The DGS 65 Gyro contains a Gyro encoder flex card (flex card) mounted inside the gyro capsule at the top of the internal assembly. This flex card is the information collector for the unit and transmits information to the microprocessor.
There are two sets of LEDs and photo transmitters built into the flex card which must operate properly. By monitoring the sequence in which these transmitters turn on and off, the microprocessor determines the direction that the aircraft’s turn.
In recent years, we have determined that older flex cards are reaching their effective life limits and are now experiencing higher failure rates.
There are two primary ways this unit can fail. First if one or both output channels of the flex card fail, the heading change information will not get to the microprocessor and the unit will no detect heading changes. This will result in a heading freeze on the HSI display. This type of failure may also be intermittent.
Second there is a circuit in the unit which monitors the electric current that is being supplied to the LEDs. If the current is interrupted this monitoring circuit with cause the unit to send a flag signal to the HSI display and the red flag will drop in view.
As with the output channel failure, the heading output will freeze. There is no type of temporary repair, bypass or jumper approved by the OEM and doing so is in violation of FAA regulations.
We recommend following the OEM repair manual procedures for repairing or overhauling the DGS 65 Gyro and only using Rockwell Collins Gyro Encoder Flexcard P/N 6342252001.
Duncan Aviation is an authorized Rockwell Collins Service Center and is able to overhaul most Rockwell Collins gyroscopes. If you ship your gyro directly to Duncan aviation for overhaul, you could receive your gyro back in 3 to 5 days using Duncan's Aviation's AOG service. When shipping your gyro to Duncan Aviation for overhaul, please follow these critical shipping procedures for a business aircraft gyroscopes.
Duncan Aviation has four avionics tech reps at your service to answer your questions or assist in troubleshooting your avionics units, including the gyro.