getting to grips with aircraft performance 如何掌握飞机性能 2(39)

Note: AFM means that the information is obtained from the Aircraft Flight Manual.
2.4.3. Limitation Codes
The nature of the takeoff weight limitation is always indicated in the takeoff charts (RTOW charts). For that purpose, different  codes are necessary (Table J12) which depend on the software used for the computation: TLC or OCTOPUS. For more details on this software, refer to the appendix 3 of this manual (“Takeoff performance software”).
LIMITATIONS CODES

TLC codes A300/A310/A320 OCTOPUS codes A318/A319/A320/A321/A330/A340 Codes 1 2 3 4 5 6 7 8 Nature Structural weight 1st or 2nd segment Runway (OEI)1 Obstacle Tire speed Brake energy Runway (AEO)2 Final takeoff Codes 1 2 3 4 5 6 7 8 9 Nature 1st segment 2nd segment Runway (OEI and AEO) Obstacle Tire speed Brake energy Structural weight Final takeoff VMU 

Table J12 : Takeoff Chart Limitation Codes
Most of the time, MTOW is obtained at the intersection of two limitation curves (Figure J13). This is why the limitation codes are always indicated with two digits in a RTOW chart.
1 OEI = One Engine Inoperative 2 AEO = All Engines operative

2.4.3.1. MTOW limited by two limitations
In Figure J13, takeoff weight is limited by obstacles and by the Accelerate Stop Distance (ASD).
An RTOW chart would indicate Limitation Code 4/3.

2.4.3.2. MTOW limited by one limitation
In Figure J14, takeoff weight is only limited by obstacles.

An RTOW chart would indicate Limitation Code 4/4.

2.4.3.3. MTOW limited by three limitations
In this particular case, a V1 range exists. As a result, whatever the selected V1 speed between a minimum V1 and a maximum V1, the MTOW remains the same while the nature of the limitation changes.  In this case, the effective takeoff V1 speed remains at the operator’s discretion.

In Figure J15, the nature of the limitation depends on the V1/VR ratio:
At V1/VRmin (Point 1): The takeoff weight is limited by both the TODN-1 and the 2nd segment (RTOW Code: 3/2).
Between V1/VRmin and V1/VRmax: The takeoff weight is only limited by the 2nd segment (RTOW Code: 2/2).
At V1/VRmax (Point 2): The takeoff weight is limited by the 2nd segment and the brake energy (RTOW Code: 2/6).
2.4.4. RTOW Chart Information

3. APPENDIX 3 : TAKEOFF PERFORMANCE SOFTWARE
3.1. P.E.P for Windows
3.1.1. What is P.E.P. ?
The PEP (Performance Engineering Programs) for a Windows’ environment is designed to provide the necessary tools not only to handle the performance aspects of flight preparation, but also to monitor aircraft performance after the flight. It is dedicated to airline Flight operations and design offices. Based on the Microsoft Windows . operating system, PEP for Windows is a standalone application which offers access to all the Airbus aircraft performance programs in a user-friendly and customizable environment.
　
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