Narrative:

During first few mins at cruise the MFDU came up with the high engine vibration checklist. In seconds before referring to checklist the checklist title turned white. Meaning the problem went away however the vibration was in the green above what we normally see. So we did the throttle slam procedure for possible ice removal and went to the back to the cabin to look in the engine. Also we descended into the clear and warmer temperatures, the engine ran fine, no longer needing any attention. At our destination we talked to maintenance and they went ahead and did a service check. The engine ran fine throughout the run-up and takeoff and climb. However, as we were getting up in altitude the engine within limits was starting to show a trend of vibration. Deciding not to go any higher or to find any precipitation we proceeded to ord and wrote the engine up so they could take a closer look. Callback conversation with reporter revealed the following information: this reporter was also an a&P mechanic early in his airline carrier. He said that he had not worked on the tay engines, but he feels that he understands some of the principles behind its operation. At first he was concerned that they had some icing effect, but after visually inspecting the inlet in-flight and noting that there was no ice visible nor had icing conditions existed during the flight he decided to investigate the situation further. He said that he requested a lower altitude and the warmer, denser air seemed to cause the #2 engine to run smoother. The reporter said that he tends to favor flying at altitudes below 30000 ft with this aircraft anyway because he thinks that it does not perform well at higher altitudes. The engine ran well for the remainder of the flight. After maintenance checked the engine during the overnight stay he again departed with the aircraft. The engine ran with the vibration indication somewhat higher than normal, but within acceptable parameters. He again discussed the situation with maintenance control and it was at this time he discovered that this particular engine had been removed from another FK100 because of vibration. His flight the day before was the first since this engine had been installed on this aircraft. Maintenance decided to again remove the engine and inspect it. Later he was told that the fan section had to be taken off of the engine for repair. He also mentioned that the technique known as the throttle slam procedure is now being taught in recurrent ground school. This procedure, apparently, helps the engine control system reset itself.

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Original NASA ASRS Text

Title: AN ACR FK100 FLC HAS AN ABNORMAL VIBRATION BEGIN IN THE #2 ROLLS-ROYCE TAY-650 ENG. THE FLC INITIALLY THOUGHT THAT THE VIBRATION MAY BE DUE TO POSSIBLE ICING, BUT THEY LATER FOUND OUT THAT THIS PARTICULAR ENG HAS A HISTORY OF THIS PHENOMENON.

Narrative: DURING FIRST FEW MINS AT CRUISE THE MFDU CAME UP WITH THE HIGH ENG VIBRATION CHKLIST. IN SECONDS BEFORE REFERRING TO CHKLIST THE CHKLIST TITLE TURNED WHITE. MEANING THE PROB WENT AWAY HOWEVER THE VIBRATION WAS IN THE GREEN ABOVE WHAT WE NORMALLY SEE. SO WE DID THE THROTTLE SLAM PROC FOR POSSIBLE ICE REMOVAL AND WENT TO THE BACK TO THE CABIN TO LOOK IN THE ENG. ALSO WE DSNDED INTO THE CLR AND WARMER TEMPS, THE ENG RAN FINE, NO LONGER NEEDING ANY ATTN. AT OUR DEST WE TALKED TO MAINT AND THEY WENT AHEAD AND DID A SVC CHK. THE ENG RAN FINE THROUGHOUT THE RUN-UP AND TKOF AND CLB. HOWEVER, AS WE WERE GETTING UP IN ALT THE ENG WITHIN LIMITS WAS STARTING TO SHOW A TREND OF VIBRATION. DECIDING NOT TO GO ANY HIGHER OR TO FIND ANY PRECIPITATION WE PROCEEDED TO ORD AND WROTE THE ENG UP SO THEY COULD TAKE A CLOSER LOOK. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THIS RPTR WAS ALSO AN A&P MECH EARLY IN HIS AIRLINE CARRIER. HE SAID THAT HE HAD NOT WORKED ON THE TAY ENGS, BUT HE FEELS THAT HE UNDERSTANDS SOME OF THE PRINCIPLES BEHIND ITS OP. AT FIRST HE WAS CONCERNED THAT THEY HAD SOME ICING EFFECT, BUT AFTER VISUALLY INSPECTING THE INLET INFLT AND NOTING THAT THERE WAS NO ICE VISIBLE NOR HAD ICING CONDITIONS EXISTED DURING THE FLT HE DECIDED TO INVESTIGATE THE SIT FURTHER. HE SAID THAT HE REQUESTED A LOWER ALT AND THE WARMER, DENSER AIR SEEMED TO CAUSE THE #2 ENG TO RUN SMOOTHER. THE RPTR SAID THAT HE TENDS TO FAVOR FLYING AT ALTS BELOW 30000 FT WITH THIS ACFT ANYWAY BECAUSE HE THINKS THAT IT DOES NOT PERFORM WELL AT HIGHER ALTS. THE ENG RAN WELL FOR THE REMAINDER OF THE FLT. AFTER MAINT CHKED THE ENG DURING THE OVERNIGHT STAY HE AGAIN DEPARTED WITH THE ACFT. THE ENG RAN WITH THE VIBRATION INDICATION SOMEWHAT HIGHER THAN NORMAL, BUT WITHIN ACCEPTABLE PARAMETERS. HE AGAIN DISCUSSED THE SIT WITH MAINT CTL AND IT WAS AT THIS TIME HE DISCOVERED THAT THIS PARTICULAR ENG HAD BEEN REMOVED FROM ANOTHER FK100 BECAUSE OF VIBRATION. HIS FLT THE DAY BEFORE WAS THE FIRST SINCE THIS ENG HAD BEEN INSTALLED ON THIS ACFT. MAINT DECIDED TO AGAIN REMOVE THE ENG AND INSPECT IT. LATER HE WAS TOLD THAT THE FAN SECTION HAD TO BE TAKEN OFF OF THE ENG FOR REPAIR. HE ALSO MENTIONED THAT THE TECHNIQUE KNOWN AS THE THROTTLE SLAM PROC IS NOW BEING TAUGHT IN RECURRENT GND SCHOOL. THIS PROC, APPARENTLY, HELPS THE ENG CTL SYS RESET ITSELF.

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.