How does a VSI work?
Static pressure enters the capsule directly and the case through a calibrated leak. The pressure difference shows the rate.
- Lag of 6–9 s
- IVSI uses accelerometer pistons to cut the lag
- Reads zero if the static source blocks
DGCA Technical General · 32 questions
Vertical Speed Indicators (VSI): DGCA Technical General Questions and Answers
32 practice questions on Vertical Speed Indicators (VSI) with answers and explanations, plus the key concepts and formulas, from the TrueHeading question bank.
About this topic
Use this page to revise Vertical Speed Indicators (VSI) for the DGCA Technical General paper. Below are the key ideas first, then 12 practice questions with answers and explanations, picked from the 32 questions in the TrueHeading bank for this topic.
In short: Static pressure enters the capsule directly and the case through a calibrated leak. The pressure difference shows the rate.
Open the full set in the student zone to answer every question, track your accuracy and take timed mock tests.
Key concepts: Vertical Speed Indicators (VSI)
1 ideas to know cold.
Practice questions: Vertical Speed Indicators (VSI)
Tap “Show answer” after you have tried each one.
Q1The rate of descent needed to hold a 3° flight path at a groundspeed of 80 kt is approximately (ft/min):
- 250
- 420
- 720
- 850
Show answer
Answer: B. 420
ROD ≈ GS × 5.3 for 3° (101.3 × GS × tan 3°).
Q2The rate of descent needed to hold a 3° flight path at a groundspeed of 90 kt is approximately (ft/min):
- 810
- 480
- 960
- 290
Show answer
Answer: B. 480
ROD ≈ GS × 5.3 for 3° (101.3 × GS × tan 3°).
Q3The rate of descent needed to hold a 3° flight path at a groundspeed of 120 kt is approximately (ft/min):
- 380
- 1080
- 640
- 1270
Show answer
Answer: C. 640
ROD ≈ GS × 5.3 for 3° (101.3 × GS × tan 3°).
Q4The rate of descent needed to hold a 3° flight path at a groundspeed of 140 kt is approximately (ft/min):
- 1260
- 740
- 450
- 1490
Show answer
Answer: B. 740
ROD ≈ GS × 5.3 for 3° (101.3 × GS × tan 3°).
Q5The rate of descent needed to hold a 3° flight path at a groundspeed of 180 kt is approximately (ft/min):
- 1910
- 570
- 1620
- 960
Show answer
Answer: D. 960
ROD ≈ GS × 5.3 for 3° (101.3 × GS × tan 3°).
Q6The VSI shows a steady 500 ft/min descent for 4 minutes. The height lost is:
- 2 500 ft
- 1 000 ft
- 4 000 ft
- 2 000 ft
Show answer
Answer: D. 2 000 ft
Height change = rate × time.
Q7The VSI shows a steady 1000 ft/min descent for 2 minutes. The height lost is:
- 1 000 ft
- 4 000 ft
- 2 000 ft
- 3 000 ft
Show answer
Answer: C. 2 000 ft
Height change = rate × time.
Q8The VSI shows a steady 2000 ft/min descent for 3 minutes. The height lost is:
- 3 000 ft
- 6 000 ft
- 8 000 ft
- 12 000 ft
Show answer
Answer: B. 6 000 ft
Height change = rate × time.
Q9The VSI shows a steady 800 ft/min descent for 5 minutes. The height lost is:
- 8 000 ft
- 4 800 ft
- 4 000 ft
- 2 000 ft
Show answer
Answer: C. 4 000 ft
Height change = rate × time.
Q10In a conventional VSI the delay between pressure inside the capsule and in the case is created by:
- a calibrated metering unit (choke)
- a bimetallic strip
- a gyroscope
- a compass card
Show answer
Answer: A. a calibrated metering unit (choke)
The case pressure lags behind the capsule.
Q11The VSI lag is typically about:
- 5 minutes
- 0.5 seconds
- 60 seconds
- 6 to 9 seconds
Show answer
Answer: D. 6 to 9 seconds
Therefore the indication should be treated carefully in manoeuvres.
Q12The VSI will give a false reading in a:
- taxi
- steady turn at constant rate only
- steady cruise
- sudden pitch change or turbulence (pitch-induced error)
Show answer
Answer: D. sudden pitch change or turbulence (pitch-induced error)
The change of attitude disturbs the static source.
More DGCA Technical General topics
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