Scale ID Annunciation (RW/APP CRS Error)

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Scale ID Annunciation display in upper left hand corner of the Primary Flight Display

The Scale ID annunciation (often called the approach reference), displayed in the upper left of the Primary Flight Display (PFD), is one of a suite of displays that comprise the PFD Navigation Performance Scales (NPS) Indications. 

In the image a runway approach course error (RW/APP CRS Error) is being displayed.  The airport is Hobart, Tasmania and the ILS approach is to runway 12.  The error has been generated because the CRS window in the MCP has the incorrect approach course (140 degrees).  If the approach course was correct, the display would be coloured white - not amber with a strike-through line.

The Scale ID Annunciation display provides, the for the selected approach type, the following approach reference information:

• Airport identifier;

• Runway approach course;

• Distance to the runway threshold; and,

• Approach type.

The display also indicates whether a runway approach course error (RW/APP CRS) has occurred.

Possible approach type displays include:

• LNAV/VNAV (LNAV and VNAV deviations).

• LOC/VNAV (Localiser with VNAV deviation).

• FAC/VNAV (IAN final approach course with VNAV deviation).

• LNAV/G/S (LNAV deviation and glideslope).

• LNAV G/P (LNAV deviation with IAN glidepath).

• ILS (ILS approach).

• FMC (IAN approach).

• GLS (GLS approach).

Airport Identifier and Display Colour

The airport identifier comprises the identifier and airport name (abbreviated).  The identifier will change depending upon the approach type.  For an ILS (and IAN approach) the identifier will be the letter I followed by the airport abbreviation.  For example, Hobart airport is YMHB.  In this case for an ILS approach the airport identifier will be IHB.

The identifier is displayed in two colours: white and amber; amber being cautionary.  The later also incorporates a strike-through line (this line dissects the airport identifier and approach course).

White indicates that all the parameters required for the approach have been completed correctly.  An amber colour/strike-through indicates that one or more of the required parameters have not been met.

Colour Combinations

The following colour combinations can be observed (further information is discussed later in the article). 

• Frequency and approach course displayed in white:

When the navigation radio is tuned to the ILS frequency, the identifier will initially display the ILS frequency (109.90) for the approach.  The frequency will then change to display the airport identifier (IHB).  Whether the colour displayed remains white or changes to amber will depend on whether both navigation radios and CRS course windows are set to the correct ILS approach.

If either display is coloured amber it indicates a RW/APP CRS error has occurred.

• Airport Identifier displayed in amber:

One navigation radio is tuned to the ILS frequency.  Tuning the second radio to the same frequency will cause the display to change from amber to white.

• Approach course displayed in amber:

One or both courses in the CRS course windows (MCP) is not set to the correct ILS approach course.

• DME and approach type:

The DME and approach type (ILS) are always displayed in white.  The DME will display the distance to the runway when the glideslope is captured by the aircraft.

Pre-Approach Tasks

Prior to commencing an approach, the following should be carried out:

• The correct frequency entered into to the navigation radios (NAV 1 & NAV 2);

• The correct approach course (for the runway selected) entered into the Captain and First Officer side CRS course windows in the MCP;

• An appropriate approach selected from the FMS database (depends on the approach type being used); and,

• The approach course for the runway entered into the heading window in the MCP.

Delay

The logic controlling the scale ID annunciation periodically interrogates that data entered into the navigation radios and MCP.  This means that a delay is often observed between the annunciation changing colour from white to amber or back again.  I am unsure of the timing.

Discussion

The indication that a RW/AP CRS error has been triggered doesn’t alwasy preclude an approach from being carried out (although it’s not recommended).  The annunciation indicates that, for the selected approach, something hasn’t been completed with regard to the configuration of the avionics.  It's rarely the case that the frequency hasn't been correctly entered into to the navigation radio; more often than not the cause of the annunciation is a CRS course discrepancy, or failure to configure the second navigation radio to the same frequency as the controlling navigation radio.   

Using the ILS approach as an example.  To correctly configure the instruments for an ILS approach and not receive a cautionary warning, the following must be completed:

• Enter the correct ILS frequency into the BOTH navigation radios; and

• Enter the correct approach course into BOTH the CRS course windows in the MCP.

It’s also recommended, but not mandatory to:

• Enter the approach course into the heading window in the MCP; and

• Enter an appropriate approach into the CDU/FMC.

If you enter the ILS frequency into the controlling navigation radio, and enter a different frequency into the other navigation radio, an amber-coloured RW/APP CRS annunciation will be generated.  Likewise, a caution will occur if the Captain-side and First Officer side CRS windows don’t display the identical ILS approach course.

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IMAGE A-1: ILS approach into runway 12 for Hobart, Tasmania (IHB).  The approach course for this approach is 120 degrees.  The controlling navigation radio (Captain-side/not shown) has been set to the correct ILS frequency (109.90).  The heading that the aircraft is flying is 120 degrees, and the compass rose is offset to the course direction that is displayed in the Captain-side CRS window (140 degrees)

Example (Hobart, Tasmania IHB)

Image A-1 shows an ILS approach into runway 12 for Hobart, Tasmania (IHB).  The approach course for this approach is 120 degrees.  The controlling navigation radio (Captain-side/not shown) has been set to the correct ILS frequency (109.90).  The heading that the aircraft is flying is 120 degrees, and the compass rose is offset to the course direction that is displayed in the Captain-side CRS window (140 degrees).

In the example, a RW/APP CRS annunciation has been triggered for an ILS approach.  The airport identifier and approach course are coloured amber with a strike-through line.   The DME is 9.4 miles and is coloured white (correct data).

This approach can be flown despite the discrepancy between the four courses (120, 180, 130 & 140 degrees) and a RW/APP CRS annunciation.  This is because the ILS approach course (120 degrees) is coupled to the ILS frequency set in the controlling navigation radio  – not the course as indicated in the CRS windows in the MCP. 

In the example you can see that the localiser has been captured (this is identified by the magenta-coloured course deviation line being centered/in-line with the course pointer) despite the CRS window displaying a course of 140 degrees.  Once the aircraft has captured the localizer it will fly the localiser heading no matter what course is displayed in the CRS window (provided it does not exceed 90 degrees).

While this example holds true for an ILS approach other approach types may behave differently.

Important Points:

• The scale ID annunciation is an amber-coloured display that annunciates when the avionics have not been correctly configured for the selected approach.  The display is a cautionary.

• The approach cannot be flown If the CRS course discrepancy is greater than 90 degrees from the ILS approach course.  This is because the aircraft will follow the direction of the course set in the CRS window (if greater than 90 degrees).

ProSim-TS

The ProSim737 avionics suite replicates the RW/APP CRS logic used in the real aircraft. 

Database Inconsistencies

In some instances the annunciation is displayed despite entering the correct information.  A possible reason for this is a scenery navigation database inconsistency. 

In older scenery designs the physical location of the localiser beacons was part of the scenery file and this information is what the simulator referred to.  With the advent of up-to-date navigational points (supplied by Navigraph) the simulator now refers to a navigational database rather than a scenery database.  An inconsistency will occur if there is a discrepancy between the location of the localiser beacons in the scenery and the information recorded in the navigational database.

Final Call

The RW/APP CRS annunciation, although confusing to the uninitiated, does not necessarily mean that an approach cannot be carried out.  However, it’s prudent before flying the approach to understand why the RW/APP CRS error has been displayed. 

In more cases than not, the reason for the cautionary annunciation is a failure to configure the navigation radios to the same frequency and/or enter the same ILS approach course into both the CRS course windows in the MCP.

Batch Files to Open and Close Flight Simulator

Opening and closing the various files and ancillary programs to operate a flight simulator can be onerous and time consuming.  While there have been several programs released that enable you to launch flight simulator with a press of a key, they seldom work with complicated platforms such as flight decks. 

One of the most commonly used methods to open files and programs is to use the start menu within Windows.  However, this is not without it’s shortcomings, and specialist knowledge is required.  An easy and trouble free approach is to use batch files.

What is a Batch File

A batch file is a script file that stores commands to be executed in a serial order.  It helps automate routine tasks without requiring user input or intervention. Some common applications of batch files include loading programs, running multiple processes or performing repetitive actions in a sequence in the system.

Also known as a batch job, a batch file is a text file created in Notepad or some other text editor.  A batch file bundles or packages a set of commands into a single file in serial order.  Without a batch file these commands would have to be presented one at a time to the system from a keyboard.

Usually, a batch file is created for command sequences when a user has a repetitive need.  A command-line interpreter takes the file as an input and executes the commands in the given order.  A batch file eliminates the need to retype commands, which saves the user time and helps to avoid mistakes.  It is also useful to simplify complex processes.

Windows usually uses the .bat extension for batch files.

Whilst there are several methods that can be used to write a batch file, I have found that the examples below operate flawlessly.

Writing a Batch File

It's a simple process to write a batch file. 

Prior to beginning, it’s wise to think about the order you want the programs to open, and whether you want a pause between opening particular files and programs.  While a pause is probably not necessary, it’s a good idea as it allows a file or program to complete its opening sequence, prior to the next file or program opening.

When you have completed writing the batch file in notepad save the file with a .bat extension.  To test the batch file double click on the saved .bat extension.

Although others will disagree, I always open the MSFS-2020 or P3d and allow the program to settle before opening any batch file or other programs.

The following examples of batch files are user-specific.  You will need to substitute the file structure with the file structure you are using.

Opening Files and Programs

• An example of a batch file to open the main flight simulator computer (server).

@Echo  off

//Alpha Main Server Computer (ALPHA-SERVER-P3)  - 09:38 - 25/08/2023

//ProSim738 V3

//ProSim Ancillary Programs

start /d "D:\Flight Simulator Files\SimStacks October 2021\SimStackSwitchv702" Switch.jar

Timeout 0.5

start /d "D:\Flight Simulator Files\FS Set Volume" FSSetvol.exe

Timeout 0.5

start /d "D:\Flight Simulator Files\SimSounds 4.0" SimSounds.exe

Timeout 1

start /d "D:\REX WeatherForce.exe

//ProSim Main Programs

start /d "D:\Flight Simulator Files\ProSim738 V3\ProSimAudio" ProsimAudio.exe

Timeout 1

start /d "D:\Flight Simulator Files\ProSim738 V3\ProSimB738" ProSimB738.exe

An example of a batch file to open the avionics suite on the second computer (client 1).

@Echo off

//Client 1 - ProSim-AR B738 Avionics Suite V3    14:07 5/09/20

//PS738 V3

//Ancillary Programs

start /d "C:\Users\user name\Documents\FSF\Programs\MSFS WideFS7" kilo

start /d "C:\Users\user name\Documents\FSF\Programs\Landing Rate Monitor" LRM.exe

start /d "C:\Users\user name\Documents\FSF\Programs\SimSounds 4.0" SimSounds.exe

//Hardware Connector

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\ProSimB738-HardwareConnector" ProSimB738-HardwareConnector.exe

//ProSim737 Displays and Indicators

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\Displays\CAPT PFD" ProsimDisplay.exe

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\Displays\CAPT ND" ProsimDisplay.exe

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\Displays\FO PFD" ProsimDisplay.exe

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\Displays\FO ND" ProsimDisplay.ex

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\Displays\EICAS" ProsimDisplay.exe

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\Displays\FLAPS" ProsimDisplay.exe

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\PS738ChronoCaptain" ProsimDisplay.exe

Timeout 3

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\ProSimIOS" ProSimIOS.exe

Closing Files and Programs

Likewise, you can also use a batch file to close files and programs sequentially or simultaneously (kill all).

An example of a batch file used to close programs on the main flight simulation computer (server).

@Echo off

//Alpha Main Server Computer (ALPHA-SERVER-P3)  - 09:38 - 25/08/2023

//ProSim738 V3 – closure batch

taskkill /IM wideclient.exe

Timeout  2

taskkill /IM ProSimAudio.exe

Timeout  1

taskkill /IM PMSounds.exe

Timeout 1

taskkill /IM Prosim737.exe

Timeout  4

taskkill /IM fs2020.exe

• im specifies the image name of the process to be terminated (for example, PMSounds.exe or ProSim737.exe).

• @echo on/off defines whether a name or message will be displayed on the console.  It’s also used for other tasks such a script troubleshooting.  I have used it in my batch files because I was told it was a good idea to do so, but if you don’t use the @echo command the batch file still works.  If you do use the @echo command I recommend you use @echo off as this will turn off this feature.

• The // syntax is used to stop the line from being read by the batch file. 

In the examples, the Taskkill command has been used to close the programs.  Taskkill will cause the program to terminate gracefully, asking for confirmation if there are unsaved changes.

To forcefully kill a process, add the /F option to the command line. Be careful with the /F option as it will terminate all matching processes without confirmation.

An example using the /F command is: Taskkill /F /IM ProSimAudio.exe.

There is debate in the computer community to the validity of closing files and programs simultaneously, as ‘killing a program’ may not allow the program enough time to save information it may be saving during the closure process.

For this reason, I'm hesitant to close flight simulator (or other programs) using a closure batch file without a timeout or delay sequence.  Needless to say, it's an easy process to configure a time delay into a batch file to create a delay before closing each program.

Timeouts

Depending upon your computer specifications, some programs may open and close at differing speeds.  If you want a program is open or close before the next program, then a delay sequence will need to be timed into your batch file. 

The timeout command is used to trigger a delay between the programs, enabling any read/write requirements to occur prior to the next program beginning it closure routine.  The numeral denotes seconds or part thereof. 

Streamlining

Once you have created and saved the batch file, a suggestion is to create a shortcut to the file.  Doing this will enable you to make changes to the batch file such as how the file is executed (minimised or maximised), the position on the screen, colour and font style used, and whether to use an icon for easy identification.  Additionally, by creating a shortcut it enables you to place the shortcut on your task bar.

To create a shortcut, right click the batch file and save as a shortcut.

Using Batch Files and ProSim IOS

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ProSim-TS IOS screen in opened to network page.  Rather than explain everything, copy the details and use trial and error to achieve your desired result

If you are using multiple computers, you may want to use the ProSim Instructor Operator Station (IOS) to trigger the opening or closure of programs (via the batch file).  When IOS is configured correctly, you will be able to open and close a batch file on one or more networked computers from one computer screen.

To configure IOS, open the network tab, select add a new action or type and select start program.  In the path to executable file on client box type the file address of the batch opening file.  Choose the start option you prefer and ensure that enabled in checked.

To close your programs, open a second action and type in to the path to executable on client box the file address of the batch closure file.

The accompanying image should be self explanatory.

There are other ways to do this, however, this method is probably the simplest.

Caveat

I am not computer technician.  I have used batch files similar to the examples shown for many years without issues.

Final Call

Batch files are but one way to minimise workload and automate the opening and closure of ancillary programs that are used with flight simulator.  The use of IOS to trigger batch files also enables the user to open and close ancillary programs from the one computer screen (instructor station).