DGCA Meteorology: Atmospheric Pressure & Altimetry Questions
153 exam-style Atmospheric Pressure & Altimetry questions for the DGCA Meteorologypaper (CPL & ATPL). The first 12 are free below with answers and explanations — sign up free to practise all of them with progress tracking.
- Q1
Flying from Low to High an altimeter would read
- AOver
- BUnder
- Cconstant
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Correct answer: B. Under
Flying from low pressure toward high pressure without resetting, the real pressure levels rise, so the aircraft is carried higher than indicated and the altimeter under-reads the true altitude.
- Q2
When a cold front passes in front of an aircraft on the ground, the altimeter will:
- AShow more altitude
- BShow low altitude
- CRemain unchanged
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Correct answer: B. Show low altitude
Cold front hikes up pressure, so the altimeter reads lower than your actual height.
- Q3
An aerodrome is at the mean sea level. Its QNH is 1014.0 hPa. Its QFF will be
- A1014.0 hPa
- B1013.25
- CDifficult to tell
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Correct answer: A. 1014.0 hPa
QFF is the pressure reduced to mean sea level using actual atmospheric conditions, while QNH uses the standard atmosphere; for an aerodrome situated at mean sea level no reduction is needed, so QFF equals QNH, here 1014.0 hPa.
- Q4
Which constant pressure altitude chart is standard for a 18289 FT pressure level (FL 180) ?
- A300 hPa
- B500 hPa
- C200 hPa
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Correct answer: B. 500 hPa
The 500 hPa constant-pressure chart corresponds to a standard pressure altitude of about 18,289 ft, i.e. approximately FL180; 300 hPa lies near 30,000 ft and 200 hPa near 39,000 ft.
- Q5
Diurnal variation of pressure occurs at intervals of:
- A12 hours
- BBoth 12 and 24 hours
- C24 hours
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Correct answer: B. Both 12 and 24 hours
Pressure shifts twice a day from solar tides and also over a 24-hour cycle.
- Q6
After landing at an aerodrome (QNH 993 hPa) it is noticed that the altimeter is still set to 1013,2 hPa and that it reads 1200 feet. What is the elevation of the aerodrome above mean sea level ?
- A1200 feet.
- B660 feet.
- C1740 feet
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Correct answer: B. 660 feet.
With 1013.2 hPa set the altimeter shows pressure altitude, 1200 ft. QNH is 993 hPa, about 20 hPa lower, equivalent to roughly 540 ft at 27 ft per hPa, so the true elevation is about 1200 minus 540, approximately 660 ft.
- Q7
An altimeter measures:
- AGPS height
- BVertical distance from the datum set on its subscale
- CTrue altitude
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Correct answer: B. Vertical distance from the datum set on its subscale
Altimeters show height based on the pressure setting you dial in.
- Q8
After landing at an aerodrome (QNH 993 hPa) it is noticed that the altimeter is still set to 1013,2 hPa and that it reads 1200 feet. What is the elevation of the aerodrome above mean sea level ?
- A1740 feet
- B2280 feet
- C660 feet.
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Correct answer: C. 660 feet.
D iffernce in pressure 1013-993= 20 1hpa = 27 feet 20hpa=540 feet with pressure setting 1013 altimetre measures elevation from a pressure level below 993 hence setting 993 will give lesser altitude 1200-540=660 feet
- Q9
An increase of 1000 ft at msl is associated with decrease of pressure of
- A100 hPa
- B33 hPa
- C3 hPa
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Correct answer: B. 33 hPa
Near mean sea level, pressure falls at roughly 1 hPa per 30 ft, so an increase of 1000 ft corresponds to a decrease of approximately 33 hPa.
- Q10
850 hPa in ISA approximately corresponds to the height
- A7,000 ft
- B5,000 ft
- C10,000 ft
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Correct answer: B. 5,000 ft
In the standard atmosphere the 850 hPa pressure level lies at about 5,000 ft (roughly 1,500 m); 700 hPa corresponds to about 10,000 ft.
- Q11
The relationship between height and pressure is made use in construction of
- AAltimeter
- BASI
- CS I
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Correct answer: A. Altimeter
With increase in height pressure reduces , this relation is used to determine the altitude of an aircraft using altimeter
- Q12
MSA given as 12,000 ft, flying over mountains in temperatures +9°C, QNH set as 1023 (obtained from a nearby airfield. What will the true altitude be when 12,000 ft is reached?
- A11,940
- B11,148
- C12,210
- D12,864
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Correct answer: D. 12,864
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