Approach and En-Route Phraseology

Approach and en-route phraseology is the standard radiotelephony exchanged between an IFR flight and the controllers who handle it between the departure tower and the destination tower: departure, area and approach control. It covers the first call after takeoff, level, heading and speed instructions, position reports, holding and delay messages, approach clearances and the handovers that chain one sector to the next.

Nearly every message here is an instruction the controller relies on for separation, so levels, headings, speeds, altimeter settings, SSR codes, transition levels and new frequencies are all read back, ending with the call sign (see radiotelephony phraseology). ICAO Doc 4444 (PANS-ATM) sets the phrases, the Manual of Radiotelephony (Doc 9432) illustrates them and SERA applies them in Europe; the FAA's versions, in the AIM, differ in places that examiners like to test. The ground and runway half of the flight is in aerodrome control phraseology.

Departure and initial contact

After takeoff the tower transfers the aircraft to departure control. In the United States the pilot does not change to the departure frequency until told to, and the controller may leave the frequency out of the clearance when it is printed on the assigned departure procedure. A departure that begins with a vector is given the initial heading before takeoff, and a heading that takes the aircraft off an RNAV SID comes with an altitude to maintain and, if necessary, a speed.

The first call to each new unit gives the call sign and, when climbing or descending, the level being passed and the cleared level: "passing flight level seven five, climbing flight level one one zero", which lets the controller verify the Mode C or Mode S readout (see transponder and SSR). The FAA form is "leaving (exact altitude), climbing to (altitude)", or "level (altitude)", where the exact altitude means the nearest 100 ft. Under ICAO procedures an aircraft in the heavy wake turbulence category adds HEAVY to its call sign on the initial call to each unit.

SID clearances in the United States have a phrase of their own. "Climb via SID" clears the aircraft to fly the SID's lateral path, to meet its published altitude and speed restrictions and to climb to its top altitude, the charted "maintain" altitude or one that ATC assigns; "climb via SID except maintain flight level one eight zero" replaces the top altitude and keeps the other restrictions. A later "climb and maintain" cancels the published altitude restrictions but not the speed restrictions. On initial contact with each new controller the pilot reports the altitude leaving and the procedure: "Cactus Seven Eleven, leaving two thousand, climbing via the Laura Two departure" (see instrument departures).

Level instructions and reporting

ICAO level instructions use CLIMB or DESCEND, with the level. MAINTAIN means continue in accordance with the specified condition and is never used in place of CLIMB or DESCEND when a change of level is intended. The common forms are:

• MAINTAIN (level) UNTIL PASSING (significant point), or UNTIL (time), or UNTIL FURTHER ADVISED;
• CROSS (significant point) AT (or ABOVE, or BELOW) (level), a crossing restriction;
• WHEN READY DESCEND (level), a clearance already in force whose timing is left to the pilot;
• AFTER PASSING (significant point) DESCEND (level), which does not allow the descent before the point;
• EXPEDITE CLIMB (or DESCENT), at the best practicable rate;
• REPORT REACHING (or PASSING) (level), acknowledged with WILCO, the report following at that level.

With the standard setting in use the level is preceded by FLIGHT LEVEL, and flight levels are spoken digit by digit except whole hundreds: "flight level one hundred" but "flight level one one zero". An altitude clearance on QNH is read back with the setting, as in "descend to altitude 3,500 feet, QNH 997 hectopascals". The transition level is read back even when it comes from the ATIS.

The FAA says "climb and maintain" and "descend and maintain". Pilot's discretion leaves the start and the rate to the pilot, but an altitude once vacated may not be reclaimed. "Descend via" on a STAR authorizes descent at the pilot's discretion to meet every published altitude and speed restriction, and the pilot reports on each new frequency the altitude leaving, the procedure and any runway transition (see standard terminal arrival routes). Asked to "verify assigned altitude as (altitude)", the pilot confirms or gives the correct figure without changing altitude.

The AIM requires some reports unprompted: on vacating an assigned altitude for a new one, when unable to climb or descend at 500 ft per minute, when the true airspeed differs from the flight plan by 5% or 10 kt, whichever is greater, and on a missed approach. A position report follows the ICAO order: call sign, position, time, level, next position and time over it, and the ensuing significant point; the first three are never omitted. The time is normally given in minutes only, "four seven" for 1447. A revised estimate is passed when the previous one is found to be more than 2 minutes in error, under SERA and, outside radar contact, under the AIM, whose North Atlantic figure is 3 minutes or more. When surveillance gives the controller adequate flight progress data, ICAO controllers say OMIT POSITION REPORTS [UNTIL (significant point)] and later RESUME POSITION REPORTING; FAA pilots stop reporting on "radar contact" and resume on "radar contact lost" or "radar service terminated".

Radar identification and vectoring phraseology

The radar controller says IDENTIFIED, usually with a position, or in FAA usage RADAR CONTACT; NOT IDENTIFIED comes with the reason and, where needed, RESUME OWN NAVIGATION. Headings are three digits with the direction of turn and no "degrees", as in TURN LEFT HEADING ZERO NINE FIVE, often with the reason: DUE TRAFFIC, FOR SPACING, FOR DELAY, or FOR DOWNWIND (or BASE, or FINAL). ONE ORBIT LEFT asks for a single 360° turn, ORBIT LEFT for continued orbits until further advised. RESUME OWN NAVIGATION ends vectoring, normally with the aircraft's position; RADAR SERVICE TERMINATED and RADAR CONTROL TERMINATED end the service (see radar services and vectoring).

In the United States a vector off a SID or STAR cancels its published altitude and speed restrictions, so the controller assigns an altitude and, if necessary, a speed, and says where to expect to resume the procedure if the aircraft is to rejoin it. A pilot uncertain of what a clearance means asks ATC at once.

Vectors toward an ILS end with an intercept. ICAO controllers normally give a closing heading of no more than 45° to the localizer, or 30° for independent or dependent parallel approaches, and ask the pilot to REPORT ESTABLISHED ON [ILS] LOCALIZER. The FAA does not expect a pilot on vectors to turn inbound without an approach clearance, which normally comes with the final vector; a pilot about to cross the final approach course without being told why asks the controller.

Speed control instructions

Speeds are given in knots, or in kilometers per hour where a State uses them, and as a Mach number at high levels. PANS-ATM steps them in multiples of Mach 0.01 at or above FL 250 and of 10 kt IAS below it; the FAA uses 5 or 10 kt steps, and Mach numbers in 0.01 steps at or above FL 240. Speed instructions are mandatory readback items, and a pilot who cannot comply says UNABLE with the reason. REDUCE TO MINIMUM CLEAN SPEED asks for the lowest safe speed with no flaps or slats extended, and REDUCE TO MINIMUM APPROACH SPEED for the lowest in the approach configuration (see structural and operating speed limits).

The FAA separates its three canceling phrases. RESUME NORMAL SPEED ends an ATC-assigned speed only where no published speed restriction applies; RESUME PUBLISHED SPEED returns the aircraft to the speeds charted on its procedure; DELETE SPEED RESTRICTIONS cancels both assigned and published ones. An approach clearance supersedes earlier speed assignments unless the controller restates them, and an assigned speed is flown within 10 kt or Mach 0.02.

Holding and expected approach times

A hold that is not published is described in full: HOLD AT (fix), (level), INBOUND TRACK (three digits), RIGHT (or LEFT) HAND PATTERN, OUTBOUND TIME (number) MINUTES, with the direction of the holding area from the fix where needed. A published hold is cleared with "hold at OKTET as published", often with EXPECT FURTHER CLEARANCE AT (time), which is a planning time and not an authority to leave the fix (see holding patterns).

An expected approach time (EAT) is the time at which ATC expects a delayed arrival to leave the holding fix to begin its approach. Asked for one, the controller answers EXPECTED APPROACH TIME (time), NO DELAY EXPECTED, or DELAY NOT DETERMINED with the reason; a later change is passed as a revised expected approach time. PANS-ATM requires an EAT to be passed by the quickest means when a hold of 30 minutes or more is expected, and a revised EAT whenever it changes by 5 minutes or more. In a stack the first aircraft to arrive is normally held lowest.

The FAA issues holding instructions with an expect further clearance (EFC) time; for a charted hold it may say only "hold east as published", and an uncharted hold names the direction from the fix by one of the eight compass points, the fix, the radial, course or airway, the leg length if DME or RNAV is used, and left turns. Without a further clearance, the pilot starts slowing 3 minutes before the clearance limit, reports the time and altitude on reaching it and reports leaving it. After a radio failure the last acknowledged EAT under ICAO procedures, or the EFC time under 14 CFR 91.185, governs when the aircraft leaves the hold (see radio communication failure).

Approach clearances and conditional instructions

The ICAO approach clearance names the procedure and the runway: CLEARED (type of approach) APPROACH RUNWAY (number), as in "cleared ILS approach runway 27". An approach clearance authorizes the published procedure only; the landing clearance is a separate transmission, and an aircraft without one may not land. A request such as REPORT FIELD IN SIGHT is acknowledged with WILCO.

The FAA adds rules of its own:

• "Cleared approach", with no type named, allows any authorized instrument approach at the airport, but not a visual or contact approach.
• A pilot cleared for the approach while on vectors or a direct routing keeps the last assigned altitude until established on a published segment, and the controller often adds "maintain (altitude) until established".
• Where a STAR ends at the approach's initial or intermediate fix, the clearance names it: "at RDFSH, cleared ILS runway 27 approach".
• RNAV aircraft may be cleared direct to an initial or intermediate fix at an intercept of no more than 90°, the pilot being told to expect a clearance direct to the intermediate fix at least 5 miles before it; a straight-in clearance is issued where the controller does not want a course reversal flown.

A conditional instruction ties the instruction to a point, a time or an event, as in AFTER PASSING (significant point) DESCEND (level) or MAINTAIN (level) UNTIL PASSING (significant point), and is read back with its condition. A pilot who cannot meet a condition or a restriction says so at once with UNABLE (see ATC clearances).

Handover and frequency changes

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Three phrases move an aircraft between frequencies. CONTACT (unit) (frequency) means change and call. MONITOR (unit) (frequency) means change and listen, without an initial call. STAND BY (frequency) FOR (unit) means wait on that frequency for the unit to call. The frequency is read back with the call sign. On 8.33 kHz channels all six digits are spoken, "one one nine decimal one zero five", except that the last two are dropped when both are zeros, so 125.100 becomes "one two five decimal one".

The FAA form is "(call sign), contact (facility) (frequency) at (time, fix or altitude)", and the pilot keeps listening on the old frequency until then. If the new controller cannot be raised, the pilot returns to the previous one for another frequency. On the first call to approach the pilot quotes the ATIS letter. At an airport without a tower or flight service station the approach controller says "change to advisory frequency approved", and the pilot broadcasts his or her position and intentions.

Library articles are written for study and exam preparation. They do not replace your aircraft's approved documentation, your operator's procedures or the regulations themselves.