Pilot of small transport twin engine atx aircraft experienced an unsafe landing gear position indica...

Attributes
ACN	255942
Time
Date	199310
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : den
State Reference	CO
Altitude	msl bound lower : 6000 msl bound upper : 14000
Environment
Flight Conditions	Mixed
Light	Dawn
Aircraft 1
Controlling Facilities	tracon : den
Operator	common carrier : air taxi
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	climbout : initial climbout : intermediate altitude other
Route In Use	enroute airway : den
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 120 flight time type : 210
ASRS Report	255942
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	aircraft : equipment problem dissipated
Consequence	faa : investigated
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Even though I retracted my 'emergency' status in this situation, the FAA is still requiring me to send them a letter explaining what happened. I have enclosed a copy of that letter. The whole problem could have been avoided by not taxiing through slush, like I did on that morning prior to departure. The ramp areas were still warm enough to create slush, yet the ambient temperature was well below freezing. I departed den at approximately XX55 am, runway 36. After I cleared the end of the runway, I retracted the landing gear and noticed the gear unlocked light remained on. Knowing the ramp areas were slushy that morning, I cycled the gear 2 more times to see if that would shed any suspected ice build-up on the gear. Each attempt failed to turn off the gear unlocked light, so I pulled the landing gear circuit breaker. I then re-engaged the circuit breaker and the gear unlocked light went out. At that time, I assumed that the slush problem had been corrected. After about 10 mins in flight, the aircraft began to vibrate about 20-30 mi west of den VOR. Again, I assumed it had something to do with slush on the bottom of the aircraft. However, there was no indication that the gear had become unlocked. When the aircraft continued to vibrate after leveling off, and not knowing the extent of slush on the airplane, I decided to declare an emergency and return to stapleton. By the time den approach started vectoring me for the ILS 36 approach, about 20 mins into the flight, the aircraft began to fly smoothly with no vibration. At that time, I decided the aircraft was functioning normally and requested that den approach retract my emergency status, which they agreed to do. In addition, I told them that this would be a precautionary landing, not an emergency landing. After landing, I inspected the aircraft and found ice build-up on the landing gear doors, struts, and wheel brackets. I cleared the entire airframe of ice. Satisfied that my problem was resolved, I continued with the flight to ril, which was uneventful.

Original NASA ASRS Text

Title: PLT OF SMT TWIN ENG ATX ACFT EXPERIENCED AN UNSAFE LNDG GEAR POS INDICATION AND ACFT VIBRATION AFTER LIFTOFF. RETURN LAND.

Narrative: EVEN THOUGH I RETRACTED MY 'EMER' STATUS IN THIS SIT, THE FAA IS STILL REQUIRING ME TO SEND THEM A LETTER EXPLAINING WHAT HAPPENED. I HAVE ENCLOSED A COPY OF THAT LETTER. THE WHOLE PROB COULD HAVE BEEN AVOIDED BY NOT TAXIING THROUGH SLUSH, LIKE I DID ON THAT MORNING PRIOR TO DEP. THE RAMP AREAS WERE STILL WARM ENOUGH TO CREATE SLUSH, YET THE AMBIENT TEMP WAS WELL BELOW FREEZING. I DEPARTED DEN AT APPROX XX55 AM, RWY 36. AFTER I CLRED THE END OF THE RWY, I RETRACTED THE LNDG GEAR AND NOTICED THE GEAR UNLOCKED LIGHT REMAINED ON. KNOWING THE RAMP AREAS WERE SLUSHY THAT MORNING, I CYCLED THE GEAR 2 MORE TIMES TO SEE IF THAT WOULD SHED ANY SUSPECTED ICE BUILD-UP ON THE GEAR. EACH ATTEMPT FAILED TO TURN OFF THE GEAR UNLOCKED LIGHT, SO I PULLED THE LNDG GEAR CIRCUIT BREAKER. I THEN RE-ENGAGED THE CIRCUIT BREAKER AND THE GEAR UNLOCKED LIGHT WENT OUT. AT THAT TIME, I ASSUMED THAT THE SLUSH PROB HAD BEEN CORRECTED. AFTER ABOUT 10 MINS IN FLT, THE ACFT BEGAN TO VIBRATE ABOUT 20-30 MI W OF DEN VOR. AGAIN, I ASSUMED IT HAD SOMETHING TO DO WITH SLUSH ON THE BOTTOM OF THE ACFT. HOWEVER, THERE WAS NO INDICATION THAT THE GEAR HAD BECOME UNLOCKED. WHEN THE ACFT CONTINUED TO VIBRATE AFTER LEVELING OFF, AND NOT KNOWING THE EXTENT OF SLUSH ON THE AIRPLANE, I DECIDED TO DECLARE AN EMER AND RETURN TO STAPLETON. BY THE TIME DEN APCH STARTED VECTORING ME FOR THE ILS 36 APCH, ABOUT 20 MINS INTO THE FLT, THE ACFT BEGAN TO FLY SMOOTHLY WITH NO VIBRATION. AT THAT TIME, I DECIDED THE ACFT WAS FUNCTIONING NORMALLY AND REQUESTED THAT DEN APCH RETRACT MY EMER STATUS, WHICH THEY AGREED TO DO. IN ADDITION, I TOLD THEM THAT THIS WOULD BE A PRECAUTIONARY LNDG, NOT AN EMER LNDG. AFTER LNDG, I INSPECTED THE ACFT AND FOUND ICE BUILD-UP ON THE LNDG GEAR DOORS, STRUTS, AND WHEEL BRACKETS. I CLRED THE ENTIRE AIRFRAME OF ICE. SATISFIED THAT MY PROB WAS RESOLVED, I CONTINUED WITH THE FLT TO RIL, WHICH WAS UNEVENTFUL.

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.

Pilot of small transport twin engine atx aircraft experienced an unsafe landing gear position indication and aircraft vibration after liftoff. Return land.