Clearances and speed control | Air Law | ATPL EASA

What exactly has been cleared?

A clearance is based on known traffic, not a waiver of every hazard.

Scope and limits

ATC clearances use known traffic conditions and the unit’s responsibilities to prevent collisions and expedite orderly flow. Issue them early enough for the crew to understand and act. The clearance limit is the point to which the aircraft is authorised to proceed, not necessarily its destination. “Via flight planned route” refers to the filed route as applicable; a named SID or STAR refers to that published route with the stated amendments and constraints.

ATC clearances generally do not relieve pilots of terrain responsibility; specified surveillance vectoring/direct-route responsibilities require the controller to maintain prescribed obstacle clearance until the pilot resumes own navigation under the applicable conditions. Do not generalise that special surveillance duty to every route clearance. The PIC still follows the rules and rejects an unsafe or unsuitable instruction.

Readback protects both sides

Always read back route clearances; runway entry, landing, take-off, hold-short, crossing and backtrack instructions; runway in use, altimeter settings, SSR codes, newly assigned communication channels, level, heading and speed instructions, and transition levels as required. Other instructions need a clear acknowledgment. The controller listens and corrects discrepancies.

An instruction to taxi to a holding point is not permission to enter or cross a runway. A conditional clearance requires the condition, identification and order to be understood; do not act until the stated condition is satisfied and all applicable requirements, including a stop bar, are resolved.

Why and where ATC changes speed

Speed can establish spacing, but aircraft capability remains a limit.

Instructions and limits

ATC uses speed control to create or maintain separation and a manageable sequence, applying it only when the aircraft can comply. Instructions are normally in 0.01 Mach increments at or above FL250 and 10-kt IAS increments below. Advise ATC if a speed is incompatible with aircraft configuration, turbulence or a stable approach.

For intermediate and final approach, only minor changes not exceeding plus or minus 20 kt IAS should be applied; speed control should not be applied after 4 NM from touchdown. A sequence instruction does not require the crew to compromise a safe landing configuration. “Resume normal speed” removes the specific ATC speed restriction but not a published or regulatory limit.

Rules change deliberately

Only the PIC initiates IFR cancellation. ATC acknowledges it, normally with the time, and passes relevant information about known IMC along the intended route when appropriate. ATC does not suggest cancellation as a means of solving a traffic problem.

ATFM is implemented when demand exceeds or is expected to exceed the capacity of the relevant ATC system. A slot or flow restriction manages the network; the tactical speed instruction and IFR clearance remain distinct controls on the actual flight.

ATS terminology 1: Advisory airspace to ALERFA

Use the defined function and reference to interpret the message; related terms are not interchangeable.