05 IFR Procedures

What is the key difference between DA/H and MDA/H?

DA/H is a decision point used without planned level-off; MDA/H is an altitude/height below which descent is not permitted without the required visual reference.

What is the difference between a 2D and a 3D instrument approach?

2D provides lateral guidance only; 3D provides both lateral and approved vertical guidance.

How are minima normally applied to a 2D approach flown using CDFA versus without CDFA?

With CDFA, DA/H is used; without CDFA, MDA/H is used.

Why is CDFA preferred for 2D approaches?

It provides a stable continuous descent and avoids level flight and large configuration/power changes close to the ground.

Does CDFA change the obstacle protection of the published procedure?

No. It is a technique for flying the published procedure.

What is the practical difference between FAF and FAP?

FAF normally marks the start of final descent on a 2D approach; FAP is the point where the nominal vertical path of a 3D approach is intercepted.

What is the operational significance of the MAPt?

It defines the latest procedure point from which the published missed approach is initiated when landing cannot continue.

Why must published step-down restrictions still be respected when using VNAV?

FMS vertical guidance does not override the obstacle-clearance requirements of the published procedure.

What is OCA/H and how does it relate to operating minima?

OCA/H is derived from obstacle-clearance criteria; operational DA/H or MDA/H cannot normally be set below the applicable obstacle/system/runway limits.

What is MSA primarily intended to provide?

Emergency obstacle clearance within the published sector; it does not necessarily guarantee navigation coverage.

What is the practical difference between an MSA and a TAA?

MSA is primarily an emergency obstacle-clearance reference; TAA forms part of the arrival structure to an RNAV approach.

What is a Type A versus Type B instrument approach operation?

Type A has DH/MDH ≥250 ft; Type B has DH below 250 ft.

How are current EASA Type B approaches divided?

CAT I: DH ≥200 ft; CAT II: 100–<200 ft; CAT III: DH <100 ft or no DH, with the associated RVR criteria.

Does current EASA terminology divide CAT III operationally into IIIA, IIIB and IIIC?

No. Current EASA rules use a single CAT III category.

What is the basic EASA approach-ban logic for CAT operations?

If reported controlling RVR/VIS is below the applicable minimum, the approach must not continue past 1,000 ft above aerodrome elevation, or into the FAS if DH/MDH is above 1,000 ft.

If RVR/VIS deteriorates below minima after the approach-ban point has been passed, must the approach immediately be discontinued?

No. It may continue to DA/H or MDA/H; the required visual-reference criteria then apply.

What is required to continue below DA/H or MDA/H?

The required visual reference must be established and maintained.

If required visual reference is lost after passing minima, what is required?

A prompt go-around.

Why can an aircraft descend slightly below DA after the go-around decision?

DA is a decision point; aircraft inertia and the transition to the missed approach can produce a small height loss.

What is the approximate geometry of a 3° descent path?

About 300–320 ft/NM or roughly a 5.2% gradient.

What is the useful mental rule for vertical speed on a 3° path?

Approximately groundspeed × 5 in ft/min.

What is the useful 3:1 descent-planning rule?

Allow roughly 3 NM for every 1,000 ft of altitude to lose.

Why does a tailwind make vertical path management more difficult on final?

Higher groundspeed gives less time per NM to lose the required altitude.

What is the standard ICAO missed-approach design climb gradient unless a higher value is published?

2.5%.

What must be checked when a higher missed-approach climb gradient is published?

Aircraft performance must be capable of meeting it under the expected conditions.

Why should a missed-approach turn not normally be started early?

Obstacle protection is based on the published turn point or procedure geometry.

Does starting a go-around mean immediately turning toward the next missed-approach waypoint?

No. The published initial missed-approach track and turn restrictions must first be respected.

What should be done when an approach cannot meet stabilised-approach criteria?

Go around rather than attempt to salvage the approach close to the ground.

Are stabilised-approach gates and exact criteria universal?

No. They are defined by the operator.

Why is a descent rate above about 1,000 ft/min operationally significant?

It should be specifically assessed/briefed because it can indicate or create an unstable approach.

What is circling operationally?

A visual manoeuvre following an instrument approach to position for landing on a runway not suitable for straight-in continuation.

What must be maintained during circling?

Required visual reference with the intended runway/runway environment while remaining within the protected circling area.

What should be done if visual reference is lost during circling?

Execute the applicable missed-approach procedure.

Why does higher circling speed increase risk?

It increases turn radius and the airspace required to remain within the protected area.

What are the three conventional holding entries?

Direct, parallel and offset/teardrop.

Are holding-entry sectors more important than remaining within protected airspace?

No. The objective is safe entry and containment; the conventional entries are standard techniques.

How is wind correction normally managed in a hold?

Correct heading for crosswind and adjust the outbound leg so the inbound track/timing is achieved.

What should take precedence over memorised generic holding speeds?

The speed published on the chart, ATC restrictions and applicable aircraft/operator limitations.

Do SID/STAR restrictions disappear automatically after an ATC shortcut or amended clearance?

No. Restrictions remain unless explicitly cancelled, replaced or rendered inapplicable by the clearance.

How should “at”, “at or above”, “at or below” and altitude windows be interpreted?

At = exact altitude; at/above = minimum; at/below = maximum; window = remain between the two published limits.

Does radar vectoring remove the crew’s responsibility for terrain and altitude awareness?

No.

What should an approach briefing concentrate on rather than simply reading the chart?

Runway/procedure, minima, key constraints, navigation setup, threats, stabilisation plan and missed approach.

Why is the missed-approach altitude an important cross-check before final approach?

An incorrectly selected altitude can create an immediate vertical-path or ATC conflict during go-around.

Why should final approach course and runway heading be compared?

A significant difference may reveal an offset approach or wrong runway/procedure selection.

Why is intercepting an ILS glide path from below preferred?

It reduces the risk of capturing a false glide path and supports a stable intercept.

What is the key procedural principle when automation guidance conflicts with a published restriction?

The published procedure and clearance take precedence unless ATC explicitly changes the restriction.