not sufficient' explicitly rules out automatic acceptance. The remaining
conditions must therefore be evaluated before a final decision is made.
Question 3
An earlier evaluation of “igniter plugs (surface-gap and constrained-gap plugs)” was
valid only under a stated condition involving “ignition activation”. That condition has now
changed. How should the earlier conclusion be treated?
A. Carry it over unchanged because the name of the evaluated topic is unchanged.
B. Treat the previous evaluation as proof that every later condition has already been examined.
C. Reverse the conclusion automatically, without considering the nature of the condition change.
D. Reassess its applicability under the new condition rather than carry it over automatically.
Correct Answer: D
Full Explanation: The earlier conclusion was conditional. Changing the condition can affect its
applicability, but does not by itself prove the opposite conclusion. A fresh comparison with the
conditions of validity is needed before the previous result is reused.
2902 Page 2
,Ente Nazionale per l’Aviazione Civile Part-66 Basic Knowledge Examination – Module 14: Propulsion Exam
Question 4
A case involving “Thermocouple principles” requires a result that distinguishes two
stated possibilities about “Engine Speed Measurement”. Which observation is insufficient
for making that distinction?
A. An observation that directly contradicts a necessary prediction of one of the two possibilities.
B. An observation predicted by one possibility and excluded by the other under the stated conditions.
C. An observation that both possibilities predict equally under the stated conditions.
D. An observation obtained by a valid check specifically separating the two competing predictions.
Correct Answer: C
Full Explanation: An outcome compatible with both possibilities does not discriminate between them.
By contrast, a valid observation that separates their predictions can help resolve the distinction. The
usefulness of evidence depends on its relationship to the competing possibilities.
Question 5
A case review treats “Turbojet engines: Design, airflow path, core components, and
operation” and “airflow path” as separate requirements. The first is confirmed; the
second has no recorded result. What conclusion is justified?
A. Both requirements are confirmed because they belong to the same review.
B. Neither requirement can be confirmed because one result is still missing.
C. The second requirement has failed because no result was recorded.
D. Only the first requirement is confirmed; the other still needs evidence.
Correct Answer: D
Full Explanation: Separate requirements need their own supporting results. A confirmed first result
does not establish the second, while a missing result is not itself a failure. The conclusion must preserve
the distinction between confirmed and unknown.
Question 6
A claim about “Gas laws, thermodynamics principles, heat transfer, and Bernoulli's
theorem in gas flow paths” is intended to hold across several conditions involving
“thermodynamics principles”. All existing observations come from only one of those
conditions. Which evidence would most strengthen the broader claim?
A. Relevant observations from the additional conditions to which the claim is being extended.
B. More copies of the existing observations, all still limited to the same condition.
C. A broader wording of the claim without extending the range of observations.
D. A list of the unexamined conditions that assumes their outcomes match the examined one.
Correct Answer: A
Full Explanation: The limitation is the range of conditions represented in the evidence. Observations
from the additional conditions address that limitation directly. Duplication or broader wording increases
neither coverage nor the basis for generalization.
2902 Page 3
, Ente Nazionale per l’Aviazione Civile Part-66 Basic Knowledge Examination – Module 14: Propulsion Exam
Question 7
A review of “Exhaust Gas Temperature (EGT) and Interstage Turbine Temperature (ITT)
systems” requires evidence for two distinct aspects of “material selection”: the stated
method and its observed result. Which submission is complete for this purpose?
A. Two descriptions of the intended method, both written before any result was observed.
B. An outcome claim with no description of how the relevant result was obtained.
C. A detailed description of the method with no record of any observed result.
D. A description of the method together with the observed result obtained by applying it.
Correct Answer: D
Full Explanation: The requirement has two parts: method and outcome evidence. Providing only one
part, even in detail or in duplicate, leaves the other unaddressed. A complete submission includes both
and connects the observed result to the method used.
Question 8
An exercise on “Stagnation thermocouples, rapid-response immersion probes, and signal
amplifiers” shows an issue only when a particular condition involving “Temperature
Indication Systems” occurs. Which follow-up best investigates that observation?
A. Examine the stated condition and compare results when it is present and absent.
B. Repeat only the condition under which the issue has never been observed.
C. Ignore the issue because it does not occur under every possible condition.
D. Assume the condition is the sole cause without making any relevant comparison.
Correct Answer: A
Full Explanation: The observation identifies a condition worth investigating, not yet a proven sole
cause. Comparing relevant conditions helps test the association and possible explanation. Avoiding the
condition or dismissing intermittent findings does not investigate the reported issue.
Question 9
In a review concerning “Pulse-type speed probes”, the stated aim is to distinguish an
observation about “Engine Pressure Ratio (EPR) measurement systems, total pressure
probes (inlet and turbine discharge)” from an assumption used to interpret it. Which note
best does so?
A. State what was observed, identify the assumption, and mark the conclusion as dependent on that
assumption.
B. Treat every assumption as verified simply because it appears in a formal report.
C. Omit the observation and state only the conclusion without identifying its dependence.
D. Present the assumption as though it had been directly observed in the same check.
Correct Answer: A
Full Explanation: The note should preserve the chain from observation through assumption to
conclusion. Making the dependence explicit enables the reader to examine it. A formal presentation
does not turn an assumption into an observed or verified fact.
2902 Page 4
