SDR SWAA2025122955405

Service difficulty report · Sense Line · Boeing 7377BD

Difficulty date: December 23, 2025
Submitted: December 29, 2025
Operation: Air carrier
Aircraft: N7741C
Make and model: Boeing 7377BD
Aircraft serial: 35788
Aircraft time: 60,837 hours, 32,364 cycles
System (JASC): 3610 · Pneumatic Distribution System
Part: Sense Line
Condition: Broken
Location: Nr 1 Engine
Stage of operation: DE
How discovered: O
Nature of condition: O
Precautionary procedure: O

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

What was found

AT 30000 CABIN ALT WARNING HORN CAME ON. THE CABIN ALT REACHED 10;000 FEET. STARTED QRH PROCEDURES AND DESCENDED TO 10;000. NO PAX MASKS DROPPED. FOUND SENSE LINE FROM BLEED AIR REGULATOR ON NR 1 ENG BROKEN. REPLACED THE LINE IAW SIP. FOUND SENSE LINE FROM PRSOV ON NR 2 ENG BROKEN. REPLACED LINE IAW SIP. LEAK & SYS TEST ACCOMPLISHED IAW AMM 36-11-00. ACCOMPLISHED SWA CABIN PRESSURE LEAK TEST CONDITIONAL INSPECTION IAW AMM 05-51-91. FOUND SENSE LINE FROM PRSOV ON NR 2 ENG LEAKING.

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