Pneumatic Systems Panel

OHP Overview | Fuel+EngineStart | OHP-Electrics

As the title implies, this panel controls the pneumatic systems of the plane. It allows the pilot to connect or disconnect the A/C packs and to use bleed air from the APU for main engines start.

In the B737, this subpanel is part of the big overhead panel. I had to separate it from the rest of the overhead stuff because of space limitations. I found a place for this panel on the right side of the cockpit, near the Com radios. I figgure that's fine, since the only time I need to pay close attention to the switches and annunciators of this panel is during engine start.


Dorel Draw design of the panel's main elements. From left to right:

  • The full drawing with all components (the "big picture") - including the position of LED's for backlighting
  • Base plate from 3mm black acrylic
  • 2nd layer panel from 3mm transparent acrylic
  • The surface of the panel, to be printed on a translucent, self adhesive foil

I decided to skip the building steps and show you the finished product right away.

All switches and buttons are wired to the EPIC, all annunciators to a Phidgets LED64 card. The round gauge in the center has two concentric needles and shows duct pressure in the two pneumatic systems of the plane.

You might have noticed the black carboard covering the annunciator blocks.

The spider LED inside each annunciator compartment is soldered onto a perforated circuit board (just like the ones used for backlighting). When the backlighting is on, it would shine right through these holes and illuminated the annunciators. To avoid this, the black carboard is used.

As always in V.3 of the cockpit, the panel is backlit.

Since this panel has many labels and lines, and most of them are very close to switches and annunciators, I had to use many spider LED to achieve uniform lighing. To avoid all that light shining through the label in the places where the label is supposed to block the passage of light, I used three layers of light blocking foil (as opposed to two in other panels).

Early test of the Flight Illusion duct pressure gauge.

Annunciators and switches on the panel are not yet connected. I just wanted to see if that little instrument does what it is supposed to do. And yes, as a matter of fact it does... I had PM Systems running on the screen in the background and manipulated the switches with the mouse. As you can see, the speed of the needles is not yet perfect, but it is quite apparent that the real instrument is doing the same thing as its digital sibling on the screen.

Format: wmv

Duration: a minute or so

Size: 15 MB