PPL(A) Theory

Flight information service and alerting service

Page ID
010-07-04
Syllabus (AMC1 FCL.210; FCL.215)
Flight information service and alerting service
Syllabus anchor
ICAO Annex 11; Doc 4444
Rule in force
Reg. (EU) 2017/373 (ATM/ANS); SERA
Regulatory baseline
SERA EAR August 2025; ATM/ANS EAR March 2025; ICAO Annex 11 (2018) and Doc 4444 (2016) for comparison
Reading time
27 min
Revising? Key concepts ↓ Test yourself ↓

Learning objectives

The idea

Flight information service is the first kind: it hands you weather, hazards and traffic you might not know about, and you decide what to do with it. Alerting service is the quiet safety net behind it: if you stop talking and never arrive, somebody notices, and somebody starts the search. Neither one flies the aeroplane for you, and neither one gives orders. You stay in command throughout.

Where FIS and alerting sit

Air traffic services have five objectives. Air traffic control serves the first three: preventing collisions in the air, preventing collisions with obstructions on the manoeuvring area, and keeping traffic orderly and expeditious. Flight information service serves the fourth: advice and information. Alerting service serves the fifth: notifying and assisting search and rescue.

So FIS does not separate aircraft. Separation is control, and control is the job of ATC. For the airspace classes and the services each class gets, see lesson 010-07-01.

Flight information service is a service that gives advice and information useful for flying safely and efficiently. Alerting service notifies the appropriate organisations about aircraft that need search and rescue aid, and helps those organisations as required.

Who provides it, and who receives it

Three kinds of unit provide both services:

"ATC unit" covers only an area control centre, an approach unit and a tower; "ATS unit" also includes flight information centres and AFIS units. A clearance is an authorisation to proceed under conditions specified by an ATC unit, so an FIC or an AFIS unit does not issue clearances of its own. It can relay a clearance that another ATS unit issued.

Who does what: aerodrome control tower, AFIS unit and flight information centre
Control tower (TWR)AFIS unitFlight information centre (FIC)
Kind of unit ATC unitATS unit, but not an ATC unitATS unit, but not an ATC unit
Where it serves Controlled aerodromeAFIS aerodrome and its associated airspaceFlight information region
FIS and alerting service YesBesides ATC serviceYesYesUnless the job is given to an ATC unit with adequate facilities
Clearances IssuesATC clearancesNoneHas none of its own; can relay clearances from other ATS unitsNoneHas none of its own; can relay clearances from other ATS units
Landing and runway in use Gives a clearance to landInforms the pilot that the runway is available for landing. The runway in use is only a suggestion: the pilot in command chooses and may refuse it, and is then given detailed traffic information on the runwayn/aServes a region, not an aerodrome
Collision-hazard information YesAs part of FIS: aircraft in Classes C, D, E, F, GYesThe same, plus aircraft, vehicles and persons on the manoeuvring areaYesAircraft in Classes C, D, E, F, G
Vehicles on the manoeuvring area ATC objective: prevent collisions with obstructions on the manoeuvring areaManages the movement of vehicles and persons only when the competent authority prescribes itn/aServes a region, not an aerodrome
Alerting Tells the FIC or ACC at once when an aircraft is in an emergency, unless that is superfluousTells the FIC or ACC at once when an aircraft is in an emergency, unless that is superfluousCentral point: collects all information on the emergency and forwards it to the RCC
Figure 1. A tower issues clearances; an AFIS unit and an FIC provide flight information and alerting but never clear. The table compares the three on clearances, runway in use, collision hazards, vehicles and alerting. Original table
Describe this figure

The table has three columns: control tower, AFIS unit and flight information centre. Only the tower is an ATC unit and issues clearances; the AFIS unit and the FIC are ATS units that can relay clearances but have none of their own. At an AFIS aerodrome the pilot is informed that the runway is available for landing, and the runway in use is only a suggestion that the pilot may refuse. The AFIS unit also passes collision-hazard information about aircraft, vehicles and persons on the manoeuvring area, and manages vehicles only if the competent authority prescribes it. All three provide alerting service: the tower and AFIS unit tell the FIC or ACC, which forwards the emergency to the RCC.

The table compares the three unit types on five points. The tower clears, the AFIS unit only informs and suggests, and the FIC informs across a whole FIR.

Who receives FIS? Every aircraft likely to be affected by the information that is either receiving ATC service or otherwise known to the ATS unit. "Otherwise known" means traffic in uncontrolled airspace, with no flight plan or continuous radio watch required, whose details and intentions the controller, FIS officer or AFIS officer knows, in practice because you called them.

Where one unit provides both ATC and FIS, ATC comes first whenever the ATC task requires it.

Rule SERA.9001(b)

Receiving FIS takes no responsibility away from the pilot-in-command. The PIC makes the final decision on any suggested change to the flight plan.

What FIS tells you

Flight information service: four nested layers of content General items for every flight sit in the outer box. Flight items sit inside it. Inside those are VFR items and AFIS items. 1 General items: all FIS • SIGMET and AIRMET • Volcanic activity and ash • Radioactive or toxic releases • Radio-navigation changes • Aerodrome/facility condition • Unmanned free balloons • Abnormal aircraft condition • Unmanned aircraft • Anything else affecting safety 2 Added for flights • Weather: departure, destination, alternates • Collision hazards (Classes C, D, E, F, G) • Surface vessels over water, on request • Messages relayed, incl. clearances 3 VFR flights only Traffic and weather along the route that make VFR impracticable 4 AFIS adds Collision hazards: aircraft, vehicles, persons on the manoeuvring area Runway in use AFIS unit gives: 1 + 2 (as relevant) + 4
Figure 2. General items apply to every flight. Flight items add to them, and VFR items and AFIS items add further on top. Original diagram
Describe this figure

Four boxes sit inside one another. The outer box holds the general items every FIS gives: SIGMET and AIRMET, volcanic activity, radioactive or toxic releases, radio-navigation changes, aerodrome and facility condition, unmanned free balloons, abnormal aircraft condition, unmanned aircraft and anything else affecting safety. Inside it, a dashed box holds the items for flights: weather at departure, destination and alternates, collision hazards in Classes C to G, surface vessels over water on request, and relayed messages including clearances. Inside that sit two boxes: VFR items (traffic and weather along the route that make VFR impracticable) and AFIS items (collision hazards on the manoeuvring area, and the runway in use). An AFIS unit gives the general and flight items as relevant, plus its own.

The figure shows four nested boxes: general items for everybody, then extras for flights, then for VFR flights, and in the centre the extras an AFIS unit adds.

The outer layer, general FIS, covers pertinent information such as SIGMET and AIRMET, volcanic ash, changes in radio navigation services, aerodrome condition (snow, ice, deep water), unmanned aircraft, abnormal aircraft configuration, and anything else likely to affect safety.

The next layer applies to flights. It adds reported or forecast weather at departure, destination and alternate aerodromes. It adds collision hazards for aircraft in Classes C, D, E, F and G, and messages, including clearances, relayed from other ATS units.

The VFR layer adds available information on traffic and weather along the route that is likely to make VFR flight impracticable. For VMC, see lesson 010-05-03.

Exam trap

"FIS will warn me of all traffic, so I am separated." Wrong. Collision-hazard information covers only known activities, and it can be incomplete because of radar or radio coverage gaps, optional radio contact and inaccurate pilot reports. For that reason ATS cannot take responsibility for always issuing it or for its accuracy, and traffic information under FIS is not separation.

How the information reaches you

FIS arrives in four ways. A directed transmission is preferred and its receipt is acknowledged. A general call is not acknowledged and is used for urgent information to several aircraft, for example a runway change or a sudden hazard. The other two are a broadcast and a data link.

Good practice

When you call an FIS unit with a VFR flight plan or without one, you make yourself "known". If you leave the frequency or land somewhere other than planned, tell the unit, so that a broken contact does not start the alerting process.

AFIS: information, not control

An AFIS unit gives flight information service for aerodrome traffic.

On top of the relevant general and flight items, AFIS adds information on collision hazards with aircraft, vehicles and persons on the manoeuvring area, and on the runway in use.

The key point is how the runway is handled. At an AFIS aerodrome the runway in use is a suggestion of the most suitable runway. Choosing and using the runway is your responsibility as PIC, and you may refuse the suggestion. The AFIS officer then gives detailed information on the traffic using the runway in use.

At an AFIS aerodrome you are told the runway is available for landing, while at a controlled aerodrome you are given a clearance to land.

Before you taxi for take-off, an AFIS unit should give you, in order and leaving out what you already have: runway in use, surface wind, QNH, then temperature (turbine aircraft only), visibility in the take-off direction if it is below 10 km (RVR where applicable), and time. Before an arriving aircraft joins the circuit, the order is shorter: runway in use, surface wind, then QNH.

Avoiding wake turbulence is entirely the PIC's responsibility.

ICAO says its air traffic services standards contain no AFIS provisions, and its alerting duties at aerodromes name only the tower and approach unit. The EU rule says AFIS units share those duties, and it lists four situations in which local rescue services are alerted first.

ATIS: the broadcast that saves frequency time

ATIS removes frequency load. It is the automatic provision of current, routine information to arriving and departing aircraft throughout 24 hours or a specified part of it. Voice-ATIS is a continuous, repetitive voice broadcast, and D-ATIS is ATIS by data link.

It uses a discrete VHF frequency whenever practicable, or else the voice channel of a suitable terminal navigation aid, preferably a VOR, and it is never transmitted on an ILS voice channel. A Voice-ATIS message should, whenever practicable, not exceed 30 seconds.

Each ATIS relates to a single aerodrome and is updated immediately on a significant change. Each message is identified by a letter of the spelling alphabet, and consecutive messages take consecutive letters.

Example ATIS, information Golf An example combined arrival and departure ATIS for Cascais (LPCS), with illustrative values, in its fixed order, with the three items that CAVOK replaces marked. Cascais (LPCS): information Golf One ATIS, one aerodrome. The next message is Hotel. 1 Aerodrome name Cascais (LPCS) 2 Arrival/departure arrival and departure 4 Designator information Golf 5 Observation time time 1020 7 Runway in use runway 35 10 Transition level transition level 60 12 Surface wind 350° magnetic, 8 kt 13 Visibility 6 km 14 Present weather light rain 15 Cloud broken 3 500 ft 16 Temperature 14 °C 17 Dew point 11 °C 18 Altimeter setting QNH 1015 hPa 20 Trend forecast no significant change 21 ATIS instructions say Golf on first call CAVOK can replace all three rows Numbers: fixed place in the 21-item order. Gaps: items not shown in this example. Example values are illustrative, not a real broadcast. CAVOK needs all three: visibility 10 km or more, no cloud of operational significance, no weather of significance to aviation.
Figure 3. An example ATIS for Cascais (LPCS), with illustrative values, in its fixed order. Select an item to see what it means, and switch to the CAVOK case to see which three items one word replaces. Original interactive
Describe this figure

The figure lists an example ATIS for Cascais (LPCS), information Golf, with illustrative values, as numbered rows. The number is the item's fixed place in the 21-item combined arrival and departure message; missing numbers are items not used in this example. The wind is given in degrees magnetic, and the cloud row follows the rule for cloud below 1 500 m (5 000 ft) or the highest minimum sector altitude. A bracket marks visibility, present weather and cloud: when visibility is 10 km or more, there is no cloud of operational significance and no weather of significance to aviation, the single word CAVOK replaces all three. The next message after Golf would be Hotel.

The figure shows an example ATIS for Cascais (LPCS), information Golf, with illustrative values, with each element labelled in order. The content follows a fixed order, so you always know where to listen for the item you need. A combined arrival and departure message has 21 items; it starts with the aerodrome name and the designator letter and ends with the trend forecast and any specific instructions. For altimeter settings and transition level, see lesson 010-06-01.

ATIS wind direction is in degrees magnetic. Cloud is reported when it is below 1 500 m (5 000 ft) or the highest minimum sector altitude, whichever is greater, plus any cumulonimbus.

CAVOK

CAVOK replaces three elements at once: visibility or RVR, present weather and cloud. It is used when, at observation time, all of these hold: visibility is 10 km or more and the lowest visibility is not reported; there is no cloud of operational significance; and there is no weather of significance to aviation. If any one of them fails, you hear the three elements in full.

Using ATIS

Rule SERA.9010(a)

The ATS unit transmits the applicable ATIS message when you ask for it. When ATIS is provided, you acknowledge receiving it when you first contact approach, tower or AFIS. The unit then gives you the current altimeter setting. Information in an acknowledged current ATIS need not be repeated, except the altimeter setting. If you acknowledge an ATIS that is no longer current, the unit either passes the updated elements or tells you to get the current ATIS.

Good practice

Listen to the ATIS before your first call, and quote its letter on first contact. This saves frequency time and lets the unit tell you only what has changed. The exact wording is in lesson 010-07-05.

VOLMET

VOLMET is different. It is meteorological information for aircraft in flight, and a VOLMET broadcast provides current METAR, SPECI, TAF and SIGMET by continuous, repetitive voice broadcast. ATIS covers one aerodrome with operational information.

Alerting service

Who gets it

Alerting service is provided to all aircraft receiving ATC service. It is provided, as far as practicable, to all other aircraft that have filed a flight plan or are otherwise known to ATS. It is also provided to any aircraft known or believed to be subject to unlawful interference.

Cover for these aircraft depends on a flight plan having been filed or the aircraft being otherwise known. See lesson 010-05-02.

Good practice

A VFR flight with no flight plan and no radio contact may leave ATS with no way of knowing it is overdue. Filing a flight plan or staying in contact with the FIS unit makes the flight "known", and so gives it alerting cover.

"Operations normal"

Unless the competent authority prescribes otherwise, an aircraft with suitable two-way radio reports 20 to 40 minutes after its last contact, whatever the purpose of that contact. The report gives identification and the words "Operations normal", and is made air-ground to an appropriate ATS unit.

A missing report is not an urgency in itself: ATS first tries to contact you, and failing that may go as far as declaring the uncertainty phase.

ICAO says its procedures allow the words "Operations normal" or the signal QRU. The EU rule says SERA specifies only the words. The 20 to 40 minute window is the same.

The alerting chain

Alerting chain from aircraft to rescue coordination centre The unit with the aircraft alerts local rescue first, tells the FIC or ACC, which advises the operator and notifies the RCC. Aircraft Emergency while with a tower, approach or AFIS unit TWR / APP / AFIS unit Tells the FIC or ACC at once, unless that is superfluous Local rescue and fire services Alerted first, per local instructions, when: an accident happens on or near the aerodrome; an aircraft’s safety may be or has been impaired; the crew asks; the situation requires it. Local instructions set what is passed on, e.g. aircraft type, type of emergency, persons on board and dangerous goods when available. 1 2 at once FIC / ACC Central point in its FIR or control area: collects all information on the emergency and forwards it to the RCC. Operator In uncertainty or alert: advised before the RCC is notified, when practicable. Gets everything sent to the RCC without delay, when practicable. 3 4 immediately RCC Rescue coordination centre: promotes efficient SAR organisation and coordinates SAR operations in its region. RCC notification Opens with INCERFA, ALERFA or DETRESFA. Then, as available and in order: caller, nature of emergency, flight plan details, last contact, last position, aircraft description, dangerous goods, action taken, remarks. Numbers show the order. Dashed box: side action or message content.
Figure 5. The unit with the aircraft alerts local rescue first and tells the FIC or ACC, which advises the operator and notifies the RCC. Original diagram
Describe this figure

The chain runs down the left: an aircraft in an emergency with a tower, approach or AFIS unit; that unit; the FIC or ACC; and the RCC. Numbered arrows give the order. Step 1 branches right: the unit first alerts local rescue and fire services, and local instructions set what it tells them. Step 2: the unit tells the FIC or ACC at once. Step 3 branches right: in uncertainty or alert the operator is advised before the RCC, when practicable. Step 4: the FIC or ACC notifies the RCC immediately, opening with INCERFA, ALERFA or DETRESFA.

The figure shows the chain as a row of boxes. The aircraft is at the left. Next come the tower, approach unit or AFIS unit that has contact with it. Then the flight information centre or area control centre, and at the right the rescue coordination centre. The operator is informed from the FIC or ACC.

An FIC or ACC is the central point for collecting all information on an aircraft emergency and forwarding it to the rescue coordination centre (RCC). The RCC coordinates search and rescue operations within a search and rescue region.

If an emergency arises while the aircraft is with a tower, approach unit or AFIS unit, that unit notifies the responsible FIC or ACC at once, and that centre notifies the RCC, unless the notification would be superfluous.

The tower, approach unit or AFIS unit also alerts the local rescue and emergency organisations first, following local instructions, when: an accident happens on or near the aerodrome; it learns that the safety of an aircraft under its jurisdiction may be or has been impaired; the crew requests it; or the situation otherwise requires it.

When an ACC or FIC decides that an aircraft is in the uncertainty or alert phase, it advises the operator when practicable before notifying the RCC. It passes all information sent to the RCC to the operator without delay whenever practicable.

Other aircraft known to be nearby are told the nature of an established emergency as soon as practicable, except unlawful interference, which ATS does not mention unless the aircraft did so first.

The three emergency phases

"Emergency phase" is the generic term for the uncertainty phase, the alert phase and the distress phase. Think of a ladder: ATS climbs one rung as its worry grows. This page owns the phases; lessons 010-07-06 and 010-10-01 link back here.

Emergency phases: uncertainty, alert, distress Three emergency phases in increasing severity, each with a codeword, timed triggers and event triggers. Phase 1 of 3: Uncertainty INCERFA Uncertainty as to the safety of the aircraft and its occupants TIMER No communication for 30 min, counted from when a call was due or from the first failed attempt to reach the aircraft, whichever is earlier TIMER Aircraft not arrived 30 min after the ETA last notified to or estimated by ATS, whichever is later NOTE Not declared if there is no doubt about the safety of the aircraft and occupants no news: escalate Phase 2 of 3: Alert ALERFA Apprehension as to the safety of the aircraft and its occupants EVENT After uncertainty: more contact attempts or inquiries give no news TIMER Cleared to land but not landed within 5 min of the estimated landing time, and no communication re-established EVENT AFIS aerodrome: circumstances set by the competent authority EVENT Operating efficiency impaired, but a forced landing is not likely EVENT Unlawful interference known or believed NOTE Evidence that allays apprehension cancels all of these except unlawful interference no news: escalate Phase 3 of 3: Distress DETRESFA Reasonable certainty of grave and imminent danger, or need for immediate assistance EVENT After alert: more failed attempts and wider inquiries point to probable distress EVENT Fuel exhausted or too little to reach safety EVENT Operating efficiency impaired so a forced landing is likely EVENT Forced landing about to be made, or already made NOTE Not declared if there is reasonable certainty of no grave and imminent danger and no need for immediate help TIMER: starts on a clock. EVENT: something happens or is learnt. An EVENT can start the alert or distress phase directly. Each phase: ATS notifies the RCC at once; the codeword comes first.
Figure 4. Three phases in rising severity, each with its codeword, its timed triggers and its event triggers. Original diagram
Describe this figure

Three boxes are stacked, from uncertainty at the top to distress at the bottom, joined by arrows labelled no news. Each carries its codeword: INCERFA, ALERFA, DETRESFA. Uncertainty is triggered by two timers: no communication for 30 minutes from the call due or the first failed attempt, whichever is earlier, or no arrival 30 minutes after the ETA last notified or estimated, whichever is later. Alert has one timer, 5 minutes after the estimated landing time for an aircraft cleared to land with no communication, and events such as continued no news, impaired efficiency or unlawful interference. Distress has events only: probable distress after inquiries, fuel exhausted, a likely forced landing, or a forced landing made or imminent.

The figure shows three rising steps, uncertainty, alert and distress, each with its triggers.

ATS units notify the RCC immediately when an aircraft is considered to be in an emergency phase, subject to the operator-first provision above.

Uncertainty phase

It is declared when either of these happens:

Alert phase

It is declared when:

Distress phase

It is declared when:

Each phase has an exception: the uncertainty phase does not apply when there is no doubt about the safety of the aircraft; the alert triggers other than unlawful interference do not apply when evidence allays apprehension; and the distress phase does not apply when there is reasonable certainty that the aircraft is not in grave and imminent danger and needs no immediate assistance.

The notification to the RCC

The notification opens with INCERFA, ALERFA or DETRESFA, then gives, as available and in order, the caller, the nature of the emergency, flight plan details, last contact and last position, aircraft description, dangerous goods, action taken and other remarks: ten items in all.

ICAO and the EU rule use the same time values: 30 minutes, 30 minutes and 5 minutes. The differences are in wording. ICAO also puts into the alert phase the case where a forced landing has not yet been judged likely or unlikely, which the EU text does not repeat, while the EU rule adds the AFIS trigger. The EU wording is the rule in force.

Worked examples

These timing examples show the method. They illustrate the rules only; they do not replace ATO instruction.

Example 1: when must I call "operations normal"?

Given: CS-ABC, a VFR aeroplane with a suitable radio, has its last contact with an FIS unit at 1015 UTC. Nothing else is planned. Method: the report is due 20 to 40 minutes after the last contact. Working: earliest = 1015 + 20 min = 1035; latest = 1015 + 40 min = 1055. Answer: you call "CS-ABC, operations normal" between 1035 and 1055 UTC.

Example 2: when does the uncertainty phase start after silence?

Given: ATS should have received a position report from CS-ABC at 1100 UTC. At 1105 the first attempt to contact it fails. Method: count 30 minutes from the earlier of the two times. Working: earlier of 1100 and 1105 is 1100; 1100 + 30 min = 1130. Answer: the uncertainty phase applies from 1130 UTC, if nothing is heard in the meantime.

Example 3: when does the alert phase start for a cleared-to-land aircraft?

Given: CS-ABC is cleared to land with an estimated landing time of 1420 UTC. It does not land and communication is not re-established. Method: add 5 minutes to the estimated landing time. Working: 1420 + 5 min = 1425. Answer: the alert phase applies from 1425 UTC.

In the real world

Real world AAIB EW/C2017/05/03 https://assets.publishing.service.gov.uk/media/5ad701d0e5274a76be66c4b5/Piper_PA-28R-201_Cherokee_Arrow_III_G-CEOF_05-18.pdf

On 25 May 2017 a Piper PA-28R-201, G-CEOF, flew VFR near Skipness, Kintyre, Scotland. The pilot was in contact with an FIS unit. The aircraft continued into poor visibility down Loch Fyne, its radar return faded at about 1050 UTC, and it probably flew into the sea. The report mentions no ATS flight plan. About 20 minutes after the last relayed call the FIS officer could neither reach nor see the aircraft, and at 1115 raised concern with the Distress and Diversion (D&D) cell, a UK national arrangement and not a SERA unit; the cell then traced the flight. The rescue coordination centre was alerted at 1320, a helicopter was tasked at 1401, and wreckage was found at 1441. Both occupants died. Overdue action began within about 20 minutes, but search and rescue assets were tasked roughly 2 h 45 min later. The report does not name the emergency phases. Being in contact with the FIS unit is what made the flight known to ATS.

Exam traps

Exam trap

"The AFIS officer clears me to land." No. Only ATC units give clearances. At an AFIS aerodrome you are told the runway is available, and the runway in use is a suggestion you may refuse.

Exam trap

"Alert phase starts when a cleared-to-land aircraft is 30 minutes late." The figure is 5 minutes after the estimated landing time, with communication not re-established. The 30-minute values belong to the uncertainty phase.

Exam trap

"Unlawful interference means the distress phase." It is an alert-phase trigger. Fuel considered insufficient to reach safety, by contrast, is a distress-phase trigger.

Exam trap

"The tower calls the RCC directly." The normal route is tower, approach or AFIS to the FIC or ACC, then to the RCC.

Explain it back

Explain it back

You are flying VFR with no flight plan, talking to an FIS unit, and you switch off the radio to change frequency without saying anything. Explain to a fellow student what ATS does when it loses you, which phase it can eventually reach, and what you could have done to avoid starting that process.

Self-check

  1. You are inbound to a small aerodrome that has an AFIS unit but no control tower. On first contact the AFIS officer passes the runway in use and traffic information. Which statement about what the AFIS officer can do is correct?
    mcq · easy
    Show answer

    An AFIS unit is not an ATC unit, so it gives no clearances of its own and informs that the runway is available. The first option describes a tower. The runway in use at an AFIS aerodrome is a suggestion the PIC may refuse, so the third is wrong. Separation and instructions are control, not FIS, so the fourth is wrong.

    Reference: SERA.8015(eb)(5); ATS.TR.305(c); GM1 ATS.TR.305(c)(2)

  2. Which situation puts an aircraft into the distress phase rather than the alert phase?
    mcq · medium
    Show answer

    Fuel considered exhausted or insufficient to reach safety is a distress-phase trigger. Unlawful interference, the 5-minute missed landing and impaired efficiency without a likely forced landing are all alert-phase triggers.

    Reference: ATS.TR.405(a)(2); ATS.TR.405(a)(3)

  3. An ATIS for a quiet aerodrome says CAVOK. Which set of elements has the word replaced?
    mcq · easy
    Show answer

    CAVOK replaces visibility or RVR, present weather and cloud, when visibility is 10 km or more, there is no cloud of operational significance and no weather of significance to aviation. Wind, temperature, altimeter setting, runway and the other items are still given.

    Reference: SERA.9010(b)(13)-(15), footnote 1

  4. The ETA for CS-ABC last notified to ATS was 1010 UTC. ATS later estimates 1020 UTC. The aircraft has not arrived and nothing is known to ease the concern. From what time does the uncertainty phase apply?
    mcq · hard
    Show answer

    For a failure to arrive, count 30 minutes from the ETA last notified or estimated, whichever is later: 1020 + 30 = 1050. 1040 is 1010 + 30, counting from the earlier time, which is the rule for overdue communication, not for arrival. 1030 is 1000 + 30, a start time that matches neither ETA. 1025 is 1020 + 5, the 5-minute figure that belongs to the alert phase for an aircraft cleared to land.

    Reference: ATS.TR.405(a)(1)(ii)

  5. A tower controller sees an aircraft under its control crash just off the end of the runway. Which action is the normal one?
    mcq · medium
    Show answer

    An accident on or near the aerodrome means the tower alerts local rescue organisations first and notifies the responsible FIC or ACC at once; that centre notifies the RCC. Calling the RCC alone skips both steps. Waiting for the operator ignores a tower duty that starts as soon as it learns of the accident. Using another aircraft as a relay is not part of the alerting chain.

    Reference: ATS.TR.400(c); ATS.TR.400(d)(1)

Key concepts

Written with ASD-STE100 writing principles: short sentences, one topic per sentence, active voice, one word for one meaning.

01

Flight information service (FIS)

FIS gives advice and information for safe and efficient flight. FIS is not air traffic control (ATC), so it does not separate aircraft or issue clearances of its own.

02

PIC responsibility with FIS

FIS does not take any responsibility away from the PIC. The PIC makes the final decision on any suggested change to the flight plan.

Rule: SERA.9001(b)

03

Emergency phase

There are 3 emergency phases: uncertainty, alert and distress.

  1. Uncertainty phase: starts 30 min after an expected communication fails to arrive, or at the first failed contact attempt if that is earlier. It also starts when the aircraft has not arrived 30 min after the later of its last notified or estimated time of arrival.

  2. Alert phase: starts 5 min after the estimated landing time of an aircraft cleared to land, if communication is not re-established. It also starts when further contact attempts and inquiries give no news after the uncertainty phase.

  3. Distress phase: starts when fuel is considered exhausted or insufficient to reach safety, or when a forced landing is likely. It also starts when further unsuccessful contact attempts indicate probable distress.

Rule: ATS.TR.405(a)

04

Alerting service

The alerting service notifies organisations about aircraft that need search and rescue (SAR) aid, and it assists them. All aircraft under ATC service receive it, and other flight-planned or known aircraft receive it as far as practicable. Aircraft known or believed to be under unlawful interference also receive it.

Rule: SERA.10001(a)

05

FIS recipients

FIS goes to every aircraft likely to be affected, if it receives ATC service or is otherwise known to the ATS unit. An aircraft is otherwise known when the unit knows its current details and intentions, usually because the pilot called the unit.

Rule: SERA.9001(a)

06

VFR flights and FIS

FIS for a VFR flight also includes available traffic and weather information along the route that is likely to make VFR flight impracticable. Collision-hazard information covers only known activities, so it can be incomplete.

Do not: use FIS traffic information as separation.

07

ATIS broadcast

ATIS gives current routine information to aircraft that arrive or depart, over 24 h or a specified part of it. Each ATIS covers one aerodrome and carries a letter of the spelling alphabet, and the next message takes the next letter.

Rule: ATS.TR.320(a)

Do: acknowledge the ATIS on first contact with approach, tower or AFIS.

The unit then gives the current altimeter setting, unless the competent authority sets another time for arrivals.

08

AFIS runway in use

AFIS adds information on collision hazards with aircraft, vehicles and persons on the manoeuvring area. The runway in use is only a suggestion, and the PIC decides whether to use it. If the PIC refuses it, the AFIS officer gives detailed information on traffic that uses the runway in use.

Rule: SERA.9005(d)

Flashcards

Print them: A6 landscape cards (PDF, front and back) · 4 cards per A4 landscape sheet (PDF, cut lines) · Key figures deck (PDF, 17 figures)

Print double-sided, flip on the short edge.

  1. 010-07-04-01No communication from an aircraft: when is the uncertainty phase declared?

    30 min after an expected communication is missing, or after the first unsuccessful contact attempt, whichever is earlier.

  2. 010-07-04-02Aircraft does not arrive: when is the uncertainty phase declared?

    30 min after the ETA last notified to or estimated by ATS, whichever is later.

  3. 010-07-04-03Aircraft cleared to land has not landed: when is the alert phase declared?

    5 min after its estimated time of landing, if communication is not re-established.

  4. 010-07-04-04How many emergency phases are there, and what are they?

    3 phases: uncertainty, alert and distress.

  5. 010-07-04-05Does the uncertainty phase apply when there is no doubt about safety?

    No. It does not apply when there is no doubt about the safety of the aircraft and occupants.

  6. 010-07-04-06After the uncertainty phase, what moves ATS to the alert phase?

    Further contact attempts and inquiries give no news. Other alert triggers also exist, such as unlawful interference.

  7. 010-07-04-07When is the distress phase declared because of fuel?

    When fuel on board is exhausted or insufficient to reach safety.

  8. 010-07-04-08Do ICAO and EU use the same emergency-phase time values?

    Yes. Both use 30 min, 30 min and 5 min for the three time triggers.

  9. 010-07-04-09Aircraft with a suitable two-way radio: when does an 'Operations normal' report come?

    20 to 40 min after the last contact, unless the competent authority prescribes otherwise.

  10. 010-07-04-10Besides the words 'Operations normal', what does ICAO allow?

    The signal QRU. SERA specifies only the words.

  11. 010-07-04-11How many items can an RCC notification contain, and which item comes first?

    10 items. The codeword INCERFA, ALERFA or DETRESFA comes first.

  12. 010-07-04-12Which aircraft receive the alerting service?

    All aircraft under ATC service, other flight-planned or known aircraft as far as practicable, and aircraft believed to be under unlawful interference.

  13. 010-07-04-13Which aircraft receive flight information service (FIS)?

    Every aircraft likely to be affected, if it receives ATC service or is otherwise known to the ATS unit.

  14. 010-07-04-14What does 'otherwise known' mean for FIS?

    The unit knows the aircraft's current details and intentions, usually because the pilot called the unit.

  15. 010-07-04-15Does FIS separate aircraft?

    No. FIS gives information and advice. Separation and collision prevention by control are the job of ATC.

  16. 010-07-04-16Can a flight information centre or AFIS unit issue its own clearances?

    No. They can relay clearances from other ATS units, but they do not issue clearances of their own.

  17. 010-07-04-17Does receiving FIS take responsibility away from the PIC?

    No. The PIC makes the final decision on any suggested change to the flight plan.

  18. 010-07-04-18What extra FIS information does a VFR flight receive?

    Available traffic and weather information along the route that is likely to make VFR flight impracticable.

  19. 010-07-04-19Can collision-hazard information from FIS be incomplete?

    Yes. It covers only known activities, so ATS cannot take responsibility for always issuing it or for its accuracy.

  20. 010-07-04-20In which airspace classes does FIS include collision-hazard information?

    Classes C, D, E, F and G.

  21. 010-07-04-21When does AFIS give visibility before taxi?

    Visibility only if it is below 10 km in the take-off or initial-climb direction; RVR when applicable.

  22. 010-07-04-22What extra information does AFIS give on top of the general and flight FIS items?

    Collision hazards with aircraft, vehicles and persons on the manoeuvring area, and the runway in use.

  23. 010-07-04-23Who decides on the runway in use at an AFIS aerodrome?

    The PIC decides. The runway in use is only a suggestion of the most suitable runway.

  24. 010-07-04-24Over what period does ATIS provide information?

    Throughout 24 h or a specified part of it.

  25. 010-07-04-25How long is a Voice-ATIS message, whenever practicable?

    Not more than 30 s, and it stays readable (guidance).

  26. 010-07-04-26How many aerodromes does one ATIS cover?

    1 aerodrome, always.

  27. 010-07-04-27Which cloud does ATIS report?

    Cloud below 1 500 m (5 000 ft) or below the highest minimum sector altitude (MSA), whichever is greater, plus any cumulonimbus.

  28. 010-07-04-28When does ATIS replace visibility, weather and cloud with CAVOK?

    When visibility is 10 km or more, lowest visibility is not reported, and there is no cloud or weather of operational significance.

  29. 010-07-04-29How many items does a combined arrival/departure ATIS contain?

    21 items, in the order listed.

  30. 010-07-04-30What does a pilot do on first contact with approach, tower or AFIS after ATIS?

    Acknowledge receipt of the ATIS. The unit then gives the current altimeter setting.

  31. 010-07-04-31After an acknowledged current ATIS, what does a directed transmission need to repeat?

    Only the altimeter setting. Other ATIS information need not be repeated.

  32. 010-07-04-32An aircraft acknowledges an ATIS that is no longer current. What does the unit do?

    It passes the updated elements without delay, or tells the aircraft to get the current ATIS.

  33. 010-07-04-33What identifies each ATIS message?

    A letter of the spelling alphabet. Consecutive messages take consecutive letters.

Sources

  1. Commission Implementing Regulation (EU) No 923/2012 (SERA) — via EASA Easy Access Rules for Standardised European Rules of the Air (SERA), August 2025, with the related AMC/GM.
  2. Commission Implementing Regulation (EU) 2017/373 (ATM/ANS), Annex I definitions and Annex IV (Part-ATS) — via EASA Easy Access Rules for ATM/ANS – Provision of Services, March 2025, with the related AMC/GM.
  3. ICAO Annex 11, Air Traffic Services, 15th edition (2018), and ICAO Doc 4444, PANS-ATM, 16th edition (2016): used for ICAO comparisons only.
  4. AAIB (UK) Bulletin 5/2018, EW/C2017/05/03, Piper PA-28R-201 G-CEOF near Skipness, 25 May 2017: 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.

Glossary

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