Flight risk assessment tool (FRAT) for Part 135: what to score and how to use the result

A Flight Risk Assessment Tool — FRAT — is a structured scoring system that converts the risk factors present on a specific flight into a documented risk band. Its purpose is not to replace pilot judgment. It is to make risk assessment consistent, auditable, and immune to the "it felt fine" problem that shows up in incident investigations.

The FAA does not mandate a specific FRAT format for Part 135 on-demand operations, but its use is strongly encouraged under Advisory Circular 120-92B (Safety Management Systems for Aviation Service Providers) and is a standard element of any functioning Part 5 SMS. Insurance underwriters and FSDO program managers increasingly look for FRAT records as evidence that an operator is actively assessing risk before dispatch — not just reactively reporting incidents after the fact.

The four FRAT categories

A well-designed FRAT covers four broad risk domains. Each domain contains individual factors; each factor is scored on a numeric scale (typically 0–2 or 0–3); the domain scores sum to a total; the total maps to a risk band.

1. Weather

The highest-weight category for most operations. Score the departure, en-route, and destination conditions independently — a flight can have good destination weather and still face significant en-route icing or convective risk.

• Visibility at departure and destination (vs. published minimums)
• Ceiling at departure and destination
• En-route IMC expected
• Icing risk (PIREPs, forecast, aircraft capability)
• Convective activity (METARs, TAFs, Prog Charts, SIGMETs)
• Winds aloft / turbulence forecast
• Mountain wave or rotor risk (terrain-specific operations)

2. Pilot factors

Currency and experience on the specific route and aircraft — not just general experience. A 10,000-hour ATP who has never flown into a specific mountain strip is not as low-risk as a 3,000-hour pilot who flies it weekly.

• Recent experience in type (hours in last 30 / 90 days)
• Familiarity with destination airport (number of prior arrivals)
• Recency in IMC (actual instrument time in last 90 days)
• Duty time approaching limit
• Rest — time since last rest period
• Reported fatigue or illness (self-reported by crew)

3. Aircraft and dispatch factors

• Deferred MEL items and their IFR/VFR applicability
• Time since last inspection
• Any open squawks not on the MEL
• Fuel state vs. planned fuel — any compression from reduced load
• Cargo or passenger special considerations (hazmat, high-value, medical)

4. Environment and operations

• Night vs. day operation
• Terrain complexity en-route
• Passenger familiarity with briefings (charter first-timers vs. repeat clients)
• Pressure to complete — any timeline or passenger pressure on the flight
• Airport familiarity (non-towered, short runway, limited lighting)

Calibrating the thresholds

The score boundaries for GREEN, AMBER, and RED are calibrated by the operator, not set by the FAA. This is intentional — risk tolerance varies by aircraft type, operation, and route. A turbine operator in the Gulf of Mexico has a different baseline than a piston operator in coastal Alaska.

A starting point used by many operators:

The thresholds should be reviewed annually or after any incident where the FRAT score did not reflect the actual risk that materialized. If the system is consistently giving GREEN on flights that turn into close calls, the thresholds or the factor weights need recalibration.

What to do with each band

GREEN: No additional action required beyond normal dispatch. Document the score and proceed.

AMBER: The dispatcher and PIC identify which factors drove the score into AMBER and document the mitigations applied before release. Examples: weather improved since the initial FRAT was run — rescore; a fatigued crew member is replaced — rescore; a briefing on the specific hazard is added to the release.

RED: The flight does not release until a named person with authority (DO, chief pilot, or whoever the operator's program designates) reviews the factors, documents a go/no-go determination, and signs the release. The sign-off must be by name and timestamp — not "ops approved."

What the record needs to show

For FSDO or insurance review, the FRAT record for a given flight needs to show:

• Date and flight identifier
• Each factor scored and its individual score
• The total score and resulting band
• For AMBER: mitigations documented
• For RED: the name, credential, and timestamp of the required sign-off

A spreadsheet works. A PDF attached to the flight release works. A system that logs the score in an append-only record tied to the dispatch works. What does not work is a verbal assessment — "we looked at it and it felt like a GREEN" — with nothing written down.

The value of a FRAT record is not in any individual entry. It is in the distribution over time: an operator who can show a trailing-12-months FRAT distribution — 80% GREEN, 18% AMBER, 2% RED, with all RED sign-offs documented — is showing an underwriter or an FSDO examiner that risk assessment is a habit, not a performance for the review.