A jetstream 3200 rejected takeoff due to fluctuating left engine RPM caused by a loose throttle lock...

Attributes
ACN	432572
Time
Date	199903
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : san.airport
State Reference	CA
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : san.tower tower : bos.tower
Operator	common carrier : air carrier
Make Model Name	Jetstream 32
Operating Under FAR Part	Part 135
Flight Phase	ground : takeoff roll
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 4600 flight time type : 2300
ASRS Report	432572
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : multi engine
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : rpm indicator other flight crewa
Resolutory Action	flight crew : rejected takeoff
Consequence	faa : investigated
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft
Primary Problem	Flight Crew Human Performance

Narrative:

As we began to accelerate on the takeoff roll, I noticed a slight fluctuation with the left RPM gauge. Prior to 70 KTS, I elected to abort and taxied clear of the runway. I immediately determined that the left RPM lever had crept back slightly. I reset it to 100% and tightened the friction lock. The first officer and I agreed that this was the cause of the fluctuation. A subsequent full power runup confirmed this and nothing out of the ordinary was noted. 1 day after this, I have been informed that the FAA is inquiring about this. As I understand it, they would like to know why I did not return to the gate and/or write anything up. It was a simple case of the RPM lever creeping back slightly because the friction lock was not tight enough. There were not any mechanical malfunctions. We remedied the situation by tightening the friction lock.

Original NASA ASRS Text

Title: A JETSTREAM 3200 REJECTED TKOF DUE TO FLUCTUATING L ENG RPM CAUSED BY A LOOSE THROTTLE LOCK.

Narrative: AS WE BEGAN TO ACCELERATE ON THE TKOF ROLL, I NOTICED A SLIGHT FLUCTUATION WITH THE L RPM GAUGE. PRIOR TO 70 KTS, I ELECTED TO ABORT AND TAXIED CLR OF THE RWY. I IMMEDIATELY DETERMINED THAT THE L RPM LEVER HAD CREPT BACK SLIGHTLY. I RESET IT TO 100% AND TIGHTENED THE FRICTION LOCK. THE FO AND I AGREED THAT THIS WAS THE CAUSE OF THE FLUCTUATION. A SUBSEQUENT FULL PWR RUNUP CONFIRMED THIS AND NOTHING OUT OF THE ORDINARY WAS NOTED. 1 DAY AFTER THIS, I HAVE BEEN INFORMED THAT THE FAA IS INQUIRING ABOUT THIS. AS I UNDERSTAND IT, THEY WOULD LIKE TO KNOW WHY I DID NOT RETURN TO THE GATE AND/OR WRITE ANYTHING UP. IT WAS A SIMPLE CASE OF THE RPM LEVER CREEPING BACK SLIGHTLY BECAUSE THE FRICTION LOCK WAS NOT TIGHT ENOUGH. THERE WERE NOT ANY MECHANICAL MALFUNCTIONS. WE REMEDIED THE SIT BY TIGHTENING THE FRICTION LOCK.

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.