getting to grips with aircraft performance 如何掌握飞机性能 1(21)

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To summarize, Amendment 25-42 required the accelerate-stop distance to include two seconds of continued acceleration beyond V1 speed, before the pilot takes any action to stop the airplane. It also introduced the notion of Accelerate-Stop Distance all engines. This revision resulted in longer accelerate-stop distances for airplanes whose application for a type certificate was made after amendment 25-42 became effective. The A320 was the first airplane to be certified under this rule, as no retroactivity was required. It was also the last one.
Although the airplane types were originally certified at different times, thus allowing the use of different amendments, both groups of airplanes were continuing in production and competing for sales and for use over some common routes. Airplanes whose designs were type-certified to the standards introduced by Amendment 25-42 were penalized in terms of payload, even though the airplane’s takeoff performance might be better from a safety perspective, than the design of a competing airplane that was not required to meet the latest standards.

This disparity in airworthiness standards has created an unfair international trade situation, affecting the competitiveness of a later design of the A320. At the June 1990 annual meeting, the FAA and JAA agreed to jointly review the current takeoff performance standards to reduce the above-discussed inequities, without adversely affecting safety. In March 1992, the JAA Notice for Proposed Amendment (NPA) 25B,D,G-244: “Accelerate-Stop Distances and Related Performance Matters” was issued, followed by the FAA Notice of Proposed Rule Making (NPRM) 93-8 on July 1993. The rule changes proposed in the NPA and in the NPRM were essentially the same, and are better known as Post-Amendment 42.
To summarize, NPA 244 and NPRM 93-08 (post-amendment 42) proposed the following rule changes: 1 – Replace the two seconds of continued acceleration beyond V1, with a distance margin equal to two seconds at V1 speed 2 – Require that the runway surface condition (dry or wet) be taken into account, when determining the runway length that must be available for takeoff. 3 – Require that the capability of the brakes to absorb energy and stop the airplane during landings and rejected takeoffs be based on brakes that are worn to their overhaul limit.
After industry feedback, NPA 244 was incorporated into JAR 25 on October 2000 (change 15), whereas NPRM 93-08 was incorporated into FAR 25 on February 1998 (amendment 25-92). The definitions provided in the following sections refer to the latest airworthiness standards (i.e. post amendment 42).
As a reminder, the certification status of the Airbus models is the following:
. Pre-amendment 42  : A300, A300-600, A310 
. Amendment 25-42  : A3201 
. Post-amendment 42  : A318, A319, A3201, A321, A330, A340 

3.1.2. Takeoff Distance (TOD)

For given operational conditions (temperature, pressure altitude, weight, etc.):
　
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