Narrative:

The incident described below occurred after completion of a .9 hour successful test flight which was accomplished after an engine removal, overhaul and reinstallation. The test flight was flown from the north las vegas airport. We departed north las vegas airport at XX44 local time, 6/xx/90, with full fuel (88 gals usable), which would provide a minimum of 5 hours and 45 mins at a fuel burn of 15 gph. I activated my VFR flight plan to P19 with rno radio. After approximately 35 mins flight time, I attempted to move the throttle from 24' as per break in instructions, but could not move throttle. I put some additional pressure on the throttle, but there was still no movement. I elected to return to north las vegas for repair. I contacted las vegas approach control approximately 20 mi south of las VOR. The controller asked if I was declaring an emergency and I responded no, I would return to north las vegas, confer with the mechanics and work the problem. I had more than 4 hours fuel remaining at that time. After conferring with the engine/airframe mechanics, I determined that 1) I should not attempt to over power the throttle, and 2) there was nothing that could be done to restore normal throttle response from the cockpit. It was also determined that the aircraft would maintain level flight with gear and full flaps extended at approximately 78 KIAS. It was also determined that I could expect a 200-250 FPM descend rate at flap limit speed of 95 KIAS. With this information in mind, I elected to declare an emergency. I contacted las approach and headed toward las int'l. I informed the controller I had more than 2 hours of fuel on board and would be making a dead stick landing to runway 25. Approach control vectored me for a right downwind to runway 25 at 4500' MSL to begin my turn to base and final at my discretion. At this time, the flaps were at 40 degrees (full extension) and gear down and propeller at 2500 RPM. Manifold pressure remained at 24'. I began a base turn at 4000' MSL. The mixture control was used as an improvised throttle; i.e., by leaning the mixture sufficiently, the engine produced no (or almost none) power. The propeller continued to windmill. This procedure was used 3 or 4 times during the base to final turn. At approximately 300-400' AGL and over the runway overrun area, the mixture was placed in the idle cut off position. T/D was normal (the stall warning chipped just prior to T/D) approximately 1500' from the approach end of runway 25. Taxiway Z was used for turnoff. The aircraft was towed to an FBO for repairs where it was determined that the throttle linkage was not adjusted properly and that the throttle linkage bellcranks were worn.

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Original NASA ASRS Text

Title: ACFT MADE AN EMERGENCY LNDG DUE TO A STUCK THROTTLE.

Narrative: THE INCIDENT DESCRIBED BELOW OCCURRED AFTER COMPLETION OF A .9 HR SUCCESSFUL TEST FLT WHICH WAS ACCOMPLISHED AFTER AN ENG REMOVAL, OVERHAUL AND REINSTALLATION. THE TEST FLT WAS FLOWN FROM THE NORTH LAS VEGAS ARPT. WE DEPARTED NORTH LAS VEGAS ARPT AT XX44 LCL TIME, 6/XX/90, WITH FULL FUEL (88 GALS USABLE), WHICH WOULD PROVIDE A MINIMUM OF 5 HRS AND 45 MINS AT A FUEL BURN OF 15 GPH. I ACTIVATED MY VFR FLT PLAN TO P19 WITH RNO RADIO. AFTER APPROX 35 MINS FLT TIME, I ATTEMPTED TO MOVE THE THROTTLE FROM 24' AS PER BREAK IN INSTRUCTIONS, BUT COULD NOT MOVE THROTTLE. I PUT SOME ADDITIONAL PRESSURE ON THE THROTTLE, BUT THERE WAS STILL NO MOVEMENT. I ELECTED TO RETURN TO NORTH LAS VEGAS FOR REPAIR. I CONTACTED LAS VEGAS APCH CTL APPROX 20 MI S OF LAS VOR. THE CTLR ASKED IF I WAS DECLARING AN EMER AND I RESPONDED NO, I WOULD RETURN TO NORTH LAS VEGAS, CONFER WITH THE MECHS AND WORK THE PROB. I HAD MORE THAN 4 HRS FUEL REMAINING AT THAT TIME. AFTER CONFERRING WITH THE ENG/AIRFRAME MECHS, I DETERMINED THAT 1) I SHOULD NOT ATTEMPT TO OVER PWR THE THROTTLE, AND 2) THERE WAS NOTHING THAT COULD BE DONE TO RESTORE NORMAL THROTTLE RESPONSE FROM THE COCKPIT. IT WAS ALSO DETERMINED THAT THE ACFT WOULD MAINTAIN LEVEL FLT WITH GEAR AND FULL FLAPS EXTENDED AT APPROX 78 KIAS. IT WAS ALSO DETERMINED THAT I COULD EXPECT A 200-250 FPM DSND RATE AT FLAP LIMIT SPD OF 95 KIAS. WITH THIS INFO IN MIND, I ELECTED TO DECLARE AN EMER. I CONTACTED LAS APCH AND HEADED TOWARD LAS INT'L. I INFORMED THE CTLR I HAD MORE THAN 2 HRS OF FUEL ON BOARD AND WOULD BE MAKING A DEAD STICK LNDG TO RWY 25. APCH CTL VECTORED ME FOR A RIGHT DOWNWIND TO RWY 25 AT 4500' MSL TO BEGIN MY TURN TO BASE AND FINAL AT MY DISCRETION. AT THIS TIME, THE FLAPS WERE AT 40 DEGS (FULL EXTENSION) AND GEAR DOWN AND PROP AT 2500 RPM. MANIFOLD PRESSURE REMAINED AT 24'. I BEGAN A BASE TURN AT 4000' MSL. THE MIXTURE CONTROL WAS USED AS AN IMPROVISED THROTTLE; I.E., BY LEANING THE MIXTURE SUFFICIENTLY, THE ENG PRODUCED NO (OR ALMOST NONE) PWR. THE PROP CONTINUED TO WINDMILL. THIS PROC WAS USED 3 OR 4 TIMES DURING THE BASE TO FINAL TURN. AT APPROX 300-400' AGL AND OVER THE RWY OVERRUN AREA, THE MIXTURE WAS PLACED IN THE IDLE CUT OFF POS. T/D WAS NORMAL (THE STALL WARNING CHIPPED JUST PRIOR TO T/D) APPROX 1500' FROM THE APCH END OF RWY 25. TXWY Z WAS USED FOR TURNOFF. THE ACFT WAS TOWED TO AN FBO FOR REPAIRS WHERE IT WAS DETERMINED THAT THE THROTTLE LINKAGE WAS NOT ADJUSTED PROPERLY AND THAT THE THROTTLE LINKAGE BELLCRANKS WERE WORN.

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.