On two separate B757-200 type aircraft; after engine low pressure fuel filters were changed; engines...

Attributes
ACN	744085
Time
Date	200706
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	ground : parked
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	ground : maintenance
Person 1
Affiliation	company : air carrier
Function	maintenance : technician
Qualification	technician : airframe technician : powerplant
ASRS Report	744085
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper documentation
Independent Detector	aircraft equipment other aircraft equipment : egt temp other other : 1
Resolutory Action	other
Consequence	other
Factors
Maintenance	contributing factor : engineering procedure contributing factor : manuals performance deficiency : scheduled maintenance performance deficiency : testing
Supplementary
Problem Areas	Aircraft Chart Or Publication
Primary Problem	Chart Or Publication
Situations
Publication	Eng Run Procs Revised

Narrative:

On aircraft X; after the engine low pressure fuel filters were changed; and subsequently during the leak check the right engine egt jumped and rose rapidly exceeding 570 limit causing engine damage and replacement. 26 days later; aircraft Y after engine low pressure fuel filters were changed; during leak check the right egt exceeded 701. Engine was run by the flight crew due to passenger on board. Crew reported egt jumped and rose rapidly. Note: I didn't run either of these engines but previous week I ran an engine for someone else and noticed an extreme jump in egt after fuel filter replacement. Couldn't find which B757 in web maintenance history. Unknown. Suspect engine needs to be wet motored to stabilize engine fuel system before engine run with ignition. Callback conversation with reporter revealed the following information: reporter stated all of his company's B757 aircraft fuel tanks are being treated with bio-cide. Engine low pressure fuel filters are routinely replaced after certain number of flight hours because of the bio-cide build-up in the filters. Due to the unexpected egt spikes incurred while accomplishing engine run fuel leak checks and subsequent engine changes; his company engineering decided to incorporate his suggestion to wet motor the engines with fuel pumps on; ignition off; before performing the normal engine run with ignition on. So far; this procedure seems to have eliminated the egt spikes after the filter changes.

Original NASA ASRS Text

Title: ON TWO SEPARATE B757-200 TYPE ACFT; AFTER ENGINE LOW PRESSURE FUEL FILTERS WERE CHANGED; ENGINES EGT TEMP SPIKED; EXCEEDED LIMITS; ENGINES CHANGED.

Narrative: ON ACFT X; AFTER THE ENG LOW PRESSURE FUEL FILTERS WERE CHANGED; AND SUBSEQUENTLY DURING THE LEAK CHK THE R ENG EGT JUMPED AND ROSE RAPIDLY EXCEEDING 570 LIMIT CAUSING ENG DAMAGE AND REPLACEMENT. 26 DAYS LATER; ACFT Y AFTER ENG LOW PRESSURE FUEL FILTERS WERE CHANGED; DURING LEAK CHK THE R EGT EXCEEDED 701. ENG WAS RUN BY THE FLT CREW DUE TO PAX ON BOARD. CREW RPTED EGT JUMPED AND ROSE RAPIDLY. NOTE: I DIDN'T RUN EITHER OF THESE ENGS BUT PREVIOUS WEEK I RAN AN ENG FOR SOMEONE ELSE AND NOTICED AN EXTREME JUMP IN EGT AFTER FUEL FILTER REPLACEMENT. COULDN'T FIND WHICH B757 IN WEB MAINT HISTORY. UNKNOWN. SUSPECT ENG NEEDS TO BE WET MOTORED TO STABILIZE ENG FUEL SYS BEFORE ENG RUN WITH IGNITION. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED ALL OF HIS COMPANY'S B757 ACFT FUEL TANKS ARE BEING TREATED WITH BIO-CIDE. ENGINE LOW PRESSURE FUEL FILTERS ARE ROUTINELY REPLACED AFTER CERTAIN NUMBER OF FLIGHT HOURS BECAUSE OF THE BIO-CIDE BUILD-UP IN THE FILTERS. DUE TO THE UNEXPECTED EGT SPIKES INCURRED WHILE ACCOMPLISHING ENG RUN FUEL LEAK CHECKS AND SUBSEQUENT ENGINE CHANGES; HIS COMPANY ENGINEERING DECIDED TO INCORPORATE HIS SUGGESTION TO WET MOTOR THE ENGINES WITH FUEL PUMPS ON; IGNITION OFF; BEFORE PERFORMING THE NORMAL ENG RUN WITH IGNITION ON. SO FAR; THIS PROCEDURE SEEMS TO HAVE ELIMINATED THE EGT SPIKES AFTER THE FILTER CHANGES.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

On two separate B757-200 type aircraft; after engine low pressure fuel filters were changed; engines egt temperature spiked; exceeded limits; engines changed.