AC 120-42B ETOPS and Polar Ops - Code7700

6/13/08 AC 120-42B15 percent increase in the 180-minute maximum diversion time and gave limited relief to ETOPScertificate holders in the specific case of North Pacific Operations.d. Since the advent of the original § 121.161, extended two-engine airplane operationshave been governed by this rule, and the process of evolving and progressive guidance hasreflected the successful and ever-increasing experience of the industry. As capable as this bodyof guidance has been in the past, it became increasingly clear that a need existed to codify all thedisparate documents into a single body of rules, and to update the existing rules to reflect all theindustry improvements such progress has used as its basis. Consequently § 121.161 was revisedto expand two-engine operational authority under successful ETOPS processes and requirecertain 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 AIRPLANESFLOWN IN LONG-RANGE OPERATIONS.a. AC 120-42 in 1985, and AC 120-42A in 1988, recognized the increasing reliability ofturbojet engines and helped to establish type design and operational practices for safe andreliable long-range operations with two-engine airplanes. As the technology and reliability oftwo-engine airplanes continued to improve, due in large measure to the requirements of thesedocuments, such operations became compatible with those long-range operations typicallyassociated with three- and four-engine airplanes. At the same time this technology broughttwo-engine airplanes to the arena of long-range operations, the infrastructure to support suchoperations was changing. Political and funding priorities forced the closure or reduction in basicservices of a number of airports, military and civilian, in remote areas that historically had beenused as diversion airports for routes over oceanic and/or desolate land areas. The increasing useof polar flights, while creating economic benefits, has also brought new challenges to theoperation. The risks associated with these areas’ remoteness, harsh climate and terrain, and theirunique operational issues, needed to be addressed to maintain an equivalent level of safety in theoperation.b. These issues began to significantly impact the viability of all long-range two-engineairplane operations under current regulations, and likewise began to erode the basic safety netthat long-range operations in three- and four-engine airplanes had relied on. Because of thesepressures and the increasing commonality of all long-range operations, the data began to showthat ETOPS requirements and processes are generally applicable to all long-rangepassenger-carrying operations, including those by three- and four-engine airplanes, and wouldimprove 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 alternateairports, adequate fire fighting coverage at these airports, and fuel planning to account fordepressurization are sound operational practices for all airplanes, including three- andfour-engine airplanes. Likewise, planning for the maximum allowable diversion and worst-casescenarios should account for all airplane time-critical systems.c. Unlike the ETOPS guidance provided for two-engine airplanes, there has been noregulatory framework governing the long-range operations of three- and four-engine airplanes.Par 201 Page 5