ISFD Knob Fabricated

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OEM ISFD (Image copyright Driven Technologies INC)

The Integrated Standby Flight Display (ISFD) is mounted in the stand-by instrument cluster in the Main Instrument Panel (MIP).  The ISFD provides redundancy should the Primary Flight Display (PFD) on the Captain or First Officer fail. 

The ISFD is not a common panel to find second hand, and working units are expensive to purchase.  I don't  have an OEM ISFD, but rather (at least for the moment) use a working virtual image displayed by ProSim737. 

ISFD knob.  Two versions: one replicates the taller NG style while the other is slightly shorter.  Although not functional, they provide a better representation of the plastic knob that previously was installed

Conversion of an OEM unit is possible, however, the unit would need to be fully operational, and  finding a working unit at a reasonable price is unlikely.  ISFDs are expensive and reuse is common.  If a unit does not meet certification standard, it's disposed of because it's broken and cannot be economically repaired.

ISFD Knob

The ISFD knob that came bundled with the MIP I purchased is very mediocre in appearance – in fact it's a piece of plastic that barely looks like a realistic knob.  I purposely have not included an image, as the design would be an embarrassment to the company that produced the MIP.

A friend of mine is a bit of a wizard in making weird things, so I asked him if he could make a knob for me.  He made two knobs – one based on the standard design seen in the Next Generation airframe and the other knob a shorter version of the same type. 

Knob being fabricated on a lathe

Attention to Detail

Attention to detail is important and each knob has the small grub screw and cross hatch design as seen on the OEM knob.  The knobs have been made from aluminum and will be primed and painted the correct colour in the near future.

A 2 axis CNC lathe was used to fabricate the knobs.  The use of a computer lathe enables the measurements of a real knob to be accurately duplicated, in addition to any design characteristic, such as cross hatching or holes to install grub screws.