SDR UIEA2015050600263

Service difficulty report · Unknown · Boeing 747409

Difficulty date: May 6, 2015
Submitted: May 6, 2015
Operation: Air carrier
Aircraft: N249BA
Make and model: Boeing 747409
Aircraft serial: 24309
Aircraft time: 73,258 hours, 14,470 cycles
System (JASC): 3610 · Pneumatic Distribution System
Part: Unknown
Condition: Malfunctioned
Location: Bleed Air Sys
Stage of operation: DE
How discovered: O
Nature of condition: O
Precautionary procedure: K

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

What was found

AT TOP, FL 370 DUCT PRESS SUDLING DROP TO 7 PSI WHEN THROTTLES RETARTED TO IDLE. CABIN ALTITUDE ROSE TO 9300 FT & STABILIZED. WITHIN 5 - 10 SECONDS PRESSURIZATION OF CABIN BEGAN TO RETURN TO NORMAL, NO OTHER NON-NORMAL NOTED. PERFORMED BITE TEST OF SYS, BITE TEST PASSED, NO FAULTS NOTED ON CMC IAW AMM 36-11-30.