The instrument approach segments

One approach, several jobs

Each segment changes what the aircraft must achieve.

From arrival to final

The five possible approach segments are arrival, initial, intermediate, final and missed approach; not every procedure has all five separately defined. An arrival route normally ends at the IAF. Initial approach brings the aircraft from the IAF toward the intermediate fix and establishes position and suitable configuration for the next segment. The intermediate segment aligns and stabilises the aircraft for final descent.

The initial-to-intermediate interception angle normally should not exceed 90 degrees for a precision approach or 120 degrees for a non-precision approach. The charted procedure may use specific reversal or racetrack arrangements; the pilot follows the published design rather than inserting an improvised shortcut.

Final approach

The final segment aligns and descends the aircraft for landing, or brings it to a position from which a visual manoeuvring/circling approach can be completed. The ILS final segment starts at the FAP where the nominal glide path intersects the specified intermediate altitude, and continues to the applicable endpoint for the procedure. A non-precision final normally starts at a FAF or at the specified point after a reversal where no FAF is provided.

The approach’s missed segment provides a protected transition away from the landing attempt. Do not treat the same line on a navigation display as permission to skip a required altitude, configuration or clearance. Track, level restrictions and required navigation performance remain relevant throughout.

When the ILS glide path fails

A remaining localiser does not preserve the original vertical guidance.

Reassess the available procedure

If glide path guidance becomes unusable, the approach can only continue as an appropriate localiser/non-precision procedure when that procedure is available, the aircraft and crew can comply, the position and altitude permit a safe transition and the applicable minima are used. Otherwise discontinue and fly the missed approach as appropriate. An ILS DA cannot simply be retained as a localiser minimum.

Brief the correct minima, step-down restrictions, MAPt identification and missed procedure. Do not chase an unreliable glide path or descend below a safe altitude while deciding. The operator’s approach continuation and stabilisation policies also apply.

A decision has a point and a reason

For a failure before final descent, there may be time to establish a safe, cleared alternative. Close to minima with no briefed alternative, a go-around is the credible response. The key question is whether a valid procedure and a safe compliant transition actually exist, not whether the runway might eventually appear.

The animation switches from ILS to a schematic localiser profile and removes the vertical guidance. The changed decision reference is explicit: it is not an animation that leaves the same descent path and merely changes its label.

Can you apply the rules?

Four original questions. Choose from the facts, then review the explanation.