DGCA Instrumentation Question Bank: 265 Free Questions

265 DGCA CPL Instrumentation practice questions with the correct answer marked and an explanation where one has been written. Free, no sign-up needed. Pressure instruments, gyroscopic instruments, compasses, air data and flight-instrument systems.

Study Instrumentation chaptersTimed Navigation mock paper

The real DGCA Navigation paper

100 questions in 3 hours. Pass mark 70%, assessed per paper, with no negative marking. Instrumentation is one of the three subjects pooled into the single DGCA Navigation paper, together with Air Navigation and Radio Navigation.

Rehearse it under the clock in the free DGCA mock test, or read the full exam pattern guide.

Instrumentation questions by chapter

Each link opens that chapter's own question set, with the number of questions in it.

Want the theory first? Every chapter also has notes on the Instrumentation subject page, and you can search all questions in the full question bank.

Sample Instrumentation questions

A few questions from the bank, with the answer and explanation under each.

1. Deviation due to coefficient A is mainly caused by:

  1. Hard iron force acting along the longitudinal axis
  2. Hard and soft iron forces acting along the lateral axis
  3. Vertical soft iron forces
  4. A misaligned lubber line
Show answer

Correct answer: D. A misaligned lubber line

Coefficient A represents a constant deviation on all headings, and is mainly caused by a mechanical misalignment of the lubber line relative to the fore-aft axis of the aircraft. It is corrected by rotating the compass body.

2. Cruising at FL390, M 0.84 is found to give a TAS of 499 kt. The ISA deviation at this level will be:

  1. −17
  2. +17
  3. +19
  4. −19
Show answer

Correct answer: B. +17

LSS = TAS/MN = 499/0.84 = 594 kt. √T = 594/38.95 = 15.25 → T = 15.25² = 232.6K = −40.4°C ≈ −40°C. FL390 is above the ISA tropopause (ISA temp = −56.5°C). Deviation = actual − ISA = −40 − (−56.5) = +16.5 ≈ +17 . See Section 12 . — Process: TAS/MN → LSS → (LSS/38.95)² → T(K) → T(°C) → compare with ISA. Practice this sequence until automatic.

3. When an adjustable aircraft datum is fitted to an artificial horizon in light aircraft:

  1. it should be checked at regular intervals
  2. it should be set to the central position and left there
  3. it should be rendered inoperative
  4. it should be set to 15°
Show answer

Correct answer: B. it should be set to the central position and left there

In light aircraft, AIC 14/1969 strongly recommends that the datum be set before flight and thereafter left alone. For aircraft over 6,000 lb MTOW, EASA requires it be rendered inoperative. Note: option (c) applies to heavier aircraft. See Section 14 . — The question specifically says "light aircraft." For heavy aircraft (>6,000 lb), render inoperative. For light aircraft — set before flight, leave it alone.

4. FANS A operates over which network and is it operated by whom?

  1. ATN, operated by SITA
  2. ACARS network, operated by ARINC
  3. SATCOM network, operated by INMARSAT
  4. VHF Data Link Mode 2, operated by Eurocontrol
Show answer

Correct answer: B. ACARS network, operated by ARINC

FANS A is designed for oceanic and remote airspace and is transmitted over the ACARS network operated by ARINC (USA). FANS B uses the ATN operated by SITA. See Section 8 and Section 9 . — FANS A = ARINC/ACARS/Oceanic. FANS B = SITA/ATN/Continental. This distinction is a classic exam question.

5. The GPWS the alert/warning information is provided by a radio altimeter with:

  1. A downward transmitting beam 60° and 30° (fore/aft and athwartship)
  2. A downward transmitting beam 30° and 60° (fore/aft and athwartship)
  3. A forward transmitting beam
  4. A downwards transmitting radio beam
Show answer

Correct answer: D. A downwards transmitting radio beam

The GPWS takes height above terrain from the radio altimeter, which transmits a radio beam downwards. The beam widths sometimes quoted describe the antenna pattern; the answer asked for is simply a downward-transmitting beam.

Quick answers

How many Instrumentation questions are in the Ghost Aviator question bank?

The Instrumentation bank currently holds 265 questions. Each has one marked correct answer, and an explanation where one has been written. They are split across 37 chapter question pages so you can practise one topic at a time.

Is the Instrumentation question bank free?

Yes. The questions, answers and explanations are free to read and practise, and you do not need to sign up. Signing in only adds saved progress and attempt history on your dashboard.

What is the DGCA Navigation paper format?

The DGCA Navigation paper is 100 questions in 3 hours, passed at 70%, with no negative marking. Instrumentation is one of the three subjects pooled into the single DGCA Navigation paper, together with Air Navigation and Radio Navigation.

How do you know the answers are correct?

Every answer is checked against an authoritative reference, such as a standard ATPL textbook, an ICAO Annex or the relevant DGCA regulation, before it is published. Anything that cannot be verified is flagged or removed rather than guessed.

How answers are verified · All DGCA exam questions

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