Direct Answer
EWINS — an Enhanced Weather Information System — is an FAA-approved program that authorizes a Part 135 (or Part 121) certificate holder, or a vendor working under it, to obtain, analyze, and in some cases produce or amend aviation weather products for flight planning and dispatch. It exists because 14 CFR §135.213(a) and §135.225(a)(1) limit a Part 135 operator's weather to the U.S. National Weather Service, an NWS-approved source, or "a source approved by the Administrator" — and an EWINS is one path to becoming that approved source, reflected in your operations specifications (commonly the aviation-weather paragraph A010).
Most on-demand Part 135 operators do not need an EWINS: if you plan from government weather products or a vendor that redistributes them unchanged, you already have an acceptable source. EWINS becomes relevant only when you want to tailor, produce, or amend weather — or depend on a commercial provider that does. The approval criteria live in FAA guidance (Order 8900.1, Vol. 3, Ch. 26), not in the CFR, and approval is case-by-case. Whatever your setup, the authorization for every weather source you use must be documented in your OpSpecs and instantly retrievable for an inspector.
What EWINS Actually Is (in Plain English)
EWINS stands for Enhanced Weather Information System. The single most common misconception is that EWINS is a product you log into. It is not. EWINS is an FAA-approved program — a combination of procedures, qualified people, and data-handling capability — that authorizes a certificate holder to do more with weather than passively read what the government publishes.
Here is the logic chain that makes it matter. Under 14 CFR §135.213(a), a Part 135 operator's weather reports and forecasts must come from one of exactly three places: the U.S. National Weather Service, a source the NWS has approved, or "a source approved by the Administrator." That third phrase is the door. An EWINS is one way to walk through it — to become a source the FAA Administrator has approved for your operation. The same approved-source language reappears in 14 CFR §135.225, which governs whether you can even begin an instrument approach.
The criteria the FAA uses to evaluate an EWINS are described in agency guidance — FAA Order 8900.1, Volume 3, Chapter 26 — not in the regulation itself. That guidance describes an approved system as one with adequate procedures, qualified personnel, and communications and data-processing capability to obtain, analyze, and disseminate aeronautical weather data. Because it is guidance, the specifics are evaluated case-by-case by your principal operations inspector, and the binding authorization ends up in your operations specifications, not in the CFR.
Three layers that have to line up
The CFR (the rule)
14 CFR §135.213 and §135.225 say weather must come from NWS, an NWS-approved source, or an Administrator-approved source. This is the same for every Part 135 operator.
Your operations specifications (the grant)
Your OpSpecs — commonly the aviation-weather paragraph A010 — translate that rule into exactly which sources your certificate is authorized to use, including any EWINS or commercial provider. This is operator-specific and binding.
FAA guidance (the how)
FAA Order 8900.1, Vol. 3, Ch. 26 describes how an EWINS is evaluated and approved. It shapes the approval but is guidance, not regulation — and it can change.
The acronym is niche — and the guidance evolves
EWINS terminology, related concepts (commercial weather information providers, internet delivery providers), and the underlying FAA guidance have shifted over the years. Treat any specific paragraph number, "automatically approved" claim, or vendor description as something to confirm against your current operations specifications and with your FSDO — not as a fixed fact. This article points you to the right rules and the right questions; your OpSpecs give the authoritative answer for your certificate.
Do You Actually Need an EWINS? (Most Operators Don't)
This is the question that matters operationally, and the honest answer surprises people: the typical on-demand Part 135 charter operator does not need an EWINS. The test is not the size of your fleet — it is what you do with the weather.
You likely do NOT need an EWINS if…
- You flight-plan from U.S. National Weather Service products — METARs, TAFs, AIRMETs/SIGMETs, area and aviation forecasts.
- Your weather vendor redistributes government products without altering the content.
- You consume weather; you do not produce, tailor, or amend forecasts your dispatch decisions rely on.
EWINS becomes relevant if…
- You want to generate your own tailored forecasts for flight planning or release.
- You amend or augment government products rather than using them as published.
- Your operation depends on a commercial provider that produces customized analyses, not just redistributes NWS data.
If you fall on the right-hand side, the next move is not to buy software labeled "EWINS." It is to look at your operations specifications and confirm what weather sources you are actually authorized to use, then work with your principal operations inspector on the appropriate authorization. A certificate holder can either operate as its own EWINS in-house or rely on a vendor's approved EWINS — but in both cases the authorization must be reflected in your OpSpecs. The vendor relationship by itself does not make a non-government source legal for your flights.
Why this is an audit issue, not just a planning preference
Because §135.225 ties the legality of starting an instrument approach to a current report from an approved reporting source, an operator relying on an unauthorized weather source has a finding waiting to happen — and the finding is documentary. The inspector is not asking whether the forecast was accurate; they are asking whether the source was authorized in your OpSpecs. That is a question you answer with a document, which is exactly why the authorization record has to be current and instantly retrievable.
Not sure your weather-source authorization is documented correctly?
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Run the Free FAA Readiness ScoreThe Rules Behind EWINS, Section by Section
Every claim below is tied to the current CFR text on Cornell Law or to FAA guidance (clearly labeled). The CFR sets the limits; your operations specifications grant the authorization.
The weather-source rule: 14 CFR 135.213
14 CFR §135.213This is the foundational rule. It defines which weather information a Part 135 operator is permitted to use for flight planning. EWINS exists because of the third option in this list — "a source approved by the Administrator."
Acceptable sources are limited
Weather reports and forecasts used for Part 135 operations must come from the U.S. National Weather Service, a source approved by the National Weather Service, or a source approved by the Administrator. There is no fourth catch-all category.
14 CFR §135.213(a)The VFR pilot-observation exception
For VFR operations, if a required report is not available, the pilot in command may use weather information based on that pilot’s own observations or those of other competent persons. This exception does not extend to IFR planning.
14 CFR §135.213(a)IFR observations have a location rule
Weather observations made for IFR operations must be taken at the airport where those operations are conducted, unless the Administrator issues operations specifications allowing observations from another location. This is one of several places your OpSpecs control what is acceptable.
14 CFR §135.213(b)Why it matters: Where the rule says "approved by the Administrator" or "operations specifications," that is where EWINS and your OpSpecs come in.
Where the source matters most: 14 CFR 135.225
14 CFR §135.225Section 135.225 governs IFR takeoff, approach, and landing minimums. It repeatedly ties go/no-go decisions to a weather report from an approved reporting facility — which is why the source authorization in your OpSpecs is not a paperwork formality but an operational gate.
Approved reporting facility required for IFR
A pilot may not begin an instrument approach unless a weather reporting facility operated by the U.S. National Weather Service, a source approved by the National Weather Service, or a source approved by the Administrator provides a current report for the airport.
14 CFR §135.225(a)(1)Latest report must support the operation
The latest weather report from that facility must indicate conditions at or above the authorized IFR landing minimums for the procedure to be initiated. The report is the trigger; the source authorization is what makes the report usable.
14 CFR §135.225(a)(2)Same approved-source language for landing
The landing-minimums provisions repeat the same approved-source requirement, including a current local altimeter setting for the destination from an approved reporting facility. An unauthorized source cannot satisfy these conditions.
14 CFR §135.225(b)Why it matters: If your dispatch leans on tailored or non-government weather, this is the rule that makes the EWINS/OpSpec authorization mandatory rather than optional.
How EWINS is authorized: operations specifications + FAA guidance
OpSpec/MSpec A010 · FAA Order 8900.1, Vol. 3, Ch. 26 (guidance)The CFR sets the rule; your operations specifications grant the specific authorization; FAA guidance describes how the EWINS approval is evaluated. All three layers have to line up — and all three produce documents an inspector can ask for.
Operations specifications are the binding grant
Your authorization to use a specific non-government weather source is reflected in your operations specifications, commonly in the aviation-weather paragraph frequently identified as A010. If a source is not covered there, it is not authorized for your operation — confirm the exact paragraph designation with your FSDO.
14 CFR §119.5 (certificate/OpSpecs)EWINS approval criteria are guidance, not CFR
FAA guidance (Order 8900.1, Volume 3, Chapter 26) describes the EWINS evaluation: an approved system must have adequate procedures, qualified personnel, and communications and data-processing capability to obtain, analyze, and disseminate aeronautical weather data. This is guidance material — it shapes the approval but is not regulation.
FAA Order 8900.1, Vol. 3, Ch. 26 (guidance)Self-EWINS or contracted EWINS
A certificate holder can operate as its own EWINS in-house or rely on a vendor’s approved EWINS. Either way, the authorization to use that source must appear in the operator’s operations specifications — the vendor relationship alone does not make a non-government source legal for your flights.
OpSpec/MSpec A010 (operator-specific)Why it matters: Approval is case-by-case. Treat any acronym, paragraph number, or "automatically approved" claim as something to verify against your current OpSpecs, not assume.
The Weather-Source Records an Inspector Will Ask For
The applicable rules — §135.213 and §135.225 — govern which sources you may use and what conditions must exist before you fly, but they do not publish a single "weather records" retention table. In practice, an inspector reviewing your weather-source compliance expects you to produce these documents on demand. Each is a document, and each has to be current and findable.
Operations specifications — the aviation-weather authorization
The OpSpec/MSpec paragraph (commonly A010) that lists which weather sources your certificate is authorized to use, including any EWINS or commercial provider. This is the single most important document in a weather-source review — it is what makes a non-government source legal for your flights.
EWINS approval and supporting procedures (if you have one)
For an in-house or contracted EWINS, the approval itself plus the procedures, communications/data-processing description, and the personnel-qualification records that supported it. FAA guidance ties the approval to demonstrated procedures, people, and capability — so those records are the proof the approval still stands.
Dispatch / flight-release documentation for IFR operations
The records showing that the §135.225 weather minimums were met for IFR takeoffs, approaches, and landings — i.e., that a current report from an approved reporting source supported the operation. This is where the source authorization and the actual operation meet on paper.
Vendor agreements and source documentation
If you rely on a commercial weather information provider, the documentation describing what the provider supplies (redistributed government products vs. tailored/produced content) and how that maps to your authorized sources. This is what an inspector uses to confirm the vendor relationship actually fits your OpSpec authorization.
FileFlo: the proof layer behind your weather-source authorization
FileFlo is a compliance document intelligence platform — and it is important to be precise about what it is not. FileFlo is not an EWINS. It does not obtain, produce, amend, or deliver weather, and it is not a weather vendor. It is the read-only proof layer that makes the documents behind your weather-source compliance current, complete, and instantly retrievable. It classifies and stores your operations specifications (including the A010 aviation-weather authorization), any EWINS approval and its supporting procedures and personnel-qualification records, and the dispatch/release documentation tied to your §135.225 IFR operations — then tracks revision currency and surfaces anything stale before an inspector finds it.
It sits alongside your existing stack and does not replace your safety management system, your dispatch or flight-planning software, or your weather provider. When a principal operations inspector asks, "Show me the authorization for this weather source," the answer is one search — across the same document domains they cover for pilot records, maintenance recordkeeping, and training programs.
Related Part 135 compliance & audit-prep reading
Frequently Asked Questions
What is EWINS in aviation?
EWINS stands for Enhanced Weather Information System. It is an FAA-approved program — not a piece of software you buy — that authorizes a Part 135 or Part 121 certificate holder (or a vendor working under it) to obtain, analyze, tailor, and in some cases produce or amend aviation weather products and forecasts for flight-planning and dispatch use. Under 14 CFR 135.213(a) and 135.225(a)(1), a Part 135 operator's weather information must come from the U.S. National Weather Service, a source approved by the National Weather Service, or a source approved by the Administrator. An EWINS is one way to become "a source approved by the Administrator," and that authorization is reflected in your operations specifications. The approval criteria are described in FAA guidance (FAA Order 8900.1, Volume 3, Chapter 26) — they are guidance, not regulation.
Does a Part 135 operator need an EWINS authorization?
Most Part 135 on-demand operators do not need an EWINS. If you flight-plan from U.S. National Weather Service products (METARs, TAFs, AIRMETs/SIGMETs, area forecasts) or from a commercial vendor that simply repackages government products without altering them, you are already using an acceptable source under 14 CFR 135.213(a) and 135.225(a)(1). An EWINS authorization becomes relevant when you want to do more than consume government weather — for example, generate your own tailored forecasts, amend or augment NWS products, or rely on a commercial provider that produces customized analyses your dispatch decisions depend on. Whether any non-government source is acceptable for your operation is determined by your FAA-approved operations specifications and your principal operations inspector, not by the vendor's marketing. Verify your specific authorization in your OpSpecs before relying on a non-government weather source.
What does an EWINS let an operator do that it could not do otherwise?
An EWINS authorization lets a certificate holder go beyond passively reading government weather. Per FAA guidance (Order 8900.1, Vol. 3, Ch. 26), an approved EWINS can obtain, analyze, and disseminate aeronautical weather data and, depending on the scope of the approval, produce or amend weather products such as tailored forecasts used for flight planning, release, and dispatch. The trade-off is rigor: to be approved, the system must demonstrate adequate procedures, qualified personnel, and communications and data-processing capability to do this reliably. That means the EWINS approval comes with a documentation burden — the procedures, personnel qualification records, and authorization itself all have to exist, be current, and be retrievable when an inspector asks.
Where is EWINS authorized — what operations specification?
An operator's authorization to use a particular weather source — including an EWINS or a commercial weather information provider — is reflected in its operations specifications, commonly in the OpSpec/MSpec paragraph addressing aviation weather information (frequently identified as A010). The operations specifications are the binding, operator-specific document; they translate the general weather-source rules of 14 CFR 135.213 and 135.225 into exactly which sources your certificate is authorized to use. If a weather source is not covered by your operations specifications, it is not an authorized source for your operation regardless of how good the product is. Always read your current OpSpecs to confirm which sources you are authorized to use, and confirm the exact paragraph designation with your FSDO.
What is the difference between an EWINS and a commercial weather provider (CWIP)?
A commercial weather information provider (CWIP) is a vendor that supplies weather products to operators. Some CWIPs simply redistribute U.S. National Weather Service products unchanged; others produce tailored or value-added forecasts. An EWINS is the FAA-approved system and set of procedures under which enhanced weather work — tailoring, producing, or amending products — is done. A Part 135 certificate holder can either act as its own EWINS (operating the system in-house) or rely on a vendor's approved EWINS, but in both cases the authorization to use that source must be reflected in the operator's operations specifications. The key compliance point: the vendor relationship does not, by itself, make a non-government source legal for your flights — your OpSpecs do.
What weather records does a Part 135 operator need to keep for an inspection?
The applicable Part 135 weather rules — 14 CFR 135.213 (weather reports and forecasts) and 135.225 (IFR takeoff, approach, and landing minimums) — govern which sources you may use and what conditions must exist before you operate, but they do not themselves set a single "weather records" retention table. In practice, an operator should be able to show, on demand: the operations specification that authorizes each weather source it uses (including any EWINS or CWIP authorization); for an in-house or contracted EWINS, the approved procedures and the personnel-qualification records that support the approval; and the flight-release or dispatch documentation that demonstrates the weather minimums of 135.225 were met for IFR operations. Treat these as inspection-critical documents that must be current and instantly retrievable — that retrievability is exactly the gap FileFlo is built to close.
Is EWINS the same as a qualified internet communications provider (QICP)?
No. They address different things. A qualified internet communications provider (QICP) is about how aeronautical information is delivered to you over the internet reliably and securely. An EWINS is about who is authorized to obtain, analyze, and — where approved — produce or amend the weather content itself. An operator can receive government weather through an internet provider and never need an EWINS; conversely, an operator that produces tailored forecasts may need EWINS authorization regardless of the delivery channel. Because the terminology and the underlying FAA guidance evolve, confirm current definitions and any applicable authorizations with your principal operations inspector rather than relying on vendor descriptions or older articles.
How does FileFlo help with EWINS and weather-source compliance?
FileFlo is a compliance document intelligence platform — the proof layer, not the weather system. It does not obtain, produce, or amend weather, and it is not an EWINS. What it does is make the documents that prove your weather-source authorization current, complete, and instantly retrievable: it classifies and stores your operations specifications (including the A010 aviation-weather authorization), any EWINS approval and its supporting procedures and personnel-qualification records, and the dispatch/release documentation tied to your 135.225 IFR operations, then tracks revision currency and surfaces anything stale before an inspector finds it. When a principal operations inspector asks "show me the authorization for this weather source," the answer is one search, not a binder hunt. FileFlo does not give legal advice or represent you to the FAA.
Make every authorization an inspector can ask for a one-search answer
Whether or not you operate an EWINS, the authorization behind every weather source you use lives in your operations specifications — and it has to be current and instantly retrievable when the FAA asks. FileFlo classifies, tracks, and surfaces those documents alongside your pilot, maintenance, and training records. Starter at $89/month. Professional at $299/month (unlimited documents and users). Five-day free trial, no credit card required.
5-day free trial · No credit card required · Cancel anytime · Not an EWINS, weather vendor, SMS, or dispatch system — the proof layer that organizes the documents they produce.