Altimeter setting procedures
Learning objectives
- State the definitions of altitude, height, flight level, transition altitude and transition level, and say which altimeter setting goes with each reference.
- Explain how a vertical position is expressed below, inside and above the transition layer, for a climb and for a descent.
- Identify when ATC or ATIS passes the transition level and the altimeter setting, which of these items you must read back, and the phraseology for levels and settings.
- Calculate the true clearance when an altimeter shows a level but the wrong subscale setting is set.
The idea
An altimeter does not measure height. It measures air pressure and turns it into a number, and the number you get depends on the reference you dial into it. Near the ground you want a reference that tells you where you are relative to terrain, so you use the local one. High up, what matters is that every aircraft uses the same reference, so nobody has to keep updating it. Somewhere in between, everyone has to switch from one reference to the other, and the rules say exactly how you describe your level during that switch. Get the reference wrong and the instrument still looks perfectly normal while the aircraft is lower than you think.
Three settings, three references
Start with the vocabulary, because the rules use each word precisely.
Altitude is the vertical distance of a level, point or object measured from mean sea level (MSL). Height is the vertical distance measured from a specified datum, for example the aerodrome. A flight level (FL) is a surface of constant atmospheric pressure related to the pressure datum 1013.2 hPa, separated from other such surfaces by specific pressure intervals. "Level" is the generic word that covers all three: height, altitude or flight level. A cruising level is a level you hold for a significant part of a flight.
Which one the altimeter shows depends on the subscale, the small window where you set a pressure. With an altimeter calibrated to the Standard Atmosphere:
- set to QNH, it indicates altitude, above MSL;
- set to QFE, it indicates height above the QFE reference datum, in practice the aerodrome;
- set to 1013.2 hPa, it can be used to indicate flight levels.
The guidance adds that "altitude" and "height" here are altimetric values, read from pressure, not geometric ones measured with a tape.
Describe this figure
The figure shows one aeroplane in level flight, with three vertical arrows running down from it, each carrying a small altimeter face. The left arrow is the longest and ends at mean sea level; it is labelled QNH, altitude above MSL. The middle arrow ends at the aerodrome, which sits on raised ground, and is labelled QFE, height above the aerodrome. The right arrow is the shortest and ends at a dashed line labelled the standard pressure surface; it is labelled 1013.2 hPa, flight level.
The figure shows one aeroplane in flight with three vertical arrows running down from it. The first arrow ends at mean sea level and is labelled QNH, altitude. The second ends at the aerodrome and is labelled QFE, height. The third ends at the standard pressure surface and is labelled 1013.2 hPa, flight level. Each arrow carries a small altimeter face showing which number you read.
Why keep more than one? Near the ground you need altitude on the local QNH, so you can compare your altimeter with charted terrain and obstacle elevations. Higher up, all aircraft on the same 1013.2 hPa datum share the same pressure error, so their flight levels stay vertically separated without anyone updating a local setting. The full theory of these settings is taught in lesson 050-01-06, and this page only uses it.
QFE has a niche role. It is useful in the circuit, because it shows height above the aerodrome, but it does not help with en-route terrain. On request, or regularly under local arrangements, ATC provides a QFE.
Think of the setting as a question you are asking the altimeter. QNH asks "how high above the sea?", QFE asks "how high above this aerodrome?", and 1013.2 asks "which pressure surface am I on?". The three answers are different numbers for the same aeroplane in the same air.
Where altitudes end and flight levels begin
The two systems need a hand-over zone, and SERA defines its edges. The transition altitude (TA) is the altitude at or below which your vertical position is controlled by reference to altitudes. The transition level (TL) is the lowest flight level available for use above the transition altitude. The transition layer is the airspace between the two. SERA uses the words "transition layer" but does not define them in its list of definitions.
You do not look up a single European number for the TA. Transition altitudes and levels in force are published per State or aerodrome and given by ATIS or ATC. SERA sets no single value.
Cruising levels are expressed as flight levels for flights at or above the lowest usable flight level or, where applicable, above the transition altitude. They are expressed as altitudes for flights below the lowest usable flight level or, where applicable, at or below the transition altitude.
SERA also uses the term "lowest usable flight level" next to the transition-altitude wording, which applies "where applicable". It does not define the term, so read it plainly as the lowest flight level you may use.
Except for the QFE landing case described just below, where a transition altitude is established, vertical position is expressed as altitudes at or below the transition altitude and as flight levels at or above the transition level. Inside the transition layer it is expressed as flight levels when climbing and as altitudes when descending.
The exception is the QFE landing case. When an aircraft is cleared to land (or told at an AFIS aerodrome that the runway is available) and completes its approach using QFE, its vertical position is expressed as height above aerodrome elevation for the part of the flight where QFE may be used. Some instrument-approach details of this case are IFR-only and outside this page.
Level flight is covered by the cruising-level rule: a cruising level above the transition altitude is a flight level, so a cruise inside the layer is also expressed as a flight level.
Put that together as a story. You take off and climb on the aerodrome QNH, so your altimeter reads altitude. Once you are above the TA, your position is given as a flight level, so, to read the value you are reporting, the altimeter has to be on 1013.2 hPa. In the descent the reverse happens: you report flight levels down to the TL, then altitudes inside the layer, so, to read the value you are reporting, the altimeter has to be on QNH once you are below the TL. SERA itself does not say at which moment you turn the subscale, only what you report. Your ATO will teach you the habit that goes with your aircraft.
Describe this figure
The figure is a side view with an aerodrome at the bottom left and a dashed flight path that climbs, cruises and descends. A dotted line marks the transition altitude, and a second dotted line above it marks the transition level, which is the lowest usable flight level; the shaded band between them is the transition layer. Below the transition altitude, the climb and the final descent are altitudes on QNH, and above the transition level the cruise is flown on 1013.2 hPa. Inside the layer, a climbing aircraft uses a flight level on 1013.2 hPa and a descending one uses an altitude on QNH, shown by an up arrow and a down arrow. On the descent side, a label says that the transition level comes from ATC or ATIS.
The figure is a side view. On the left, an aerodrome sits at the ground. A climb line rises from it. Below a horizontal line marked transition altitude, the climb is labelled altitude on QNH. A shaded band above that line is the transition layer, and its upper edge is marked transition level, the lowest usable flight level. Above the band the aircraft cruises, labelled 1013.2 hPa. On the right, a descent line comes back down. It is marked with "transition level from ATC or ATIS", and below the transition level it is labelled QNH. Two small arrows inside the band say "climbing: flight level" and "descending: altitude".
Describe this figure
Without JavaScript, the figure is three stacked bands: at or above the transition level, flight levels on 1013.2 hPa; the transition layer; and at or below the transition altitude, altitudes on QNH. In the layer, a climbing aircraft reports a flight level on 1013.2 hPa and a descending one reports an altitude on QNH. With JavaScript, you enter the transition altitude, the transition level, climb, cruise or descent, and your level. The widget highlights your band and says which setting to have and whether to report an altitude or a flight level, with the reason in plain words. In level flight inside the layer it also reports a flight level on 1013.2 hPa, because a cruising level above the transition altitude is expressed as a flight level.
The interactive widget lets you type a transition altitude, a transition level, a phase (climb, cruise or descent) and your current altitude or flight level. It answers with the setting you should have (QNH or 1013.2 hPa) and how the level is reported (altitude or flight level), with the reason in plain words. It is a learning aid only, not for flight. If it does not load, use the figure above.
Classify four positions. For this exercise only, take a transition altitude of 4 000 ft and a transition level of FL 050, and take QNH as 1013 hPa for simplicity so that an altitude and a flight level carry the same number. These are invented numbers, not published values.
Given: TA 4 000 ft, TL FL 050.
Method: first ask where you are, then whether you are climbing or descending, and apply the expression rule.
Working:
- Climbing at 3 500 ft: at or below the TA, so you report an altitude, on QNH.
- Climbing at 4 500 ft: inside the transition layer and climbing, so you report a flight level, FL 045, with 1013.2 hPa set.
- Descending at FL 050: at the TL, so you report a flight level.
- Descending at 4 500 ft: inside the layer and descending, so you report an altitude, on QNH.
Answer: altitude, flight level, flight level, altitude. The same 4 500 ft is a flight level on the way up and an altitude on the way down.
"I am in the transition layer, so I always report a flight level." Wrong: the expression depends on the direction. Climbing gives a flight level, descending gives an altitude.
What this means for a VFR cruise
The semicircular cruising levels you learn in the rules of the air (lesson 010-05-03) are listed as flight level, feet and metres. For example FL 035 is also 3 500 ft or 1 050 m. Combined with the basic requirement above, a VFR cruising level is flown as an altitude on QNH when it is at or below the TA, and as a flight level on 1013.2 hPa when it is above it.
Two boundaries move with the transition altitude. Where the TA is lower than 10 000 ft (3 050 m) AMSL, FL 100 replaces 10 000 ft as the boundary in the VMC minima table (this is a "must"), and the airspace-class table says it "should" be used as well. Those subjects belong to lessons 010-05-03 and 010-07-01.
"VFR flights always fly on QNH." Not above the transition altitude, where cruising levels are flight levels on 1013.2 hPa, VFR included.
Where the numbers reach you
The setting is only useful if someone gives it to you. SERA has ATC pass it at fixed points.
ATC gives the flight crew the transition level in due time before they reach it during descent. The guidance says this can be done by voice, ATIS broadcast or data link.
Unless ATC knows you already have it from a directed transmission, a QNH setting is included in the descent clearance when you are first cleared to an altitude below the transition level, in the approach clearance or the clearance to enter the traffic circuit, and in the taxi clearance for departing aircraft.
The ATIS, where provided, carries the same information. An ATIS for arriving and departing aircraft contains, in a fixed order, the transition level (if applicable) and the altimeter setting or settings. Arrival-only and departure-only broadcasts also contain both items.
When you establish contact with approach, tower or AFIS, you acknowledge receipt of the ATIS. The ATS unit then gives you the current altimeter setting, or gives it at another time prescribed for arriving aircraft. The altimeter setting is the one ATIS item that is still passed in a directed transmission after you have acknowledged the ATIS.
Before take-off, set the aerodrome QNH from the taxi clearance or the ATIS and check that the altimeter reads close to the aerodrome elevation. A large difference means a wrong setting or an unserviceable altimeter. This guide gives no tolerance figure, so use the one your ATO or operator publishes.
En route below the transition altitude, update your QNH from ATS, ATIS or VOLMET as you fly into an area with different pressure. Update the QNH whenever you are given a new value.
Read-back
The flight crew always read back altimeter settings and transition levels, whether the controller gave them or they came from the ATIS. The same list covers the runway in use, SSR codes, new frequencies, and level, heading and speed instructions.
"Roger" is therefore not enough for a QNH. You say the number back, because that is how a misheard digit gets caught.
In an emergency descent, ATS actions may include advising the minimum flight altitude and the altimeter setting for the area.
Saying it on the radio
Standard phraseology must be used wherever it exists, and plain language only when it cannot serve.
Levels are described as "FLIGHT LEVEL (number)", "[HEIGHT] (number) FEET" or "[ALTITUDE] (number) FEET". The word ALTITUDE or HEIGHT may be added where clarification is needed, for example "DESCEND TO ALTITUDE TWO THOUSAND FEET". Pressure settings are passed as "QNH (number) [units]" or "QFE (number) [units]".
Numbers have their own rule: the altimeter setting is transmitted digit by digit, except that 1 000 hPa is said "ONE THOUSAND". So 1009 is "QNH one zero zero nine" and 993 is "QNH nine nine three". Flight levels are also digit by digit, except whole hundreds: FL 180 is "flight level one eight zero" and FL 200 is "flight level two hundred".
Two ATS phrases are worth knowing. "CHECK ALTIMETER SETTING AND CONFIRM (level)" is what ATC or a flight information service says when it suspects your setting or level is wrong. The low-altitude warning is "(call sign) LOW-ALTITUDE WARNING, CHECK YOUR ALTITUDE IMMEDIATELY, QNH IS (number) [units]", optionally followed by the minimum flight altitude.
| Situation | ATS says | Pilot reads back |
|---|---|---|
| Current setting, after you have acknowledged the ATIS | “Charlie Sierra Alfa Bravo Charlie, QNH one zero zero nine.” | “QNH one zero zero nine, Charlie Sierra Alfa Bravo Charlie.” |
| A QNH of 1 000 hPa: the one setting not said digit by digit | “Charlie Sierra Alfa Bravo Delta, QNH one thousand.” | “QNH one thousand, Charlie Sierra Alfa Bravo Delta.” |
| A QNH of 993 hPa, with a level given as an altitude | “Charlie Sierra Alfa Bravo Charlie, QNH nine nine three, descend to altitude two thousand feet.” | “QNH nine nine three, descend to altitude two thousand feet, Charlie Sierra Alfa Bravo Charlie.” |
| A level given as a flight level, digit by digit | “Charlie Sierra Alfa Bravo Echo, descend to flight level one eight zero.” | “Descend to flight level one eight zero, Charlie Sierra Alfa Bravo Echo.” |
| A level given as a flight level, whole hundred | “Charlie Sierra Alfa Bravo Echo, descend to flight level two hundred.” | “Descend to flight level two hundred, Charlie Sierra Alfa Bravo Echo.” |
| ATS doubts your setting or your level | “Charlie Sierra Alfa Bravo Delta, check altimeter setting and confirm altitude two thousand feet.” | Check the subscale, then confirm the level. This card gives no fixed wording for the reply. |
| Low-altitude warning | “Charlie Sierra Alfa Bravo Charlie, low-altitude warning, check your altitude immediately, QNH is nine nine three.” The minimum flight altitude may follow. | Check your altitude, set the QNH given and read it back: “QNH nine nine three, Charlie Sierra Alfa Bravo Charlie.” |
| All call signs are invented. A unit (hPa) may follow the number. Read-back wording and call-sign style vary: use your ATO’s instruction. Learning aid, not an operational reference. | ||
Describe this figure
The table has one row per situation and three columns: the situation, what ATS says and what the pilot reads back. The first three rows are about QNH: a current setting of one zero zero nine, a setting of one thousand, which is the one setting not said digit by digit, and a setting of nine nine three given with a descent to an altitude of two thousand feet. The next two rows give levels as flight levels, one eight zero digit by digit and two hundred as a whole hundred. The last two rows are the request to check the altimeter setting and confirm the level, and the low-altitude warning with a QNH of nine nine three. A footer says that the call signs are invented and that wording varies with the ATO.
The figure is a three-column card: situation, what ATS says, what the pilot reads back. Its rows cover an ATIS-acknowledged QNH, a QNH of 1 000 said "one thousand", a QNH of 993 said digit by digit, FL 200 against FL 180, a level given as an altitude in feet, the "check altimeter setting and confirm" call, and the low-altitude warning, each with an invented call sign.
Hear it, say it. Given: the controller says "Charlie Sierra Alfa Bravo Charlie, QNH nine nine three, descend to altitude two thousand feet."
Method: read back the setting and the level, both in standard form.
Working: the setting is 993, said digit by digit. The level is an altitude, so the word "altitude" and the unit "feet" stay in.
Answer: "QNH nine nine three, descend to altitude two thousand feet, Charlie Sierra Alfa Bravo Charlie." Check your ATO's instruction for the exact order and call-sign style you should use.
Worked examples
The first worked example, classifying four positions around the transition layer, is in the section on altitudes and flight levels above. This one shows the cost of a wrong setting.
What a wrong subscale hides. The real-world case below used these figures, and you can reproduce the arithmetic.
Given: indicated level 2 500 ft; true altitude about 1 570 ft; a mast of 1 358 ft AMSL four nautical miles away.
Method: subtract to find how much lower the aircraft was than the instrument showed, then subtract the mast elevation from the true altitude to find the real clearance.
Working:
- Error = 2 500 ft - 1 570 ft = 930 ft lower than displayed.
- Clearance above the mast = 1 570 ft - 1 358 ft = 212 ft.
Answer: the aircraft was 930 ft lower than displayed, and about 212 ft above the top of the mast. At the indicated 2 500 ft the crew would have believed they had 1 142 ft of clearance. The 930 ft comes from the AAIB report; the method for estimating such an error from the pressure difference is taught in lesson 050-01-07.
This content is educational. It does not replace ATO instruction or your aircraft's POH/AFM.
In the real world
On 24 November 2006 an Airbus A310 approaching Birmingham was cleared to 2 500 ft but still had 1013 hPa set instead of the Birmingham QNH of 982 hPa. The altimeters showed 2 500 ft, while by the AAIB's estimate the aircraft was at about 1 570 ft, some 930 ft lower. A TV mast of 1 358 ft AMSL stood 4 NM away. The radar controller saw the descent below 2 500 ft, told the crew to climb and queried the QNH, which revealed the error.
The lesson is in the numbers. With too high a setting the altimeter over-reads, so the aircraft is lower than indicated. This is exactly why a QNH is included in the descent clearance and why it is read back: each is a chance to catch the error before it matters. The case involved an airliner, but the same error is available to any pilot who forgets one step in the descent checks.
Read the full report: AAIB Bulletin 4/2007, EW/G2006/11/10, Airbus A310 F-OJHH.
AAIB Bulletin 4/2007, EW/G2006/11/10: an Airbus A310 descended on 1013 hPa instead of a QNH of 982 hPa, about 930 ft lower than displayed, near a 1 358 ft mast. A radar controller spotted it and queried the QNH.
Exam traps
"Transition level and transition altitude are the same thing." No. The TA is an altitude, the top of the altitude regime. The TL is the lowest flight level available above it. The layer between them is the transition layer.
"Once I have acknowledged the ATIS, ATC will not give me the QNH again." The altimeter setting is the exception: it is still passed in a directed transmission.
"A 'roger' is enough for a QNH." Altimeter settings and transition levels are mandatory read-back items.
"QNH 1000 is read one zero zero zero." The only setting not said digit by digit is 1 000 hPa, which is "ONE THOUSAND".
"QFE gives altitude, and a flight level is a height in hundreds of feet above the sea." QFE gives height above the aerodrome datum, QNH gives altitude, and a flight level is a pressure surface referred to 1013.2 hPa.
Explain it back
Imagine a student asks why you say "flight level" when climbing through the transition layer but "altitude" when descending through it. In your own words, tell them which setting is on the subscale at each point, what the altimeter is being asked to show, and why a wrong setting can leave you lower than the instrument says.
Self-check
-
In a State whose transition altitude is 6 000 ft and whose transition level is FL 070, you are descending through 6 500 ft inside the transition layer. How is your vertical position expressed?mcq · medium
Show answer
Inside the transition layer the expression depends on direction: flight levels when climbing, altitudes when descending, so B is right (and QNH is the setting that makes the altimeter show it). A treats the layer like the airspace above the transition level. C confuses height with the QFE case, which applies only where QFE is used for the approach. D ignores the climbing/descending split.
Reference: SERA.8015(eb)(1); SERA Article 2(134)-(135)
-
You are flying a VFR semicircular cruising level that lies above the transition altitude. Which statement is correct?mcq · easy
Show answer
Cruising levels above the transition altitude are expressed as flight levels, and a flight level is referred to the 1013.2 hPa datum, so C is right, VFR included. A describes the altitude regime at or below the transition altitude. B mixes up height (QFE, above the aerodrome) with a cruising level. D pairs flight levels with QNH, but QNH makes the altimeter read altitude.
Reference: SERA.3110; GM1 Article 2(78)
-
You are inbound to a controlled aerodrome. You have listened to the ATIS and acknowledged it on first contact with the approach controller. Which statement about what happens next is correct?mcq · medium
Show answer
The altimeter setting is the ATIS item that is still passed in a directed transmission after you acknowledge the ATIS, and altimeter settings and transition levels are always read back, so B is right. A is the common wrong belief. C is wrong because QNH is part of the clearances ATC gives (descent below the transition level, approach or circuit entry, taxi), while QFE is given only on request or under local arrangements. D is wrong because read-back covers every altimeter setting and transition level, whether from the controller or the ATIS.
Reference: SERA.9010(a)(2)-(3); SERA.8015(e)(1); SERA.8015(eb)(3)-(4)
-
Your altimeter shows 2 500 ft, but you left 1013 hPa set instead of the QNH, which is lower. Your true altitude is about 1 570 ft, and a mast with a top elevation of 1 358 ft AMSL lies ahead. How much clearance do you actually have above the top of the mast, and why was the altimeter wrong?mcq · hard
Show answer
True altitude minus mast elevation is 1 570 - 1 358 = 212 ft. A setting higher than the real QNH makes the altimeter over-read, so the aircraft is lower than indicated. B has the right number but the wrong direction. C subtracts the mast from the indicated 2 500 ft, which is the clearance you wrongly believe you have. D gives the size of the display error (2 500 - 1 570), not the clearance, and again the wrong direction.
Reference: AAIB Bulletin 4/2007, EW/G2006/11/10; SERA.8015(eb)(3)(i)
-
A controller transmits: 'Charlie Sierra Alfa Bravo Charlie, QNH one thousand, descend to altitude two thousand feet.' Which pilot read-back is correct, and why?mcq · medium
Show answer
The setting and the level instruction are both read back, in standard form: 1 000 hPa is said 'one thousand' and the level stays an altitude in feet, so C is right. A applies digit-by-digit to 1 000 hPa, the one exception, and drops the unit of the level. B is wrong because altimeter settings must be read back even if they also came from the ATIS. D turns an altitude below the transition level into a flight level.
Reference: SERA.14035(a)(1)(ii); GM3 SERA.14035(a)(1)(ii); SERA.8015(e)(1); AMC1 SERA.14001, Appendix 1, 1.1.1
Key concepts
Written with ASD-STE100 writing principles: short sentences, one topic per sentence, active voice, one word for one meaning.
Transition altitude and level
The transition altitude (TA) is the altitude at or below which the vertical position is controlled by reference to altitudes. The transition level (TL) is the lowest flight level available for use above the transition altitude. Between the TA and the TL lies the transition layer, where pilots use flight levels in a climb and altitudes in a descent. Rule: SERA.8015(eb)(1)
QNH, QFE and standard setting
With QNH set, a pressure altimeter reads altitude; with QFE set, it reads height above the aerodrome. With 1013.2 hPa set, it reads flight levels, so all aircraft on that datum keep their vertical separation. Near the ground, a pilot needs QNH for terrain clearance.
Cruising levels
A cruising level is a flight level at or above the lowest usable flight level, or above the transition altitude where one applies. Below the lowest usable flight level, or at or below the transition altitude, a cruising level is an altitude. Rule: SERA.3110(a), SERA.3110(b)
Transition level and QNH clearances
ATC must give the transition level in due time before the aircraft reaches it during descent. ATC includes QNH in the descent clearance below the transition level, the approach clearance and the departure taxi clearance, unless the aircraft already has it. Even after the ATIS acknowledgement, ATC still gives the altimeter setting in a directed transmission. Rule: SERA.8015(eb)(2), SERA.8015(eb)(3)(i)–(iii)
Read-back of altimeter settings
The flight crew must read back altimeter settings and transition levels, whether ATC gives them or ATIS contains them. Rule: SERA.8015(e)(1)(iii)–(iv) Do: Read back each altimeter setting and transition level exactly as ATC gives it.
Phraseology for settings and levels
The altimeter setting is transmitted digit by digit, except 1 000 hPa, which is said ONE THOUSAND. Flight levels use the words FLIGHT LEVEL, and feet use HEIGHT or ALTITUDE where clarification is needed. Pressure settings are passed as QNH or QFE followed by the number and its units. Rule: SERA.14035(a)(1)(i)–(ii)
VFR semicircular levels
Below the transition altitude, a VFR semicircular level is flown as an altitude on QNH. Above the transition altitude, the same kind of level is flown as a flight level on 1013.2 hPa. The full VFR level rule is covered on page 010-05-03. Rule: SERA.3110, SERA.5005(g)
Wrong altimeter setting risk
A subscale setting higher than the actual QNH makes the altimeter over-read, so the aircraft is lower than indicated. In a 2006 case at Birmingham, the crew kept 1013 hPa set instead of the QNH of 982 hPa. The AAIB estimated the aircraft was about 930 ft below its displayed altitude of 2 500 ft.
Flashcards
Print them: A6 landscape cards (PDF, front and back) · 4 cards per A4 landscape sheet (PDF, cut lines) · Key figures deck (PDF, 3 figures)
Print double-sided, flip on the short edge.
010-06-01-01What does the transition altitude (TA) define?
The altitude at or below which vertical position is controlled by reference to altitudes.
010-06-01-02What is the transition level (TL)?
The lowest flight level available for use above the transition altitude.
010-06-01-03What is the transition layer?
The airspace between the transition altitude and the transition level.
010-06-01-04In the transition layer, which level type do you use when climbing?
Flight levels when climbing; altitudes when descending.
010-06-01-05Which altimeter setting makes the altimeter read altitude above mean sea level?
QNH.
010-06-01-06Which altimeter setting makes the altimeter read height above the aerodrome?
QFE.
010-06-01-07Which subscale setting makes the altimeter read flight levels?
The standard setting, 1013.2 hPa.
010-06-01-08Why do aircraft above the transition altitude all use 1013.2 hPa?
All aircraft on the same datum share the same pressure error, so their flight levels keep vertical separation.
010-06-01-09When is a cruising level expressed as a flight level?
At or above the lowest usable flight level or, where applicable, above the transition altitude.
010-06-01-10When is a cruising level expressed as an altitude?
Below the lowest usable flight level or, where applicable, at or below the transition altitude.
010-06-01-11When must ATC give the transition level during descent?
In due time before the aircraft reaches the transition level.
010-06-01-12Which clearances carry a QNH setting?
The descent clearance below the transition level, the approach or circuit-entry clearance, and the departure taxi clearance, unless the aircraft already has it.
010-06-01-13Does ATC still give the altimeter setting after the ATIS is acknowledged?
Yes. ATC gives the altimeter setting in a directed transmission, even after the ATIS acknowledgement.
010-06-01-14Which ATIS items always include the transition level and the altimeter setting?
ATIS for arriving and departing aircraft contains the transition level, if applicable, and the altimeter setting(s).
010-06-01-15What must the flight crew read back?
Altimeter settings and transition levels, whether ATC gives them or ATIS contains them.
010-06-01-16How is an altimeter setting transmitted?
Digit by digit, except 1 000 hPa, which is said ONE THOUSAND.
010-06-01-17How is QNH 1009 spoken?
QNH one zero zero nine.
010-06-01-18Which words start a flight level in a clearance?
FLIGHT LEVEL, followed by the number.
010-06-01-19How is a VFR semicircular level flown below the transition altitude?
As an altitude on QNH.
010-06-01-20How is a VFR semicircular level flown above the transition altitude?
As a flight level on 1013.2 hPa.
010-06-01-21When the transition altitude is lower than 10 000 ft, what replaces 10 000 ft as the VMC band boundary?
FL 100, which replaces 10 000 ft (3 050 m) AMSL.
010-06-01-22The subscale is 1013 hPa but the QNH is 982 hPa. Is the aircraft higher or lower than indicated?
Lower. The altimeter over-reads with a setting higher than the QNH.
010-06-01-23In the Birmingham case, how far below its displayed 2 500 ft was the aircraft?
About 930 ft, by the AAIB estimate (about 1 570 ft actual).
010-06-01-24How is a pressure setting passed in met information or circuit instructions?
QNH or QFE, followed by the number and its units.
Sources
- Commission Implementing Regulation (EU) No 923/2012 (SERA): Article 2; SERA.3110; SERA.8015; SERA.9010; SERA.14035; Appendix 1 — via EASA Easy Access Rules for Standardised European Rules of the Air (SERA), August 2025, with the related AMC/GM.
- AAIB, Bulletin 4/2007, EW/G2006/11/10, Airbus A310 F-OJHH: gov.uk.
This page is educational. It does not replace instruction at your ATO or your aircraft's POH/AFM. Rules change: check the regulation in force.