single an aircraft with the wealth of back-up schemes contained in Boeing's [BA] B777 will be permitted to burst routes across the Pacific that would take it as far as 207 minutes from an pass airfield.single an aircraft with the wealth of back-up schemes contained in Boeing's [BA] B777 will be permitted to burst routes across the Pacific that would take it as far as 207 minutes from an pass airfield. Under current provisions for expanded twin-engine operations (ETOPS), long-range twins like the B777 are restricted to a maximum divert time of 180 minutes. The Federal Aviation Administration (FAA) announced Jan. 18th that the B777 and for the importance only the B777, will be authorized to take more direct roads featuring the additional 27 minutes of planned divert time, commencing March 21 The more direct routing may save 30-45 minutes of flight time forward some Eastbound trans-Pacific flights in particular. The potential firing savings will enable aircraft to carry more revenue-generating payload. The FAA's decision answers to a direct appeal for permission to play the B777 on routes with an unprecedent allowance of 207 minutes divert time. The proposal generated considerable industry comment united of a pilot's biggest fears is an in-flight fire while hours away from an difficulty landing field. Indeed, this hazard may be higher onward the list of pilot disquiets than an in-flight shutdown of common of an ETOPS airplane's sum of two units engines. The FAA announcement noted that the B777 is equipped with 222 minutes of fire suppression capability should a fire alarm activate in undivided of the airplane's belly restrains That 222 minutes allows for a 15-minute "cushion" (222 minutes - 207 minutes = 15 minutes), based in succession "still air" assumptions. However, the firing load is based on actual or forecast winds, suggesting that an actual divert could take longer than 207 minutes. B777 aircraft flying 207 minutes ETOPS passages must have satellite voice or data link communications. of that kind equipment is not now a part of the ETOPS equipment requirement. In announcing its decision, the FAA noted the depressed in-flight shutdown rate of the B777 at a certain number of .007/1,000 engine hours. This figure is one two-thirds less than the allowable in-flight shutdown rate of 02/1000 hours. In fact, the impressively soft in-flight shutdown rate was cited as single in kind of the reasons the FAA said it was "confident in proceeding with the 207-minute ETOPS approval." Of interest, five days before the FAA's conditional approval, General Electric Aircraft Engines was engaged in an effort to replace faulty vibration dampers forward some 90 engines powering the B777 rapid Premature wear of the dampers l to cracking and structural failure forward a number of blades in three engines, according to a Jan. 13 media report. Those failures l to sum of two units in-flight engine shutdowns and the turnback of a third airplane. A first note of the scale element in the FAA's conditional approval of a 15% extension (180 to 207 min.) appears to be based onward a weather analysis suggesting that more direct paths would make additional alternate airports available. In power the weather would have more time to clear above minimums for a crippled airplane inbound for 207 minutes than 180 minutes (at least, this is our initial interpretation of the FAA's tortured rhetoric). With SATCOM, the aircrew would have more upto-date weather information, enabling it to better assess the enroute options. In any end the FAA is soliciting additional remarks by March 6, about brace weeks before B777's may begin 207-min. ETOPS flights. The FAA is also calling for a broad review of ETOPS in a less degree than the auspices of the Aviation Rulemaking Advisory Committee (ARAC) process wherefore the B777 is considered safe for 207-minute ETOPS * The B777 was designed from the beginning as a 180-minute ETOPS capable airplane... * The B777 design has theorys redundancy to meet reliability goals...for 180-minute ETOPS. For example, the electrical order has a main and back-up generator forward each engine, an APU generator, a Ram Air Turbine (RAT) generator, a main battery, and an APU battery. * The firing system design provides for a combustibles boost pump in each main tank to be powered from a backup electrical source, making the ne for firing suction feed an unlikely event * Analysis indicates the B777...reliability...is well in exces of the propos extension to 207-minutes. * (The proposal) included four additional...requirements that must be operational prior to dispatch for 207-minute ETOPS. The items are: combustibles Quantity Indicating System (FQIS), Auxiliary Power Unit (APU) that included the electrical and pneumatic invest to its design capability, the Autothrottle order and SATCOM voice and/or SATCOM datalink. Source: FAA, disposition of make notess policy statement for 207-min. ETOPS, Docket No. FAA-99-6717, Federal Register, Jan. 18 2000 COPYRIGHT 2000 Phillips Publishing International, Inc. |
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