Narrative:

On may sat, 2004 I was tasked with changing an engine electronic controller (eec) on the left hand engine of aircraft X (a boeing 717-200) this was an rii item. After I changed the eec, I went back to double check the connections to ensure that they were all tight, then the inspector went over the connections to ensure that they were tight. After that we went up to the cockpit and followed the maintenance manual on checking the software compatibility from side to side, and checked the lru (eec) for any current faults or long-term faults. Then just to be sure everything was correct; after we did the MM reference, we started the engine and ran it for a while, shut the engine down, and went back into the lru (eec) and checked for faults again, with none noted. The aircraft departed ZZZ, and flew to ZZZ1. Sometime between ZZZ and ZZZ1 or while at ZZZ1 the cannon plug P1000-J6 came loose causing a low level status alert (P1000-J6 is the plug for the dedicated generator). The ZZZ1 mechanics trouble shot the fault per the F.I.M. And found the cannon plug loose. The boeing 717 amm procedure for changing the eec references amm ch. 70-50-01-910-801 for installing cannon plugs, which states in step (3) sub step (D) make sure that the blue line in receptacle cannot be seen when the connector is tight. I do not know what happened to cause the cannon plug to back off and be loose, whether it was cross-threaded, or not secured completely, there was no in flight shutdown or emergency. By not knowing what exactly happened, I can't make any recommendations to prevent this in the future. Callback conversation with reporter revealed the following information: the reporter stated the unit was replaced and the FAA required inspection was performed with engine operation test run ok. The reporter said the connector was tightened and the blue line was invisible. The reporter stated the design of the connector is wrong with very fine threads and always with the concern of cross threading the connector.

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Original NASA ASRS Text

Title: A B717 ON SUBSEQUENT FLT AFTER L ENG ELECTRONIC ENG CTL REPLACEMENT RECEIVED LOW LEVEL STATUS ALERT. MAINT FOUND EEC PWR CONNECTOR LOOSE.

Narrative: ON MAY SAT, 2004 I WAS TASKED WITH CHANGING AN ENG ELECTRONIC CTLR (EEC) ON THE L HAND ENG OF ACFT X (A BOEING 717-200) THIS WAS AN RII ITEM. AFTER I CHANGED THE EEC, I WENT BACK TO DOUBLE CHECK THE CONNECTIONS TO ENSURE THAT THEY WERE ALL TIGHT, THEN THE INSPECTOR WENT OVER THE CONNECTIONS TO ENSURE THAT THEY WERE TIGHT. AFTER THAT WE WENT UP TO THE COCKPIT AND FOLLOWED THE MAINT MANUAL ON CHECKING THE SOFTWARE COMPATIBILITY FROM SIDE TO SIDE, AND CHECKED THE LRU (EEC) FOR ANY CURRENT FAULTS OR LONG-TERM FAULTS. THEN JUST TO BE SURE EVERYTHING WAS CORRECT; AFTER WE DID THE MM REF, WE STARTED THE ENG AND RAN IT FOR A WHILE, SHUT THE ENG DOWN, AND WENT BACK INTO THE LRU (EEC) AND CHECKED FOR FAULTS AGAIN, WITH NONE NOTED. THE ACFT DEPARTED ZZZ, AND FLEW TO ZZZ1. SOMETIME BETWEEN ZZZ AND ZZZ1 OR WHILE AT ZZZ1 THE CANNON PLUG P1000-J6 CAME LOOSE CAUSING A LOW LEVEL STATUS ALERT (P1000-J6 IS THE PLUG FOR THE DEDICATED GENERATOR). THE ZZZ1 MECHANICS TROUBLE SHOT THE FAULT PER THE F.I.M. AND FOUND THE CANNON PLUG LOOSE. THE BOEING 717 AMM PROC FOR CHANGING THE EEC REFERENCES AMM CH. 70-50-01-910-801 FOR INSTALLING CANNON PLUGS, WHICH STATES IN STEP (3) SUB STEP (D) MAKE SURE THAT THE BLUE LINE IN RECEPTACLE CANNOT BE SEEN WHEN THE CONNECTOR IS TIGHT. I DO NOT KNOW WHAT HAPPENED TO CAUSE THE CANNON PLUG TO BACK OFF AND BE LOOSE, WHETHER IT WAS CROSS-THREADED, OR NOT SECURED COMPLETELY, THERE WAS NO IN FLT SHUTDOWN OR EMER. BY NOT KNOWING WHAT EXACTLY HAPPENED, I CAN'T MAKE ANY RECOMMENDATIONS TO PREVENT THIS IN THE FUTURE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE UNIT WAS REPLACED AND THE FAA REQUIRED INSPECTION WAS PERFORMED WITH ENG OP TEST RUN OK. THE RPTR SAID THE CONNECTOR WAS TIGHTENED AND THE BLUE LINE WAS INVISIBLE. THE RPTR STATED THE DESIGN OF THE CONNECTOR IS WRONG WITH VERY FINE THREADS AND ALWAYS WITH THE CONCERN OF CROSS THREADING THE CONNECTOR.

Data retrieved from NASA's ASRS site as of July 2007 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.