Part 135 Flight Locating Requirements Without a Flight Plan

Executive Summary

14 CFR 135.79 is a conditional rule. It applies to "each flight, for which an FAA flight plan is not filed" ^[1], and it asks each Part 135 certificate holder to have procedures that do three things: give the operator at least the information required in a VFR flight plan; provide for timely notification of an FAA facility or search and rescue (SAR) facility if an aircraft is overdue or missing ^[2]; and give the operator the location, date and estimated time for reestablishing communications where communications cannot be maintained ^[1]. Paragraph (b) requires the flight locating information to be retained at the principal place of business, or at places designated in the procedures, until the flight is complete ^{[2] [1]}. The eCFR text reviewed for this report was current as of 16 October 2026 ^[1].

A map of aircraft position alone does not establish those elements. The ADS-B Out message set required by 14 CFR 91.227 carries position, velocity, an aircraft identification and an ICAO 24-bit address ^[3]. On a reading of that element list, it carries no communications-gap plan, no notification record and no retained flight-locating file.

FAA Advisory Circular (AC) 136-5, dated 2026-01-23, describes an Enhanced Flight Following Center (EFFC) for commercial air tour operators ^[4]. The FAA's description calls the EFFC "one way, but not the only way" to address flight locating ^[4], and the AC says conformity "is voluntary only." It is guidance, not a universal mandate.

The rule text contains no minute threshold for "timely." Notification timing therefore sits in the operator's approved procedures. The FAA's own alerting clocks, such as the half hour after estimated time of arrival (ETA) in the Aeronautical Information Manual (AIM), describe FAA practice for a filed VFR plan and are not operator thresholds ^[5].

For system selection, the useful objects are a condition, event and record matrix (Table 1), a decision tree that starts with "FAA flight plan filed?" and defers every threshold to the operator's procedures, and test cases for missing updates, conflicting identifiers, communications blackouts and archived records. The ADS-B Out rule applies only in defined airspace ^[6], so equipage does not guarantee a usable position report. Approved operator procedures, operations specifications and manuals remain the controlling documents; this report explains the rule and does not replace them.

Introduction and Background

When a tracking product is proposed to a US Part 135 operator, operations-control leads, chief pilots and IT teams face a narrow question: does it also preserve what the flight-locating rule needs when no FAA flight plan is filed? It matters most to air-tour and remote-area operators, whose flights may leave usual communications coverage.

This report treats 14 CFR 135.79 as a system requirements source, separating what the rule says from what FAA guidance recommends and what an operator's approved procedures say. It does not describe how to conduct a search, and nothing here replaces an operator's approved manual, operations specifications (OpSpecs) or the judgment of the persons authorized to exercise operational control. The jurisdiction is the United States; Canadian and European rules differ and are out of scope.

Two points frame the analysis. The rule is conditional on the absence of an FAA flight plan, so a system must record whether a plan was filed. And "timely" is not quantified, so any alert timer must come from the operator's approved procedures rather than a vendor default.

Research limits: the current text of FAA Order 8900.1, Volume 3, Chapter 25, Section 5, the inspector guidance for flight locating, could not be retrieved from an FAA host, so its present wording is not characterized. OpSpecs are operator-specific and were not available. No public benchmark of flight-following coverage or alert latency was found, and none is invented. Vendor statements are attributed to vendors. Regulatory claims rest on the eCFR (current as of 16 October 2026), the Federal Register, FAA advisory material and the AIM.

Scope and the Conditional Trigger of 14 CFR 135.79

What the rule requires

The rule opens with the obligation: each certificate holder "must have procedures established for locating each flight, for which an FAA flight plan is not filed" ^[1]. The sub-paragraphs are separate duties implying different data.

• Information (a)(1): procedures must provide "at least the information required to be included in a VFR flight plan" ^[1].
• Notification (a)(2): procedures must "provide for timely notification of an FAA facility or search and rescue facility" if an aircraft is overdue or missing ^[2].
• Communications gap (a)(3): procedures must give the operator "the location, date, and estimated time for reestablishing communications" for flights in areas where communications cannot be maintained ^[2].
• Retention (b): flight locating information "shall be retained" at the principal place of business or other designated places, until "the completion of the flight" ^[2].
• Furnishing (c): the operator must give its FAA representative a copy of the procedures and changes, unless they are in a manual required under Part 135 ^[1].

The rule does not use the words "flight release" and names no software category, tracking technology or staffing model. A flight release or trip authorization, where an operator uses one, is an operator procedure; the flight-locating record should carry a reference to it so the two can be matched.

Why the trigger matters for software

A filed flight plan removes the flight from this rule's scope as written, but filing is not the same as a plan being open. The AIM states that a VFR flight plan "is not normally required" within the continental United States ^[5], and that Air Traffic Control "does not have the ability to determine if an aircraft is operating on an active VFR flight plan" ^[5]. A system that stores only "plan filed: yes or no" loses information. Separate fields for filing, activation and closure let the operator's procedures decide which state removes a flight from the flight-locating path.

Who the rule reaches, and air tours

Part 135 applies to the commuter or on-demand operations of each person who holds or is required to hold an Air Carrier Certificate or Operating Certificate ^[7], and commercial air tours conducted by holders of Part 135 OpSpecs must comply with Part 136, Subpart A ^[8]. Part 136 defines a commercial air tour as "a flight conducted for compensation or hire in an airplane, powered-lift, or rotorcraft where a purpose of the flight is sightseeing" ^[9]. The binding obligation under 135.79 therefore attaches to the Part 135 certificate holder; for Part 91 air tour operators, AC 136-5 treats such procedures as a recommendation.

Accountability, Operational Control and Rule History

Accountability for an overdue or missing notification

The rule assigns the procedures to the certificate holder, not to a vendor or a software product. Under 14 CFR 135.77, each certificate holder "is responsible for operational control" ^[10] and lists in its manual "the name and title of each person authorized by it to exercise operational control" ^[10]. Operational control means "the exercise of authority over initiating, conducting or terminating a flight" ^[11], and the manual must contain "flight locating procedures, when applicable" ^[12].

A practical reading, offered as analysis and not as an FAA interpretation, is that the accountable party for the overdue or missing notification is the certificate holder acting through the people and roles named in its manual and OpSpecs. Software can prompt, display and record; the record should show who decided to notify, which facility was notified, and how and when. A vendor that monitors on the operator's behalf changes who performs a task, not who answers for it; the allocation depends on the operator's OpSpec A008 and manual text, which this report cannot see.

A short rule history

The current text reflects Amendment 135-110, published at 72 FR 31684 on 7 June 2007 ^[2]. In that rulemaking the FAA stated that the amendments "provide operators with greater flexibility to take advantage of future technology" ^[13] and that it received no comments on the proposal to amend the section ^[13]. The preamble ties equipment choice to "the availability of compatible communication facilities on the route to be flown" ^[13]. The rule is technology-neutral: it says "communications" and prescribes no radio, telephone, datalink or satellite messaging.

Regulatory Minimum Versus Operator-Approved Procedures

The regulatory minimum

The minimum is the rule text above: procedures, a retained record and a copy for the FAA. It does not require an Enhanced Flight Following Center, a minimum update interval, a tracking technology or an alert timer; such numbers in vendor materials are design parameters unless an approved procedure adopts them.

What AC 136-5 adds, and what it does not

AC 136-5 is titled "Enhanced Flight Following Center (EFFC) for Commercial Air Tour Operators" ^[4]. The distinction the reader must preserve is explicit in the text:

• Not mandated: "While EFFCs are not mandated by regulations, they are highly recommended for all" commercial air tour operators ^[14].
• Voluntary: the AC states that "Conformity with the guidance document is voluntary only" ^[14].

Some voluntary recommendations in the AC bear on software requirements. It recommends that an operator establish and document "alternate flight locating procedures in the event the" primary flight monitoring application becomes inoperative ^[14]. For monitoring, it cites an "acceptable industry standard" of position updates "every 15 minutes or less," electronic or verbal ^[14]. That figure is the AC's statement of industry practice for flight monitoring. It is not a requirement of 135.79, and this report does not propose it as a threshold.

Where the approved procedures live

The question for a system is where the required procedures are written and who can read them.

• Manual: flight locating procedures, when applicable, are a required manual content item.
• Accessibility: appropriate manual parts must be accessible to flight, ground and maintenance personnel at all times ^[15], and a manual accessed electronically must display its date of last revision ^[12].
• FAA copy: the operator furnishes its FAA representative a copy of the procedures and changes.

If a system embeds a timer, call tree or notification template, those items effectively become part of how the procedure is performed. The operator should decide, with its FAA principal inspector, whether the manual text needs to describe the system, and keep the manual revision date aligned with configuration changes.

The Record Contract for Flight Locating

Information the procedures must capture

Paragraph (a)(1) points to the information required in a VFR flight plan. The most direct reference is 14 CFR 91.153(a), which lists items including:

• Aircraft identification: the aircraft identification number and, if necessary, its radio call sign ^[16].
• Pilot: the full name and address of the pilot in command ^[16].
• Departure: the point and proposed time of departure ^[17].
• Route: the proposed route, cruising altitude and true airspeed ^[16].
• First landing: the point of first intended landing and the estimated elapsed time until over that point ^[17].
• Fuel: the amount of fuel on board, in hours ^[17].
• Persons aboard: the number of persons in the aircraft, except where that information is otherwise readily available to the FAA ^[16].

Form-based descriptions differ. For international-format domestic plans, the AIM lists minimum Item 19 entries that include endurance, persons on board, pilot contact information and aircraft color ^[18]. These sources do not list identical fields, so the operator's procedures must state which set it adopts (for example the 91.153 list plus aircraft color and a contact number), and the system schema should match the approved text rather than a vendor template.

Communications-gap information

Paragraph (a)(3) is a plan, not a measurement, so a position display does not supply it. The system needs a place for the location, date and estimated time for reestablishing communications for any flight that will operate where communications cannot be maintained. The rule does not say how the operator learns that information. A schema should hold the expected location, the date and time in UTC, the expected channel, who supplied the information and when, and prior versions when the plan changes in flight.

Timestamp provenance and identifiers

Each timestamp in a flight-locating record has an origin: a pilot or dispatcher entry time, the device time of a position fix, the server receive time, or the time an alert was generated. When these differ, the record should say which one an event used. Identifiers have the same problem. The operator's flight number, the registration, the broadcast flight ID, the ICAO address and a tracker device ID may all refer to one flight. The AIM states that a Call Sign Mis-Match is generated when the transmitted flight ID does not match the filed identification ^[19]. A dated mapping table is a supporting record for any alert.

Retention, Electronic Records and the Record Matrix

Retention and electronic records

Paragraph (b) sets an event, completion of the flight, and a location. It does not state a number of days. Other Part 135 records carry explicit periods; completed load manifests, for example, are kept for at least 30 days ^[20]. Keeping flight-locating files longer than the rule's floor is an operator decision that should be written into the procedures.

For electronic storage, FAA AC 120-78B, which applies to Title 14 records kept electronically, states that backup measures must "maintain and provide access to records in the event of a system failure" ^[21]. For a hosted tracking product, that translates into contract questions about export, outage access and who holds the archive.

Table 1: condition, event and record matrix

Table 1 below proposes a matrix an operator can adapt. The owner column lists roles for the operator to assign; the rule names only the certificate holder. Every threshold is deferred to approved procedures.

The matrix makes one point visible: only the communications-gap comparison and part of the overdue decision depend directly on position data. The other rows are structured records and human decisions, which is why a map alone cannot satisfy the information, communications-gap and retention parts of the rule.

Event Flow and Decision Tree

The first branch: is an FAA flight plan filed?

The tree begins with the rule's own question and contains no durations; every "procedure-defined" step refers to the operator's approved text.

FAA flight plan filed for this flight?
|-- Yes: record filing reference, activation status and closure status.
|        Flight is outside the 135.79(a) trigger as written; other approved
|        operational control procedures continue to apply.
|-- No (or not yet activated, per operator definition):
     1. VFR-plan information received and stored (91.153 set or operator set)?
        No  -> escalate to person authorized to exercise operational control.
        Yes -> continue.
     2. Will any part of the route lack communications?
        Yes -> store location, date, estimated time to reestablish.
        No  -> continue.
     3. Expected contact point reached or expected contact received?
        Yes -> update record, continue to completion.
        No  -> open event; show last position, its source and its age.
     4. Human review by authorized person (procedure-defined).
        Contact established -> record how, when, by whom; close event.
        Not established     -> follow approved overdue or missing procedure.
     5. Notification of FAA facility or SAR facility (procedure-defined).
        Record facility, method, time, person, reference.
     6. Flight completed or otherwise resolved -> record completion marker.
        Retention runs at least to this marker.

Illustrative flow from departure to completion (no time values)

1. Departure: the record holds the VFR-plan information, the filing status and any communications-gap plan before the flight begins.
2. En route: position, message and check-in events are appended with source and timestamp provenance.
3. Expected contact missed: the system opens an event and shows the last position and its age; it does not declare the aircraft overdue.
4. Human review: the authorized person decides, under the approved procedure, whether the event is a data gap, a late check-in or an overdue aircraft, and the decision is recorded.
5. Notification: if the procedure calls for it, the person notifies an FAA or SAR facility; the record captures facility, method, time and reference.
6. Completion: a completion marker closes the file; the procedures' retention rule applies.

The receiving side helps in designing the handoff fields. The AIM states that air route traffic control centers and flight service stations "will alert the SAR system when information is received from any source that an aircraft is in difficulty, overdue, or missing" ^[22]. The Air Force Rescue Coordination Center describes itself as the single agency coordinating on-land federal SAR in the 48 contiguous states (Source: www.af.mil) and says it ties directly into the FAA alerting system (Source: www.af.mil). For Alaska, a 2013 National Guard Bureau article describes the Alaska Rescue Coordination Center mission as responding "to aircraft events over the land mass of Alaska" (Source: www.nationalguard.mil), and lists searching for overdue aircraft among its tasks (Source: www.nationalguard.mil). ICAO regional guidance frames alerting as an air traffic services obligation for aircraft with an ATS unit (Source: www.icao.int), a framing a US operator without a flight plan cannot assume applies. For flights without a plan, the operator's notification is a primary information path, which is why the record of what was known, and when, is the central evidence.

Clocks that belong to someone else

Time values in FAA material should not be imported into software as operator thresholds. The AIM says that if a pilot fails to report or cancel a flight plan within one half hour after ETA, search and rescue procedures are started ^[5]; that describes a filed VFR plan, and nothing in it defines "timely" in 135.79.

What Tracking Feeds Can and Cannot Prove

ADS-B Out

ADS-B Out is a broadcast, mandated only in defined airspace: Class B and Class C airspace areas, and Class E airspace at and above 10,000 feet MSL over the 48 contiguous states and the District of Columbia, among others ^{[6] [23]}. The rule requires transmission of position and velocity at least once per second while airborne ^[3].

Coverage depends on line of sight. The AIM notes that low altitude or antenna shielding may cause reduced range or loss of aircraft contact ^[24]. The FAA also states that remote areas without radar coverage, like much of Alaska, now have surveillance with ADS-B ^[25]. Regional coverage does not guarantee coverage for a given aircraft, altitude and location.

Identifiers are the second limit. The broadcast flight ID may differ from the registration, and a mismatch with the filed identification generates a Call Sign Mis-Match ^[19]. The FAA's Privacy ICAO Address (PIA) program gives eligible aircraft "an alternate, temporary ICAO aircraft address" ^[26], so a lookup by hex code may not resolve to the registered aircraft.

ACARS, datalink and satellite

A Collins communication management unit is documented as managing multiple air-to-ground subnetworks ^[27]. Satellite providers describe coverage in their own terms. Inmarsat's Classic Aero page claims "full global coverage over all major flight routes" ^[28], a route statement and not a claim for every point on earth, while a Globalstar product page notes that its map "indicates areas of potential satellite coverage only" ^[29], and that actual coverage may vary with terrain ^[29]. Iridium describes its network as covering "the entire earth" ^[30] and its 9603 module as offering global two-way messaging ^[31], and Inmarsat notes that Classic Aero supports ADS-C, a contract-based reporting protocol used in oceanic regions ^[28]. These are vendor statements about networks; they say nothing about whether installed equipment reported at a given moment.

International material gives context, not a Part 135 rule. ICAO describes aircraft tracking as an automated four-dimensional position at a reporting interval of 15 minutes or less (Source: www.icao.int), recommended in all areas of operation and required in oceanic areas for specific categories of aircraft (Source: www.icao.int), and notes that aircraft over land are typically tracked by ground receivers or radar (Source: www.icao.int).

Table 2: what each feed can and cannot establish

Table 2 summarizes the evidentiary reach of common inputs. The "cannot establish alone" column is an analytical reading of the cited descriptions, not a quotation.

No single input establishes all three parts of the rule. Position feeds support monitoring and event review; the information, gap-plan and notification records are written by people or integrated workflows and then retained.

Vendor Evaluation Questions

What opened vendor pages document

The items below come from vendors' own public pages, retrieved in October 2026, and are described as the vendors describe them. Vendor pages are live and may have changed since retrieval. They are not assessments of suitability under 135.79, and no compliance claim is inferred.

• myFLIGHTDATA: its page shows a dashboard panel with an "Overdue Check-In" tile ^[35], states that every fleet message stays in "a permanent, searchable history" ^[35], and documents an offline mode in which pilots can use previously synchronized manuals in Airplane Mode ^[35]. It also describes scheduling that checks pilot legality, currency and maintenance status ^[35] and a "GO / WATCH / NO-GO operational gate board" ^[35]. The page text does not describe how check-in times are captured, who is notified or how records are retained.
• ForeFlight: Standard Tracking uses the terrestrial ADS-B network ^[32], the Enhanced Tracking subscription uses space-based ADS-B ^[32], and its map compares what the aircraft flew to what was planned ^[32].
• FlightAware: its Firehose page lists datalink and ACARS providers among integrated inputs ^[36], a feature to "replay data to review an event or obtain historical data" ^[36], and polygon-based entry and exit events ^[36]; its Global plan lists automated flight history reports ^[37], and its data-sources page describes ACARS position reports integrated through data link providers ^[33].
• Blue Sky Network: help pages document alerts by email or SMS ^[38], device-side geofences on supported devices ^[39], a statement, at the time of retrieval, that only the last four months of alert logs are accessible online ^[38], and server-side geofences processed on the server ^[39].
• SKYTRAC: its flight-following page documents a notification when a user-set ETA is reached and the aircraft has not arrived ^[40], export via API, KML, CSV or Excel ^[40], notifications for departures, arrivals and geofence events ^[40], and forwarding of position data on request ^[40].
• Spidertracks: its homepage lists "CAD-style dispatch, real-time tracking, mission control" among platform modules ^[41] and describes customers across EMS, public safety, charter, offshore and cargo operations ^[41].

The pages range from map-centered tracking to broad operations suites. A packaged vendor that ranked in a search for this topic, FileFlo, was not opened during this research, so it is not characterized here.

Questions to ask any vendor

• Structured information: does the system store VFR-plan information as versioned fields with the user and time of each entry?
• Communications gap: can a flight carry a planned location, date and time for reestablishing communications, and compare actual contact to it?
• Alert source: do alert timings come from the operator's approved procedure, and are rule changes logged?
• Human decision: can the system record the authorized person's decision and the facility, method, time and reference of a notification made by phone outside the system?
• Timestamp provenance and audit trail: does each event distinguish device, receive and entry time, and can edits and deletions be reviewed?
• Retention and export: can the operator set retention and export a per-flight file? Compare any documented log window, such as the four months noted above, with the operator's own decision.
• Data rights and outage: can the operator obtain raw positions and logs, and what happens during a vendor outage?
• Fallback: what happens when the internet connection or application fails, and does it match the operator's alternate procedures?

Integration Fallback

Many operators hold schedule, communications and tracking in separate approved systems. When no packaged product covers the record contract, three options exist: configure what current vendors offer, add a documented manual step with a form-based record, or build a bridge that copies data between the already approved systems into one flight-locating record. A bridge is a software integration, not a change to any regulatory obligation, and it does not replace flight following, dispatch or an approved tracking service. Operators who need a packaged flight-tracking or flight-following product should look to established vendors in that category.

Test Cases for System Acceptance

Each expected result is a record, not a time value; pass conditions refer to the approved procedures.

• No position update: feed a flight whose positions stop. Expected: the system opens an event, shows last position, source and age, and does not mark the aircraft overdue without a human decision.
• Conflicting identifiers: send position data under a broadcast flight ID that differs from the filed identification, and under an alternate address. Expected: the event resolves to one flight through the dated mapping table, or it is flagged for review.
• Communications blackout: record a gap plan, then run three variants: contact re-established before the plan, after it, and not at all. Expected: planned and actual contact are both retained.
• Notification record: complete a notification by phone outside the system. Expected: person, facility, method, time and reference are entered and retained.
• Archived and status-change records: change a flight's filing status, complete it, then retrieve the full file and audit trail from the archive at the places designated in the procedures.
• Outage and fallback: disable the tracking application and primary internet connection. Expected: the alternate procedure can be followed, and manual entries show their provenance. Also confirm that a source omitting an aircraft because of data filtering reads "no data from this source."

Data Analysis and Evidence

Scale of the population

The FAA's Safe Air Charter page shows 1,837 Part 135 certificate holders and 11,582 Part 135 authorized aircraft, with no date on the page; the figures were re-read on that page on October 20, 2026 ^[42]. ADS-B equipage is larger: the FAA's equipage table, headed "As of October 1, 2026," lists 173,663 equipped US aircraft ^[43].

Table 3: numbers that appear near flight locating

Table 3 lists numeric values found in the sources and what each governs, so no number is copied into an alert rule without the right authority.

Every time value in the evidence belongs to another regime: broadcast mechanics, ATC practice, guidance, a different record or a vendor setting. The only quantity in 135.79 itself is a retention event, which supports treating notification timing as a configuration of the operator's approved procedure and logging who set it.

Implications and Future Directions

For procurement. Table 1 can become acceptance criteria before a demonstration. A product that shows an overdue view but cannot store a communications-gap plan, a notification decision and a per-flight archive covers part of the requirement; the rest can be met by configuration, a manual step or an integration, as the operator and its FAA principal inspector decide.

For AC 136-5 adoption. The AC is new and voluntary. Air-tour operators may adopt some, all or none of its EFFC recommendations; no public adoption data was found. Operators adopting parts of it should document which.

For AI-assisted tools. Software that summarizes feeds, ranks events or drafts notification text can reduce workload. A model's output is not a flight-locating record until a named person accepts it, inputs inherit the coverage and identifier limits described earlier, and the decision to notify an FAA or SAR facility remains with the persons the operator has authorized. Such a tool should keep inputs, outputs and the human action in the retained file.

Frequently Asked Questions

What does 14 CFR 135.79 flight locating require?

Procedures, for each flight without an FAA flight plan, that provide VFR-plan information, timely notification of an FAA or SAR facility when an aircraft is overdue or missing, and the location, date and estimated time for reestablishing communications, plus retention until the flight is complete.

What are Part 135 flight locating procedures in practice?

They are the written procedures in the operator's approved manual. The rule fixes their content elements, not their form.

Is flight following the same as flight locating?

No. Flight locating under 135.79 is the conditional procedure for flights without an FAA plan. The rule does not define "flight following," and a monitoring system should not be assumed to satisfy flight locating.

Does a flight following center have to be built?

No. AC 136-5 says EFFCs are not mandated by regulations, and the FAA's page describes the EFFC as one way, but not the only way to address flight locating.

How long must flight locating records be retained?

The rule's text is "until the completion of the flight" at the principal place of business or other designated places ^[2]. It states no longer period; any longer retention is an operator decision.

Which operational control records matter for flight locating?

The certificate holder lists the persons authorized to exercise operational control ^[10]. For each flight, the flight-locating file should show who held that role, what they knew and when, and what they decided.

Do Part 135 operators need to file VFR flight plans?

The AIM treats a VFR flight plan as not normally required within the continental United States, and 135.79 applies when none is filed. Whether an operator's own procedures require a plan is a question for its manual.

What does an overdue-aircraft escalation look like?

The rule requires "timely notification" and does not define it. A workable record shows the event, the human review, the notification and the closure, with each step's person and time. The thresholds belong to the approved procedures; the FAA clocks in Table 3 describe other contexts.

Conclusion

In summary, 14 CFR 135.79 asks for procedures and a retained record, not a particular tracking product. The three content elements, the conditional no-flight-plan trigger and the retention-until-completion paragraph define what an operator's approved procedures must cover and what a system must be able to hold. A position map supports monitoring and the review of an event, but it does not by itself hold VFR-plan information, a communications-gap plan, a notification decision or a retained file.

AC 136-5, issued 2026-01-23, offers the EFFC as one acceptable approach for commercial air tours and states that it is not mandated. The operator's approved manual and OpSpecs remain the controlling documents, and the operator, through the people it has authorized, remains accountable for the overdue or missing notification. The practical outputs are Table 1 as an acceptance matrix, the decision tree that starts with the filing question, and the acceptance test cases. Operators should confirm the current wording of their own procedures, OpSpecs and FAA inspector guidance, and consult their FAA principal inspector, before any system change.