cbr 01.2 - aircraft operations pt 1

Instrument Procedure Design

* Instrument procedures are designed separately for each **runway** and each **runway category**
* The procedure design regards aircraft performance with
* All engines operating
* References tracks or bearings
* So that neccesary wind corrections have to be introduced by the crew

Types of departure procedures

* Straight departure
* Turning departure

Straight departure

* Departure track within 15° from the centreline
* Wherever possible, designation of a straight departure is preferable, but the design of the procedure is determined by the surrounding terrain and airspace characteristics

Turning depature

* Each time a change of track greater than 15° is required, the procedure is called a turning departure
* However, they require a segment of straight climb until the height of 394 ft (120 m) above the **Departure End of the Runway (DER)** is reached
* In cases which turning is not advised until reaching the **DER,** such info is always placed on the departure chart
* Usually, procedure design allows for the **Turning Point (TP) location** not earlier than **600 meters** from the departure threshold

Use of **omnidirectional procedures**

Used when:

* An aerodrome is not equipped with a navigation aid suitable for an instrument procedure design
* he navigation aid does not provide any track guidance

define **omnidirectional departure**

A kind of procedure that can be applied at aerodromes which **do not** require a specifc route to be flown for **obstacle avoidance** or for **ATC purposes**

advantages of **omnidirectional procedures**

* Possibility of flexible adjustment of track to the demands of each flight
* **However,** the aircraft has to climb at least 120 m/394 ft on the extended centreline before commencing the first turn
* A turn of more than 15° may be made only if 90 m/295 ft obstacle clearance is provided

Obstacle avoidance with omnidirectional departures

* **Sector borders** can be defined by bearings and distances from the centre of the turn area
* The standard **Procedure Design Gradient (PDG)** for a departure procedure is equal to **3.3%**
* However, sector restriction may influence the **minimum altitude** or **minimum gradient of climb** required during departure

How is procedure climb gradient affected when more than one sector is restricted?

* Omnidirectional departures

Procedure climb gradient will be the highest required

How do obstacles in the proximity of the aerodrome affect departures?

If they rule out omnidirectional departure procedure introduction, the **required ceiling and visibility** have to allow for **maintaining visual terrain separation** during the departure

What are **protected areas** in **instrument approaches?**

* **Specified protected areas** are on both sides of the track centreline to provide for **obstacle clearance in a straight segment**
* Generally, it is comprised of a **primary** and **secondary area**
* Sometimes, there are cases when only the primary is specified

**Primary protected area**

* Where full obstacle clearance is assured in the primary area
* Constitutes half of the total width of the protected area
* Obstacle clearance provided decreases from obstacle clearance at the inner edge, to zero at the outer edge

What 5 segments are instrument procedures divided into?

1. Arrival segment
2. Initial approach segment
3. Intermediate approach segment
4. Final approach segment
5. Missed approach segment

How do the 5 segments for instrument procedures differ?

* In terms of surfaces or areas providing obstacle protection
* Each one’s beginning and ending is designated by a **fix**

**Arrival segment**

* A transition between the en-route and approach phase of flight
* Lasts up to the Initial Approach Fix (IAF)
* IAF marks beginning of the initial approach segment

**Initial approach segment**

* Begins at the **Initial Approach (IAF)**
* Ends at the **Intermediate Fix (IF)**
* MOC in the primary area equals **at least 1,000 ft/300 m**
* Maximum intermediate segment interception angle equals 90º for PAs, 120º for NPAs

**Intermediate approach segment**

* Begins at the **Intermediate Fix (IF)**
* Ends at the **Final Approach Fix (FAF)**
* A point of transition onto the final approach segment
* Speed and configuration adjustments for landing
* Small gradient of descent
* **MOC** - at least 492 ft / 150 m

**Final approach segment**

* Begins at the **Final Approach Fix (FAF)**
* Ends at the **Missed Approach Point (MAPt)**
* Alignment and final descent for landing
* Straight-in landing or circling
* Final approach configuration and speed
* Optimum descent 3º (5.2%)
* **MOC -** 492 ft / 150 m to zero

**Missed approach segment**

* Begins at the **Missed Approach Point (MAPt)**

What are **fix tolerance area dimensions** dependent on?

* Distance from the facility
* Accuracy of the navigation aid
* Calculated separately for
* ILS
* VOR
* NDB

Tolerance area navigation aid accuracy factors

Calculated on a **root sum square** of the following:

* Ground system tolerance
* Airborne receiving system tolerance
* Flight technical tolerance
* Only applies to facilities providing **track**

Angular accuracy of an **ILS localizer (LOC)**

* Providing track guidance: ± 2.4º
* Not providing track: ± 1.4º

Angular accuracy of an **VOR**

* Providing track guidance: ± 5.2º
* Not providing track: ± 4.5º

Angular accuracy of an **VOR**

* Providing track guidance: ± 6.9º
* Not providing track: ± 6.2º

define **Final Approach Fix (FAF)**

* Its maximum distance from the threshold should be equal to 10 NM
* Fix tolerance should not be larger than 1 NM
* Specified for each Non-Precision Approach (NPA)
* For Precision Approaches (PA), a FAP, marking the beginning of the precision segment, is designated instead of the FAF

Descent gradient for precision approach

* Preferably should be planned according to the optimum glide path angle of 3º, which accounts for 5.2% descent gradient
* This is a standard value, but can be increased when necessary due to obstacles or noise abatement

Equation for glide path angle

grad \[%\] = tan(5.5º) x 100 = 9.6º

Aircraft categories by aircraft speed

* Based on aircraft speed at threshold (Vat), which is calculated as:
* 1.3 times stall speed in clean configuration (Vso)
* 1.23 times stall speed in landing configuration with the maximum certified take-off mass (Vs1g)

Types of approach

* Straight-in approach
* Circling approaches

Straight-in approach

Deflected from the runway centreline by a maximum of 30º right or left are preferable

Circling approach

* Used when terrain or other constraints make it impossible to remain in the acceptable range of runway alignment
* In most cases, the final approach track of such a procedure is aligned with some portion of the runway

Types of obstacle clearance

* Minimum Sector Altitude (MSA)
* Terminal Arrival Altitude (TAA)

\
Used to provide at least 1,000 ft/300 m obstacle clearance in each sector of a usually 25 NM-radius circle from a specific point

What the specific point of an obstacle clearance sector is based off of

* RNAV point
* Aerodrome Reference Point (ARP)
* For MSA
* Navigational aid associated w/ the approach procedure
* For TAA
* Initial Approach Fix (IAF) or Intermediate Fix (IF)

Define **Obstacle Clearance Altitude/Height (OCA/H)**

The lowest altitude, or height above the threshold or aerodrome elevation, that the pilot can descend to, and which still provides the appropriate obstacle clearance

OCA/H for **Precision Approach (PA)** or **Approach Procedure w/ Vertical guidance (APV)**

* Defined as the **lowest altitude (OCA)** or t**he lowest height (OCH)** above the threshold elevation
* A Missed Approach (MAP) must be initiated to ensure compliance with the appropriate obstacle clearance criteria

OCA/H for **Non Precision Approach (NPA)**

* **Lowest altitude** **(OCA)**
* **Lowest height** above aerodrome elevation (OCH)
* Further descent violates obstacle clearance criteria
* Includes **Minimum Obstacle Clearance (MOC)** over the highest approach obstacle
* Fixed value of 90 m / 295 ft for approaches without **Final Approach Fix (FAF)**
* 75 m / 246 ft for approaches with FAF

Visual manoeuvring (circling) OCA/H

* Lowest altitude
* Lowest height above aerodrome elevation (OCH)
* Further descent violates obstacle clearance criteria
* Obstacle clearance criteria - obstacle height plus MOC
* MOC is a fixed margin dependent on aircraft category
* OCH minimum value dependent on aircraft category

Operational minima factors

* Meteorological conditions
* Crew training
* Aerodrome specifications
* Offset approach track
* Altimeter error/temperature error
* Category of operation

define **operation minima**

OCA/OCH + Operational safety margin

* Precision approaches, approaches with vertical guidance
* Decision Altitude/Height (DA/H)
* Non-precision approaches
* Minimum Descent Altitude/Height (MDA/H)
* Circling approaches
* Minimum Descent Altitude/Height (MDA/H)