Instrument procedures

B. 25 NM

The MSA gives at least 1000 ft obstacle clearance within 25 NM (46 km) of the navigation aid, IAF or IF.

C. 6.5 %

Optimum 5.2 % (3 degrees); maximum 6.5 % for Categories A and B and 6.1 % for C to E.

A. 300 m (1000 ft)

300 m (1000 ft) in the initial segment, reducing to zero at the outer edge of the secondary area. It then reduces from 300 m to 150 m through the intermediate segment.

A. 30 degrees or less

Thirty degrees or less. Beyond that, or if the descent gradient is too steep, the procedure becomes a circling approach.

B. Initial approach fix (IAF)

The initial segment runs from the IAF to the intermediate fix. The FAF is where the final segment begins.

C. Reduces from 300 m to 150 m

The intermediate segment is the transition: its MOC reduces from 300 m (984 ft) to 150 m (492 ft).

A. Procedure turn

That is the definition of a procedure turn. A racetrack uses two 180-degree turns in the same direction; a base turn has no opposite-direction turn.

C. 1.3 x the stalling speed in the landing configuration at maximum certified landing mass

Vat = 1.3 x Vso (or 1.23 x Vs1g, whichever is higher), in the landing configuration at maximum certificated landing mass.

B. 91 to 120 kt

A below 91 kt, B 91-120, C 121-140, D 141-165, E 166-210 kt.

B. At or above the OCA/H

The OCA/H is the lowest level at which the obstacle clearance criteria are met, so the MDA/H is set at or above it and is never a fixed figure.

A. At the missed approach point (MAPt)

On a non-precision approach, if the required visual reference is not established at the MAPt, go around at once. On a precision approach you go around at the DA/H.

A. The lowest height above the relevant threshold elevation used in establishing compliance with the obstacle clearance criteria

OCA/H is the lowest altitude or height that meets the obstacle clearance criteria. OCA is referenced to mean sea level; OCH to the threshold (or aerodrome) elevation. The DA/H is set at or above it.

A. An approach by an IFR flight when part or all of an instrument approach is not completed and the approach is flown by visual reference to terrain

A visual approach is an IFR flight choosing to finish its approach visually. A VFR flight simply lands under VFR - that is not a "visual approach" in the ATC sense.

A. Visibility or RVR, and DA/H

For precision approaches: visibility or RVR plus a decision altitude or height. For a non-precision approach it is visibility or RVR with an MDA/H, and sometimes a ceiling.

A. 2.5 %

A 2.5 % missed approach gradient. The 3.3 % figure is the departure procedure design gradient.

C. 5

Up to five: arrival, initial, intermediate, final and missed approach. Not every procedure has all five.

A. Zero

Obstacle clearance is zero at the DER and grows at 0.8 % of the distance flown - the difference between the 3.3 % design gradient and the 2.5 % obstacle surface.

C. DA/DH

Precision approaches and APV use a decision altitude or height; non-precision approaches use an MDA/H. At the DA/H, without the required visual reference, you go around.

B. Non-precision approach

An SRA gives azimuth guidance and advisory heights only - no glide path - so it is a non-precision approach. PAR is the radar approach that counts as precision.

A. 15 degrees

Within 15 degrees of runway alignment. A turn of more than 15 degrees makes it a turning departure.

A. A 180-degree turn from the facility onto an outbound track for 1, 2 or 3 minutes, then a 180-degree turn in the same direction to the inbound track

Two 180-degree turns in the same direction, with a timed (or DME-limited) outbound leg in between. The 45/180 manoeuvre is a procedure turn; the last option describes a base turn.

B. Base turn

That is a base turn. The outbound and inbound tracks of a base turn are not reciprocal - that is what separates it from a procedure turn.

B. 3 degrees

Three degrees - a 5.2 % descent gradient, about 318 ft per NM. That is also why a 3-degree glide path meets the intermediate altitude 3-10 NM out.

A. Within 4 NM for at least 95 % of the flying time

Plus or minus 7.4 km (4 NM) for at least 95 % of the total flying time.

A. 15 NM

The oceanic contingency procedure is to turn at least 45 degrees left or right and establish a same- or opposite-direction track offset 15 NM (28 km) from the assigned track centreline, then change level so as not to meet traffic on the normal levels.

Our independent check could not confirm this answer from the official sources we hold; treat it with care and confirm with your instructor.

C. Final approach segment

The final approach segment runs from the FAF (or FAP) to the MAPt - the part where you are lined up and descending to land. The intermediate segment is where speed and configuration are set up for it.

A. 120 m (394 ft)

Climb straight ahead on the runway centre line to 120 m (394 ft) before turning, and not sooner than 600 m from the start of the runway. Helicopters may turn at 90 m (295 ft).

A. Less than 91 kt

Category A is below 91 kt at the threshold - light training aircraft live here.

A. A series of predetermined manoeuvres by reference to flight instruments, with specified protection from obstacles

A set of predetermined manoeuvres, flown on instruments with obstacle protection, from the IAF (or an arrival route) to a point from which a landing can be completed - or to a hold or en-route clearance if not.

B. 141 to 165 kt

D is 141-165 kt. C is 121-140 kt and E is 166-210 kt.

A. Final approach point (FAP)

On a precision approach the final segment starts at the FAP - where the intermediate altitude meets the glide path. The FAF belongs to non-precision approaches.

A. More than 2 m (7 ft) below the aerodrome elevation

OCH is normally measured from the threshold, but if the threshold is more than 2 m (7 ft) below the aerodrome elevation, the aerodrome elevation is used.

A. Start of climb (SOC)

Initial phase: MAPt to SOC. Intermediate phase: SOC to where 50 m (164 ft) of obstacle clearance is reached. Final phase: from there onward.

B. Right

Standard holding uses right turns. A left-hand hold must be published or instructed.

C. ILS

The conventional precision approaches are ILS, MLS and PAR. VOR and NDB approaches are non-precision.

A. Required navigation performance

Required navigation performance: a statement of the navigation performance needed to operate in a defined airspace.

A. Procedures for Air Navigation Services

Procedures for Air Navigation Services, for example PANS-ATM (Doc 4444) and PANS-OPS (Doc 8168).

A. 30 degrees

With two approaches running side by side, a go-around on one must not turn into the traffic on the other. So the missed approach tracks are designed to split apart by at least 30 degrees.

A. Direct

Sector 1 is the parallel entry, sector 2 the offset (30 degree) entry and sector 3 the direct entry: having reached the fix, turn to follow the holding pattern.

A. Over which the full minimum obstacle clearance is applied

Each segment is split into a primary area in the middle, where the full MOC applies, and secondary areas either side, where the clearance tapers to zero at the outer edge.

A. Initial, intermediate and final

Only the approach itself has an arrival and an initial segment. The missed approach has three phases: initial (from the MAPt to the start of climb), intermediate and final.

A. Also controlling, if reported and relevant

The touchdown RVR always controls. When the mid-point and stop-end RVR are reported and relevant, they are controlling too - the pilot does not choose to ignore them.

A. Dependent parallel approaches

Dependent: radar separation is kept between aircraft on the adjacent centrelines, so the approaches depend on each other. Independent: no such separation minima are prescribed between the two streams.

A. An en-route alternate

Take-off alternate: for a problem shortly after take-off when the departure aerodrome cannot be used. En-route alternate: for an abnormal or emergency condition en route. Destination alternate: when landing at the destination becomes impossible or inadvisable.

A. Type A, CAT I precision approach

Type A: MDH or DH at or above 75 m (250 ft) - it includes non-precision, APV and CAT I precision approaches with DH of 75 m or more. Type B: DH below 75 m. A CAT II approach always has a DH below 75 m, so it cannot be Type A.