SDR ASAA2017101822241

Service difficulty report · Reference Unit · Boeing 737890

Difficulty date: October 18, 2017
Submitted: October 19, 2017
Operation: Air carrier
Aircraft: N589AS
Make and model: Boeing 737890
Aircraft serial: 35686
Aircraft time: 38,010 hours, 11,498 cycles
System (JASC): 3420 · Attitude and Direction Data System
Part: Reference Unit
Part number: HG2050AC11
Part serial: 98111055
Condition: Failed
Location: Air Data
Part time: 8,308 hours, 2,730 cycles
Stage of operation: CR
How discovered: O
Nature of condition: J
Precautionary procedure: A

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

LEFT IRS FAULT LIGHT ILLUMINATED. ACFT GROUNDED. AIR TURNBACK. ACCOMPLISHED A BITE TEST OF ADIRS. FOUND INFLIGHT FAULTS 34-21002 IR FAIL, 34-21009 ENTER HEADING, 34-21037 IR DATA INVALID. COMPLIED WITH FIM 34-21-806, 34-21-803, 34-21-808. REMOVED AND REPLACED LEFT AIR DATA INERTIAL REFERENCE UNIT IAW AMM 34-21-01-000-801, AND 34-21-01-400-801. OPS TESTED IAW AMM 34-21-00-710-801, OPS NORMAL.