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SDR ZLWA20160926001

Open the Markdown

Service difficulty report · Bleed Air Sys · Gulstm GIV

FAA SDR system

Difficulty date
June 28, 2016
Submitted
September 26, 2016
Operation
Air carrier
Aircraft
N36MW
Make and model
Gulstm GIV
Aircraft serial
1480
Aircraft time
7,600 hours, 3,456 cycles
Engine
Rroyce TAY6118
Engine time
7,316 hours, 3,357 cycles
System (JASC)
4950 · APU Bleed Air System
Part
Bleed Air Sys
Condition
Low
Location
Apu
Stage of operation
IN
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

DURING MAINTENANCE INVESTIGATION OF REPORTED LOW APU BLEED AIR PRESSURE DURING ENGINE START CYCLE, A DISCREPANCY BETWEEN AFM REV 49 DATED 10 DEC 2012 AND AMM REV 26 DATED SEPT 2015 FOR APU BLEED AIR PRESSURES REQUIRED FOR ENGINE START WAS DISCOVERED. AMM ENGINE OPS TEST 71-00-00 REQUIRES 20 PSI MINIMUM FOR ENGINE START. AFM STARTING ENGINES PROCEDURES REQUIRE 25 PSI MINIMUM FOR ENGINE START. THIS DIFFERENCE CAUSES CONFLICT BETWEEN AIRCRAFT CREW AND MAINTENANCE FOR AIRCRAFT RETURN TO SERVICE. ASC 465C-APU, INSTALLATION OF 36-150G, HAS BEEN ACCOMPLISHED FOR ENHANCED PERFORMANCE OF APU AND BLEED AIR SYSTEM.