Avielevate / DGCA CPL papers / Aviation Meteorology / Pressure and Altimetry
Pressure and Altimetry — DGCA CPL Aviation Meteorology
Chapter 02 of the Aviation Meteorology paper. 97 practice questions in the Avielevate bank, every one with its answer key, filterable into a timed set on this chapter alone.
What this chapter covers
The learning objectives we file Pressure and Altimetry questions under, and how many sit behind each. These come straight out of the bank and are regenerated whenever it changes — they are what is there today, not a claim.
| Learning objective | In the bank |
|---|
| 0302 Atmospheric Pressure & Pressure Datums | 19 questions |
| 0303 Air Density | 9 questions |
| 0304 Pressure Systems & Altimeter Setting Calculations (QNH/QFE/QFF) | 28 questions |
| 0309 Altimetry – Pressure & Temperature Effects on Altitude | 41 questions |
Sample Pressure and Altimetry questions, answered and explained
Real questions from this chapter, with the answer marked and the reasoning written out — the same explanations you get inside the app.
030048 · Pressure and Altimetry
If air is diverging at upper levels, what would you expect at the surface?
- ARising pressure with clearing skies
- BRising pressure with cloud forming
- CFalling pressure with clearing skies
- DFalling pressure with cloud forming
Why that is the answer
Divergence in the upper atmosphere means air is being carried away faster than it arrives, so mass is removed from the top of the column above that point. Removing mass aloft reduces the weight of the overlying air, so surface pressure FALLS. To replace the departing air, the atmosphere responds with rising motion beneath the divergence, so surface air ascends and converges into the developing low. Ascending air cools adiabatically toward its dew point, so cloud FORMS and weather deteriorates. This upper-divergence-over-surface-convergence coupling is the classic mechanism for surface low deepening. Options a and b are wrong because they predict a pressure rise, which requires upper convergence, not divergence. Option c correctly gives falling pressure but wrongly has cloud dissipating; rising air makes cloud, not clears it. The answer is d, fall in pressure with cloud forming.
- Upper divergence removes mass from the column
- Less mass overhead means surface pressure falls
- Rising air replaces the departing air
- Ascending air cools, forming cloud
- Answer is d, fall in pressure with cloud forming
030306 · Pressure and Altimetry
If the air mass you are flying through is warmer than the ISA standard, what would you expect?
- ATrue altitude equal to indicated altitude
- BTrue altitude below indicated altitude
- CTrue altitude decreasing
- DTrue altitude above indicated altitude
Why that is the answer
An altimeter is calibrated against the International Standard Atmosphere, which assumes a fixed temperature (15°C at MSL) and lapse rate (about 1.98°C/1000 ft up to the tropopause). When the actual atmosphere is warmer than this ISA assumption, the air is less dense, so any given pressure level physically occurs HIGHER above the surface than it would under standard conditions. Because the altimeter converts sensed pressure to an indicated altitude using the standard, colder assumption, it under-reads relative to where the aircraft truly is: the true altitude is higher than the indicated altitude. This is the safe side of the 'hot to cold, look out below' mnemonic — flying in warm air means you have more real terrain clearance than the altimeter suggests, not less. (The converse, colder-than-ISA air, causes the dangerous case where true altitude is lower than indicated.) None of the other options correctly describe this relationship: true and indicated are not simply equal, nor does true altitude decrease or become lower than indicated when the air is warmer than ISA. Therefore option d is correct.
- Altimeters assume ISA temperature (15°C MSL, ~1.98°C/1000 ft lapse) when converting pressure to altitude.
- Warmer-than-ISA air is less dense, so a given pressure level sits physically higher than under standard conditions.
- The altimeter, using the colder standard assumption, under-reads relative to the aircraft's true position.
- Therefore true altitude is higher than indicated altitude when flying in air warmer than ISA.
- Correct answer: d — true altitude will be higher than indicated altitude.
030371 · Pressure and Altimetry
En route from Marseilles to Palma you notice true altitude climbing, even though QNH is identical at both locations. What might explain this?
- ARecheck the QNH value
- BRecheck the radio altimeter
- CThe air over Palma is warmer
- DPalma's elevation is lower than Marseilles's
Why that is the answer
An altimeter is a pressure instrument: it measures the height of a fixed pressure level (the QNH datum, 1013.25 hPa reduced to MSL locally) and displays it as altitude assuming the ISA standard atmosphere below the aircraft. In reality, pressure levels are further apart in height in warm air than in cold air, because warm air is less dense and expands vertically (a taller, less dense column) while cold, dense air compresses the same pressure levels closer together. If the QNH at both Marseilles and Palma is identical, the sea-level reference is unchanged, so any change in TRUE altitude (the aircraft's real height above MSL, as would be shown by GPS or a radio/radar altimeter over flat terrain) at a constant indicated/pressure altitude must be due to a change in the temperature of the air mass being overflown. An increasing true altitude with unchanged QNH and constant indicated altitude means the air below the aircraft has become warmer, causing the isobaric (pressure) surfaces to bulge upward — the aircraft, which rides on a constant pressure surface, is physically higher even though the altimeter reading (referenced to that pressure surface) has not changed. Options a and b (recheck QNH/radio altimeter) wrongly assume instrument error rather than a real atmospheric effect, and option d is contradicted by identical QNH values, which already accounts for elevation differences. The correct answer is c.
- Altimeter reads height of a pressure surface, calibrated to ISA
- QNH unchanged at both stations, so the sea-level pressure reference is identical
- True altitude rising means the pressure surface the aircraft rides on has physically risen
- Warm air is less dense/expands vertically, pushing pressure levels higher
- Therefore Palma's air mass is warmer than Marseilles' → answer c
Free while we are testing
Avielevate is in an open testing period — nobody is being charged. Create an account, fill in
the short form on the pricing page, and we switch on three months of full access: the whole
bank, timed mock exams, explanations and weak-topic analytics.
Avielevate is a preparation tool. Always study alongside the official DGCA
publications and the approved reference material for your course.
Frequently asked
How many Pressure and Altimetry questions are there for the DGCA CPL Aviation Meteorology paper?
Avielevate's bank carries 97 published Pressure and Altimetry questions for Aviation Meteorology, mapped across 4 learning objectives. Every one has its answer key, and explanations are being written across the whole bank.
How much of the Aviation Meteorology paper is Pressure and Altimetry?
The DGCA does not publish a per-chapter breakdown of its papers, so nobody can honestly tell you — and we will not guess. What we can tell you is what students who have just sat a paper reported meeting, which is measured rather than rumoured: that is the exam recall report inside the app.
What is the best way to revise Pressure and Altimetry?
Sit a short timed set on this chapter alone, tag how sure you were of each answer, then drill the two that actually leak marks: the ones you got right while guessing, and the ones you got wrong while confident. Avielevate does that tagging for you and puts anything you got wrong back in front of you on a spaced schedule.
The rest of the Aviation Meteorology paper
One account covers every chapter of every paper.
← All Aviation Meteorology chapters · All six DGCA CPL papers