# SDR CALA2022021600404

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: February 16, 2022
- Submitted: February 16, 2022
- Operation: Air carrier
- Aircraft: [N16709](https://openairdocs.org/aircraft/N16709), registered now
- Make and model: Boeing 737724
- Aircraft serial: 28779
- Aircraft time: 74,474 hours, 26,483 cycles
- System (JASC): [3451 · DME/TACAN System](https://openairdocs.org/jasc/3451)
- Part: Strap
- Part number: NA
- Condition: Loose
- Location: 1 And 2
- Stage of operation: UK
- How discovered: O
- Nature of condition: O
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CALA2022021600404

## Discrepancy

BOTH NAV1 AND NAV2 SHOW FAIL. NAV1 THRU 10K FT NAV2 15 MIN LATER TS PER FIM 22-15-00 TASK 813. MULTIPLE FAULTS FOUND DURING BITE AFTER CONFERRING WITH TOMC IN REGARDS TO THE NAV TUNING PANEL LIBRARY TEST. FAILURE 1 AND 2, ACMP FIM 34-31 TASK 801 WITH PARTICULAR ATTENTION TO THE GROUNDING OF THE P5. IF NO DEFECTS FOUND REPLACE THE P5-28 MODULE. PERFORMED BONDING CHECK AND FOUND GRD STUD  GD604AC TO SEAT TRAC FOUND SECOND STRAP LOOSE . RESECURED   STRAP AND BONDING CHECKED THE FINAL READING ON THE OVERHEAD PANEL WAS .15 MILL OHMS. PLEAS K GOOD , BUT FROM STRAP TO PANEL 230 MIIL OHMS .CLEANED STRAP ON GOOD. E PERFORM  FIM 34-31 TASK808  PART F (1)THROUGH(D). GRD STUD AND READIND WAS.15 MILL OHMS.THEN CHECKED OVERHEAD PAN EL RAIL AND FOUND IT OVER RANGE . REF FIM 34-31 TASK 808 STEPS F(1)A-D CHECKED GND BLOCKS AND SWITCHING PNL GNDS, NO STRAY VOLTAGE NOTED. NO FAIL INDICATIONS ON EITHER NAV CNTRL PNLS.

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