Method
How the Score Is Built
What This Page Is
This page describes how FlightReady turns a flight's data into a number and a set of findings, as the product does it on the date above. It is versioned: when the method changes, the version and the changelog at the foot of the page change with it. Where something is planned rather than built, it says so.
An Index, Not a Probability
The 0–100 number is a Relative Risk Index. Higher means more hazard than usual for flights like this one. It ranks; it does not measure likelihood. A 64 is not a 64% chance of anything, and FlightReady publishes no probability of its own.
Each of ten factors is scored 0–100 from tables set by people, not fitted to outcomes. The index is the weighted mean of the factors that could be scored, using the published weights below. Outcome data does not yet establish the size of any weight.
A factor that could not be read is left out of the mean and its weight is shared among the rest — with one guard: a missing factor is never allowed to lower the index. If counting it at its most benign measured reading would give a higher index, the higher value stands.
- Low0–29
- No additional review required.
- Elevated30–59
- Review the flagged drivers before departure.
- High60–79
- Apply mitigations, or defer.
- Review Required80–100
- Requires authorisation before departure.
A band names what a school's policy asks for next. It is not a verdict, and the same cut points apply in every school and every account.
The Factors and Their Weights
Each share is that factor's weight in a fully informed index (engine v7). When a factor is missing, the others' shares grow in proportion.
- Weather23.1%
- METAR and TAF at each end over the departure window, and SIGMET and G-AIRMET advisories along the route.
- Pilot readiness13.9%
- Your pilot profile — hours, recency, certificate — and your answers to the preflight fitness check.
- Personal minimums13.9%
- The minimums you set, against each field's current METAR ceiling and visibility, the crosswind on the best runway, runway length and night.
- Aircraft readiness11.1%
- The aircraft you selected and its profile.
- Terrain / route9.3%
- The highest terrain along the route against your planned cruise altitude.
- Airport / airspace7.4%
- Runway length at each end (FAA NASR), field elevation and the field's accident record.
- Accident history7.4%
- NTSB accident records near the route, as counts and dates.
- NOTAMs4.6%
- NOTAMs at the departure and destination.
- Human factors4.6%
- Your answers about outside pressure and other human factors.
- Weight & balance4.6%
- The latest weight-and-balance calculation saved for the selected aircraft.
What Is Shown Ahead of the Number
Some findings matter more than any average, so they are shown before the index, at every screen width, and are never folded into it silently:
- Your minimums
- Any personal minimum the flight exceeds.
- Weather
- IFR or LIFR in the current report at either end.
- NOTAMs and TFRs
- NOTAMs graded critical, and TFRs along the route or over the practice area.
- Weight, fuel and runway
- Weight and balance out of limits or not calculated, fuel below reserve, and a runway shorter than your minimum.
Today these findings inform the pilot's decision; they do not lock it. A Go against a flight the engine flags for review is recorded with the pilot's reason. On a school flight, an exceeded minimum, a critical finding, a school threshold or an index of 75 or more sends the flight to review under the school's policy, and the school cannot release a flight whose review was rejected, or an aircraft with a grounding squawk or a maintenance hold, whoever asks. Planned, not yet built: weather hard stops that set a flight's status whatever the index says, each cited to the regulation or the school rule it enforces.
When Data Is Missing
Every factor is reported as read, estimated or unavailable, and the result carries a data-completeness figure: how much of what the index depends on was actually read. A source that could not be read is shown as missing. It is never shown as clear.
When the weather at either end, the forecast the flight needs, the NOTAMs, the TFR check or the SIGMET and G-AIRMET advisories could not be confirmed, or the inputs have aged since the check ran, the result does not state its most favourable finding. It reads “Incomplete — verify manually” and names what was not confirmed.
Known gaps, being closed: when terrain cannot be resolved, or when no pilot profile or aircraft is set, those factors are scored at a stated default rather than marked unavailable; and the weight-and-balance factor reads the latest calculation saved for the aircraft, which may belong to an earlier flight.
Where the Data Comes From
Each saved briefing lists its sources. As of the date above, they are:
- NOAA Aviation Weather Center
- METAR, TAF, PIREP, SIGMET and G-AIRMET, read when the check runs. US Government work, public domain.
- NOTAMs
- SkyLink, a commercial NOTAM service used under its own terms, and the FAA's NOTAM service where it answers. Not a sole source: read NOTAMs in an official briefing.
- FAA TFR list
- Temporary flight restrictions and their details from tfr.faa.gov. Public domain; the FAA describes it as informational and not a sole source.
- Terrain
- USGS elevation, from AWS Terrain Tiles: 3DEP (formerly NED), GMTED2010 and SRTM terrain data courtesy of the U.S. Geological Survey. Public domain in the US.
- Runways and airports
- FAA NASR runway data on the 28-day cycle, and an airport index built from FAA and OurAirports records. Public domain.
- NTSB accident data
- The NTSB aviation accident database, ingested and searched near the route. Public domain. FlightReady's summaries are not NTSB findings.
- NOAA National Blend of Models
- On local flights, when a recent model run is on hand, the chance of a low ceiling or visibility over a practice area, shown as issued with its model run and forecast hour. NOAA open data.
- OpenSky Network
- Live ADS-B traffic near the route, read only through FlightReady's licensed access and shown as context with its read time. It is not part of the index.
- What you enter
- Your pilot profile, aircraft, personal minimums, weight and balance, and preflight answers.
Maps are drawn with Mapbox; no map data feeds the index. FlightReady is not affiliated with, or endorsed by, the FAA, the NTSB, NOAA or the National Weather Service.
How Often It Looks Again
A check reads its sources when you run it; it is not a live feed. Route Watch re-checks watched routes once a day, at 11:10 UTC, for departures in the next 72 hours, and emails you when the result crosses your threshold.
What FlightReady Will Never Claim
These are not claimable at FlightReady's scale, or not true of the product by design. The same list drives the check that every page and email in the product is held to.
NeverNot claimable at FlightReady's scale, or not true of the product by design.
- A per-flight probability of an accident or a fatality.About 1.5 million training flights would be needed to detect a 50% miscalibration of the instructional accident rate.
- That FlightReady reduces or prevents accidents by any amount.No causal design at FlightReady's scale can establish it.
- That a flight is safe, cleared or approved, or that safety is guaranteed.FlightReady states findings; the pilot in command decides (14 CFR 91.3). Unknown is never safe.
- That the index or any FlightReady number is a probability, a percentage risk or a prediction of an accident.The index is ordinal: it ranks hazard, it does not measure likelihood.
- That the model, the score or the method is validated.Say exactly what was verified, on how many forecast-observation pairs, in which published report.
- Confidence, as a word or a percentage, for how complete the data is.Completeness is a count of what was and was not read; call it data completeness.
- Monte Carlo, or any simulation, before a simulation of forecast uncertainty ships.Earlier material implied a Monte Carlo that does not exist.
- A monitoring cadence the scheduler does not run, such as 'every 15 minutes' or 're-scored until departure'.Production schedules are daily; state the cadence actually scheduled.
- FAA approval or certification, an official briefing, dispatch or operational control, 'AC 120-78B-conformant', or 'policy-as-code satisfies 141.93(a)'.None is true of the product; counsel signs off any wording that mentions the FAA.
- Any claim about a named competitor on a public page.Public pages state FlightReady's own commitments. Internal competitive claims are dated and expire 90 days after their last verification.
Verification Before Any Probability
What may be said is unlocked in stages, and each stage needs published evidence before its claim is made. The only probabilities shown today are National Weather Service guidance, as issued and labelled.
Claimed nowBacked by evidence today.
- A transparent, rules-based Relative Risk Index: a heuristic index from expert-set factor scores and weights, never a probability.
- Every factor and its weight is published, and the weights are expert-set rather than fitted to outcomes.
- Data completeness is shown, and a source that could not be read is shown as missing, never as clear.
- The method is published, dated and versioned, with a changelog.
- FlightReady records information and decisions; it does not make them. The pilot in command is the final authority (14 CFR 91.3).
- Inputs come from named public sources, listed with their licences on the method page and on each saved briefing.
Next, in this order: a public verification of NWS guidance against archived observations — how often LAMP and NBM ceiling and visibility forecasts were right, by lead time and station. Only after that, a FlightReady probability that a named weather condition at your arrival time exceeds your limit, for the stations and lead times the verification covers, and nowhere else.
NextNot claimed until its evidence is published.
- A calibrated probability that a named weather variable at your ETA exceeds your limit, for verified strata only.Not claimed until: Verification targets met, and the report published, for that variable, lead time, station class, guidance product and region
- A public verification of NWS guidance (LAMP and NBM) against archived observations, published before any FlightReady probability.Not claimed until: The verification of NWS guidance published
- Simulation of forecast uncertainty behind an input-uncertainty range.Not claimed until: The simulation ships, versioned and reproducible
- Named customers, quotes and case studies.Not claimed until: A real customer's written permission, and counsel review under the FTC rule on reviews and testimonials (16 CFR Part 465)
Later, and only when the data exists — not on a calendar:
LaterGated on data volume or a peer-reviewable study, not on the calendar.
- Population-level accident-rate ratios from NTSB data for a named condition.Not claimed until: A peer-reviewable technical note
- Flights in higher index bands had higher rates of a named surrogate event.Not claimed until: Enough recorded events (at least 77-135) and validation on later flights
- Pilot-specific proficiency indicators associated with a named surrogate event.Not claimed until: Evidence from enough pilots, each with enough linked flights
Who Decides
FlightReady records information and decisions; it does not make them. The pilot in command is directly responsible for, and is the final authority as to, the operation of the aircraft (14 CFR 91.3). On a school flight, the school decides whether its aircraft is released under its own policy; once released, the pilot in command is the final authority.
FlightReady is not an official weather briefing, a dispatch or operational control system, or a substitute for flight instruction. Verify weather, NOTAMs, airworthiness and your minimums with official sources before every flight: read the terms
Changelog
- v1.0October 6, 2026
- First publication. Engine v7, ten weighted factors (traffic is context, not weighted), bands risk-taxonomy-v1.