A carbon cub ss pilot had difficulty controlling the aircraft because of the nose down trim conditio...

Narrative:

Arriving at my destination in light to moderate turbulence; I noticed that my elevator trim was not actuating. I reset the circuit breaker; but this did not resolve the issue. Since the trim was in a nose down condition I needed to exert significant additional back pressure to control the descent and landing properly. I decided to alert the tower controller that I was requesting a precautionary standby landing due to this condition. I checked all of the systems I could think of; but could not resolve the condition of heavy nose down trim. I made my approach and bounced slightly at touchdown due to the wind and heavy control pressure so I decided to go around to enter a slightly longer pattern for a more stabilized approach. On my second approach I landed without any incident and returned to my hangar. On further investigation I discovered that I had inadvertently switched off the trim forward priority switch leaving me with no electric trim. The aircraft does not have a manual trim control. This mistake was due to my having hung my headset volume control/battery pack too near to the trim priority switch such that when I experienced some turbulence and I reached up to adjust my headset volume control and when I released it; it swung back and flipped off the trim switch. I knew the switch was there but simply forgot it while checking else where for the problem. Since the aircraft is brand new with approximately 20 hours total time since leaving the factory; this problem will not be likely to occur again because it will be a firm part of my future landing checklist items. The airplane has excellent characteristics even without trim control and the pilot will continue to improve his skills.

Original NASA ASRS Text

Title: A Carbon Cub SS pilot had difficulty controlling the aircraft because of the nose down trim condition and determined after landing that he had inadvertently turned the Trim Priority Switch OFF when he hung a headset near it.

Narrative: Arriving at my destination in light to moderate turbulence; I noticed that my elevator trim was not actuating. I reset the circuit breaker; but this did not resolve the issue. Since the trim was in a nose down condition I needed to exert significant additional back pressure to control the descent and landing properly. I decided to alert the Tower Controller that I was requesting a precautionary standby landing due to this condition. I checked all of the systems I could think of; but could not resolve the condition of heavy nose down trim. I made my approach and bounced slightly at touchdown due to the wind and heavy control pressure so I decided to go around to enter a slightly longer pattern for a more stabilized approach. On my second approach I landed without any incident and returned to my hangar. On further investigation I discovered that I had inadvertently switched off the trim forward priority switch leaving me with no electric trim. The aircraft does not have a manual trim control. This mistake was due to my having hung my headset volume control/battery pack too near to the trim priority switch such that when I experienced some turbulence and I reached up to adjust my headset volume control and when I released it; it swung back and flipped off the trim switch. I knew the switch was there but simply forgot it while checking else where for the problem. Since the aircraft is brand new with approximately 20 hours total time since leaving the factory; this problem will not be likely to occur again because it will be a firm part of my future landing checklist items. The airplane has excellent characteristics even without trim control and the pilot will continue to improve his skills.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1012685
Time
Date	201205
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Light Sport Aircraft
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Route In Use	Direct
Flight Plan	None
Component
Aircraft Component	Horizontal Stabilizer Trim
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Private
Experience	Flight Crew Last 90 Days 18 Flight Crew Total 860 Flight Crew Type 40
Events
Anomaly	Aircraft Equipment Problem Less Severe Inflight Event / Encounter Unstabilized Approach

A carbon cub ss pilot had difficulty controlling the aircraft because of the nose down trim condition and determined after landing that he had inadvertently turned the trim priority switch off when he hung a headset near it.