getting to grips with aircraft performance 如何掌握飞机性能 1(30)

The loss of gradient versus the bank angle is provided in the Airbus Flight Manual (AFM), as well as in the Airbus Performance Program Manual (PPM) as shown in Figure C19.

On airbus fly-by-wire aircraft, the autopilot limits the bank angle at takeoff with one engine inoperative to 15°. Some Engine Out Standard Instrument Departures (EOSID) require a turn to be performed with a bank angle of 20° or more. When a turn with more than a 15° bank angle must be carried out, the aircraft must be manually flown.
4.2.5. Takeoff Flight Path with Obstacles
Once the obstacles are taken into account, the maximum takeoff weight at brake release must be calculated so that the net flight path clears the most penalizing obstacle with a vertical margin of 35 feet (or 50 feet when the bank angle is greater than 15°).

Obstacle A (Figure C20), imposes a minimum Net second segment gradient and, therefore, a minimum Gross second segment gradient. This results in a takeoff weight limitation.
Obstacle B helps determine the minimum acceleration height. This height must be between 400 feet and the maximum acceleration height (10 minutes at TOGA). The minimum acceleration height ensures a vertical clearance of 35 feet (or 50 feet) between the net flight path and the obstacle.
The net acceleration segment is longer than the gross one, as the end of both segments is assumed to be reached after the same flight time.
4.2.6. Takeoff Funnel
The takeoff funnel represents an area surrounding the takeoff flight path, within which all obstacles must be cleared, assuming they are all projected on the intended track. The contours of this area, also called departure sector, differ between the JAR and the FAR regulations, and will be dealt with separately in the following section.

“JAR-OPS 1.495
(a) An operator shall ensure that the net take-off flight path clears all obstacles […] by a horizontal distance of at least 90 m plus 0.125 x D, where D is the horizontal distance the aeroplane has traveled from the end of the take-off distance available or the end of the take-off distance if a turn is scheduled before the end of the take-off distance available. For aeroplanes with a wingspan of less than 60 m a horizontal obstacle clearance of half the aeroplane wingspan plus 60 m plus 0.125 x D may be used.”

The semi-width at the start of the departure sector is a function of the aircraft’s wingspan. The following Table (C9) provides the values for each aircraft type:
AIRCRAFT TYPE  WINGSPAN  Semi-width at the start of the departure sector (1/2 E0) 
A300-B2/B4/600  44.84 m (147 ft 1 in)  83 m (271 ft) 
A310-200/300  43.90 m (144 ft 1 in)  82 m (269 ft) 
A318/A319/A320/A321  34.10 m (111 ft 10 in)  78 m (253 ft) 
A330-200/300  60.30 m (197 ft 10 in)  90 m (296 ft) 
A340-200/300  60.30 m (197 ft 10 in)  90 m (296 ft) 
　
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：getting to grips with aircraft performance 如何掌握飞机性能 1(30)