Narrative:

During flight, may/xx/97, flight crew called on commercial radio during the first leg of the flight (ZZZ/YYY). They stated they had a throttle alignment problem during takeoff and climb. The throttles were misaligned with the power setting the same (#2 throttle lagging), during climb the #2 throttle moved up and aligned with #1, without any parameters changing. This all took place with the autothrottle and pmc's on. During cruise all engine parameters and throttle behavior appeared normal. Throttle alignment problems can be very difficult to analyze. In order to isolate the throttle stagger problem, I needed more information. Since all engine performance and throttle alignment was normal during cruise, I asked the flight crew if they could make the next takeoff with the pmc's off so I can determine if it was an autothrottle or a pmc problem. After arrival into YYY, maintenance accomplished a ground check and could not find any problems. They asked if they should defer the pmc's and I told them not to because I wasn't sure if it was bad and needed more information. If the pmc's are deferred, then they may not be used at all. So I felt leaving the pmc's operational would help me to determine what the real problem is, so the throttle stagger was deferred. Ground checks for engine operation cannot duplicate the flight environment, therefore it is very helpful if I am able to get input from the flight crew. The flight crew was cooperative and very helpful in assisting me to try and determine what was causing the throttle stagger. After the aircraft arrived in ZZZ a flight crew member called to inform me how the system operated with the pmc's off. Apparently the throttle stagger wasn't affected by the pmc's on or off.

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Original NASA ASRS Text

Title: A B737-300 RPTED THROTTLE ALIGNMENT PROBS AT TKOF AND CLB BUT OK IN CRUISE. CREW REQUESTED TO TURN OFF PMC AND CHK THROTTLE ALIGNMENT ON NEXT TKOF AND CLB.

Narrative: DURING FLT, MAY/XX/97, FLC CALLED ON COMMERCIAL RADIO DURING THE FIRST LEG OF THE FLT (ZZZ/YYY). THEY STATED THEY HAD A THROTTLE ALIGNMENT PROB DURING TKOF AND CLB. THE THROTTLES WERE MISALIGNED WITH THE POWER SETTING THE SAME (#2 THROTTLE LAGGING), DURING CLB THE #2 THROTTLE MOVED UP AND ALIGNED WITH #1, WITHOUT ANY PARAMETERS CHANGING. THIS ALL TOOK PLACE WITH THE AUTOTHROTTLE AND PMC'S ON. DURING CRUISE ALL ENG PARAMETERS AND THROTTLE BEHAVIOR APPEARED NORMAL. THROTTLE ALIGNMENT PROBS CAN BE VERY DIFFICULT TO ANALYZE. IN ORDER TO ISOLATE THE THROTTLE STAGGER PROB, I NEEDED MORE INFO. SINCE ALL ENG PERFORMANCE AND THROTTLE ALIGNMENT WAS NORMAL DURING CRUISE, I ASKED THE FLC IF THEY COULD MAKE THE NEXT TKOF WITH THE PMC'S OFF SO I CAN DETERMINE IF IT WAS AN AUTOTHROTTLE OR A PMC PROB. AFTER ARR INTO YYY, MAINT ACCOMPLISHED A GND CHK AND COULD NOT FIND ANY PROBS. THEY ASKED IF THEY SHOULD DEFER THE PMC'S AND I TOLD THEM NOT TO BECAUSE I WASN'T SURE IF IT WAS BAD AND NEEDED MORE INFO. IF THE PMC'S ARE DEFERRED, THEN THEY MAY NOT BE USED AT ALL. SO I FELT LEAVING THE PMC'S OPERATIONAL WOULD HELP ME TO DETERMINE WHAT THE REAL PROB IS, SO THE THROTTLE STAGGER WAS DEFERRED. GND CHKS FOR ENG OP CANNOT DUPLICATE THE FLT ENVIRONMENT, THEREFORE IT IS VERY HELPFUL IF I AM ABLE TO GET INPUT FROM THE FLC. THE FLC WAS COOPERATIVE AND VERY HELPFUL IN ASSISTING ME TO TRY AND DETERMINE WHAT WAS CAUSING THE THROTTLE STAGGER. AFTER THE ACFT ARRIVED IN ZZZ A FLC MEMBER CALLED TO INFORM ME HOW THE SYS OPERATED WITH THE PMC'S OFF. APPARENTLY THE THROTTLE STAGGER WASN'T AFFECTED BY THE PMC'S ON OR OFF.

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.