Narrative:

The aircraft hadn't been flown in 2 or 3 weeks, and had accumulated a considerable amount of bird excrement on the tail surfaces. I brushed off the excess on preflight and thought nothing of it. The flight from home base (K84) to 9k4 was uneventful, with the exception of a stickiness in the controls at and shortly after rotation. As the aircraft accelerated, the problem disappeared, and I assumed it was due to the bird dung possibly in a hinge somewhere. Upon takeoff from 9k4, the problem recurred, except the elevator jammed immediately after my pitch down after rotation to accelerate to vy. After vigorous attempts at freeing the mechanism, it finally became free nearly at the end of the runway. I pitched up hard and began a sharp right turn to avoid a trailer park which sits at the end of the clearway for runway 18. The controllers once again appeared normal after this, until I slowed to rotation speed purposely to investigate at a safe altitude. They then jammed once again and required considerable force to move. Upon landing at home base, I examined the elevators more closely and found that a burr had developed in the trim guide, causing the elevator trim to stick at the given position quite securely at the burr. Evidently, the bird dung had corroded the metal over time, eroding the metal surface. This episode could have been detected on the taxi to the runway by performing a simple 'flight controls-free and correct' check. Lack of recent experience with the aircraft and admitted complacency precluded such action, unfortunately. Also, never again will I assume bird dung to be hazardous only to the appearance of the aircraft. Placed just right, it can be downright murderous!

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Original NASA ASRS Text

Title: CORROSION ON ELEVATOR CAUSED BY BIRD DROPPINGS LEADS TO LOSS OF ACFT CTL.

Narrative: THE ACFT HADN'T BEEN FLOWN IN 2 OR 3 WKS, AND HAD ACCUMULATED A CONSIDERABLE AMOUNT OF BIRD EXCREMENT ON THE TAIL SURFACES. I BRUSHED OFF THE EXCESS ON PREFLT AND THOUGHT NOTHING OF IT. THE FLT FROM HOME BASE (K84) TO 9K4 WAS UNEVENTFUL, WITH THE EXCEPTION OF A STICKINESS IN THE CTLS AT AND SHORTLY AFTER ROTATION. AS THE ACFT ACCELERATED, THE PROB DISAPPEARED, AND I ASSUMED IT WAS DUE TO THE BIRD DUNG POSSIBLY IN A HINGE SOMEWHERE. UPON TKOF FROM 9K4, THE PROB RECURRED, EXCEPT THE ELEVATOR JAMMED IMMEDIATELY AFTER MY PITCH DOWN AFTER ROTATION TO ACCELERATE TO VY. AFTER VIGOROUS ATTEMPTS AT FREEING THE MECHANISM, IT FINALLY BECAME FREE NEARLY AT THE END OF THE RWY. I PITCHED UP HARD AND BEGAN A SHARP RIGHT TURN TO AVOID A TRAILER PARK WHICH SITS AT THE END OF THE CLEARWAY FOR RWY 18. THE CTLRS ONCE AGAIN APPEARED NORMAL AFTER THIS, UNTIL I SLOWED TO ROTATION SPD PURPOSELY TO INVESTIGATE AT A SAFE ALT. THEY THEN JAMMED ONCE AGAIN AND REQUIRED CONSIDERABLE FORCE TO MOVE. UPON LNDG AT HOME BASE, I EXAMINED THE ELEVATORS MORE CLOSELY AND FOUND THAT A BURR HAD DEVELOPED IN THE TRIM GUIDE, CAUSING THE ELEVATOR TRIM TO STICK AT THE GIVEN POS QUITE SECURELY AT THE BURR. EVIDENTLY, THE BIRD DUNG HAD CORRODED THE METAL OVER TIME, ERODING THE METAL SURFACE. THIS EPISODE COULD HAVE BEEN DETECTED ON THE TAXI TO THE RWY BY PERFORMING A SIMPLE 'FLT CTLS-FREE AND CORRECT' CHK. LACK OF RECENT EXPERIENCE WITH THE ACFT AND ADMITTED COMPLACENCY PRECLUDED SUCH ACTION, UNFORTUNATELY. ALSO, NEVER AGAIN WILL I ASSUME BIRD DUNG TO BE HAZARDOUS ONLY TO THE APPEARANCE OF THE ACFT. PLACED JUST RIGHT, IT CAN BE DOWNRIGHT MURDEROUS!

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.