Distance measuring equipment or DME determines an aircraft’s distance to the next VHF omni-directional range (VOR) station. Pilots use this information to determine the direction the aircraft is moving in relation to the station.
Rockwell Collins has issued Service Information Letter (SIL1-01) that calls for the inspection of the capacitors in the DME-42/DME-442 units for date codes. These units are installed on a variety of business aircraft.
If these codes are beyond seven years, they need to be replaced. If they are not replaced, the unit will fail eventually and probably not when it’s convenient.
In addition to the capacitors called out in the SIL, we have found additional capacitors needing replacement.
SILs are not required, however it is valuable information an operator should take notice of when having to send in the DME unit for repair/overhaul.
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