066-1072-04

ADF navigation and timer functions

In normal ADF operation, the receiver tunes a selected nondirectional radio beacon frequency and processes the received signal for use by a compatible bearing indicator. The bearing display points toward the station according to the approved installation and operating mode. ADF information remains subject to radio propagation, terrain, weather, coastal refraction, station serviceability and electrical interference, so it must be interpreted under the applicable flight procedures.

The BFO function supports reception of suitable unmodulated identification signals where operationally required. The dual display and FRQ transfer control let the crew manage active and standby frequency information. FLT/ET and SET/RST controls provide the installed timer functions. These convenience functions do not change the underlying ADF bearing system and should be checked separately during functional testing.

System composition and signal path

A representative chain is crew frequency selection at the KR 87 → receiver tuning and signal processing → approved loop and sense antenna system → selected NDB transmission → processed bearing output → compatible cockpit ADF indicator. Audio identification is routed through the aircraft audio system where configured. Exact companion-unit models, connector pins and signal formats must be confirmed from the aircraft wiring diagram rather than selected by appearance.

A loss of bearing can originate in the receiver, antenna, antenna cable, bearing indicator, audio path, power, wiring or external station conditions. The receiver should therefore be tested as part of the full ADF installation. Related navigation products in the same catalog category may operate in the same aircraft but are not automatically interchangeable or included with this unit.

Exact plate, installation and inspection

The authentic identification photograph shows the KR 87 ADF Receiver designation, Part Number 066-1072-04, serial number 60576, TSO C41c and DO-160 references, and Singapore manufacture marking. Those details belong to the photographed -04 unit. Exact dimensions, weight, current consumption, lighting supply and environmental category should be verified from the approved data for this specific Part Number before installation.

Receiving inspection should compare the complete plate, serial number, bezel, display window, knobs, keys, mounting features, connector condition and overhaul documentation. Bench and aircraft testing should cover power-up, active and standby frequency display, transfer function, ADF mode, BFO, timer functions, dimming, audio identification and valid bearing output through compatible equipment. Any test must follow current approved maintenance data and use suitable radio test equipment.

Overhauled supply and ordering information

This 066-1072-04 KR 87 is offered in Overhauled condition from partner stock with a six-month warranty. The quotation will identify the allocated serial number, overhaul organization, release certificate, bench-test status and included accessories. A mounting tray, connector, antenna, bearing indicator, audio interface, wiring and installation hardware are supplied only when expressly listed.

For an inquiry, specify Part Number 066-1072-04, model KR 87, aircraft type, installed indicator and antenna configuration, supply and lighting requirements, connector or tray requirement, quantity and required certification. Related avionics can be reviewed in the Garmin / BendixKing / Honeywell / Collins category. Final eligibility and interchangeability must be established through the aircraft equipment list and approved installation data.

Maintenance records should retain the exact suffix and modification status because a model-only entry can obscure configuration differences during later replacement or troubleshooting.