NOSS was developed as an ICAO sponsored activity with the support of IFATCA and numerous ANSPs.  NOSS is an ICAO-endorsed best practice for the collection of safety data during normal ATM operations.  As such, ICAO has produced guidance material on NOSS (ICAO Document 9910) and TEM (Circular 314).

ATNS have operated a mature Safety Management System for many years and we have established safety metrics which have served us well. In the second half of 2011 we identified the need to ‘validate’ our safety metrics. ATNS operates at 21 airports and we have around 600 ATS staff. With such a large spread we decided to conduct NOSS over two separate years. NOSS I provided us with the ideal set of indicators and the first survey was conducted at several units in ATNS from October 2011 - January 2012. The purpose of NOSS was to provide a diagnostic snapshot of typical operations at ATNS. The 2011 /12 survey focussed on terminal and en-route operations. In 2012 we conducted NOSS II, to provide a diagnostic snapshot of typical operations at participating towers. Both NOSS I and II provided us with a number of safety recommendations, all of which have been implemented.

The biggest benefit of NOSS to ATNS was that we were provided with measurable data which could prioritize safety actions and budget allocation. The inclusion of relevant data from the NOSS Archive was invaluable, particularly in the context that this provided.  

A further benefit to ATNS was the level of ownership that resulted from the ATCO staff after the observation phase. ATCOs took a special interest in their own area of expertise towards implementing the safety recommendations. It was not uncommon to see observers taking the lead on any number safety improvements. Management’s role was in the background with an emphasis on enabling the “safety champions”, in support of outcomes that the entire organization would benefit from.     

As a result of NOSS I and II we have achieved our best safety performance in recent years when our number of safety events per 100 000 movements dropped to 1.37 events / 100 000 movements in September 2013.

ATNS recognizes the value-add of NOSS and we will continue to re-run NOSS from time to time.   

Air Traffic Navigation Services - South Africa


ANSP Experiences

We already have a number of well-established processes to capture safety related Operational data. Each process is designed to capture a particular aspect of the operation. For example, we have:

  • Event reporting: which consists of a mandatory reporting system (AOR), and confidential safety reporting system (Argus)
  • Investigations: including preliminary investigations conducted by the site, followed by independent investigations conducted by the safety group.
  • Unit Audits: these are regularly scheduled audits of the operational and administrative aspects of a unit.
  • SMS Assessments: this process evaluates the overall performance of our Safety Management System (SMS), i.e. the degree to which the goal of the SMS is being achieved.
  • Safety reviews: which are employed to determine whether risks related to current or planned operations are being managed effectively, and
  • Hazard Identification and Risk Analyses: which are a key aspect of the risk management process applied prior to the introduction of changes to the Operation.

 NOSS complements these existing processes.

One of the key benefits of NOSS is Risk Management, specifically the proactive identification of hazards and risks. NOSS is a data collection tool during Normal Operations; therefore there is no triggering event to initiate the NOSS process. The language of Threat and Error Management is aimed at front line personnel, however the findings translate into risk management information, and senior management can use the findings to help prioritize safety management activity. It helps us to answer the question of “Where do we need to focus our efforts?”

Because NOSS is different from each of our other safety data collection tools (e.g. Unit Audits, Investigations, Safety Reviews), it provides an excellent opportunity to identify “converging lines of evidence” – if we see similar issues using different methodologies it provides a higher level of confidence for assessing the risk level. 

NOSS also identifies areas where Threats are being well-managed; thereby allowing the organization to know what is working well.

Many of the benefits of NOSS derive from the 10 Principles of NOSS- the principle of “Joint Management/controller association endorsement”, “Voluntary participation” of the controllers being observed, and having a “trusted data collection site” have contributed to the strong trust in the NOSS process at NAV CANADA.

NOSS fosters a positive safety culture through an engaged workforce. Again, the voluntary participation, the peers observing peers, and the involvement of controllers in data collection, data cleaning, and providing feedback to other controllers have led to strong engagement of the workforce. This engagement continued into the change management processes, where controllers were very interested in getting involved in the mitigation of the issues.

 Additional benefits:

  • NOSS fosters cooperation with the regulator (Transport Canada)
  • NOSS demonstrates organization’s safety commitment and SMS maturity
  • Threat and Error framework allows for easier exchange of safety issues with customers who are applying LOSA, and with other air traffic service providers who are applying NOSS. We’ve had excellent exchanges with air operators.

In summary NOSS provides:

  • Rich source of data
  • Impetus for discussion and enhancement
  • Individual and organizational awareness/learning

Ann Lindeis, PhD

Director, Safety & Human Performance



The NOSS program has been very successful for Airways and it is now a respected, regular and useful process used within our organisation.  

Airways New Zealand has been involved in the development and implementation of NOSS from the outset. Since NOSS was made a recommended practice by ICAO,  Airways has run three full NOSS surveys of our radar facilities and major towers. 

NOSS has provided us with a wealth of scientifically valid data that has significantly contributed to building a coal face level picture of what is occurring in our operational environment and, more importantly, what the root causes of events are based on a structured methodology i.e. Threat and Error Management.  This was a significant step forward for us as existing data sources gave limited insight into the root causes behind events.

NOSS has been extremely well received by our people as it provides outputs they directly relate to and the process is largely driven by peers who they respect.  Additionally, the process provided additional security for our people as it was endorsed and supported by the organisation and the controller’s union.

Running the NOSS observations is only half the process and it is how the data is used to generate meaningful change that is the most important element.  Airways has used the outputs from NOSS to target specific areas for improvement e.g. raising standards of inter sector co-ordination and improving RTF performance across the organisation. 

The pleasing outcome is that successive NOSS surveys have indicated significant improvements in areas that were targeted through improvement programs.  In addition to specific campaigns, NOSS data has been used for a more generic safety improvement program called PULSE (Professionals Us Leading Safety, Everywhere).   This program was staff lead and based on the principle of defining professional standards and attributes and increasing Human Factors knowledge.  This program generated a very significant improvement in safety performance outcomes in our service delivery area. 

Paul Fallow

Main Trunk Manager

Airways New Zealand