Narrative:

I was to perform a task of checking aircraft engines' bleed bands per a task card on aircraft X which had a scheduled 'a' check. The task card that is in use states to close the bleed bands and check for any signs of defects and references you to the amm for this procedure. Having done this procedure many times in the past; I chose to do this off of memory rather than have the amm reference with me. I and another person proceeded to perform this task by disconnecting the air lines from the bleed band actuator and an air line to the hma (fuel control). I disconnected the air line from the bleed band actuator while the other person disconnected the air line from the hma. At the end of the end of the task; the air line to the hma was left off for I was sidetracked by another individual to help do a different task and for the fact that I personally did not disconnect it to begin with (not putting blame on anyone else). I signed the task card off as being completed. The aircraft was held on the ground for at least a day due to other problems noted during a different task that was being performed. After the aircraft was released; it was taken to the gate where it went on a revenue flight. During this flight the aircraft was apparently losing power on takeoff. The pilots and maintenance controller decided to continue to its destination. After reaching their desired altitude; the aircraft regained power and continued normal operations for the rest of the flight. When the aircraft landed; the pilots wrote what happened up and maintenance was called to investigate what happened. The air line was found not to be connected; causing the bleed bands to not close during takeoff; which resulted in a lack of power at takeoff. Once the aircraft reaches the desired altitude; power is pulled back and the bleed bands open up; thus the reason for normal operations after altitude was reached. 2 engines had overtemped for longer than allowed; the aircraft was ferried to the main hub where they were borescoped and found to have no defects and the aircraft was later released for revenue flight. I feel that if the company's task card would have been written out on how to perform this task and have an operations check at the end of the task card that this would have been prevented. I have brought up and have attempted to change many company task cards throughout the yr to only a few that prevail. Callback conversation with reporter revealed the following information: the reporter stated the 'bleed bands' are a circular bleed valve on the engine high pressure compressor that opens and closes and is controled by the hma or fuel control. On takeoff; the bleed valve is closed; increasing engine power. When the engine thrust lever is retarded; as in cruise power; the bleed control opens the circular bleed valve; unloading the front of the high compressor; preventing compressor stall. The reporter also stated the reason the company will not allow ground testing of the engines after maintenance is to save on fuel costs.

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Original NASA ASRS Text

Title: AN AVRO 85 WAS DISPATCHED AND OPERATED WITH THE #1 AND #2 ENGS' HIGH PRESSURE BLEED SYS INOP DUE TO LINE FROM FUEL CTL TO BLEED CTL VALVE NOT RECONNECTED DURING MAINT.

Narrative: I WAS TO PERFORM A TASK OF CHKING ACFT ENGS' BLEED BANDS PER A TASK CARD ON ACFT X WHICH HAD A SCHEDULED 'A' CHK. THE TASK CARD THAT IS IN USE STATES TO CLOSE THE BLEED BANDS AND CHK FOR ANY SIGNS OF DEFECTS AND REFS YOU TO THE AMM FOR THIS PROC. HAVING DONE THIS PROC MANY TIMES IN THE PAST; I CHOSE TO DO THIS OFF OF MEMORY RATHER THAN HAVE THE AMM REF WITH ME. I AND ANOTHER PERSON PROCEEDED TO PERFORM THIS TASK BY DISCONNECTING THE AIR LINES FROM THE BLEED BAND ACTUATOR AND AN AIR LINE TO THE HMA (FUEL CTL). I DISCONNECTED THE AIR LINE FROM THE BLEED BAND ACTUATOR WHILE THE OTHER PERSON DISCONNECTED THE AIR LINE FROM THE HMA. AT THE END OF THE END OF THE TASK; THE AIR LINE TO THE HMA WAS LEFT OFF FOR I WAS SIDETRACKED BY ANOTHER INDIVIDUAL TO HELP DO A DIFFERENT TASK AND FOR THE FACT THAT I PERSONALLY DID NOT DISCONNECT IT TO BEGIN WITH (NOT PUTTING BLAME ON ANYONE ELSE). I SIGNED THE TASK CARD OFF AS BEING COMPLETED. THE ACFT WAS HELD ON THE GND FOR AT LEAST A DAY DUE TO OTHER PROBS NOTED DURING A DIFFERENT TASK THAT WAS BEING PERFORMED. AFTER THE ACFT WAS RELEASED; IT WAS TAKEN TO THE GATE WHERE IT WENT ON A REVENUE FLT. DURING THIS FLT THE ACFT WAS APPARENTLY LOSING PWR ON TKOF. THE PLTS AND MAINT CTLR DECIDED TO CONTINUE TO ITS DEST. AFTER REACHING THEIR DESIRED ALT; THE ACFT REGAINED PWR AND CONTINUED NORMAL OPS FOR THE REST OF THE FLT. WHEN THE ACFT LANDED; THE PLTS WROTE WHAT HAPPENED UP AND MAINT WAS CALLED TO INVESTIGATE WHAT HAPPENED. THE AIR LINE WAS FOUND NOT TO BE CONNECTED; CAUSING THE BLEED BANDS TO NOT CLOSE DURING TKOF; WHICH RESULTED IN A LACK OF PWR AT TKOF. ONCE THE ACFT REACHES THE DESIRED ALT; PWR IS PULLED BACK AND THE BLEED BANDS OPEN UP; THUS THE REASON FOR NORMAL OPS AFTER ALT WAS REACHED. 2 ENGS HAD OVERTEMPED FOR LONGER THAN ALLOWED; THE ACFT WAS FERRIED TO THE MAIN HUB WHERE THEY WERE BORESCOPED AND FOUND TO HAVE NO DEFECTS AND THE ACFT WAS LATER RELEASED FOR REVENUE FLT. I FEEL THAT IF THE COMPANY'S TASK CARD WOULD HAVE BEEN WRITTEN OUT ON HOW TO PERFORM THIS TASK AND HAVE AN OPS CHK AT THE END OF THE TASK CARD THAT THIS WOULD HAVE BEEN PREVENTED. I HAVE BROUGHT UP AND HAVE ATTEMPTED TO CHANGE MANY COMPANY TASK CARDS THROUGHOUT THE YR TO ONLY A FEW THAT PREVAIL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE 'BLEED BANDS' ARE A CIRCULAR BLEED VALVE ON THE ENG HIGH PRESSURE COMPRESSOR THAT OPENS AND CLOSES AND IS CTLED BY THE HMA OR FUEL CTL. ON TKOF; THE BLEED VALVE IS CLOSED; INCREASING ENG PWR. WHEN THE ENG THRUST LEVER IS RETARDED; AS IN CRUISE PWR; THE BLEED CTL OPENS THE CIRCULAR BLEED VALVE; UNLOADING THE FRONT OF THE HIGH COMPRESSOR; PREVENTING COMPRESSOR STALL. THE RPTR ALSO STATED THE REASON THE COMPANY WILL NOT ALLOW GND TESTING OF THE ENGS AFTER MAINT IS TO SAVE ON FUEL COSTS.

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.