FOD Severity and Risk Matrix

The Purpose of Risk Scoring

Not all FOD carries the same risk, and treating every finding identically wastes attention. Risk scoring makes sure resources are allocated in proportion to the danger. It also gives your team a shared, defensible way to decide what needs escalation. The FOD risk matrix in the guide multiplies two simple ratings, each on a four-point scale.

Severity Levels: How Bad Would the Damage Be?

Severity asks a single question: if this item caused damage, how bad would it be?

• 1, Low: unlikely to damage equipment or injure anyone under any foreseeable scenario. Examples are paper, cardboard or plastic film in a non-critical area.
• 2, Moderate: could affect housekeeping, process reliability or minor equipment, but is unlikely to cause injury or major damage. Examples are tape, tie wrap, a rag or a small plastic piece.
• 3, High: could damage equipment, tires, tooling or assemblies, or create an ingestion or entanglement risk, and could cause injury. Examples are a fastener, metal chip, safety wire, gravel in a movement area or a personal item in a critical area.
• 4, Critical: could threaten the aircraft, mission, personnel, critical product or flight hardware, with potential for catastrophic damage or fatal injury. Examples are a tool, a suspected part or sharp metal in a critical area, or debris in or near an engine intake.

Likelihood Levels: How Often, and How Well Controlled?

Likelihood asks how often this happens, or how likely it is to cause damage given the controls in place.

• 1, Rare: no similar finding in recent history and the controls are effective.
• 2, Possible: an occasional similar finding. Controls generally work but are not perfect, perhaps once every few months.
• 3, Likely: a repeat finding with a known control weakness. The pattern is clear.
• 4, Frequent: a common finding or known unresolved source. Controls are absent or consistently failing.

This is where your FOD trend data earns its keep. Without a history of findings, likelihood is a guess. With it, you can see whether an item is a one-off or a known problem that has not been fixed.

Risk Score and Required Response

The FOD risk score is severity multiplied by likelihood, and the score sets the response and timeline:

• 1 to 3, Low: monitor, log and trend, with no immediate individual action. Review at the monthly trend meeting.
• 4 to 6, Medium: assign corrective action, identify the source and implement a control. Action is assigned within one week and closed within 30 days.
• 8 to 12, High: escalate to the program owner and start a formal investigation with corrective action and verification. Investigation begins within 24 hours and action is assigned within one week.
• 16, Critical: immediate escalation and stop-work consideration, formal investigation and notification of senior leadership. Immediate, and not to be deferred.

Scoring Examples From the Guide

• A paper wrapper in a corridor in an awareness area scores severity 1 and likelihood 2, so 2: monitor.
• A tie wrap on a hangar floor in a control area, first occurrence, scores 2 by 1, so 2: monitor.
• A washer on a runway centerline scores 3 by 2, so 6: assign corrective action and inspect the runway more often.
• A socket found under an engine after maintenance scores 4 by 2, so 8: escalate and investigate tool control.
• Safety wire on a hangar floor, the third time this month in the same bay, scores 3 by 3, so 9: escalate and investigate formally.
• The same socket type, third occurrence in the engine area in two months, scores 4 by 4, so 16: immediate escalation and stop-work consideration.

Severity Depends on Location

The same item can carry different severity in different places. The guide shows a washer scoring severity 1 in an awareness area, 2 to 3 on a hangar floor in a control area and 4 in a critical zone such as an engine intake. A tie wrap runs from 1 to 3, and safety wire from 1 or 2 up to 4. Train personnel to ask two questions: what is this item, and where is it? Location is the fundamental severity question, which is why FOD area classification and clearly marked zones matter. Durable, high-contrast floor tape or paint at the boundaries between classifications, such as a red line marking a FOD Critical area, together with FOD signs and floor tape, makes the zone obvious at a glance.

Connecting the Matrix to Investigation

The matrix works alongside the category codes in the FOD classification system. It also feeds investigation triggers. A single finding that scores 8 or higher warrants a repeat investigation regardless of whether it is a repeat, and so does any TOOL or PART finding. Use the repeat FOD investigation worksheet and the corrective action tracker to carry those cases to closure.

Thresholds and timelines should suit your operation, so review them with leadership and adapt them where needed. The free FOD Prevention Program Guide includes the full rating tables and worksheets.