ILS X/Y/Z – What’s the Difference?

ILS XYZ

On Instrument Approach Charts (IAPs), there are often instances in which the specific ILS approach is followed by a suffix, these suffixes can fall under letters -X, -Y, or -Z. So, what are the differences and reasoning behind these designations being assigned? According to Chapter 4 of the Federal Aviation Administration’s Instrument Approach Guide, the … Read more

What is Calculated Take Off Time (CTOT)

Calculated Take Off Time

In congested airspaces, Air Navigation Service Providers (ANSPs) have several frameworks which help to manage the air traffic flow across a country or region. European airspace is a primary example of a region that encounters heavily congested traffic conditions. Due to the complexity of European airspace consisting of over 25 individual ANSPs, a set of … Read more

What is a Step Climb?

During the pre-flight phase, the flight crew of the aircraft conducts flight planning for the flight. As part of this flight planning, the routing, weather, speeds, and cruise altitude are determined. For a conventional short to medium-haul flight, a cruising altitude is filed as part of the flight plan. In some instances, in which the … Read more

What is Top of Climb (T/C)?

top of climb

Top of Climb, commonly abbreviated as T/C or TOC, is the calculated point at which the aircraft reaches its cruising altitude.  At the Top of Climb, the aircraft levels off and is neither descending nor ascending; the climb phase of flight has now been completed.  It is important that the flight crew have determined T/C … Read more

How to Calculate Top of Descent (T/D)? 

How to Calculate Top of Descent

In en-route flight management and planning, Top of Descent (T/D) is the calculated point during a flight in which the aircraft begins descent for the arrival airport. Top of Descent (T/D) can be calculated either manually or automatically.  On modern commercial aircraft, T/D calculations are performed automatically by the Flight Management System (FMS).  How is … Read more

Inertial Navigation System (INS) and Inertial Reference System (IRS) – Differences and Functions

Inertial Navigation System (INS) and Inertial Reference System (IRS)

Commercial aircraft navigation systems consist of processes which provide a positioning system to the aircraft. These positioning systems communicate with the onboard navigation systems. This communication allows the exact location of the aircraft to be identified. In order to achieve accurate positioning, aircraft are equipped with Inertial Reference Systems (IRS) or Inertial Navigation Systems (INS). … Read more

What is Form Drag? | Aviation Glossary

What is Form Drag

In aerodynamics, there are various categories of drag used to provide a distinctive classification of different types. Due to the depth and complexity often surrounding the aerodynamics of an airfoil, it is necessary to clarify the enforcing drag types present. Form drag can be defined as the drag created following the departure of airflow (known … Read more

Flaperons | Aviation Glossary

flaperon

On fixed-wing aircraft, there are numerous aerodynamic devices installed which serve a number of functions. These functions include the generation of lift and drag across the airfoil. Two of the aerodynamic devices found on aircraft are flaps and ailerons. Flaps being lift-generating devices in which the chord of the wing can be changed while also … Read more

Noise Abatement | Aviation Glossary

Noise Abatement

In areas surrounding most airports, there is typically an initiative undertaken by various stakeholders with the objective of mitigating noise pollution. This noise pollution can be apparent in areas in which aircraft arrive and depart on a frequent basis. Known as Noise Abatement, it is typically delivered through a set of procedures which document and … Read more