Understanding the Differences:
-Safety Policy & Objectives,
-Safety Performance Indicators (SPIs),
-Safety Performance Targets (SPTs), and
-Lagging vs. Leading Indicators in Aviation Safety Management
In the modern aviation industry, safety is managed through a performance-based approach as required by ICAO Annex 19 (Safety Management) and detailed in the Safety Management Manual (Doc 9859, 4th Edition).
At the heart of this system are four interconnected concepts:
-Safety Policy & Objectives,
–Safety Performance Indicators (SPIs),
–Safety Performance Targets (SPTs), and
the distinction between lagging and leading indicators.
While they are often discussed together, each plays a distinct role in helping organizations move from reactive accident prevention to proactive risk management.
This article clarifies the differences, explains their relationships, and provides practical aviation examples to help safety managers, accountable executives, and SMS practitioners implement these elements effectively.
A. Safety Objectives: The High-Level “North Star”
Safety objectives are brief, high-level statements that describe the desired safety outcomes an organization (or State) aims to achieve. They represent the strategic vision and commitment to safety.
ICAO Definition (Doc 9859): “A brief, high-level statement of safety achievement or desired outcome to be accomplished by the State safety programme (SSP) or service provider’s safety management systems (SMS).”
They are derived from the organization’s top safety risks (identified through hazard identification and risk assessment) and form the foundation for everything that follows.
Characteristics: Qualitative or broadly quantitative, long-term oriented, and aligned with the organization’s overall Safety Policy.
Examples:
ATO Ensure 100% compliance with pre-flight inspections and aircraft walk-around procedures.
CAMO Maintain effective oversight of contracted maintenance organisations.
AMO: Ensure full compliance with regulatory requirements and approved procedures.
Part-NCC Maintain an effective fatigue management system.
AOC Maintain the highest standards of crew resource management (CRM).
Safety objectives do not include specific numbers or metrics, they set the direction. They are reviewed periodically (e.g., annually, quarterly, monthly) as part of the safety performance review process.
B. Safety Performance Indicators (SPIs): The Measurable Metrics
Safety Performance Indicators (SPIs) are the specific, data-based parameters used to monitor and assess how well the organization is performing against its safety objectives.
ICAO Definition: “A data-based parameter used for monitoring and assessing safety performance.”
They can be high-consequence (serious events) or lower-consequence (routine deviations or process compliance).
SPIs are selected because they are relevant to the organization’s specific risks, operations, and context.
Example SPIs/SPTs:
1. ATO – Ensure 100% compliance with pre-flight inspections and aircraft walk-around procedures
SPI: Percentage of flights where the pre-flight inspection and walk-around were fully documented as completed in accordance with the approved checklist.
SPT: ≥ 99.8% compliance per month (with zero tolerance for any undocumented walk-around on training or check flights).
2. CAMO – Maintain effective oversight of contracted maintenance organisations
SPI: Percentage of contracted maintenance organisations that received a satisfactory oversight audit/assessment within the planned surveillance interval (including ramp checks, document reviews, and quality audits).
SPT: 100% of contracted maintenance providers audited as per the CAMO oversight plan within the last 12 months, with all major findings closed within 30 days.
3. AMO – Ensure full compliance with regulatory requirements and approved procedures
SPI: Percentage of maintenance tasks and work packages completed in full compliance with the approved Maintenance Organisation Exposition (MOE), procedures, and regulatory requirements (verified through internal quality audits and sampling).
SPT: ≥ 98% compliance rate per quarter, with zero open Level 1 (safety-critical) findings from internal or external audits.
4. Part-NCC – Maintain an effective fatigue management system
SPI: Percentage of flight crew duty periods that remained within the approved Fatigue Risk Management System (FRMS) limits (including flight time, duty time, and rest requirements).
SPT: 100% of all duty periods conducted within FRMS limits, with any fatigue-related reports investigated and acted upon within 7 days.
5. AOC – Maintain the highest standards of crew resource management (CRM)
SPI: Percentage of Line Checks, LOFT/LOE sessions, and recurrent training sessions where CRM and Threat & Error Management (TEM) performance were assessed as “Satisfactory” or better by the examiner/instructor.
SPT: ≥ 95% of all assessed CRM/TEM events rated satisfactory or above, with any “Unsatisfactory” cases followed by immediate additional training and re-assessment.
C. Safety Performance Targets (SPTs): The Specific Goals
Safety Performance Targets (SPTs) are the planned, time-bound levels of performance that the organization sets for each SPI. They represent the “acceptable” or “desired” level of achievement.
D. Lagging vs. Leading Indicators: Reactive vs. Proactive Measurement
SPIs (and their associated SPTs) are further classified by when they provide information about safety performance:
Examples:
Lagging SPI: “Number of serious incidents (e.g., runway excursions) per 10,000 flight hours” — tells you what has already gone wrong.
Leading SPI: “Percentage of pilots who completed stabilized-approach training on time” or “Number of voluntary hazard reports submitted per month” — tells you whether the system is healthy before an incident occurs.
Best Practice: Use a balanced mix of both. Lagging indicators confirm that your controls are working; leading indicators help you act before problems materialize. ICAO and industry guidance (e.g., SM ICG) strongly recommend this combination for effective safety performance management.
How These Elements Work Together in an SMS
The relationship is hierarchical and cyclical:
-Safety Objectives (strategic “what we want to achieve”) → drive the selection of
-SPIs (measurable metrics) → for which you set
-SPTs (specific targets).
Practical Tips for Implementation
-Start with your top 3–5 safety risks to select meaningful SPIs.
-Ensure SPIs are SMART (Specific, Measurable, Achievable, Relevant, Time-bound).
-Define clear data sources, responsibilities, and alert thresholds.
-Review performance quarterly at the Safety Review Board (SRB) or equivalent.
-Document everything in your SMS manual and use it to demonstrate compliance during audits.
Conclusion
Safety objectives provide the vision, SPIs give you the dashboard, SPTs set the goals, and the lagging/leading distinction ensures you are both learning from the past and shaping the future. Organizations that master these concepts move beyond mere regulatory compliance to genuine, data-driven safety excellence.
By implementing them thoughtfully — as encouraged in ICAO Doc 9859 — aviation service providers can achieve measurable, continuous improvement in safety performance while maintaining an acceptable level of safety (ALoSP).
If you would like a downloadable template for SPIs/SPTs, more detailed examples tailored to your operation (airline, ATO, CAMO, AMO, Part-NCC, aerodrome, MRO, etc.), or help aligning these with your current SMS manual, just let me know sms@mycs.swiss !
Thank you for your attention!
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