I’ve posted this image of the Main Instrument Panel (MIP) of the B737-800NG to briefly examine a few of the differences between a real MIP and a reproduction MIP. Although a reproduction MIP may appear identical to the real item, there can be subtle differences.
Let’s look at a few of these differences using the photograph as a reference.
LEFT: MIP (OEM) from 737-800 NG (click image to enlarge).
Bezel. The bezel is the frame that surrounds the display units (DUs). In the real aircraft the bezel forms part of the display unit, which is why the bezel breaks open in the lower area; to allow access to and removal of the unit.
If you carefully look you will note there are no screws that hold the bezel in place to the MIP. Quite a few manufactures use Phillip head screws in each corner of the bezel to attach the bezel to the MIP.
In the real aircraft the bezel is made from machined aluminum.
Landing Gear Lever. The real aircraft has a smaller than often seen landing gear knob (the translucent knob). Further, when the landing gear is in the down and locked position, the red trigger located on the gear shaft completely recesses between the two half-moon protectors. The trigger also is spring-loaded allowing the gear lever to be unlocked by depressing the trigger in specific conditions.
Fuel Flow Reset Switch. The real aircraft incorporates a switch/toggle with a larger defined and bulbous-looking head, rather than a standard-style toggle most manufacturers use. The OEM toggle is also very specific in operation (3 way pull & release).
The knobs used on the MIP. These knobs are called general purpose knobs (GPK) and it's uncommon for a reproduction knob to look identical to an OEM knob. OEM knobs present with curved rather than straight edges and have the grub screw located in a different position. Many reproduction knobs lack this detail and have the grub screw located at the rear of the knob.
Furthermore, OEM knobs have an inside metal shroud (circular metal retainer) and a metal grub screw thread, both important to ensure operational longevity of the knob; reproduction knobs usually do not have this. The shroud can be important as it increases the longevity of the knob as it stops the acrylic from being worn down over time with continual use.
The NG also has a backlit black coloured line that runs adjacent to a translucent line on the front of the knob; at night this line is backlit. Most of the replica knobs have a black line which is a transfer (sticker) that has been hand applied to the knob. Stickers and transfers over time often lift, especially at the ends and hand application is often haphazard with some transfers straight and other a little off center.
In my opinion, any high end MIP of considerable financial outlay should have appropriate knobs that are high fidelity and replicate the OEM item.
If you look carefully at the photograph you will note that the knobs have curved edges and the Used Fuel Reset Switch has a bulbous appearing toggle.
I am currently writing a short article on "knobs" which will be published in the near future.
Annunciators (Korrys). The annunciators on reproduction MIPs use LED technology, are only lights/lamps/indicators, and may exhibit an incorrect colour hue in contrast to the OEM part. Reproductions can also be lacking with regard to the legend, as OEM legends are lazer cut and well-defined.
Annunciators in the real aircraft are illuminated by 28 Volt bulbs contrasting the low brightness LEDs seen in reproduction Korrys - this alone can make a huge difference in aesthetics. Finally, the push to test function seen in the real item, to my knowledge, is lacking in reproductions.
- Note that some newer airframes may use LEDs in favour of bulbs.
Colour. Boeing grey (RAL 7011), has a specific RAL colour number; however, rarely is every MIP or aviation part painted exactly the same grey colour; there are sublime differences in shade, colour and hue. Inspect any flight deck and you will observe small colour variations. Type RAL 7011 into Google and note the varying shades for a specific RAL number.
Dimensions & 1:1 Ratio. High-end MIPs for the most part are very close to the correct 1:1 ratio of the real item and differences, if noticeable, are marginal. But, less expensive MIPs can have the incorrect dimensions. It's not only the overall dimensions that are important, but the dimensions of the spaces, gaps and holes in the MIP that allow fitment of the various instruments and modules.
Whilst this may not be a concern if you're using the stock gauges, etc that came packaged with your MIP, it can become problematic if you decide to use OEM parts. There is nothing worse that using a Dremel to enlarge a hole in a MIP that isn't quite the correct size. Worse still, is if the hole in larger than it should be.
Musings - Does it Matter ?
If everything fits correctly into whatever shell you're using, then a small difference here and there is inconsequential. However, if you are striving for 1:1 100% accuracy then it's essential to know what’s reproduced factually and what is fiction (Disneyland).
I have only mentioned differences based on what can be seen in the photograph. There are additional nuances that differ between MIP manufacturers.
System Simulation is a Priority
As I move more into my project, I realize that many items available in the reproduction market are not identical to the real aircraft; a certain artistic license has been taken by many manufacturers. This said, while it's commendable to have an exact reproduction of a flight deck, keep in mind that a simulator is primarily a simulation of aircraft systems.
Of course this doesn't mean you throw everything to the wind aesthetically. To do so would mean you would have an office chair, desk and PMDG in front of you. Aesthetics are important as they stimulate by visual cues, a level of immersion that allows the virtual pilot to believe they are somewhere other than their own home.
If you inspect real-world flight simulators used by aircraft companies, you will quickly note, that many of the simulators do not replicate everything or strive to have everything looking just like the real aircraft. Simulators are designed for training and whilst a level of immersion must be apparent, replicating aircraft systems takes priority.
B 737-800 NG Project Status
The overheads are my main concern at the moment; however, I am also working on replacing as much as possible on the Main Instrument Panel with OEM items. Once completed, all that will remain is the FDS MIP skeleton and a few bits and pieces. A decision has yet to be made concerning replacement of the glareshield.
The question is probably asked - why not replace the FDS MIP with a OEM MIP. Whilst this is possible, a NG style OEM MIP apart from being difficult to find and expensive, would require consdierable fabrication to use in a Flight Simulator. It's far easier to use a commerical MIP as a template and then replace as much as possible with OEM items.
As the MIP project progresses updates will be made.
Acronyms & Glossary
Annunciator - A single coloured light or group of lights used as a central indicator of status of equipment or systems in an aircraft. Usually, the annunciator panel includes a main warning lamp or audible signal to draw the attention of operating personnel to the annunciator panel for abnormal events or conditions. To annunciate means to display or to become audible. Annunciators are often called Korrys; Korry is a manufacturer of annunciators.
FDS - Flight Deck Solutions
Korry – See Annunciator. A brand of annunciator used in the Boeing 737 airframe.
Legend - The plastic lens plate that clips to the annunciator. the legend is the actual engraved writing on the lense.
MIP - Main Instrument Panel.
OEM - Original Aircraft Manufacture (aka real aircraft part).
RAL - International colour matching system.