Human Reliability Assessment In ATM: the CARA tool

Transcription

1 Human Reliability Assessment In ATM: the CARA tool Barry Kirwan EUROCONTROL Experimental Centre France

2 What I m going to talk about CARA: Controller Action Reliability Assessment HRA How CARA works How it was developed Application Example Validation check )

3 Where does CARA fit in HRA? Document & Feed forward to Ops Task Analysis Human Error Identification Define Error Reduction Measures HRA Process Model the human in the safety case Evaluate the human contribution Consider Human Dependence Quantify Human Error Probability

4 Elements of Quantification the HEART template Define the Generic Task Type (GTT) Human Error Assessment & & Reduction Technique Williams, 1985 Calculate the Human Error Probability (HEP) =GTTxEPC i..n Consider Error Producing Conditions (EPCs) Assess how much each EPC affects task performance

5 Generic Task Types

6 Deriving the Generic Tasks - the Model Underlying CARA Attention and Action Hierarchy Position take-over A. Offline tasks B. Checking Monitoring Confirming/ updating mental picture Sector plan D. Solving conflicts E. Plan aircraft in/out of sector F. Manage routine traffic G. Issuing instruction s to ac C. Monitoring for conflicts Workload monitoring Managing requests Radar FPS Info displays Reminders Verbal Instruction Datalink Non-communication

7 Quantification Sources Other HRA techniques Published HF Studies Real world Data collection Simulator Data

8 Task Context Generic Task Type HEP Uncertainty Bounds A. Offline tasks A. Offline tasks B1. Active search of radar or FPS, assuming some confusable information on display B. Checking B2. Respond to visual change in display (e.g. aircraft highlighted changes to low-lighted) B3. Respond to unique and trusted audible and visual indication C. Monitoring for conflicts or unanticipated changes D. Solving conflicts C1. Identify routine conflict Holding Value C2. Identify unanticipated change in radar display (e.g. change in digital flight level due to aircraft deviation or corruption of datablock). D1. Solve conflict which includes some complexity. Note, for very simple conflict resolution consider use of GTT F. D2. Complex and time pressured conflict solution (do not use time pressure EPC) Holding Value

9 E. Plan aircraft in/out of sector F. Manage routine traffic E. Plan aircraft in/out of sector F. Routine element of sector management (e.g. rule-based selection of routine plan for an aircraft or omission of clearance). G1. Verbal slips G. Issuing instructions G2. Physical slips (two simple choices) M. Technical and support tasks M3. Routine maintenance task

10 Pilot actions

11 Error Producing Conditions

12 Sources of Error Producing Conditions Incidents & Error Classification Schemes (eg HERA) HRA Models (eg CREAM, NARA, HEART SPAR-H Human Factors Literature on ATM Performance

13 Error Producing Conditions (examples) x11 x10 Traffic Complexity Time Pressure Unfamiliarity x20 x3 Vigilance EPCs Procedures x5 x5 Poor equipment feedback Cognitive Overload Shift Handover On 0n the job Training x8 x6 x10

14 What does it look like, What does it tell us?

15 CARA in practice: airport example Aircraft Need to 1 speed fails to up exit airport runway throughput ATCO Aircraft fails 1 vacates to identify runway a/c1 early stopped Or Aircraft ATCO 2 fails anticipates to warn this, a/c2 lands in time sooner a/c2 a/c1

16 CARA in practice Task: Identify AC1 stopped: Audible and visual warning: Controller identifies AC 1 is stationary within the OFZ Generic Task Type: B3. Respond to unique and trusted audible and visual indication Human Error Probability: Error Producing Conditions: None identified Assumptions/ HF Requirements Assumptions/ HF Requirements: Well designed alarm with unique compelling audible signal (non-startling); directional from radar display; visual alarm flashing until acknowledged (flash rates as per standards); attentiongaining; trials must verify HF acceptability

17 CARA in practice Task: Warn AC2 in time: - Audible and visual warning: Controller identifies AC 1 is stationary within the OFZ Generic Task Type: F: Routine instruction or clearance Human Error Probability: Error Producing Conditions: Time Pressure Maximum Affect x11 Assessed Proportion of Affect: 0.2 Human Error Probability: Assumptions/ HF Requirements Assumptions/ HF Requirements: Assume controllers trained to warn AC2 rather than talk to AC1 to identify the problem procedures need to be developed/assessed and trained

18 An example of CARA in action E+00 Task HEP = = E-01 HEP E E-03 Audio/Visual Visual Audible and visual alarm Visual alarm only No visual or audible alarm HEART assessment Interface Neither Original HEP

19 How does it compare to HEART?

20 Ground-Based Augmentation System Safety Case

21 1 HEART Value CARA Value A1 A2 A3a A3b A4 B1 B2 B3 B4 B5 C2a C2b C4

22 Key Findings from GBAS study for CARA GTT application more straightforward Fewer EPCs Required - better match at GTT level Similar error probabilities Identified improvements to CARA

23 Future work Data collected on alarm response Internal Review 08 Manual Production (08) Application in Macro Safety Case (SESAR)

24 24 Questions?

25 Do the Generic Tasks Match Safety Case Needs? ASAS (Airborne Separation Assurance System) Instruct wrong aircraft Give ASAS instruction to non-asas equipped aircraft Fail to detect ASAS aircraft deviation Send incorrect spacing Link wrong aircraft on screen Fail to detect deceleration of aircraft Pilot exceeds spacing Pilot targets wrong aircraft Pilot turns early RVSM (Reduced Vertical Separation Monitoring) Fail to detect level bust Issue wrong flight level clearance Fail to react in time to short term conflict alert Fail to provide collision avoidance advice Fail to use correct emergency terminology Fail to detect non-rvsm aircraft Fail to coordinate aircraft into sector with conflict-free trajectory F F/G1 C2 F G2 C2 P P P C2 F B3 D2 G1 C1 E