Part 121 and Part 117 Aviation Regulations Study Guide

Part 121 Regulations for Departure and Takeoff Alternates

• Departure Legality Relative to Weather Minimums: Under Part 121, a flight is permitted to depart even if the weather at the departure airport is currently below the approach minimums for landing, provided the weather remains within the legal takeoff minimums.

• Takeoff/Departure Alternate Requirements:     * Trigger for Alternate: A takeoff alternate is required whenever the weather at the departure airport is below the minimums required for landing at that same airport.     * Rationale: This regulation exists to provide a nearby landing option in the event of an engine failure or other emergency occurring immediately after takeoff that necessitates an immediate landing.     * Distance/Time Criteria: The designated takeoff alternate must be located within $1\,hour$ of the departure airport. This calculation is based on cruise speed in still air with one engine inoperative.     * Operational Specifications (OpSpecs): Depending on the specific airline's OpSpecs, there may be specific fuel limitations associated with the selection of a takeoff alternate.

Destination Alternates and the 123 Rule

• General Filing Requirement: The determination for filing a destination alternate is fundamentally guided by the "123 rule."

• Exceptions to Filing an Alternate: A destination alternate is not required if the forecast weather within $1\,hour$ before to $1\,hour$ after the Estimated Time of Arrival (ETA) at the destination meets the following criteria:     * Ceiling: Greater than $2000\,ft$.     * Visibility: Greater than $3\,sm$.

Derived Alternate Minimums Calculation Methods

• Method 1: One Operational Navigational Facility:     * This applies when there is only one available approach to a single runway.     * Derived Ceiling: Minimum Decision Height (DH) or Minimum Descent Altitude (MDA) $+ 400\,ft$.     * Derived Visibility: Published landing visibility minimums $+ 1\,mile$.

• Method 2: Two Operational Navigational Facilities:     * This applies when there are at least two different navigational facilities providing approaches to different runways. Opposite ends of the same runway (e.g., Runway 9 and Runway 27) are considered different runways for this calculation.     * Derived Ceiling: The higher of the two applicable Decision Heights (DH) $+ 200\,ft$.     * Derived Visibility: The greater of the two applicable visibilities $+ \frac{1}{2}\,mile$.

Exemption 3585 and 17347 (Conditional TAF Remarks)

• Definition of Conditional Statements: In a Terminal Aerodrome Forecast (TAF), remarks labeled as TEMPO (temporary) or PROB (probability) are considered conditional statements.

• General Rule for Exemption 3585/17347: This exemption allows for the dispatch of a flight to a destination even when conditional remarks in the TAF suggest weather below landing minimums at the ETA.

• TAF Body Requirements: To use the exemption, the main body of the TAF (the primary forecast) must indicate weather at or above the required minimums at the ETA.

• Mandatory Second Alternate: If the conditional remarks indicate weather below minimums at the ETA (but the main body is above), the flight must be dispatched with a second alternate. If the conditional remarks do not state weather is below minimums, a second alternate is not required under this specific rule.

• Specific Weather Minimum Requirements (Main Body):     * At Destination: Must be at or above landing minimums.     * At First Alternate: Must be at or above derived alternate minimums.     * At Second Alternate: Must be at or above derived alternate minimums.

• Specific Weather Minimum Requirements (Conditional Remarks):     * At Destination: Visibility must be no less than $\frac{1}{2}$ of the required approach visibility.     * At First Alternate: Ceiling and visibility must be no less than $\frac{1}{2}$ of the derived alternate ceiling and visibility.     * At Second Alternate: Weather must be specifically at or above the whole derived alternate minimums.

• Memory Item: "HALF HALF WHOLE" (referring to the requirements for Destination, 1st Alternate, and 2nd Alternate conditional remarks).

• Administrative Requirement: If a flight is released using this exemption, the remarks section of the dispatch release must explicitly state: "Flight released under Exemption 17347."

The Marginal Rule and Additional Alternate Constraints

• Marginal Rule Definition: A second alternate is mandatory if the destination weather is exactly at the approach minimums AND the first alternate weather is exactly at the derived alternate minimums.

• Second Alternate Weather Minimums: The weather for the second alternate must meet or exceed the alternate minimums for both the main TAF body and any conditional phrases.

• Visibility Threshold: If destination visibility in conditional phrases is exactly $\frac{1}{2}$ of the required approach visibility, the flight must follow the release protocols for Exemption 17347.

• FM (From) and BCMG (Becoming) TAF Remarks: If these terms appear in the forecast, the weather must meet the full alternate minimums; they do not fall under the $\frac{1}{2}$ rule of conditional statements.

Operational Procedures and Regulatory Limitations

• Approach Legality at the FAF: Under Part 121, a pilot is prohibited from beginning an instrumental approach if, prior to reaching the Final Approach Fix (FAF), the reported visibility for the airport is less than the published minimums for that specific approach.

• International Licensing: For international flights, at least one member of the flight crew must have their Federal Communications Commission (FCC) license on their person. Both the Captain and First Officer are not required to have it simultaneously during the flight as long as one does.

• Oxygen Use at Altitude: If one pilot leaves the cockpit at an altitude of $25,000\,ft$ or higher, the remaining pilot is required to wear and use an oxygen mask.

• ATC Authority: Air Traffic Control (ATC) does not have the legal authority to instruct a pilot to violate or exceed any airspeed restriction regulations.

• Cabin Staffing: There is a requirement of at least $1\,flight\,attendant$ for every $50\,passengers$ on board.

RVSM (Reduced Vertical Separation Minimum) Equipment Requirements

To operate in RVSM airspace, the aircraft must be equipped with the following four items:

• Two independent altitude measurement systems.

• An altitude alerting system.

• An automatic altitude control system.

• A Secondary Surveillance Transponder (SSR) capable of altitude reporting.

FAR Part 117: Flight Crew Rest and Duty Limitations

• General Scope: Part 117 dictates rest requirements specifically for flight crews conducting passenger operations under Part 121.

• Required Rest Period: Before starting any Flight Duty Period (FDP) or reserve period, a crew member must have $10\,consecutive\,hours$ of rest, measured from the time they were released from their previous duty.

• Sleep Opportunity: Within the $10\,hour$ rest period, the crew must be provided with an uninterrupted sleep opportunity of at least $8\,hours$.

• Daily Flight Time Limits:     * If the flight starts between $0500$ and $1800$: The limit is $9\,hours$.     * At all other start times: The limit is $8\,hours$.

• Cumulative Flight Time Limits:     * $1000\,hours$ per calendar year.     * $100\,hours$ within any $28\,consecutive\,days$.

• Cumulative Flight Duty Time Limits:     * $60\,hours$ within any $7\,consecutive\,days$.     * $190\,hours$ within any $28\,consecutive\,days$.