Note: If the airplane is at or below maximum ENG OUT altitude when an engine
becomes inoperative, select and execute the ENG OUT CRZ page.
Maintain engine out cruise speed using manual thrust adjustments.
If required to cruise at maximum altitude, set MCT, establish a climb and decelerate slowly to ENG OUT CRZ speed. At level off select ENG OUT LRC for best fuel economy.
An alternate target driftdown speed can be selected using the MOD CRZ or ENG OUT D/D page. LRC speed would result in a lower driftdown altitude but better fuel performance. A company specified speed could be selected and provides for a higher driftdown speed and a shorter flight time to the alternate.
An ENG OUT ALT can be entered on the MOD CRZ or ENG OUT D/D page. If an engine out cruise altitude lower than the computed maximum altitude is entered, the FMC commands a cruise descent at approximately 1250 fpm rather than a driftdown schedule.
Unless altered by the pilot, the level off cruise mode will be the same as was used during driftdown. FMC fuel and ETA calculations for driftdown and the remainder of the trip will be consistent with the selected speed mode. For best fuel performance select the engine-out LRC mode following a minimum drag speed (E/O) driftdown.
When VNAV is not used during engine out, set MCT on the operative engine and maintain altitude until the airplane decelerates to the displayed appropriate engine out speed. Use engine out speed from the FMC while descending to the engine out cruise altitude. Remain at MCT until the airplane accelerates to LRC, then maintain LRC speed with manual thrust adjustments. If the FMC is inoperative use turbulence penetration airspeed to driftdown and the engine out long-range cruise tables in the QRH.
High Altitude High Speed Flight
The airplane exhibits excellent stability throughout the high altitude / high Mach range. Mach buffet is not normally encountered at high Mach cruise. The airplane does not have a Mach tuck tendency.
With Mach trim inoperative, the airplane exhibits a neutral trim change when accelerating to speeds approaching MMO. When the Mach trim system is operative, the airplane exhibits a nose up trim change that increases steadily as the airplane accelerates to speeds approaching MMO. The stabilizer motion associated with this nose up trim change is imperceptible without careful scrutiny of the aisle stand indicator.
As speed nears MMO, drag increases rapidly. At high weights, sufficient thrust may not be available to accelerate to MMO in level flight at normal cruising altitudes.
ETOPS
Extended Range Operation with Two Engine Airplanes (ETOPS) are those flights which include points at a flying distance greater than one hour (in still air) single engine cruise speed from an adequate airport. Improved technology and the increased reliability of two engine airplanes has prompted a re-examination of the rules governing their flights over oceans or desolate areas.
ETOPS Requirements and Approval
Operators conducting ETOPS are required to comply with the provisions of FAA Advisory Circular 120-42A or other applicable governing regulations. An airline must have an ETOPS configured airplane, and approved flight operations and maintenance programs in place to support ETOPS operations.
The Minimum Equipment List (MEL) and the Dispatch Deviation Guide (DDG) include dispatch relief levels appropriate to ETOPS.
The airline ensures that the ETOPS airplane is in compliance with the requirements of the appropriate Boeing Configuration, Maintenance and Procedures (CMP) documents. The airline's maintenance department must develop programs which monitor and report reliability of the engines, airframe and components. The Minimum Equipment List (MEL) and the Dispatch Deviation Guide (DDG) have been expanded to address the improved redundancy levels and the additional equipment unique to ETOPS configured airplanes.
Flight and Performance
Crews undertaking ETOPS flights must be familiar with the suitable enroute alternates listed in the flight plan. These airports must meet ETOPS weather minima which require an incremental increase above conventional alternate minimums, and be located so as to ensure that the airplane can divert and land in the event of a system failure requiring a diversion.
Planning an ETOPS flight requires an understanding of the area of operations, critical fuel reserves, altitude capability, cruise performance tables and icing penalties. The Operations Manual provides guidance to compute critical fuel reserves which are essential for the flight crew to satisfy the requirements of the ETOPS flight profile. Fuel corrections must be made for winds, non-standard atmospheric conditions, performance deterioration caused by engines or airframe, and (if applicable) flight through forecast icing conditions.
Procedures
Normal procedures on ETOPS flights do not differ from standard operation. However, during the last hour of ETOPS cruise, the FAA currently requires that a fuel crossfeed valve check be performed on aircraft with a single crossfeed valve. This verifies that the crossfeed valve is operating so that on the subsequent flight, if an engine fails, fuel feed is available from both main tanks through the crossfeed valve.
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本文链接地址：757 Flight Crew Training Manual 机组训练手册(39)
