Navigation and ATC
Vulnerabilities Warrant Attention as Satellite based Navigation Grows

The International Civil Aviation Organization and other authorities recommend backup inertial-reference systems, ground-based navaids, and radar surveillance and vectoring to mitigate interference — unintentional and intentional — with navigation signals from space. Improved satellites and augmentation systems will help to lessen risks under instrument flight rules.

What is PRNAV ?

Precision-RNAV (P-RNAV) is the natural progression from Basic RNAV (B-RNAV) which became mandatory in European Airspace in April 1998 for en-route operations. Initial application is in the Terminal Area and P-RNAV track keeping equates to cross track accuracy of RNP 1 ( or - 1NM). P-RNAV procedures are designed to a common set of design principles specific to RNAV equipped aircraft. These P-RNAV procedures will replace the wide variation of RNAV procedures in European ECAC Terminal Airspace that do not have a common basis.

Standard Calls

Standard phraseology is essential to ensure effective crew communication, particularly in today's operating environment, which increasingly features Two-crewmember operation and, International / worldwide contexts involving crewmembers with different native languages.

Vertical Situation Display For Improved Flight Safety

Boeing has developed a vertical situation display to help prevent controlled flight into terrain and approach and landing accidents. In addition, the vertical situation display is designed to reduce airline operating costs by decreasing the number of missed approaches, tail strikes, and hard landings and by reducing vertical navigation training time.

RVSM Heightens Need for Precision in Altitude Measurement

Technological advances have honed the accuracy of aircraft altimeters, but false indications still can occur at any altitude or flight level. Some involve limitations of the altimeters themselves, but most are associated with the weak link in altimetry the human.

RNP In Daily Operations

This document has been published by Westjet and is well illustrated.

Polar Routes

This Boeing document provides some information to better understand safe and efficient Polar Operations.

Polar Operations

This Boeing document provides some information needed to implement safe and efficient Polar Operations.

Pilots and ATC Communications

English is the international language of aviation. But even when pilots and controllers both speak English fluently, there are pitfalls in the nature of language and the ways that language is heard. Subtle miscues can subvert messages that seem clear to the sender. Pilots and controllers must be aware of, and avoid, common types of linguistic misunderstandings. Ultimately, an intelligent voice interface may cut through confusion.

NAT Doc 007 – 2024

NAT Doc 007 is the main go-to guidance doc for ops over the North Atlantic. All the specifics about how to operate an aircraft safely through the complex airspace of the region are here

Introduction To Navigation

This introduction to Navigation covers Methods & equipment, procedures, Navigation and the FMC.


What you should know about IATA In-flight Broadcast Procedure (IFBP).

HF Guidance

Everything is said in the title...

How VNAV Works

What is VNAV and how it works: another interesting document from Boeing

Getting to grips with FANS

The purpose of this Airbus brochure is to provide Airbus Industrie aircraft operators with the agreed interpretations of the currently applicable CNS/ATM (i.e. FANS) regulations.

Getting to grips with ETOPS

The purpose of this Airbus brochure is to provide Airbus operators with: the currently applicable ETOPS regulations, as published in the various relevant circulars, and the agreed interpretations thereto, which have been defined in the frame of the JAA/FAA Harmonization Committee.

Getting To Grips with Modern Navigation

The purpose of this brochure is to provide Airbus aircraft Operators with the agreed interpretations of the currently applicable RNP and RVSM and RNAV regulations.

Getting To Grips With RNP AR

The Performance Based Navigation concept allows to optimize the instrument procedure design with the aircraft navigation performance. This concept is used en route, to reduce aircraft separation, and in terminal area to optimize arrival and departure procedures. The utmost development of Performance Based Navigation for approach, missed approach and departure is known under different names. FAA initially referred to RNP SAAAR Operations, SAAAR standing for Special Aircraft and Aircrew Authorization Required. ICAO now refers to RNP Operations with Authorization Required (RNP AR). This brochure aims at providing Airbus customers with the background information necessary to launch an RNP AR project.

Correcting The Effect of Magnetic Variation

Airlines should make sure they update their inertial reference systems to the latest magnetic variation (MagVar) tables in order to avoid potentially hazardous magnetic heading-related navigation errors

Continuous Descent Arrivals

The US FAA reviews the concept of a CDA approach: a flight procedure where the vertical profile of an arrival has been optimized so that it can be flown with engines « idle » from a high altitude (potentially from cruise) until touch down on the runway.

Constant-angle non precision approach

CDFA is a technique, consistent with stabilized approach procedures, for flying the final approach segment of a non-precision approach (NPA) procedure as a constant descent, without level-off, from an altitude at or above the final approach fix altitude to a point approximately 15 m (50 ft) height above the landing runway threshold or the point where the flare manoeuvre should begin for the type of aircraft flown.

Common Conceptual Model Approach To Vertical Navigation Automation

Applying a common conceptual model approach to vertical navigation automation. A publication from the International Center for Air Transportation Massachusetts Institute of Technology, Cambridge (USA).

ACAS Bulletin Nr 24

Investigating RAs

ACAS Bulletin Nr 22

ATC instructions

ACAS Bulletin Nr 23

Equipment matters

ACAS Bulletin Nr 21


ACAS Bulletin Nr 20

Low Level events

ACAS Bulletin Nr 19

Interactions flight crew

ACAS Bulletin Nr 18

Notable recent operational events

ACAS Bulletin Nr 17

Level Off RA

ACAS Bulletin Nr 16

TCAS Traffic Advisories

ACAS Bulletin Nr 15

Not So Fast

ACAS Bulletin Nr 14

Version 7.1 is Coming

ACAS Bulletin Nr 13

Reversing to Resolve

ACAS Bulletin Nr 12

Focus On Pilot Training

ACAS Bulletin Nr 10

When ATC meets TCAS II

ACAS Bulletin Nr 11

ACAS world is moving on

ACAS Bulletin Nr 09

Frequently Asked Questions

ACAS Bulletin Nr 08

TCAS II Operations in European RVSM Airspace

ACAS Bulletin Nr 07

Dos and Don'ts of TCAS II Operations

ACAS Bulletin Nr 06

Incorrect use of the TCAS traffic display

ACAS Bulletin Nr 05

Controller and Pilot ACAS regulation and training

ACAS Bulletin Nr 04

TCAS II and VFR traffic

ACAS Bulletin Nr 03

Wrong reaction to ''Adjust Vertical Speed''

ACAS Bulletin Nr 02

RAs and 1000 ft level-off manoeuvres

ACAS Bulletin Nr 01

Follow the RA!


Terrain awareness can be defined as the combined awareness and knowledge of the following: aircraft position,aircraft altitude, applicable minimum safe altitude (MSA), terrain location and features, and other hazards.

Understanding RNP Approaches

Many years experience of Performance Based Navigation (PBN) based on GNSS (Global Navigation Satellite Systems) such as GPS for en-route and terminal area navigation has led to an extension of the same principle to RNAV approaches as an alternative to those relying entirely on ground-based aids. The good understanding of the RNP approach is essential.

ACAS Bulletin Nr 25

Near collision over Yaizu