CHAPTER 1. GENERAL
100. APPLICABILITY. This advisory circular (AC) concerns those certificate holders applying for approval to conduct Extended Operations (ETOPS) under Title 14 of the Code of Federal Regulations (14 CFR) part 121, § 121.161, as well as those certificate holders applying for approval to conduct flights where a portion of which traverse either the North or South Polar Areas, as defined in part 121, § 121.7. This AC also provides guidance in resolving operational issues to certificate holders currently conducting such operations.
101. CANCELLATIONS. The following AC’s and policy letters are canceled:
• AC 120-42A, Extended Range Operation with Two-Engine Airplanes, dated December 30, 1988
• ETOPS Policy Letter (EPL) 95-1, 138-Minute ETOPS Operational Approval Criteria, dated December 19, 1994
• EPL 20-1, 207-Minute ETOPS Operational Approval Criteria, dated March 21, 2000
• Federal Aviation Administration (FAA) Policy Letter, Guidance for Polar Operations, dated March 5, 2001
102. RELATED REGULATIONS. 14 CFR part 21, § 21.4; part 25, § 25.1535; part 121, §§ 121.7, 121.97, 121.99, 121.106, 121.135, 121.161, 121.162, 121.191, 121.197, 121.374,
121.410, 121.415, 121.565, 121.624, 121.625, 121.631, 121.633, 121.646, 121.687, 121.689,
121.703, 121.704, and 121.705; and part 121, appendix P (http://www.gpoaccess.gov/ecfr).
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CHAPTER 2. BACKGROUND ON ETOPS
200. ETOPS REGULATORY REQUIREMENTS.
a. All two-engine airplanes and three- and four-engine passenger-carrying airplanes operated under part 121 are required to comply with § 121.161. This regulation imposes special requirements for ETOPS for these airplanes. These operations are defined as:
(1) Two-Engine Airplanes. These are flights whose planned routing contains a point farther than 60 minutes flying time from an adequate airport at an approved one-engine inoperative cruise speed under standard conditions in still air.
(2) Passenger-Carrying Airplanes with More Than Two Engines. These are flights whose planned routing contains a point farther than 180 minutes flying time from an adequate airport at an approved one-engine inoperative cruise speed under standard conditions in still air.
b. To conduct ETOPS, the specified airplane-engine combination must be certificated to the airworthiness standards of transport-category airplanes and be approved for ETOPS. Airplane certification guidance for ETOPS can be found in §§ 121.162 and 25.1535. As with all other operations, a certificate holder requesting any route approval must first show that it is able to satisfactorily conduct operations between each required airport as defined for that route or route segment, and any required en route alternate airport. Certificate holders must show that the facilities and services specified in §§ 121.97 through 121.107 (domestic and flag operations) and §§ 121.113 through 121.127 (supplemental and commercial operations) are available and adequate for the proposed operation. In addition, the certificate holder must be approved for ETOPS under part 121. This AC provides the additional guidance for certificate holder approval for ETOPS.
201. EVOLUTION OF ETOPS.
a. Section 121.161 has an extensive historical basis, which began as early as 1936. Before obtaining approval for operation in 1936, an applicant operating an airplane with two piston engines were required to show that intermediate fields available for safe takeoffs and landings were located at least at 100-mile intervals along the proposed route. In 1953, § 121.161 imposed the 60-minute rule on two- and three-engine airplanes. In 1964, three-engine airplanes were exempted, leaving the restrictions only on two-engine airplanes based on the lack of satisfactory engine reliability in the operation. In response to improvements in engine design and reliability, and responding to the needs of industry, the FAA has provided guidance for deviations from the rule that have allowed two-engine operations to expand incrementally beyond the initial 60-minute restriction. Currently, engine reliability has improved to a level where the safety of the operations is not impacted so much by the number of engines, but by other factors that affect operations of all airplanes whose routings take them great distances from adequate airports.
Throughout the evolution of the current § 121.161, the following factors have remained constant:
(1) The rule has always applied to all areas of operation, and has not been limited to overwater operations.
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(2) Any additional restrictions imposed or, alternatively, any deviations granted to operate in excess of the basic requirements, were based on a finding by the Administrator that adequate safety would be provided in the proposed operation and current levels of safety would be maintained when all factors were considered. This finding was never limited to engine reliability alone.
(3) The airports used in meeting the provisions of the rule must be adequate for the airplane used (that is, available for safe landings and takeoff with the weights authorized).
(4) Adequate levels of safety within the operation are to be maintained. Operations over increasingly remote areas and the possibility of increased diversion lengths have a potentially negative impact on the safety of the diversion, and thus the operation as a whole. Additional regulatory requirements are intended to ensure that this potential increase in risk is mitigated and that adequate levels of safety within operations are retained.
(5) When considering the impact of operating at greater distances from airports, the certificate holder must show that the operation can be conducted at a level of reliability that maintains an acceptable level of risk.
b. In June of 1985, responding to the industry’s desire to take advantage of the increased reliability and capabilities of two-engine airplanes, the FAA issued AC 120-42. This AC provided guidance on one means of obtaining deviation authority from § 121.161 to allow two-engine airplanes to operate on routes up to 120 minutes from an adequate airport after demonstration of specific levels of in-service experience and systems reliability. The FAA amended this AC in 1988 (AC 120-42A) to permit two-engine airplanes to operate up to 180 minutes from an adequate airport. These ACs introduced the term “ETOPS” for those specific Extended Operations and addressed airplane and engine design aspects, maintenance programs, and operations. Both of these ACs encompassed the following precepts:
(1) Reliance on a two-step approval that included type design of the airplane-engine combination and approval of the certificate holder’s operation.
(2) Risk, as measured by diversion length, is mitigated by application of regulations and guidance reflecting current best practices that address the type certification of the ETOPS airplane and its systems as well as the operational environment of such operations.
(3) ETOPS can be managed successfully, and the level of safety can be maintained, by up-to-date regulations and guidance that articulate quantifiable standards of reliability and experience.
c. The original guidance for extended-range operations with two-engine airplanes in AC 120-42 allowed an increase of up to 15 percent to the maximum diversion time of 120 minutes. This provision was eliminated with the release of the guidance in AC 120-42A, providing for operations up to 180 minutes. Recognizing a need for ETOPS diversion authority between 120 and 180 minutes, the FAA reinstated the 138-minute provision by issuing EPL 95-1 in 1994. In March of 2000, at the request of the industry, the FAA issued ETOPS Policy Letter (EPL) 20-1, 207 Minute ETOPS Operation Approval Criteria. This document provided a similar Page 4 Par 201
15 percent increase in the 180-minute maximum diversion time and gave limited relief to ETOPS certificate holders in the specific case of North Pacific Operations.
d. Since the advent of the original § 121.161, extended two-engine airplane operations have been governed by this rule, and the process of evolving and progressive guidance has reflected the successful and ever-increasing experience of the industry. As capable as this body of guidance has been in the past, it became increasingly clear that a need existed to codify all the disparate documents into a single body of rules, and to update the existing rules to reflect all the industry improvements such progress has used as its basis. Consequently § 121.161 was revised to expand two-engine operational authority under successful ETOPS processes and require certain operations of all passenger-carrying part 121 airplanes to adopt ETOPS requirements.
This AC reflects current § 121.161 regulatory requirements.
202. ETOPS APPLICABILITY TO ALL PASSENGER-CARRYING AIRPLANES FLOWN IN LONG-RANGE OPERATIONS.
a. AC 120-42 in 1985, and AC 120-42A in 1988, recognized the increasing reliability of turbojet engines and helped to establish type design and operational practices for safe and reliable long-range operations with two-engine airplanes. As the technology and reliability of two-engine airplanes continued to improve, due in large measure to the requirements of these documents, such operations became compatible with those long-range operations typically associated with three- and four-engine airplanes. At the same time this technology brought two-engine airplanes to the arena of long-range operations, the infrastructure to support such operations was changing. Political and funding priorities forced the closure or reduction in basic services of a number of airports, military and civilian, in remote areas that historically had been used as diversion airports for routes over oceanic and/or desolate land areas. The increasing use of polar flights, while creating economic benefits, has also brought new challenges to the operation. The risks associated with these areas’ remoteness, harsh climate and terrain, and their unique operational issues, needed to be addressed to maintain an equivalent level of safety in the operation.
b. These issues began to significantly impact the viability of all long-range two-engine airplane operations under current regulations, and likewise began to erode the basic safety net that long-range operations in three- and four-engine airplanes had relied on. Because of these pressures and the increasing commonality of all long-range operations, the data began to show that ETOPS requirements and processes are generally applicable to all long-range passenger-carrying operations, including those by three- and four-engine airplanes, and would improve the safety and viability of such operations. All long-range passenger-carrying airplanes, regardless of the number of engines, needed a viable diversion airport in the case of onboard fire, medical emergency, or catastrophic decompression. Ensuring availability of en route alternate airports, adequate fire fighting coverage at these airports, and fuel planning to account for depressurization are sound operational practices for all airplanes, including three- and four-engine airplanes. Likewise, planning for the maximum allowable diversion and worst-case scenarios should account for all airplane time-critical systems.
c. Unlike the ETOPS guidance provided for two-engine airplanes, there has been no regulatory framework governing the long-range operations of three- and four-engine airplanes.
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For example, in emergencies such as loss of cabin pressure, current regulations require adequate oxygen supplies but do not require the operator to consider the amount of extra fuel necessary to reach a diversion airport.
(1) An analysis of operational data shows that between 1980 and 2000, 33 of the 73 cruise depressurization events on one manufacturer’s airplanes occurred on airplanes with more than two engines.
(2) A study conducted by this manufacturer using a modern four-engine aircraft carrying normal route planning fuel reserves raises issues about the adequacy of the current fuel planning requirements in the event of a diversion.
d. Operational data shows that the diversion rate for all airplane-related and non-airplanerelated causes are comparable between two-engine airplanes and airplanes with more than two engines. Consequently, the FAA has found that there is a need for all passenger carrying operations beyond 180 minutes from an adequate airport to adopt many of the ETOPS requirements that have been based on sound safety principles and successfully proven over many years of operations. Accordingly, the FAA revised § 121.161 to include passenger-carrying airplanes with more than two engines in these long-range operations.
203. EXTENDED OPERATIONS.
a. Since 1985, the acronym, ETOPS, has been defined as “extended twin-engine operations” and has been limited to part 121 airplanes with only two engines. Current regulations have extended these applications to all passenger-carrying airplanes operating in both 14 CFR parts 121 and 135, and the acronym has now been redefined to mean “extended operations.”
This is to acknowledge the similarity of certain long-range passenger-carrying operations of all airplanes operating today, and the common issues that impact such operations.
b. Since 1988, the ETOPS limit for two-engine airplanes has been 180 minutes from an adequate airport at an approved one-engine inoperative cruise speed under standard conditions in still air (excluding the limited authority in the North Pacific given under EPL 20-1, 207-Minute ETOPS Operational Approval Criteria, dated March 21, 2000). Service experience has shown that although limited, this authority has satisfactorily supported the vast majority of the world’s current aviation routes.
c. Those areas not supported within 180-minute diversion authority tend to be routes over remote areas of the world that are uniquely challenging to the operation. These areas include the South Polar Region, a small section in the South Pacific, the southern South Atlantic Ocean between South America and Africa, the southern Indian Ocean and the North Polar area under certain winter weather conditions. The additional operational challenges of these routes are equally demanding of all airplanes, regardless of the number of engines, and include such issues as extremes in terrain and meteorology, as well as limited navigation and communications infrastructure. Support of a necessary diversion and subsequent recovery in such areas demands added training, expertise, and dedication from all certificate holders. The development of ETOPS requirements is intended to address all these issues.
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d. Even though for continuity with current two-engine ETOPS the existing acronym ETOPS is retained, the ETOPS acronym has been re-defined. ETOPS has been expanded to include all passenger-carrying airplane operations where a proposed flight plan includes any point that is greater than 180 minutes from an adequate airport (at an approved one-engine inoperative cruise speed under standard conditions in still air).
204. PRECLUDE AND PROTECT.
a. The whole premise of ETOPS has been to preclude a diversion and, if it were to occur, to have programs in place to protect the diversion. Under this concept, propulsion systems are designed and tested to ensure an acceptable level of in-flight shutdowns (IFSD), and other airplane systems are designed and tested to ensure their reliability. Two-engine airplane maintenance practices are enhanced to better maintain and monitor the condition of the engines and systems significant to ETOPS. The design of these enhanced practices has been a major factor in the joint development of the FAA’s and industry’s aggressive steps to develop a foundation to resolve problems with airplane systems and engines in order to minimize the potential for procedural and human errors, thereby precluding a diversion.
b. However, despite the best design, testing, and maintenance practices, situations occur that may require an airplane to divert. Regardless of whether the diversion is for technical (airplane system- or engine-related) or non-technical reasons, the certificate holder must have a flight operations plan to protect that diversion. For example, such a plan must include ensuring that pilots are knowledgeable about diversion airport alternates and weather conditions (§ 121.631), have the ability to communicate with the certificate holder’s dispatch office and air traffic control (ATC) (§§ 121.99 and 121.122), and have sufficient fuel to divert to the alternate (§ 121.646). Under the “preclude and protect” concept, various failure scenarios need to be considered. For example, during the design of the airplane, time-limited systems such as cargo compartment fire suppression/containment capability are considered. Fuel planning must account for the possibility of decompression or the failure of an engine with considerations for in-flight icing conditions. Best options under these scenarios should be provided to the pilot before and during the flight.
c. This philosophy has been critical to the success of two-engine ETOPS in the past and has been applied to these airplanes in operations beyond 60 minutes from an adequate airport.
This application is based on the requirements of § 121.161 and the engine inoperative diversion requirements of § 121.565. In-service data shows that all airplanes, regardless of the number of engines, divert from time to time for various causes. All passenger-carrying operations conducted where there are a limited number of en route airports, where the support infrastructure is marginal, or where there are challenging weather conditions should adopt many of the same elements of the same preclude and protect concept. If certificate holders plan to operate passenger-carrying airplanes with more than two engines in areas where en route airports are farther away than 180 minutes, these operations are also required to meet certain standards defined under ETOPS to ensure that all efforts are made to preclude a diversion, and if a diversion does occur, that procedures are in place to protect that diversion.
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205. ETOPS AREAS OF OPERATION.
a. ETOPS areas of operation are defined by § 121.7 to be areas beyond a certain distance from adequate airports measured by an airplanes one-engine inoperative cruise speed under standard conditions in still air. Because of the impact such distances might have on the diversion time of an airplane, regulatory guidance has been established for the planning, operational, and equipage requirements for such operations. A certificate holder must apply to the FAA for approval to operate in an ETOPS area using the methodologies in this AC or other means approved by the FAA. When approval is granted, the ETOPS authority for a specific ETOPS area of operations will be noted in the certificate holder’s operations specifications (OpSpecs).
b. Most ETOPS authorities for two-engine ETOPS beyond 180 minutes are limited to a specific geographical region. Historically, ETOPS authorities for two-engine airplanes up to 180 minutes were developed based on a specific need in a particular operating area. Limiting expanded ETOPS authority beyond 180 minutes (for two-engine airplanes) serves several purposes.
(1) The primary importance is the preclusion of an arbitrary use of diversion authority beyond that necessary to complete the operation safely and efficiently. Because it is accepted that increased diversion times potentially increase the risk of the operation a certificate holder must make every effort to plan ETOPS with a maximum diversion distance of 180 minutes or less, if possible.
(2) It should be a goal of all two-engine airplane flight planning to operate to the shortest diversion time that provides the widest range of options in the event of a diversion while recognizing the economic benefits of a more direct route and the safety benefits of diverting to an airport that is well equipped. Tying increased diversion authority to specific areas of operation accomplishes this goal while sufficiently addressing the operational needs of the industry.
(3) Likewise, this focus on specific needs and areas of operation does not add impetus to any perceived rationale for further degradation in the availability or capabilities of en route alternates in remote areas of the world. Although the industry has no direct authority to affect the actions of sovereign nations, it is reasonable to base operations on the value of en route alternate availability at reasonable diversion distances.
(4) In consideration of the successful history of three- and four-engine airplane operations and the reliability and redundancy of current engines used in this operation, ETOPS for these airplanes does not have similar restrictions and ETOPS authorities are not limited to geographic areas. However, like twin-engine operators, the three- and four-engine operator is required to designate the nearest available ETOPS alternate along the planned route of flight and must remain within a 240 minute diversion time if possible.
c. In its application for ETOPS authority, the certificate holder will typically request a specific ETOPS area of operation based on an analysis of proposed routings and the availability of airports sufficient to support the operational requirements of the ETOPS regulations. Because the operating rules distinguish between ETOPS up to 180 minutes, and ETOPS beyond 180 Page 8 Par 205
minutes, the requested level of ETOPS authority in a certificate holder’s application will necessarily have to be assessed differently for ETOPS beyond 180 minutes.
(1) Two-Engine Airplanes up to 180-Minute ETOPS and 207-Minute ETOPS Authority in the North Pacific Area of Operations. The ETOPS area of operation is the area bounded by distance circles representing the approved one-engine inoperative cruise speed under standard conditions in still air chosen by the applicant. The actual flight plan must comply with the fuel supply requirements in § 121.646(b) and must therefore account for wind. However, the flight planning limitations of § 121.633(a) for airplane systems do not require the operator to account for wind in such calculations for flight planning and for determining the ETOPS area of operations in these cases. This allows the applicant to choose an operating authority in his or her application that is based on the “ETOPS area of operation” determination. In other words, the distance from alternates in a certificate holder’s route planning exercise will be the same value used to determine the type design criteria for the airplane-engine combination used in the operation, and the ETOPS approval necessary to fly the route under all flight planning conditions.
(2) ETOPS Beyond 180 Minutes (Two-Engine Airplanes and All Passenger- Carrying Airplanes With More Than 2 Engines). As required by § 121.633(b), for ETOPS beyond 180 minutes for all airplanes, the ETOPS operation must account for the effects of wind and temperature on the calculated distances. Consequently the planning for an ETOPS flight beyond 180 minutes is more complex.
(a) The certificate holder should first conduct a route planning exercise for each planned city pairing to determine the diversion authority needed in still air conditions. If the route or segments of the route exceed 180 minutes based on one engine inoperative speed and still air, then a secondary planning exercise (that may be required seasonally) should be conducted that factors in expected winds and temperatures on that route. The distance between adequate alternate airports on the route is converted into time (minutes) computed for all engine cruise speed, as well as engine inoperative speed. The number of minutes cannot exceed the time-limited system certified capability (cargo fire suppression and the other most limiting system)that is identified in the Configuration Maintenance Procedures (CMP) or Aircraft Flight Manual (AFM) (or any other FAA-approved manufacturer’s document) less the 15-minute pad.
The operator needs to determine how much system capability is required for the planned route and equip its airplane to have sufficient margins. Finally, for the actual flight, the operator’s flight planning must be within the airplane systems capability for the selected ETOPS alternate airports on the planned route based on diversion times that are calculated using known or forecast winds and temperature conditions.
(b) As a minimum, the certificate holder must ensure that the time-limited systems requirements of § 121.633(b) are met at the equal-time points between ETOPS alternates determined by the most limiting en route fuel supply requirements of § 121.646(b), commonly referred to as the ETOPS critical fuel scenario. Certificate holders flying three- and four engine airplanes, prior to the established installation time and certification time requirements of the regulation for these systems and their airplanes, are exempt from these flight planning limitations.
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(c) Once the required fire suppression systems are installed (no later than February15, 2013 for turbine powered airplanes with more than two engines) the certificate holder must follow the flight planning limitations of § 121.633(b)(1). As required by § 121.162(d), for airplanes with more than 2 engines manufactured on or after February 17, 2015, the CMP document for that model will list the airplane’s most limiting ETOPS Significant System time issued in accordance with § 25.3(c). The Certificate holder operating an airplaneengine combination with more than two engines is required to comply with § 121.633(b)(2) if the CMP lists the most limiting ETOPS Significant System time.
d. Credit for the Driftdown. For the purposes of computing distances for ETOPS Area of Operation, credit for driftdown may be taken.
e. Actual Diversion Time. Actual diversion time may exceed the authorized diversion time as long as the flight is conducted within the authorized ETOPS Area of Operation, and complies with the requirements of § 121.633.
206. ETOPS ALTERNATE REQUIREMENTS.
a. One of the distinguishing features of ETOPS operations is the concept of an en route alternate airport being available where an airplane can divert following a single failure or a combination of failures that require a diversion. Most airplanes operate in an environment where there usually is a choice of diversion airports available within a close proximity to the route of flight. However, a certificate holder conducting ETOPS may only have one alternate airport within a range dictated by the endurance of a particular airframe system (for example, the cargo fire suppressant system), and that system or system failure may dictate the approved maximum diversion time for that route. Therefore, it is important that any airport designated as an ETOPS alternate have the capabilities, services, and facilities to safely support the operation. The weather conditions at the time of arrival should provide assurance that adequate visual references will be available upon arrival at decision height (DH) or minimum descent altitude (MDA), and that the surface wind conditions and corresponding runway surface conditions will be acceptable to permit the approach and landing to be safely completed with an engine and/or systems inoperative.
b. At dispatch, an en route alternate must meet ETOPS alternate weather requirements in § 121.625 and as specified in Chapter 3, paragraph 303c(5) of this AC and in the certificate holder’s OpSpecs. Because of the natural variability of weather conditions with time, as well as the need to determine the suitability of a particular en route alternate before departure, such requirements are higher than the weather minimums required to initiate an instrument approach.
This is necessary prior to the time that the instrument approach would be conducted, to provide for some deterioration in weather conditions after planning. This increases the probability that the flight will land safely after a diversion to an alternate airport. The airport of departure (takeoff) and the destination airport (unless used concurrently as an ETOPS alternate) are not required to meet the weather minima for ETOPS alternates, as these airports are subject to other regulations (e.g., §§ 121.617, 121.621, and 121.623).
c. While en route, the forecast weather for designated ETOPS alternates should remain at or above operating minima. This provides ETOPS flights with the ability to resolve all diversion Page 10 Par 205
decisions successfully throughout the flight. The suitability of an en route alternate airport for an airplane that encounters an in-flight situation that necessitates a diversion during ETOPS operations is based on a determination that the airport still is suitable for the circumstances, and the weather and field conditions at that airport permit an instrument approach to be initiated and a landing completed.
207. ETOPS IN-SERVICE EXPERIENCE REQUIREMENTS.
a. When AC 120-42 was first released in 1985, two-engine ETOPS was a new concept and ETOPS approvals were sought on airframe-engine combinations that were already in service.
Hence, it was logical to establish criteria for approvals based on in-service experience. At that same time, the FAA recognized the possibility that other approval methods could be developed without in-service experience, and accordingly, provided statements that recognized those options. The original two-engine ETOPS requirements for engine reliability were based on a world fleet in-service experience of 250,000 hours. For 120-minute ETOPS, the FAA additionally required the certificate holder to have 12-consecutive months of operational in-service experience with the airplane-engine combination (AEC). For 180-minute ETOPS, the FAA required the certificate holder to have previously gained 12 consecutive months of operational in-service experience with the specified AEC conducting 120-minute ETOPS. These basic, two-engine in-service requirements have been retained and are discussed in Appendix 3.
Achieving these levels of experience, combined with the required levels of engine reliability, is an acceptable means of attaining ETOPS approval for operators of two-engine airplanes.
b. At the time AC 120-42A was drafted, the FAA recognized that a reduction of two-engine in-service experience requirements or substitution of in-service experience on another airplane would be possible. Any reduction was to be based on an evaluation of the certificate holder’s ability and competence to achieve the necessary reliability for the particular AEC in ETOPS. For example, a reduction in in-service experience would be considered for a certificate holder who could show extensive in-service experience with a related engine on another airplane that had achieved acceptable reliability. The FAA also allowed certificate holders unable to initially fly ETOPS routes at the lesser thresholds to make use of ETOPS simulation or demonstration programs in their application for 180-minute ETOPS. Eventually specific guidance material (AC 120-42A, appendix 7, Accelerated ETOPS Operational Approval) was developed by the FAA permitting ETOPS without accumulating in-service experience in the airplane-engine combination. Most subsequent ETOPS approvals have been granted under these guidelines and this method is retained in Appendix 3.
208. OPERATIONAL RELIABILITY AND SYSTEMS SUITABILITY REQUIREMENTS.
a. The safety of long-range operations such as ETOPS depends on the reliability of all airplane systems including the propulsion systems. Time-limited systems such as cargo compartment fire suppression/containment capability must be considered (§ 121.633). The certificate holder must also have an established program that monitors the reliability of systems significant to ETOPS (§ 121.374).
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b. In order to achieve and maintain the required engine reliability standards, the certificate holder operating a two-engine airplane in ETOPS should assess the proposed maintenance and reliability program’s ability to maintain a satisfactory level of airplane systems reliability for the particular airplane-engine combination. All certificate holders should design the flight operations and, if applicable, the maintenance programs for ETOPS with an objective to preclude diversions and, if a diversion does occur, to protect that diversion. Required ETOPS maintenance practices also must minimize the potential for procedural and human errors that could be detrimental to the safety of the operation. Fuel planning must account for the possibility of a depressurization and/or failure of an engine with considerations for in-flight icing conditions (§ 121.646).
c. The type design requirements for ETOPS certification consider the probability of occurrence of conditions that would reduce the capability of the airplane or the ability of the flight crewmember to cope with an adverse operating condition. System failures or malfunctions occurring during extended range operations could affect flight crewmember workload and procedures. Although the demands on the flight crewmember may increase, a manufacturer applying for ETOPS type design approval must consider crew workload, operational implications, and the crew's and passengers' physiological needs during continued operation with failure effects for the longest diversion time for which it seeks approval. The manufacturer must also conduct flight tests to validate the adequacy of the airplane's flying qualities and performance, and the flightcrew's ability to safely conduct an ETOPS diversion with expected system failures and malfunctions. An ETOPS operator should carefully consider the possible adverse effects that changes in airplane equipment or operating procedures may have on the original evaluations conducted when the airplane was approved for ETOPS before implementing such changes.
d. Following a determination that the airframe systems and propulsion systems are ETOPS type design approved as per part 25, an in-depth review of the applicant’s required ETOPS programs will be accomplished to show the ability to achieve and maintain an acceptable level of systems reliability, and to safely conduct these operations.
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