The Control Display Unit (CDU) is the pilot interface to the FMC (Flight Management Computer).
Historical Context - What is a CDU, FMC & FMS ?
The first true FMC was introduced in 1984 with the release of the Boeing 737-300. In its most basic description, the CDU can be described as a computer that can store flight and navigation data and perform detailed and comprehensive assessments of the stored data, providing the pilot with up date information that is relative to safe and accurate flight. The CDU interacts with the autopilot and flight director, auto-throttle and internal reference system (IRS).
The navigation database is used to store route information which the autopilot will fly when in LNAV mode. When given data such as YMHB & KSEA, it takes inputs from the fuel summation unit to give a gross weight and best speeds for take off, climb, cruise, descent, holding, approach, etc. These speeds can all be flown directly by the autopilot & auto-throttle in VNAV mode.
Flight Management System (FMS)
The integrated system, of which the FMC is just one component, is known as the Flight Management System (FMS) The FMS can be defined as being capable of four dimensional area navigation (latitude, longitude, altitude & time) while optimizing performance to achieve the most economical flight possible.
An aircraft will only have one FMC installed, however, dependent upon company regulations, air safety and routing (flying over water), many operators will have two CDU's installed for redundancy. Think of the CDU as a keyboard to your computern (FMC).
Flight Deck Solution’s PRO Mx CDU – Excellent Functionality & Rock Solid Software
The CDU manufactured by Flight Deck Solutions (FDS) is an outstanding piece of simulation engineering. The unit is well built, solid, replicates a real B737 style CDU 1:1, and more importantly the software is reliable, robust and does what it’s supposed to do.
The functionality of the unit replicates the functions of a real CDU, with the added benefit of several add on functions that deal exclusively with commands used in flight simulator, such as the ability to set ADF, transponder and COM frequencies, various sim commands such as pause, accelerate flight and cabin announcements.
FSD’s CDU does not mimic every option available on a real CDU; in the real world airline companies have the opportunity to purchase specific options they believe are relevant to their flight operations. This said, many of the variations have been included along with the main stay functions.
The CDU is used throughout a flight, therefore, reliability is expected. The software that drives the unit and provides the data has not let me down – it runs flawlessly. Even if you type the wrong commands into the unit, the software does not crash or malfunction.
The unit does not ship with navigation data included. The navigational database which includes STARS and SIDS must be purchased separately from Navigraph and then installed into Sim Avionics. Download and installation of the database is very easy and most of the install is automated.
The benifit of being able to regularly update the navigational database is obvious.
LEFT: The CDU at night with the only illumination being from the actual CDU unit.
The Actual Unit
The CDU body and bezel (front plate) is manufactured from high grade metal while the rear section that houses the electronics is plastic. A USB and VGA cable connects to the videocard output on the computer. The unit is DZUS complaint and drops into the rails in the MIP with perfect precision. The CDU keyboard is made from high definition injection-molded plastic and the keys are dimpled and back-lit. The keys are very tactile and when depressed an audible click is heard ensuring you know the key has been depressed. The unit has a dimmable display with the dim switch located on the actual unit. In in the interest of replicating the real CDU, FDS has included a functional metal carry bracket that folds out from the edge of the bezel - not necessary but a nice touch.
The WOW factor
I have left the best feature of the CDU to last – the display. WOW is the only word to describe the display. The display is a colour VGA display unit sporting 800 x 600 resolution. What this means is that the script on the display is VERY clean, VERY readable and VERY sharp. Differing colours (white, green and magenta) help to distinguish between functions that are activated or in stand-by mode. The use of colour greatly enhances the unit’s readability.
I'm using Sim Avionics and the set-up of the CDU was relatively painless. You must designate which CDU you are installing (Captain, First Officer or Instructor), edit a few lines in the .ini file to ensure it recognises the correct CDU, and configure the display location. The only teething issue I had was ensuring that the monitor display window size was correctly positioned on the screen for the location of the CDU. It took quite a few attempts to get the position "just right".
Manual & Tuition
A manual explaining the functions of the CDU and/or tutorial is not included. In my opinion, FDS should develop a video tutorial that runs you through the basic functions of the unit including a simulated flight. A manual explaining the install and set-up procedure is included.
I'd strongly recommend purchasing Bill Bulfer's FMC Guide. This guide will allow you to get the most from the CDU. I'll be reviewing the FMC Guide in a future post.
I have nothing but the highest praise for this unit and in my opinion this is the BEST piece of flight simulation equipment I have owned or used.
My Rating 10/10
Please note that this review is my opinion only and is not endorsed.
A short video depicting some of the more commonly used keystrokes of the Flight Deck Solutions CDU. I have not used any particular sequence. The video is mainly to show the screen resolution and the uptake speed after depressing a key. Double click video to vuew full screen.