NOSS: The Methodology and Early Findings Chris Henry The University of Texas Human Factors Research Project The University of Texas at Austin UT Human Factors Research Project © Copyright

The University’s Role Member of the ICAO NOSS Study Group Jointly conducted the first two trials of the NOSS methodology with Airservices Australia and Airways New Zealand.

NOSS Operating Characteristics Over-the-shoulder observations during normal shifts Joint Management/Union sponsorship Voluntary participation De-identified, confidential, and non-disciplinary data collection Specifically designed form for collection of data Trained and calibrated observers Trusted data collection sites Data cleaning process Targets for safety enhancement Feedback results to the controllers

Threats Threat: An event or error that occurs outside the influence of the controller, but which requires their attention and management if safety margins are to be maintained. Air Navigation Service Provider (Internal) Threats Air Traffic Control – Pilot Interaction Threats Environmental Threats

Threats Threat Categories Air Navigation Service Provider (Internal) Threats Airborne Threats Environmental Threats Examples Errors by other controllers Similar call signs Adverse weather Unserviceable equipment Language difficulty Airspace design Procedures A/C flying unassigned heading Restricted Airspace Coordination issue Pilot not responding to call Traffic mix Computer malfunction Other pilot errors Turbulence

Errors Error: An observed deviation from organizational expectations or controller intentions Communication Errors Procedural Errors Equipment / Automation Errors Traffic Handling Errors

Errors Error Categories Communication Procedural Equipment / Computer Traffic Handling Examples Phraseology Readback / Hearback error Missed call Coordination error Checklist Briefing error Aircraft transfer Flight progress strip error Did not check RWY prior to issuing TO clearance AC label inaccurate info Communication system manipulation Radar screen range selection Late decent Incorrect clearance instruction No altitude instruction

Undesired States Controller Console Setup US’s Traffic State US’s Inaccurate representation of traffic Traffic situation not being monitored Incomplete handover Traffic State US’s Separation not assured RWY/TXY not verified to be clear for progress

NOSS Trial Data NOSS trials LOSA archive 5.7 3.7 2.6 0.6 0.5 88% 63% Threats per observation 5.7 3.7 Errors per observation 2.6 Undesired States per observation 0.6 0.5 Percentage of observations with an internal threat 88% 63% Percentage of observations with pilot/ATC interaction threats 87% 54% Percentage of observations with environmental (common) threats 78% 75%

Preliminary Findings Greater threat prevalence of internal and ATC/pilot interactions when compared to LOSA A few pilot – ATC interaction issues Similar call signs Readback / phraseology issues

Methodological Challenges Will it work in the various ATC environments? Focus on positions Concerns Observability: A similar number of observable errors are seen in NOSS and LOSA Lack of proceduralization / standardization: There may be reason to compare organizations with different procedures

What’s Next? NOSS & LOSA: What can each add to the other? Reliability and validity studies in conjunction with FAA NAV CANADA NOSS area/terminal trial Airservices Australia tower trial Fully operational NOSS in 2006? Airservices?

cshenry@mail.utexas.edu www.psy.utexas.edu/HumanFactors