Extended Range Operation with Two-Engine Airplanes (ETOPS)


The information’s given in here are selected/extracted from FAA AC 120-42A dated 12/30/98 and related to dispatch purposes only. For detailed information view the original source at http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/

Background information

The need for an ETOPS regulation is basically defined by the following FAR regulations, restricting the operation of airplanes.

Part 121 OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS
Subpart H--Aircraft Requirements

Sec. 121.161

Airplane limitations: Type of route.

(a) Unless authorized by the Administrator, based on the character of the terrain, the kind of operation, or the performance of the airplane to be used, no certificate holder may operate two-engine or three-engine airplanes (except a three-engine turbine powered airplane) over a route that contains a point farther than 1 hour flying time (in still air at normal cruising speed with one engine inoperative) from an adequate airport.
(b) Except as provided in paragraph (c) of this section, no certificate holder may operate a land airplane (other than a DC-3, C-46, CV-240, CV-340, CV-440, CV-580, CV-600, CV-640, or Martin 404) in an extended overwater operation unless it is certificated or approved as adequate for ditching under the ditching provisions of part 25 of this chapter.
(c) Until December 20, 2010, a certificate holder may operate, in an extended overwater operation, a nontransport category land airplane type certificated after December 31, 1964, that was not certificated or approved as adequate for ditching under the ditching provisions of part 25 of this chapter.
Amdt. 121-251, Eff. 1/19/96

Part 121 OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS
Subpart I--Airplane Performance Operating Limitations

Sec. 121.191

Airplanes: Turbine engine powered: En route limitations: One engine inoperative.

(a) No person operating a turbine engine powered transport category airplane may take off that airplane at a weight, allowing for normal consumption of fuel and oil, that is greater than that which (under the approved, one engine inoperative, en route net flight path data in the Airplane Flight Manual for that airplane) will allow compliance with paragraph (a) (1) or (2) of this section, based on the ambient temperatures expected en route:
(1) There is a positive slope at an altitude of at least 1,000 feet above all terrain and obstructions within five statute miles on each side of the intended track, and, in addition, if that airplane was certificated after August 29, 1959 (SR 422B) there is a positive slope at 1,500 feet above the airport where the airplane is assumed to land after an engine fails.
(2) The net flight path allows the airplane to continue flight from the cruising altitude to an airport where a landing can be made under Sec. 121.197, clearing all terrain and obstructions within five statute miles of the intended track by at least 2,000 feet vertically and with a positive slope at 1,000 feet above the airport where the airplane lands after an engine fails, or, if that airplane was certificated after September 30, 1958 (SR 422A, 422B), with a positive slope at 1,500 feet above the airport where the airplane lands after an engine fails.
(b) For the purposes of paragraph (a)(2) of this section, it is assumed that--
(1) The engine fails at the most critical point en route;
(2) The airplane passes over the critical obstruction, after engine failure at a point that is no closer to the obstruction than the nearest approved radio navigation fix, unless the Administrator authorizes a different procedure based on adequate operational safeguards;
(3) An approved method is used to allow for adverse winds:
(4) Fuel jettisoning will be allowed if the certificate holder shows that the crew is properly instructed, that the training program is adequate, and that all other precautions are taken to insure a safe procedure;
(5) The alternate airport is specified in the dispatch or flight release and meets the prescribed weather minimums; and
(6) The consumption of fuel and oil after engine failure is the same as the consumption that is allowed for in the approved net flight path data in the Airplane Flight Manual.

Amdt. 121-143, Eff. 6/26/78

Part 121 OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS
Subpart I--Airplane Performance Operating Limitations

Sec. 121.193

Airplanes: Turbine engine powered: En route limitations: Two engines inoperative.

(a) Airplanes certificated after August 26, 1957, but before October 1, 1958 (SR 422). No person may operate a turbine engine powered transport category airplane along an intended route unless he complies with either of the following:
(1) There is no place along the intended track that is more than 90 minutes (with all engines operating at cruising power) from an airport that meets the requirements of Sec. 121.197.
(2) Its weight, according to the two-engine-inoperative, en route, net flight path data in the Airplane Flight Manual, allows the airplane to fly from the point where the two engines are assumed to fail simultaneously to an airport that meets the requirements of Sec. 121.197, with a net flight path (considering the ambient temperature anticipated along the track) having a positive slope at an altitude of at least 1,000 feet above all terrain and obstructions within five miles on each side of the intended track, or at an altitude of 5,000 feet, whichever is higher.
For the purposes of paragraph (a)(2) of this section, it is assumed that the two engines fail at the most critical point en route, that if fuel jettisoning is provided, the airplane's weight at the point where the engines fail includes enough fuel to continue to the airport and to arrive at an altitude of at least 1,000 feet directly over the airport, and that the fuel and oil consumption after engine failure is the same as the consumption allowed for in the net flight path data in the Airplane Flight Manual.
(b) Aircraft certificated after September 30, 1958, but before August 30, 1959 (SR 422A). No person may operate a turbine engine powered transport category airplane along an intended route unless he complies with either of the following:
(1) There is no place along the intended track that is more than 90 minutes (with all engines operating at cruising power) from an airport that meets the requirements of Sec. 121.197.
(2) Its weight, according to the two-engine-inoperative, en route, net flight path data in the Airplane Flight Manual, allows the airplane to fly from the point where the two engines are assumed to fail simultaneously to an airport that meets the requirements of Sec. 121.197, with a net flight path (considering the ambient temperatures anticipated along the track) having a positive slope at an altitude of at least 1,000 feet above all terrain and obstructions within 5 miles on each side of the intended track, or at an altitude of 2,000 feet, whichever is higher.
For the purposes of paragraph (b)(2) of this section, it is assumed that the two engines fail at the most critical point en route, that the airplane's weight at the point where the engines fail includes enough fuel to continue to the airport, to arrive at an altitude of at least 1,500 feet directly over the airport, and thereafter to fly for 15 minutes at cruise power or thrust, or both, and that the consumption of fuel and oil after engine failure is the same as the consumption allowed for in the net flight path data in the Airplane Flight Manual.
(c) Aircraft certificated after August 29, 1959 (SR 422B). No person may operate a turbine engine powered transport category airplane along an intended route unless he complies with either of the following:
(1) There is no place along the intended track that is more than 90 minutes (with all engines operating at cruising power) from an airport that meets the requirements of Sec. 121.197.
(2) Its weight, according to the two-engine inoperative, en route, net flight path data in the Airplane Flight Manual, allows the airplane to fly from the point where the two engines are assumed to fail simultaneously to an airport that meets the requirements of Sec. 121.197, with the net flight path (considering the ambient temperatures anticipated along the track) clearing vertically by at least 2,000 feet all terrain and obstructions within five statute miles (4.34 nautical miles) on each side of the intended track. For the purposes of this subparagraph, it is assumed that--
(i) The two engines fail at the most critical point en route;
(ii) The net flight path has a positive slope at 1,500 feet above the airport where the landing is assumed to be made after the engines fail;
(iii) Fuel jettisoning will be approved if the certificate holder shows that the crew is properly instructed, that the training program is adequate, and that all other precautions are taken to ensure a safe procedure;
(iv) The airplane's weight at the point where the two engines are assumed to fail provides enough fuel to continue to the airport, to arrive at an altitude of at least 1,500 feet directly over the airport, and thereafter to fly for 15 minutes at cruise power or thrust, or both; and
(v) The consumption of fuel and oil after the engine failure is the same as the consumption that is allowed for in the net flight path data in the Airplane Flight Manual.

AC Number: AC 120-42A Date: 12/30/98


Subject:

Extended Range Operation with Two-Engine Airplanes (ETOPS)

Related Regulation(s):
Part 21, Part 25, Part 33, Part 121 Section Number(s):
Sec. 21.3, Sec. 25.1309, Sec. 25.901, Sec. 25.903, Sec. 33.19, Sec. 33.75, Sec. 121.161, Sec. 121.197, Sec. 121.373, Sec. 121.565, Sec. 121.703

4. DEFINITIONS.

a. Airport.

(1) Adequate.

For the purpose of this AC, an adequate airport is an airport certified as an FAR Part is 139 airport or is found to be equivalent to FAR Part 139 safety requirements.

(2) Suitable.

For the purpose of this AC, a suitable airport is an adequate airport with weather reports, or forecasts, or any combination thereof, indicating that the weather conditions are at or above operating minima, as specified in the operation specifications, and the field condition reports indicate that a safe landing can be accomplished at the time of the intended operation.
b. Auxiliary Power Units (APU). A gas turbine engine intended for use as a power source for driving generators, hydraulic pumps, and other airplane accessories and equipment and/or to provide compressed air for airplane pneumatic systems.
(1) An essential APU installation provides the bleed air and/or mechanical power necessary for the dispatch of a transport category airplane for operations other than extended range operations with two-engine airplanes.
(2) An APU installation which is intended to serve as one of the three or more independent alternating current (AC) electrical power sources required for extended range operations provides the bleed air or mechanical power necessary for the safe flight of a two-engine transport category airplane approved for extended range operation under a deviation from FAR Section 121.161 and is designed and maintained to provide a level of reliability necessary to perform its intended function.
c. ETOPS Configuration Maintenance and Procedures (CMP) Standard. The particular airplane configuration minimum requirements including any special inspection, hardware life limits. Master Minimum Equipment List (MMEL) constraints, and maintenance practices found necessary by the FAA to establish the suitability of an airframe-engine combination for extended range operation.
d. Engine. The basic engine assembly as supplied by the engine manufacturer.
e. Extended Range Operations. For the purpose of this AC, extended range operations are those flights conducted over a route that contain a point further than one hour flying time at the approved one-engine inoperative cruise speed (under standard conditions in still air) from an adequate airport.
f. Extended Range Entry Point. The extended range entry point is the point on the aircraft's outbound route which is one-hour flying time at the approved single-engine inoperative cruise speed (under standard conditions in still air) from an adequate airport.
g. Fail-Safe. A design methodology upon which the FAR Part 25 airworthiness standards are based. It requires the effect of failures and combination of failures to be considered in defining a safe design. (Refer to Appendix 2 for a more complete definition of fail-safe design concepts.)
h. In-flight Shutdown (IFSD). When an engine ceases to function in flight and is shutdown, whether self-induced, crew initiated or caused by some other external influence (i.e., IFSD for all causes; for example: due to flameout, internal failure, crew-initiated shutoff, foreign object ingestion, icing, inability to obtain and/or control desired thrust, etc.).
i. System. A system includes all elements of equipment necessary for the control and performance of a particular major function. It includes both the equipment specifically provided for the function in question and other basic equipment such as that necessary to supply power for the equipment operation.
(1) Airframe System. Any system on the airplane that is not a part of the propulsion system.
(2) Propulsion System. The airplane propulsion system includes: each component that is necessary for propulsion; components that effect the control of the major propulsion units; and components that effect the safe operation of the major propulsion units.

10. OPERATIONAL APPROVAL CONSIDERATIONS.

d. Flight Dispatch Considerations.

(1) General. The flight dispatch considerations specified in this section are in addition to, or amplify, the requirements contained in FAR Part 121 and specifically apply to extended range operations. Although many of the considerations in this AC are currently incorporated into approved programs for other airplanes or route structures, the unique nature of extended range operations with two-engine airplanes necessitates a reexamination of these operations to ensure that the approved programs are adequate for this purpose.

(2) Master Minimum Equipment List (MMEL). System redundancy levels appropriate to extended range operations should be reflected in the MMEL. An operator's MEL may be more restrictive than the MMEL considering the kind of ER operation proposed and equipment and service problems unique to the operator. Systems considered to have a fundamental influence on flight safety may include, but are not limited to the following:

(i) Electrical, including battery;
(ii) Hydraulic;
(iii) Pneumatic;
(iv) Flight instrumentation;
(v) Fuel;
(vi) Flight control;
(vii) Ice protection;
(viii) Engine start and ignition;
(ix) Propulsion system instruments;
(x) Navigation and communications;
(xi) Auxiliary power-units;
(xii) Air conditioning and pressurization;
(xiii) Cargo fire suppression;
(xiv) Emergency equipment; and
(xv) Any other equipment necessary for extended range operations.

(3) Communication and Navigation Facilities. An airplane should not be dispatched on an extended range operation unless:
(i) Communications facilities are available to provide under normal conditions of propagation at the normal one-engine inoperative cruise altitudes, reliable two-way voice communications between the airplane and the appropriate air traffic control unit over the planned route of flight and the routes to any suitable alternate to be used in the event of diversion;
(ii) Nonvisual ground navigation aids are available and located so as to provide, taking account of the navigation equipment installed in the airplane, the navigation accuracy necessary for the planned route and altitude of flight, and the routes to any alternate and altitudes to be used in the event of an engine shutdown; and
(iii) Visual and nonvisual aids are available at the specified alternates for the authorized of approaches and operation minima.

(4) Fuel and Oil Supply.
(i) General. An airplane should not be dispatched on an extended range operation unless it carries sufficient fuel and oil to meet the requirements of FAR Part 121, and any additional fuel that may be determined in accordance with subparagraph 10.d.(4)(ii). In computing fuel requirements, advantage may be taken of driftdown and at least the following should be considered as applicable:
(A) Current forecast winds and meteorological conditions along the expected flightpath at one-engine inoperative cruising altitude and throughout the approach and landing;
(B) Any necessary operation of ice protection systems and performance loss due to ice accretion on the unprotected surfaces of the airplane;
(C) Any necessary operation of auxiliary power units;
(D) Loss of airplane pressurization and air conditioning; consideration should be given to flying at an altitude meeting oxygen requirements in the event of loss of pressurization;
(E) An approach followed by a missed approach and a subsequent approach and landing;
(F) Navigational accuracy necessary; and
(G) Any known Air Traffic Control (ATC) constraints.
(ii) Critical Fuel Reserves. In establishing the critical fuel reserves, the applicant is to determine the fuel necessary to fly to the most critical point and execute a diversion to a suitable alternate under the conditions outlined in subparagraph 10.d.(4)(iii) --the Critical Fuel Scenario. These critical fuel reserves should be compared to the normal FAR Part 121 requirements for the flight. If it is determined by this comparison that the fuel to complete the critical fuel scenario exceeds the fuel that would be on board at the most critical point, as determined by Part 121 requirements of the FAR, additional fuel should be included to the extent necessary to safely complete the critical fuel scenario. In consideration of the items listed in subparagraph 10.d.(4)(i), the critical fuel scenario should allow for: a contingency figure of 5 percent added to the calculated fuel burn from the critical point to allow for errors in wind forecasts, a 5 percent penalty in fuel mileage**, any Configuration Deviation List items, both airframe and engine anti-icing; and account for ice accumulation on unprotected surface if icing conditions are likely to be encountered during the diversion. If the APU is a required power source, then its fuel consumption should be accounted for during the appropriate phase(s) of flight. (**In lieu of an applicant's established value for inservice deterioration in cruise fuel mileage.)
(iii) Critical Fuel Scenario. The following describes a scenario for a diversion at the most critical point. The applicant should confirm the scenario to be used in determining the critical fuel reserve necessary is operationally the most critical considering both time and airplane configuration (e.g., 2 engine versus 1 engine at 10,000 feet, nonstandard airplane configuration not shown to be extremely improbable, paragraph 8.c.(2)(ii)(D)).
(A) At the critical point, consider simultaneous failure of an engine and the pressurization system (critical point based on time to a suitable alternate at the approved one-engine inoperative cruise speed).
(B) Immediate descent to and continued cruise at 10,000 feet at the approved one-engine inoperative cruise speed or continued cruise above 10,000 feet if the airplane equipped with sufficient supplemental oxygen in accordance with FAR Section 121.329.
(C) Upon approaching destination, descent to 1,500 feet above destination, hold for 15 minutes, initiation of an approach followed by a missed approach and then execution of a normal approach and landing.

(5) Alternate Airports. An airplane should not be dispatched on an extended range operation unless the required takeoff, destination and alternate airports, including suitable en route alternate airports to be used in the event of engine shutdown or airplane system failure(s) which require a diversion, are listed in the cockpit documentation (e.g., computerized flight plan). Suitable en route alternates should also be identified and listed in the dispatch release for all cases where the planned route of flight contains a point more than one hour flying time at the one-engine inoperative speed from an adequate airport. Since these suitable en route alternates serve a different purpose than the destination alternate airport and would normally be used only in the event of an engine failure or the loss of primary airplane systems, an airport should not be listed as a suitable en route alternate unless:
(i) The landing distances required as specified in the AFM for the altitude of the airport, for the runway expected to be used, taking into account wind conditions, runway surface conditions, and airplane handling characteristics, permit the airplane to be stopped within the landing distance available as declared by the airport authorities and computed in accordance with FAR Part 121.197.
(ii) The airport services and facilities are adequate for the applicant operator's approved approach procedure(s) and operating minima for the runway expected to be used; and
(iii) The latest available forecast weather conditions for a period commencing one hour before the established earliest time of landing and ending one hour after the established latest time of landing at that airport, equals or exceeds the authorized weather minima for en route alternate airports in Appendix 3. In addition, for the period commencing one hour before the established earliest time of landing, and ending one hour after the established latest time of landing at that airport, the forecast crosswind component, including gusts,for the landing runway expected to be used should be less than the maximum permitted crosswind for landing.
(iv) During the course of the flight, the flightcrew should be informed of any significant changes in conditions at designated en route alternates. Prior to a 120-minute extended range flight proceeding beyond the extended range flight proceeding beyond the extended range entry point, the forecast weather for the time periods established in subparagraph 10d(5)(iii), landing distances, and airport services and facilities at designated en route alternates should be evaluated. If any conditions are identified (such as weather forecast below landing minima) which would preclude safe approach and landing, then the pilot should be notified and an acceptable alternate(s) selected where safe approach and landing can be made.

(6) Airplane Performance Data. No airplane should be dispatched on an extended range flight unless the operator's Operations Manual contains sufficient data to support the critical fuel reserve and area of operations calculation. The following data should be based on FAA-approved (see Paragraph 8.d.(3)) information provided or referenced in the Airplane Flight Manual.
(i) Detailed one-engine inoperative performance data including fuel flow for standard and nonstandard atmospheric conditions and as a function of airspeed and power setting, where appropriate, covering
(A) Driftdown (includes net performance);
(B) Cruise altitude coverage including 10,000 feet;
(C) Holding;
(D) Altitude capability (includes net performance); and
(E) Missed approach.
(ii) Detailed all-engine-operating performance data, including nominal fuel flow data, for standard and nonstandard atmospheric conditions and as a function of airspeed and power setting, where appropriate, covering:
(A) Cruise (altitude coverage including 10,000 feet); and
(B) Holding.
(iii) Details of any other conditions relevant to extended range operations which can cause significant deterioration of performance, such as ice accumulation on the unprotected surfaces of the airplane, RAM Air Turbine (RAT) deployment, thrust reverser deployment, etc.
(iv) The altitudes, airspeeds, thrust settings, and fuel flow used in establishing the ETOPS area of operations for each airframe-engine combination must be used in showing the corresponding terrain and obstruction clearances in accordance with FAR Section 121.191.

f. Operations Limitations.



(1) Area of Operation.
(i) An operator may be authorized to conduct extended range operations within an area where the diversion time at any point along the proposed route of flight to an adequate airport is 75, 120 or 180 minutes at the approved one-engine cruise speed (under standard conditions in still air).
Appendices 1, 4, and 5 provide criteria for operation at the different diversion times.
(ii) The area which meets the considerations in Paragraph 9.f.(1)(i) may be approved for extended range operations with two-engine airplanes and should be specified in the operations specifications as the authorized area of operations.

(2) Flight Dispatch Limitation. The flight dispatch limitation should specify the maximum diversion time from a suitable airport an operator can conduct a particular extended range operation. The maximum diversion time at the approved one-engine inoperative cruise speed (under standard conditions in still air) should not be any greater than the value established by subparagraph 10.f.(1)(i).
(i) Use of Maximum Diversion Time. The flight dispatch considerations should ensure that extended range operation is limited to flight plan routes where the approved maximum diversion time to suitable airports can be met. Operators should provide for:
(A) Compliance with FAR Section 121.565 where, upon occurrence of an in-flight shutdown of an engine, the pilot should promptly initiate diversion to fly to and land at the nearest airport, in point of time, determined to be suitable by the flightcrew.
(B) A practice to be established such that in the event of a single or multiple primary system failure, the pilot will initiate the diversion procedure to fly and land at the nearest suitable airport, unless it has been demonstrated that no substantial degradation of safety results from continuation of the planned flight.
(ii) Criteria for Maximum Diversion Times. The criteria for different maximum diversion times are detailed in Appendices 1, 4, and 5.

(3) Contingency procedures should not be interpreted in anyway which prejudices the final authority and responsibility of the pilot in command for the safe operation of the airplane.

APPENDIX 3. SUITABLE EN ROUTE ALTERNATE AIRPORTS

1. GENERAL

a. One of the distinguishing features of two-engine extended range operations is the concept of a suitable en route alternate airport being available to which an airplane can divert after a single failure or failure combinations which require a diversion. Whereas most two-engine airplanes operate in an environment where there is usually a choice of diversion airports available, the extended range airplane may have only one alternate within a range dictated by the endurance of a particular airframe system (e.g., cargo fire suppressant), or by the approved maximum diversion time for that route.
b. It is, therefore, important that any airport designated as an en route alternate has the capabilities, services, and facilities to safely support that particular airplane, and that the weather conditions at the time of arrival provide a high assurance that adequate visual references are available upon arrival at decision height (DH) or minimum descent altitude (MDA), and that the surface wind conditions and corresponding runway surface conditions are within acceptable limits to permit the approach and landing to be safely completed with an engine and/or systems inoperative.

2. ADEQUATE AIRPORT.

As with all other operations, an operator desiring any route approval should show that it is able to satisfactorily conduct scheduled operations between each required airport other than that route or route segment. Operators should show that the facilities and services specified in FAR Section 121.97 through 121.107 for domestic and flag air carriers (FAR Sections 121.113 through 121.127 for supplemental air carriers and commercial operators) are available and adequate for the proposed operation. For the purpose of this advisory circular, in addition to meeting Part 121 requirements of the FAR, those airports which meet the provisions of Part 139 and those foreign airports which are determined to be equivalent to the provisions of subparts D and E of FAR Part 139 for that particular airplanes are considered to be adequate airports.

3. SUITABLE AIRPORT.

For an airport to be suitable for the purpose of this advisory circular, it should have the capabilities, services, and facilities necessary to designate it as an adequate airport, and have weather and field conditions at the time of the particular operation which provide a high assurance that an approach and landing can be safely completed with an engine and/or systems inoperative in the event that a diversion to the en route alternate becomes necessary. Due to the natural variability of weather conditions with time as well as the need to determine the suitability of a particular en route airport prior to departure, the en route alternate weather minima for dispatch purposes are generally higher than the weather minima necessary to initiate an instrument approach. This is necessary to assure that the instrument approach can be conducted safely if the flight has to divert to the alternate airport. Additionally, since the visual reference necessary to safely complete an approach and landing is determined, among other things, by the accuracy with which the airplane can be controlled along the approach path by reference to instruments and the accuracy of the ground-based instrument aids, as well as the tasks the pilot is required to accomplish to maneuver the airplane so as to complete the landing, the weather minima for nonprecision approaches are generally higher than for precision approaches.

4. STANDARD EN ROUTE ALTERNATE AIRPORT WEATHER MINIMA.

The following are established for flight planning and dispatch purposes with two-engine airplanes in extended range operations. These weather minima recognize the benefits of precision approaches, as well as the increased assurance of safely completing an instrument approach at airports which are equipped with precision approaches to at least two separate runways, (two separate landing surfaces). A particular airport may be considered to be a suitable airport for flight planning and dispatch purposes for extended range operations if it meets the criteria of Paragraph 3 of this Appendix and has one of the following combinations of instrument approach capabilities and en route alternate airport weather minima:

a. A Single Precision Approach:

Ceiling of 600 feet and a visibility of 2 statute miles or a
ceiling of 400 feet and a visibility of 1 statute mile above the lowest authorized landing minima; whichever is higher.

b. Two or More Separate Precision Approach Equipped Runways:

Ceiling of 400 feet and a visibility of 1 statute miles or a
ceiling of 200 feet and a visibility of 1/2 statue mile above the lowest authorized landing minima; whichever is higher.

c. Non-precision approach(es):

Ceiling of 800 feet and a visibility of 2 statute miles or a
ceiling of 400 feet and a visibility of 1 statute mile above the lowest authorized landing minima; whichever is higher.

5. LOWER THAN STANDARD EN ROUTE ALTERNATE AIRPORT WEATHER MINIMA.

Lower than standard en route alternate airport weather minima may be considered for approval for certain operators on a case-by-case basis by the Director, Flight Standards Service, at suitably equipped airports for certain airplanes which have the certificated capability to safely conduct Category II and/or Category III approach and landing operations after encountering any failure condition in the airframe and/or propulsion systems which would result in a diversion to an en route alternate airport. Subsequent failures during the diversion, which would result in the loss of the capability to safely conduct and complete Category II and/or Category III approach and landing operations, should be shown to be improbable. The certificated capability of the airplane should be evaluated considering the approved maximum diversion time. Lower than standard en route alternate weather minima may be considered at suitably equipped airports, if appropriate, for those airplanes which have these approved capabilities considering the established maximum diversion time.

6. EN ROUTE ALTERNATE SUITABILITY IN FLIGHT.

The suitability of an en route alternate airport for an airplane which encounters a situation inflight which necessitates a diversion, including the provisions of FAR Section 121.565, while en route on an extended range operation is based on a determination that the airport is still suitable for circumstances, and the weather and field conditions at that airport will permit an instrument approach to be initiated and a landing completed.

APPENDIX 5. ETOPS OPERATIONAL PROGRAM CRITERIA

a. Dispatch Considerations.

(1) MEL.

The MEL should reflect adequate levels of primary system redundancy to support 180-minute (still air) operations. The systems listed in Paragraph 10.d.(2)(i) through (xv) should be considered.

(2) Weather.

An operator should substantiate that the weather information system which it utilizes can be relied upon to forecast terminal and en route weather with a reasonable degree of accuracy and reliability in the proposed area of operation. Such factors as staffing, dispatcher training, sources of weather reports and forecasts, and when possible, a record of forecast reliability should be evaluated.

(3) Fuel.

The critical fuel scenario should also consider fuel required for all engine operations at 10,000 feet or above 10,000 feet if the airplane is equipped with sufficient supplemental oxygen in accordance with FAR Section 121.329.

(4) Operational Control Practices and Procedures.

During the course of the flight, the flightcrew should be informed of any significant changes in conditions at designated en route alternates. Prior to a 180-minute ETOP flight proceeding beyond the extended range entry point, the forecast weather for the time periods established in paragraph 10.d(5)(iii), landing distances, and airport services and facilities at designated en route alternates should be evaluated. If any conditions are identified (such as weather forecast below landing minima) which would preclude safe approach and landing, the pilot should be notified and an acceptable alternate(s) selected where safe approach and landing can be made. The maximum diversion time to the newly selected alternate(s) should not exceed 180 minutes at the approved single-engine inoperative cruise speeds (under standard conditions in still air).

(5) Flight Planning.

Operators should provide for compliance with FAR Section 121.565. The effects of wind and temperature at single-engine inoperative cruise altitude should be accounted for. In addition, the operator's program should provide flightcrews with information on suitable airports appropriate to the route to be flown which are not forecast to meet Appendix 3 en route alternate weather minima. Airport facility information, and other appropriate planning data concerning these airports should be provided to flightcrews for use in complying with FAR Section 121.565 when executing a diversion.

End