Why are unstable approaches continued?

Ewout Hiltermann

IASSOctober 2013

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Recommendations

• Aircraft operators:

Use flight data to analyse event flights with the crew for organizational learning.

• Aviation industry:

Develop and implement new technical and procedural solutions to effectively control this risk.

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What’s the Problem?

• Landing accidents are most common accidents

• Relation between unstable approaches and landing accidents

• ± 1000 unstable approaches are flown every day

• Only 3 % of unstable approaches result in go-around

• Why is risk control inadequate?

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Flight Data Monitoring (FDM)

• Data validation shows:

• Data have no context

• The key question remains: why?

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Our Method

1. Trigger events in flight data

2. Assessment of events

3. Decision by Safety Manager

4. Flight analysis with crew (‘Flight Replay’)

5. Organizational learning

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Success factors

• Just culture

• Staff of Flight Safety dept are gatekeeper

• Attendance of flight crew is rostered

• Confidential setting, Chief Pilot / Instructor involved

• Pilot unions involved to monitor the process

• Open atmosphere

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Agreement between unions and company

Flight analysis with crew is intended exclusively as a learning exercise for both the crew and KLM Cityhopper.

The flight analysis will have no adverse consequences whatsoever for the crew.

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1. Expectation to bring the aircraft to the runway2. Perceived pressure by punctuality objective3. Decision gates IMC/VMC, grey area 4. Goal fixation and continuation bias5. Misperception of height above runway

6.Landing perceived safer than go-around

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What did we learn? Some human factors

Human Factors overview

1. Expectation to bring the aircraft to the runway

2. Perceived pressure by punctuality objective

3. Decision gates IMC/VMC, grey area

4. Goal fixation and continuation bias

5. Misperception of height above runway

6. Landing perceived safer than go-around

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Conclusions

• Risk control is generally inadequate because:

– There is no ‘unstable approach warning system’

– Human factors preclude timely crew action

– International recommendations are ineffective

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Recommendations

• Aircraft operators:

Use flight data to analyse event flights with the crew for organizational learning.

• Aviation industry:

Develop and implement new technical and procedural solutions to effectively control this risk.

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Questions?