Alternate Airports: Part 135'S Essential Requirements

The Federal Aviation Regulations (FAR) outline specific requirements for alternate airports in Part 135, which pertains to commuter and on-demand operations. These regulations, detailed in the Electronic Code of Federal Regulations (eCFR), establish the operating limitations and weather requirements that must be adhered to. While the eCFR serves as an updated online version, the Code of Federal Regulations (CFR) is the official legal print publication containing aviation rules and regulations. The requirements for alternate airports are essential for ensuring the safe and efficient operation of commuter and on-demand aircraft, with the relevant regulations providing crucial guidelines for pilots and aviation professionals.

Operating Requirements: Commuter and on-demand operations

Part 135 outlines the operating requirements for commuter and on-demand operations, as well as the rules governing persons on board such aircraft. This part applies to all certificate holders operating under this section, with some exceptions for on-demand operations with smaller aircraft (19 or fewer passenger seats) and commuter operations with 9 or fewer passenger seats.

For those operating aircraft under Part 135, there is a duty to make a determination of suitability. This means that each certificate holder must assess the suitability of each person occupying an exit seat to the extent necessary to perform the applicable functions outlined in paragraph (d) of this section.

In terms of operational requirements, those conducting commuter or on-demand operations must comply with the applicable rules of this chapter when operating inside the United States. When operating outside the United States, they must comply with Annex 2, Rules of the Air, to the Convention on International Civil Aviation, or the regulations of the respective foreign country, whichever is applicable. They must also comply with any more restrictive rules of parts 61 and 91 of this chapter, provided they do not violate the aforementioned Annex or foreign regulations.

Additionally, Part 135 includes specific requirements for transition plans. Before March 19, 1996, certificate holders outlined in paragraph (a)(1) were required to submit a transition plan to the FAA for moving from commuter requirements to the requirements for domestic or flag operations. This plan included details on obtaining new operations specifications, compliance with applicable requirements, and adhering to compliance date schedules.

Part 135 also includes various subparts that outline specific requirements for different aspects of commuter and on-demand operations, such as flight operations, aircraft and equipment, operating limitations, flight crewmember requirements, crewmember rest and duty periods, training, and airplane performance limitations.

VFR/IFR Operating Limitations

VFR Limitations:

VFR flying relies on visual cues outside the aircraft for navigation and obstacle avoidance. VFR pilots must maintain the ability to fly visually and are limited by weather conditions and visibility. They cannot operate in clouds or low visibility and must maintain a certain distance from clouds to avoid potential conflicts with IFR aircraft. VFR pilots are also restricted from operating too close to obstacles and in uncontrolled airspace when the ceiling is less than 1,000 feet without a minimum flight visibility of 2 miles. Additionally, VFR pilots may need special permission to enter certain classes of airspace.

IFR Limitations:

IFR allows for more precise navigation along direct routes, providing efficiency and safety by allowing flights above clouds and obstacles. However, IFR requires pilots to follow a pre-determined flight route and altitude, with deviations allowed only in emergencies or special circumstances. IFR operations also mandate the use of specific weather reports or forecasts, or a source approved by the Administrator, to ensure safe navigation. Aircraft operating under IFR must carry enough fuel to complete the intended flight, including reaching an alternate airport and maintaining a specified amount of additional flight time.

These VFR/IFR Operating Limitations and Weather Requirements ensure safe and efficient flight operations for both types of flight rules, providing guidelines for pilots to make informed decisions based on weather conditions, aircraft equipment, and personal proficiency.

Weather Requirements

According to the regulations, there are specific criteria that need to be considered for alternate airport requirements. These requirements are in place to ensure that aircraft have a safe option to divert if the weather at the intended airport deteriorates or other unforeseen circumstances arise. The weather requirements for Part 135 alternate airport considerations are as follows:

Firstly, the ceiling height, which refers to the vertical distance between the earth's surface and the base of the lowest layer of clouds, should be at least 1,500 feet above the lowest circling approach Minimum Descent Altitude (MDA). This ensures that pilots have sufficient vertical clearance during the approach and landing phase.

In cases where a circling instrument approach is not authorized for the airport, the regulations specify an alternative criterion. The ceiling height should be either 1,500 feet above the lowest published minimum or 2,000 feet above the airport elevation, whichever of these two options is higher. This ensures that pilots have the necessary vertical clearance even when a circling approach is not available.

Additionally, the visibility requirements for the alternate airport are crucial. The forecasts should indicate a visibility of at least three miles. Alternatively, if there are specific visibility minimums in place for the airport, the forecast visibility should be at least two miles more than the lowest applicable visibility minimums. This ensures that pilots can safely navigate and land at the airport.

To ensure the accuracy and timeliness of these weather requirements, the forecasts and reports are considered valid for a specific time frame. The weather reports and forecasts should indicate that these criteria will be met for at least one hour before and after the estimated time of arrival at the alternate airport. This provides a reasonable timeframe for the aircraft to safely arrive and operate at the alternate airport.

In summary, the weather requirements for Part 135 alternate airport considerations are essential for ensuring the safety of flight operations. By adhering to these criteria, pilots and operators can make informed decisions, ensuring they have a suitable diversion option if needed. These requirements help mitigate the risks associated with unforeseen weather changes or other operational challenges that may arise during the flight.

Standard instrument approach procedure

A standard instrument approach procedure (SIAP) is a series of predetermined maneuvers for the orderly movement of aircraft under instrument flight rules (IFR) to enable them to arrive at a point from which a landing can be made. SIAPs are published for each airport and are instrumental in ensuring safe and efficient arrivals, especially in low-visibility conditions or when an aircraft is unable to establish visual contact with the airport. These procedures are crucial for Part 135 operators, who often conduct flights in varying weather conditions and need to ensure safe and compliant operations. While Part 135 does not explicitly mandate an alternate airport for every flight, having a well-defined SIAP for the intended destination is essential for safe operations and compliance with regulations.

SIAPs typically consist of several segments, including initial approach fixes (IAF), intermediate fixes (IF), final approach fixes (FAF), and missed approach points (MAP). These fixes are predetermined geographical locations that serve as navigational references for aircraft during the approach. The IAF is the point where the approach procedure commences, providing initial guidance to the aircraft. The IFs are waypoints along the approach route that help guide the aircraft toward the final approach segment. The FAF marks the beginning of the final approach segment, and it is from this point that the aircraft commences its descent to the airport. Should conditions not allow a landing, the MAP defines the point at which the missed approach procedure should be initiated, guiding the aircraft away from the airport to a safe altitude.

These approach procedures are meticulously designed, taking into account the specific characteristics of the airport, surrounding terrain, and available navigation aids. They are published on aeronautical charts, providing pilots with essential information such as the route to be followed, minimum altitudes, and any specific procedures or restrictions that must be adhered to. By following the SIAP, pilots can ensure a stable and predictable approach path, maintaining a safe distance from obstacles and terrain while also being prepared for any necessary actions in the event of a missed approach.

For Part 135 operators, having a comprehensive understanding of SIAPs is vital. It enables them to conduct safe and compliant operations, especially when flying into airports with challenging terrain or less-than-ideal weather conditions. By adhering to the published procedures, operators can ensure that their aircraft arrive at the intended destination safely and efficiently, even when visual conditions are not favorable. This also helps in maintaining the required level of safety and standardization across the industry, contributing to the overall safety record of Part 135 operations.

Weather reports and forecasts

According to the regulations, an operator must consider the weather reports and forecasts for the first airport of intended landing and the alternate airport. These reports and forecasts should cover at least a one-hour period before and after the estimated time of arrival. This ensures that pilots have up-to-date information about the weather conditions at both airports.

The regulations outline specific criteria that must be met regarding ceiling height and visibility. Firstly, the ceiling height should be at least 1,500 feet above the lowest circling approach Minimum Descent Altitude (MDA). If a circling instrument approach is not authorized for the airport, the ceiling must be at least 1,500 feet above the lowest published minimum or 2,000 feet above the airport elevation, whichever is higher.

Additionally, the visibility requirements state that the forecast visibility for the airport should be at least three miles or two miles more than the lowest applicable visibility minimums, whichever is greater. These criteria ensure that pilots have sufficient visibility to navigate and land safely.

By adhering to these weather report and forecast requirements, operators can make informed decisions about alternate airports and ensure the safety of their flights. These regulations are in place to mitigate the risks associated with adverse weather conditions and provide clear guidelines for Part 135 operators to follow.

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