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Mission Statement 

The purpose of FLAPS-2-APPROACH is two-fold:  To document the construction of a Boeing 737 flight simulator, and to act as a platform to share aviation-related articles pertaining to the Boeing 737; thereby, providing a source of inspiration and reference to like-minded individuals.

I am not a professional journalist.  Writing for a cross section of readers from differing cultures and languages with varying degrees of technical ability, can at times be challenging. I hope there are not too many spelling and grammatical mistakes.

 

Note:   I have NO affiliation with ANY manufacturer or reseller.  All reviews and content are 'frank and fearless' - I tell it as I see it.  Do not complain if you do not like what you read.

I use the words 'modules & panels' and 'CDU & FMC' interchangeably.  The definition of the acronym 'OEM' is Original Equipment Manufacturer (aka real aicraft part).

 

All funds are used to offset the cost of server and website hosting (Thank You...)

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Journal Archive (Newest First)

Entries in Flight Simulator (58)

Tuesday
Sep202016

White Caps for Locking Toggle Switches on Overhead

It has taken a very long time to collect the assortment of OEM needed parts to complete the forward and aft overhead panels.  Finally the build is now in progress and it’s hoped completion will be towards the end of 2016.

LEFT:  Lower electrical panel showing reproduction latex-style cap (ELEC 2) and OEM Honeywell Switch Accessory 15PA90-6W (ELEC 1). Click to enlarge.   For those with keen eyes - yes that is a voice recorder in the lower panel - more to follow in later posts.  Of interest are the two different white caps (read main text). 

Earlier on, I had purchased several dozen Honeywell toggle switches, however, for whatever reason the white caps on the toggles were either missing or damaged.  I was intending to use reproduction white push-on caps (aka white condoms), but the caps failed to  fit snugly to the OEM switches, and their appearance was slightly different to the OEM version - the ends of the caps looked rather bulbous.

My next choice was to use latex caps that are used in automotive industry.  Once again, the appearance was slightly different and the automotive caps sported a small nipple at the end of each cap where they had been connected to the plastic retaining spur; I found the appearance of the nipple disconcerting.

Short of viable options, I purchased the OEM white caps from Honeywell which is the company that supplies Boeing.  If you carefully look at the above picture of the lower electrical panel (click image to enlarge picture), you will observe the nearest toggle switch has been fitted with an automotive style cap; the nipple and joining line is clearly visible.  The second toggle switch is fitted with the Honeywell white cap.

OEM White Cap Anatomy

The reproduction slip-on caps currently available on the market bear little resemblance to those made by Honeywell.

LEFT:   Honeywell Switch Accessory 15PA90-6W showing internal screw thread.  The thread screws onto the stem of the toggle switch (click to enlarge).

Most of the reproduction white caps are either a push-on condom style, or are a white-capped head attached to a slender hollow shaft.  The shaft then slides over the existing switch stem.

The Honeywell caps are not slip-on latex but a solidly-produced head with an internal aluminium thread.  The head is designed to be screwed directly to the shaft of the toggle switches.  Firmly attached to this head is the white latex cap. 

Mounting

To mount the white cap on a toggle, witch you must first gently heat the switch stem which will loosen the head of the toggle.  It then is an easy matter to screw off the head and replace it with the OEM head.

Measurements

Not everyone wants to utilise OEM parts.  As such I have provided the measurements of the switch head (courtesy of Honeywell) for those who wish to try their hand at making their own white caps.

As the overhead build continues, I will be posting more articles that showcase the overhead and the various panels and functionality.

If you are searching for the other syle of white caps used on the overhead, the part number is 69-44578-2.

Glossary

Honeywell – Avionics conglomerate that is heavily involved in the defence and aviation industries.
OEM – Original Equipment Manufacture (aka real aircraft part).

Friday
Aug262016

Assembly of Forward Overhead Panel

Construction of the simulator began in 2011.  It is now 2016 and I am perplexed to why the build has taken so long to complete.   Of course, opting to try and use OEM (Original Equipment Manufacture) parts whenever possible has added significant time to the project -  especially the procurement of parts.

LEFT:  Forward overhead using OEM parts (click to enlarge).

Most of the parts that make up the forward overhead have now been obtained and assembly of the components is well advanced.   Very soon the wiring from the panels to the Phidgets cards will begin.  This will be followed by several hours of testing to check correct functionality and to ensure perfect harmony between components and systems. 

A basic frame has been constructed to enable the overhead to be easily positioned to enable the wiring to be done with a little more ease.  After the forward overhead is completed, work on the aft overhead will commence.  Rome, it seems, was not built in a day.

Certainly, completion of the forward overhead will be the major project over the next few months.

Thursday
Aug042016

FS-FlightControl Instructor Operating Station (IOS) - Review

Virtual flyers can be grouped into three broad groups.  Those that are satisfied using a desktop simulator, those that gravitate toward a professional simulator, and those that strive to replicate, as close as possible, a Level D simulation.  No matter which group you belong, there is a requirement for a feature-rich, reliable, and stable Instructor Operator Station (IOS).

LEFT:  Opening screen for FS-FlightControl IOS on the server computer.  IOS can be easily configured to automatically open after Windows start-up.  (click to enlarge).

This post will introduce the Instructor Station FS-FlightControl, developed by AB-Tools GmbH, a company located in Germany.  The review is not meant to be comprehensive as such a document would be as long as the product’s operating manual.  Rather, we will examine some of the product’s features prior to making an assessment of the software’s reliability and ease of use.

What is IOS - Do I need It

IOS is an acronym for Instructor Operating Station.  At its simplest, it's the menu system in Flight Simulator that enables you to choose from several parameters to create a pre-programmed flight scenario. 

A dedicated instructor station is far more than a few options to alter the time, place, and scenario in the simulator.  A good instructor station should enable you to set basic flight scenarios, in addition to being able to monitor set tasks and parameters.  The software should provide clear and readable displays, be set out logically, be easy to operate, and also be able to initiate system failures.  Furthermore, the software must be stable, reliable and consistent in its output.

There are several Instructor Operating Stations available on the market and most high-level avionics suites come with a ready-made IOS as part of their software.  Therefore, the question must be asked - why is there a need to purchase a stand-alone IOS.  

Put bluntly, many generic instructor stations have been added at the back-end of an avionics suite.  These instructor stations can lack functionality, features, and ease of use.  Furthermore, their layout is often not optimal or configurable.

IOS Features - FS-FlightControl

The features and functionality that are supported by IOS are extensive, however, bear in mind that the instructor station has been designed to operate across different simulator platforms and avionics suites; not every feature may operate with the intended avionics suite.  For example, flight plans can be generated and sent to FSX in the standard .pln format, but they cannot be send directly to ProSim-AR in the correct format (as at the time of writing).

LEFT:  Screen shot showing the POSITION page display of IOS.  Note the easy to navigate menu at the bottom area of the screen (twelve modules).  This menu system is available on all IOS pages and enables quick and easy navigation between modules (click to enlarge).

I have purposely not duplicated what has already been written on the FS-FlightControl website.  The website provides a well detailed description of the features and functionality of the software and includes numerous screen shots.

Broadly speaking, IOS has been developed around 12 main modules.  Like-minded themes have been grouped into whatever module is specific to the subject.  If the information exceeds what can be displayed on one page, then one or more sub-pages (sub-tabs) are provided.  There is a gamut of features

Main Modules

Position:   Aircraft re-position, runway preference, aircraft scenario, approach presets, airport selection and re-position options.

Map:   Street map, satellite map and height map.   Navaids, AI aircraft, weather, aircraft location, compass and route/flight plan overlay.

Flight Planing:   Route and flight plan generation with load tool.  Importing and exporting of data with flight plan generated onto roving MAP.

Conditions:   Environmental conditions relating to weather (artificial and real-time), visibility (CAT presets), winds, clouds, precipitation, altitude levels, barometric pressure, presets, time and season, accelerated time, and user-generated conditions.  This section is very detailed and is examined in several sub-tabs.  Many of the presets are as easy as clicking a button on the screen.  For example, ILS visibility conditions can be generated by clicking one of the CAT buttons (CAT I, II, III, IIIa/b/c).

Push back:   Graphical interface enabling push back of aircraft at any angle and distance.

Fuel/Load:   Fuel volume, passenger, crew and cargo weights, aircraft weights (ZFW), center of gravity (%CG) and load tool.

View/Slew:   Alters external camera views of aircraft and enables the slewing of aircraft.

Failures:   Aircraft system failure conditions that can be triggered immediately, at pre-defined times, or at random.

Statistics:   Approach statistics - Graphical representation of aircraft in relation to vertical and lateral position, aircraft position, ground altitude, vertical speed, pitch, and bank angle.  Results can be exported to Google Earth for further analysis.

Network:   Module to control all computers and software within your simulation network (server and any number of client computers).

Aircraft:   Selectable list of aircraft options re: altitude, speed, direction, radios, TCAS alert status, engine parameter outputs, throttle outputs, autopilot, light and switches, etc. 

Settings:   Customization of all aircraft, map, and program parameters: colours, fonts, map layouts, etc.  Additionally, other variables can be customised such as CAT visibilities and decision heights.

Favoured Features

I’ll be honest, the more I use IOS the more I enjoy my simulation experience.  At the very least, IOS provides a reliable way to store various approach scenarios to numerous airports at different times, seasons and weather conditions.   Granted, that this can be done from the flight simulator menu, however, it cannot be done as cleanly nor as quickly as it can from the IOS module.

Although I do not use all the features available in the program, there are several that I continually use.  It is these I will discuss in further detail.

POSITION:  Position refers to the position of the aircraft whether it be on the ground or in the air.  IOS enables the user to select from several ground positions such as the gate, runway, terminal, base approach, straight-in approach, etc. A click of the mouse will position your aircraft to any of several preset locations. 

I find this to be a very good time saver, especially if you do not want to simulate a long taxi or some other part of the flight but wish to concentrate only on one aspect – such as the approach phase.  In addition to various presets, this page also allows customized approaches to be generated and saved.

Another aspect of this page deserves mention; the ability to select a chosen aircraft livery, parameter list (fuel state, trim, radio frequencies, etc) and save this to custom-named 'slot'.  This is another time-saving feature and easy method to choose a pre-saved livery of an aircraft type.

STATISTICS:   For those who fly by the numbers and want to improve their approach techniques, the statistics section provides a graphical interface that records the vertical and lateral deviation of the approach.  It also records airspeed, vertical speed and several other characteristics.

CONDITIONS:   Conditions broadly refers to environmental and weather conditions at the airport selected, or at various pre-selected waypoints or weather stations.  Changing weather conditions, visibility, season and time is as easy as clicking a button.

This page is exceptionally feature-rich and the instructor station can generate live weather, weather from an imported METAR string or any number of pre-saved weather themes.  For those interested in setting up specific weather events, for flight training, it is very easy to do so.  

MAP:  The map is a hidden gem that enables you to overlay a wealth of information onto a street or satellite map of the area of operation. 

LEFT:  Screenshot showing MAP display page.  Many advanced features that can be displayed as a map overlay.  The tabs along the sides of the page can be clicked to turn features on or off (click to enlarge).

 For example, the user aircraft and AI aircraft are graphically represented along with all navigation aids which includes VORS, NDBs, high and low jetways, ILS feathers and waypoints.  Wind direction and current barometric pressure can also be displayed along with the current SID, STAR or route.  Whilst on the ground all aprons, runways and taxiways are shown.  Navigating to an assigned runway could not be easier as the user aircraft icon shows the position of the aircraft at all times. 

As with all windows, the MAP can be displayed as a separate screen on another monitor.  Therefore, it is possible to have IOS open on two monitors with one monitor showing the MAP view while the other monitor displays a different view.

An added advantage is the ability to position your aircraft anywhere on the map and create a position fix along with altitude, direction, pitch, bank, airspeed and radio frequencies.  This information can be saved for future activation from the POSITION page.  This enables you to quickly and easily set-up an approach and save this approach for future use.

For those that fly on-line, VATSIM, IVAO and PilotEdge are supported.

NETWORK:  IOS enables the user to program the software to control what programs open or close on any computer that is connected to the network.

For example, I use a batch file  to open and close flight simulator, ProSim-AR and other FS related programs (weather, flight analysis, etc).  IOS when turned on from the client will automatically execute the opening of the batch file on the server computer.  Likewise, when triggered, IOS will engage the batch file I use to close flight simulator and other ancillary programs.  Additionally, a time delay can be configured to cause a delay between the closure of programs and the turning off of the server computer.  

Installation of IOS - Server and Client

The software package is downloaded from the developer’s website and consists of a self-extracting .exe file. 

As IOS has networking capability, it's not necessary to install IOS to the computer that has flight simulator installed; it will operate on a client computer.  Additionally, a wizard is used to direct you through the installation process and configuration.  Networking to a client is done via SimConnect.  FSUPIC and WideFS are not required.

LEFT:  Screenshot showing the PUSH BACK display page (click to enlarge). 

Although networking is achieved through the use of SimConnect which can, at times, be problematic, I did not experience any issues with SimConnect in relation to the installation and networking of the instructor station. 

Configuration

Configuring the program to suit your requirements is done from the SETTINGS page.  Variables can be altered for each aircraft, and aircraft profiles can easily be created that save particular parameters or conditions.  Likewise, the software can be altered to enable a particular font style and colour to be displayed along with a zoom value and size.  The process is straightforward.

Pretty much everything in IOS is able to be configured to your liking.

One aspect of IOS I found to be very handy, was that when you close the instructor station it will keep the last known settings.  This means the parameters for the next flight session (if not altered) will be identical to the last.

Ease of Use

The IOS program is set-out intuitively and the various pages (modules) follow a logical sequence with like-minded themes bundled together on the same page.  The twelve page main menu located at the bottom of each page is promulgated across all pages and enables quick access to various features. 

LEFT:  Screenshot showing the FAILURES display page.  Note the open conditions call-out box.  There are several sub-pages (sub-tabs) that deal with failures.  Failures are an important asset to enthusiasts striving for realism (click to enlarge).

Unlike other instructor stations, all information relating to a specific theme is located on the one main page (for example, failures or position page); it is not necessary to navigate between several pages trying to find the information.  Furthermore, the screen display can resized to either fill your display or only part fill it.

Another advantage is the implementation of large-style buttons that enable quick and accurate identification of a module.  Everything is easy to find and access.

Program Administration

Program administration encapsulates the opening and closing of programs from one or multiple computers. 

Without an instructor station or the use of batch files, several programs must be opened on the client and server computer to begin a flight.  This takes time and the process can be unwieldy.

If the instructor station is configured correctly, it is a two-step process to begin a flight.  First the computers must be turned on.  Second, from the client the FS-ControlControl IOS icon is depressed.  Once IOS opens on the client computer it will communicate with the server computer (via SimConnect) and open any number of programs on the server (assuming they have been configured correctly in the IOS NETWORK page).  

Once Flight Simulator opens and you are on the flight line it’s only a matter of using the instructor station to alter any variables particular to the flight (airport, aircraft position, weather, fuel, weight, etc).  All changes are automatically promulgated across the network to Flight Simulator.

The important aspect to note, is that other than turning on the server and client computers, everything is done from the one screen on the client computer using the one mouse/keyboard.  Likewise, when closing the simulator session everything can be done, including turning off the server computer, from the instructor station.

Cross-Platform Operations

The IOS operates with Microsoft Flight Simulator X (FSX/FS10) including Steam Edition, and with Lockheed Martin Prepar3D® 1.x, 2.x and 3.x. in a Windows environment.  A separate APP is available for Android and Apple (iOS).  The software works traditionally using the keyboard and mouse in addition to being optimized for touch screens.  IOS can be run either on the computer that has Flight Simulator installed or from a networked client computer.

Stability and Speed

The last thing anyone wants is a crash to desktop caused by a bug-ridden piece of software that exhibits stability issues, poor performance, and does not operate consistently.  

The stability of the instructor station is excellent.  In my simulator set-up the IOS is installed on a client computer and networked to Flight Simulator located on a server computer.  The software loads quickly and interacts with the simulator seamlessly.  

The speed at which software interacts with Flight Simulator is important and it’s pleasing to note that IOS commands do not exhibit any significant time lag between the client and server computers.  There is no time lag when switching between any of the interface screens on the instructor station.  Surprisingly, this includes the MAP mode.  Often a high definition map with several overlays cannot generate its resultant map within an acceptable time. 

This said, internet connection speed may cause users to experience different speeds.

The time taken to open the instructor station from the icon on the client computer is approximately 10-15 seconds.

Updates to IOS (Annual Fee)

The software developer is very proactive and software updates with improvements, minor fixes and new features are regularly provided free of charge.  

LEFT:  Screenshot showing the CONDITIONS display page.  This page has several sub-pages that deal with conditions.  For example, real weather, presets, season, ILS visibility and accelerated time.  Note the display box in the lower left side that shows the frame rates (click to enlarge).

However, the update period is only for one year following purchase.  After this period has lapsed, an annual fee will need to be paid to enable future updates to be used.  The annual fee is only for updates, the original software will still function.

Do you need to update ?  If you are happy with what you have, then no.  However, if you are seeking specific functionality then an update may have this functionality.  A list showing the updates can be read in the INFO section of the software. 

The developer realizes that each person’s requirements for an instructor station is different, and as such, entertains ideas and suggestions for additional features or improvements from end-users.

Support

FS-FlightControl does not have a dedicated forum, however the developer  replies promptly to all e-mails sent via the software help page.  

A benefit of sending e-mail directly from the software is that the log files from your system are automatically attached to any outgoing message.  This enables the developer to easily understand the issue, saves time in asking for further information, and leads to a faster resolution.

Dedicated Manual

A manual for any in-depth software is an absolute necessity.  It is pleasing to note that the developer has written a manual and does not rely on a forum to provide answers to common questions.

The manual, which reflects the latest software build, is accessed from the FS-FlightControl IOS website.  If necessary a .pdf is available on request.  

Additionally, the manual can also be accessed directly from the software.  Each page has several small question marks (?) that when clicked navigate the user to the appropriate help section in the manual.  If you find the questions marks unsightly, then they can be turned off from the SETTINGS page.

Software Trial

This review has only examined several of the features that the instructor station is capable of.  To enable a comprehensive examination of the software, IOS can be installed with full functionality (including any prospective updates) for a period of 14 days.  After this time has elapsed, the software will need to be purchased.

Final Call

Considering the scope of what an instructor station does and how it can be used to enhance the effectiveness of a simulator, there is little doubt that a good IOS is essential.    

I've spent considerable time using the FS-FlightControl IOS and although this review touches on but a few of the features of IOS, I believe this software to be superior to other contemporary products.   It certainly has enhanced how I use the simulator leading to a more enjoyable experience.

The IOS software and further information can be downloaded at FS-FlightControl IOS.

  • Please note I have no affiliation with FS-FlightControl.  I have not been provided with ‘free’ software, nor did I receive a discount in return for a favourable review.  The comments and recommendations I have made are my own.
  • Flight Simulator, in this article, refers to the use FSX/FS10.  I use the B737 avionics suite developed by ProSim-AR.
Thursday
Jun232016

RNAV, RNP, LNAV and VNAV Operations - Overview 

New flyers to the Boeing 737NG often become confused understanding the various terminology used with modern on-board navigational systems.

Although the concepts are easy to understand, the inter-relationship between systems can become blurred when the various types of approaches and departures are incorporated into the navigational system.

LEFT:  Collins Mode Control Panel (MCP) showing illuminated LNAV annunciation (click to enlarge).

This post will not provide an in-depth review of these systems; such a review would be lengthy, confusing and counterproductive to a new virtual flyer.  Rather, this post will be a ‘grass-roots’ introduction to the concept of RNAV, RNP, LNAV and VNAV.  I will also touch on the concept of Performance Based Navigation (PBN).

In the Beginning there was RNAV  

RNAV is is an acronym for Area Navigation (aRea NAVigation). 

Prior to complex computers, pilots were required to use established on-the-ground navigational aids and would fly directly over the navaid.  Such a navaid may be a VOR, NDB or similar device.  Flying over the various navaids was to ensure that the flight was on the correct route.  Often this entailed a zigzag course as navaids could not be perfectly aligned with each other in a straight line - airport to airport. 

When computers entered the aviation world it became possible for the computer to 'create' an imaginary navigation aid based on a direction and distance from a ground-based navaid.  Therefore, a straight line could be virtually drawn from your origin to destination and several waypoints could be generated along this line.   The waypoints were calculated by the computer based on ground VORs and positioned in such a way to ensure more or less straight-line navigation.

In essence, RNAV can be loosely defined as any 'straight line' navigation method similar to GPS that allows the aircraft to fly on any desired path within the coverage of referenced NAVAIDS.

Required Navigation Performance (RNP) and Performance Based Navigation (PBN)

Simply explained, Required Navigation Performance (RNP) is a term that encompasses the practical application of advanced RNAV concepts using Global Navigation Satellite Systems (GNSS).

However, there is a slight difference between RNP and RNAV although the principles of both systems are very similar. 

RNAV airspace generally mandates a certain level of equipment and assumes you have a 95% chance of keeping to a stated level of navigation accuracy.  On the other hand, RNP is performance based and requires a level of on-board performance monitoring and alerting.  This concept is called Performance Based Navigation (PBN).

RNAV and RNP both state a 0.95 probability of staying within 1 nm of course.  But RNP (through PBN) will let you know when the probability of you staying within 2 nm of that position goes below 0.99999.  In essence, RNP and PBN enable an aircraft to fly through airspace with a higher degree of positional accuracy for a consistently greater period of time. 

To achieve this level of accuracy a selection of navigation sensors and equipment is used to meet the performance requirements.  A further enhancement of this concept is the use of RNP/ANP (Required Navigation Performance and Actual Navigation Performance.  Advanced RNAV concepts use this comparative analysis to determine the level or error between the required navigation (the expected path of the aircraft) and the actual navigation (what path the aircraft is flying.)  This information is then displayed to the flight crew.

LNAV and VNAV

LNAV and VNAV are parts of the Flight Guidance System, and are acronyms for Lateral Navigation and Vertical Navigation'.  Both these functions form part of the automation package that the B737NG is fitted with.

LNAV is the route you fly over the ground. The plane may be using VORs, GPS, DME, or any combination of the above. It's all transparent to the pilot, as the route specified in the clearance and flight plan is loaded into the Flight Management System (FMS), of which the Flight Management Computer (FMC) is the interface.

The route shows up as a magenta line on the Navigation Display (ND), and as long as the LNAV mode on the Mode Control Panel (MCP) is engaged and the autopilot activated, the aircraft will follow that line across the ground. LNAV however, does not tell the plane what altitude to fly, VNAV does this.

VNAV is where the specified altitudes at particular waypoints are entered into the FMS, and the computer determines the best way to accomplish what you want.  The inputs from VNAV are followed whenever the autopilot is engaged (assuming VNAV is also engaged).  

The flight crew can, if necessary alter the VNAV constraints by changing the descent speed and the altitude that the aircraft will cross a particular waypoint, and the computer will re-calculate where to bring the throttles to idle thrust and begin the descent, to allow the aircraft to cross the waypoint, usually in the most economical manner.

VNAV will also function in climb and take into account airspeed restrictions at various altitudes and will fly the aircraft at the desired power setting and angle (angle of attack) to achieve the speed (and efficiency) desired.

There is not a fast rule to whether a flight crew will fly with LNAV and VNAV engaged or not; however, with LNAV and VNAV engaged and the autopilot not engaged, LNAV and VNAV will send their signals to the Flight Director (F/D) allowing the crew to follow the F/D cue display and hand fly the aircraft the way the autopilot would if it were engaged.

Reliance on MCP Annunciators

LNAV and VNAV have dedicated annunciators located on the Mode Control Panel (MCP).  These annunciators illuminate to indicate whether  a particular mode is engaged. 

LEFT:  Flight Mode Annunciator (FMA) showing LNAV and VNAV Path Mode engaged.  The Flight Director provides a visual cue to the attitude of the aircraft while the speed is controlled by the the FMC.  CMD indicates that the autopilot is engaged (ProSim737 avionics suite).

However, reliance on the MCP annunciators to inform you of a mode’s status is not recommended.  Rather, the Flight Mode Annunciator (FMA) which forms part of the upper area of the Primary Flight Display (PFD) should be used to determine which modes are engaged.  Using the FMA will eliminate any confusion to whether VNAV (or any other function) is engaged or not.

This post explains the Flight Mode Annunciators (FMA) in more detail.

Summary

In summary, RNAV is a method of area navigation that was derived from the use of VOR, NDBs and other navaids.  RNP through it use of GNSS systems has enabled Area Navigation to evolve to include LNAV and VNAV which are sub-systems of the Flight Guidance System -  LNAV is the course across the ground, and VNAV is the flight path vertically. 

Historically, navigation has been achieved successfully by other methods, however, the computer can almost always do things better, smoother and a little easier – this translates to less workload on a flight crew.  

In my next post, we will discuss RNAV approaches and how they relate to what has been discussed above.

References

The information for this article came from an online reference for real-world pilots.

Acronyms and Glossary

Annunciator – Often called a korry, it is a light that illuminates when a specific condition is met
DME – Distance Measuring Equipment
FMA - Flight Mode Annunciator
FMC – Flight Management Computer
FMS – Flight Management System
GPS – Global Positioning System
GNSS - Global Navigation Satellite System
LNAV – Lateral Navigation
MCP – Mode Control Panel
ND – Navigation Display
NPA - Non Precision Approach
PBN - Performance-based Navigation
RNAV – Area Navigation
RNP - Required Navigation Performance
VNAV – Vertical Navigation
VNAV PTH – Vertical Navigation Path
VNAV SPD – Vertical Navigation Speed
VOR – VHF Omni Directional Radio Range

Thursday
May122016

Knobs Aren't Knobs - Striving for the Perfect Knob

In Australia during the early 1980’s there was a slogan ‘Oils Ain't Oils’ which was used by the Castrol Oil Company.   The meaning was simple – their oil was better than oil sold by their competitors.  Similarly, the term ‘Knobs aren’t Knobs’, can be coined when we discuss the manufacture of reproduction knobs; there are the very good, the bad, and the downright ugly.

Boeing Knobs

As a primer, there are several knob styles used on the Main Instrument Panel, forward and aft overhead, various avionics panels, and the side walls in the B737-800 NG

If you search the Internet you will discover that there are several manufacturers of reproduction parts that claim their knobs and switches are exactly identical to the OEM knobs used on Boeing aircraft – don’t believe them, as more often than not they are only close facsimiles.

In this article, I will primarily refer to the General Purpose Knobs (GPK) which reside for the most part on the Main Instrument Panel (MIP).  Boeing call these knobs Boeing Type 1 knobs.

Why Original Equipment Manufacturer (OEM) Knobs Are Expensive

Knobs are expensive, but there are reasons, be they not be very good ones.  

LEFT:  The real item – a Boeing Type 1 General Purpose Knob (GPK) and issue packet.  There can be nothing more superior to an OEM part, but be prepared to shell out a lot of clams (click to enlarge).

The average Boeing style knob is made from painted clear acrylic resin with a metal insert. On a production basis, the materials involved in their manufacture are minimal, so why do OEM knobs cost so much…   Read on.

There are two manufacturers that have long-term contracts to manufacture and supply Boeing and Airbus with various knobs, and both these companies have a policy to keep the prices set at an artificially high level.

Not all flight decks are identical, and the requirements of some airlines and cockpits are such that they require knobs that are unique to that aircraft model; therefore, the product run for knobs for this airframe will be relatively low, meaning that to make a profit the company must charge an inordinate amount of money to cover the initial design and production costs.

A high-end plastic moulding machine is used to produce a knob, and while there is nothing fancy about this type of technology and the process is automated, each knob still requires additional work after production.  This work is usually done by hand.

Once a knob has been produced, it must be hand striped and finished individually to produce a knob that is translucent and meets very strict quality assurance standards.  Hand striping is a complex, time consuming task. 

Additionally, each knob must undergo a relatively complex paint spraying procedure which includes several coats of primer and paint, and a final clear protective coating.  Spray too much paint and the translucent area (called the pointer) inside the twin parallel lines will not transmit light correctly.  Spray too little paint and the knob can suffer from light bleed.  There is a fine line during production when it is easy to ruin an otherwise good knob with a coat of thickly applied paint. 

Finally, any part made for and used by the aviation industry must undergo rigorous quality assurance, and be tested to be certified by the countries Aviation Authority.  Certifying a commercial part is not straightforward and the process of certification takes considerable time and expense.  This expense is passed onto the customer.

Replicating Knobs - OEM Verses Reproduction

It’s not an easy process to replicate a knob to a level that is indiscernible from the real item.  Aside from the design and manufacture of the knob, there are several other aspects that need to be considered: functionality, painting, backlighting, robustness and appearance to name but a few. 

LEFT:  Often disregarded during the manufacture of reproduction knobs is the inner metal sleeve.  The sleeve protects the material from being worn out from continual use (click to enlarge).

Backlighting and Translucency

To enable the knob to be back lit calls for the knob to be made from a translucent material.  Unfortunately many reproduction knobs fall short in this area as they are made from an opaque material.

The knob must also be painted in the correct colour, and have several coats of paint applied in addition to a final protective layer.  The protective layer safeguards against the paint flaking or peeling from the knob during normal use.  In the photograph below, you can see where extended use has begun to wear away part of the knob's paint work revealing the base material.

Set Screws and Metal Inserts

Often lacking in reproduction knobs is a solid metal set screw (grub screw).

The task of the set screw to secure the knob against the shaft of the rotary so that when you  turn/twist the knob it does not rotate freely around the shaft.  Plastic set screws can be easily worn away causing the knob to freely rotate on the shaft of the rotary encoder. 

LEFT:  Detail of the grip and metal set screw.  The set screw is important as it enables the knob to be secured against the shaft of the rotary.    This knob previously was used in a Boeing 737-500 (click to enlarge).

The position of the set screws on the knob also deserves attention.  Correctly positioned set screws will minimize the chance of rotational stress on the shaft when the knob is turned.

Of equal concern is the hole on the underside of the knob where the rotary shaft is inserted.  The hole should be sheathed in metal.  This will increase the knob’s service life.  If the hole does not have a metal sheath, it will eventually suffer from wear (disambiguation) caused by the knob being continually being turned on its axis.   Finally, the knob must function (turn/twist) exactly as it does in the real aircraft.

Reproduction knobs may fail in several areas:

(i)    The knob has various flaws ranging from injection holes in the molded plastic to being the incorrect size or made from an inferior plastic material;
(ii)    The knob does not use metal set screws, and the set screws are not located in the correct position on the knob;
(iii)    The knob has a poorly applied decal that does not replicate the double black line on NG General Purpose Knobs.  The adhesive may not be aligned correctly and may peel away from the knob;
(iv)    The knob is made from a material that does not have the ability to transfer light (translucent pointer);
(v)    The knob does not appear identical in shape to the OEM part (straight edge rather than curved);
(vi)    The paint is poorly applied to the knob and peels off.  OEM knobs have several thin coats of paint followed by hard clear coating of lacquer to ensure a long service life;
(vii)    The colour (hue) of the knob does not match the same hue of the OEM product; and,
(viii)    The circular hole in the rear of the knob, that connects with the shaft of the rotary encoder does not have inner metal sleeve.  

The time it takes to manufacture a knob is time consuming, and to produce a quality product, there must be a high level of quality assurance throughout the manufacturing process.

Older Classic-style Knobs

It's common knowledge that many parts from the classic series airframe (300 through 500) are very similar, if not identical to the parts used in the Next Generation airframe.  Unfortunately, while some knobs are identical most are not.

The knobs may function identically and be similarly designed and shaped, but their appearance differs.  Knobs used in the Next Generation sport a twin black-coloured line that abuts a translucent central line called the pointer, classic series knobs have only a central white line.

Rotary Encoders

Although not part of the knob, the rotary encoder that the knob is attached deserves mention.

A fallacy often quoted is that an OEM knob will feel much firmer than a reproduction - this is not quite true.  Whilst it is true that an OEM knob does has a certain tactile feel, more often than knot the firmness is caused by the rotary that the knob is attached to.

Low-end rotary encoders that are designed for the toy market are flimsy, have a plastic shaft, and are easy to turn.  In contrast, rotaries made for the commercial market are made from stainless steel and are firmer to turn.

Also, low end rotaries and knobs are made from plastic and with continual use the plastic will wear out prematurely resulting in the knob becoming loose.

Final Call

Whether you use reproduction or OEM knobs in your simulator is a personal choice; It doesn't play a huge part in the operation of a simulator.  After all, the knobs on a flight deck are exactly that – knobs.  No one will know you have used a reproduction knob (unless low end reproductions have been chosen).

LEFT:  Many reproduction knobs fit the bill, and for the most part look and feel as they should.   It's easy to criticise the injected plastic being a little uneven along the edge, but this is unseen unless you are using a magnifying glass.

However, the benefit of using a real aircraft part is that there is no second guessing or searching for a superior-produced knob.  Nor is there concern to whether the paint is the correct colour and shade, or the knob is the correct shape and design – it is a real aircraft part and it is what it is.  But, using OEM knobs does have a major set-back - the amount of money that must be outlaid.  

But, second-hand OEM NG style knobs are not easy to find and often there is little choice but to choose the ‘best of the second best’. 

BELOW:  Cross section of a Boeing Type 1 General Purpose Knob.