What is the purpose of the Boeing SCAP module?

Question

The Boeing SCAP module will be used to calculate the takeoff and landing performance data. But what exactly does the Boeing SCAP module contain and how is it used to calculate takeoff and landing performance for the aircraft?

Answer 1

The Standardized Computerized Airplane Performance (SCAP) interface is a standardised model for calculating aircraft performance of air transport category aircraft. The SCAP standard is developed and maintained by IATA and leading aircraft manufacturers.

From the IATA website:

One particularly complex requirement is the calculation of takeoff performance data. Most airlines use programs supplied by the airplane manufacturers for each airplane type, and interface these programs with their own computer operating environment, airfield database, and data output format requirements.

In order to reduce the development effort for the airlines (interfacing with different airplane manufacturers' programs) and manufacturers (meeting individual airline requirements for customer-specific features) there are clear advantages in standardizing as much as possible the input/output features of these programs, and also data formats.

Having recognised this potential benefit, IATA, ATA and several manufacturers set up a Standardized Computerized Airplane Performance Task Force (SCAP TF).

A SCAP module is a FORTRAN program that implements the SCAP standard. It takes a set of well defined inputs to produce a well defined output.

The advantage of this approach is that it is possible for a third party to design a software program that requires aircraft performance data without having access to this proprietary data. The software can then be used for aircraft performance calculations of any aircraft as long as it has access its SCAP modules.

There are 6 SCAP specifications for Takeoff, Landing, Climbout, Inflight, Noise and APM (Aircraft Performance Monitoring).

I don't have access to the official SCAP specification, but from what I can find online I gather that for take-off performance the following is required:

• TODA (Take-Off Distance Available)
• TORA (Take-Off Run Available)
• ASDA (Accelerate Stop Distance Available)
• runway elevation
• runway surface condition
• runway heading
• wind speed and direction
• ambient Temperature
• QNH
• MEL/CDL items affecting performance
• max take-off thrust and reduced (FLX) option
• anti-icing options
• flap settings
• V₁/V_R (fixed or opt)
• V₂/V_S (fixed or opt)
• minimum acceleration altitude
• actual take-off weight

I gather the landing SCAP module needs:

• LDA (Landing Distance Available)
• runway surface condition
• runway elevation
• runway heading
• wind speed and direction
• ambient temperature
• MEL/CDL items affecting performance
• approach type (CAT I/II/III)
• anti-icing options
• presence of residual ice
• flap setting (fixed or opt)
• expected landing weight