All indications of the gear down. Upon touchdown the landing gear retracted.

Attributes
ACN	90783
Time
Date	198807
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : abi
State Reference	TX
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	landing other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : cfi pilot : instrument
Experience	flight time last 90 days : 247 flight time total : 5048 flight time type : 537
ASRS Report	90783
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 207 flight time total : 2688 flight time type : 1103
ASRS Report	90922
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency none taken : unable
Consequence	faa : investigated faa : reviewed incident with flight crew other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

After making a normal VFR approach, including all normal checklist and use of VASI, a normal T/D on runway 17R at abi, the landing gear retracted immediately. There was no cockpit indication, such as gear warning horn or master caution light activated, only the feeling that we were airborne again. I was not aware of what was happening, but knew that things were not normal. I started to flare again, even though it was apparent that there was no increase in altitude. Soon thereafter a horn sounded. I believe it was the stall warning horn. I continued to flare until the aircraft touched down. At that point it was very apparent that things were not normal. I kept the aircraft on the centerline with the rudder until the aircraft slowed to the point the rudder wasn't effective. The aircraft came to rest to the right of the centerline. All passenger were disembarked west/O incident. Callback conversation with reporter revealed the following: aircraft was a leased aircraft and a required service bulletin reference the landing gear had not been complied with. Gear handle does have a detent and everything was normal when the gear was first put in the down position. Company was aware if the service bulletin was not complied with, the gear could retract at any time. Is not sure if this bulletin came from the FAA or mfg. No injuries on evacuate/evacuation.

Original NASA ASRS Text

Title: ALL INDICATIONS OF THE GEAR DOWN. UPON TOUCHDOWN THE LNDG GEAR RETRACTED.

Narrative: AFTER MAKING A NORMAL VFR APCH, INCLUDING ALL NORMAL CHKLIST AND USE OF VASI, A NORMAL T/D ON RWY 17R AT ABI, THE LNDG GEAR RETRACTED IMMEDIATELY. THERE WAS NO COCKPIT INDICATION, SUCH AS GEAR WARNING HORN OR MASTER CAUTION LIGHT ACTIVATED, ONLY THE FEELING THAT WE WERE AIRBORNE AGAIN. I WAS NOT AWARE OF WHAT WAS HAPPENING, BUT KNEW THAT THINGS WERE NOT NORMAL. I STARTED TO FLARE AGAIN, EVEN THOUGH IT WAS APPARENT THAT THERE WAS NO INCREASE IN ALT. SOON THEREAFTER A HORN SOUNDED. I BELIEVE IT WAS THE STALL WARNING HORN. I CONTINUED TO FLARE UNTIL THE ACFT TOUCHED DOWN. AT THAT POINT IT WAS VERY APPARENT THAT THINGS WERE NOT NORMAL. I KEPT THE ACFT ON THE CENTERLINE WITH THE RUDDER UNTIL THE ACFT SLOWED TO THE POINT THE RUDDER WASN'T EFFECTIVE. THE ACFT CAME TO REST TO THE RIGHT OF THE CENTERLINE. ALL PAX WERE DISEMBARKED W/O INCIDENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: ACFT WAS A LEASED ACFT AND A REQUIRED SVC BULLETIN REF THE LNDG GEAR HAD NOT BEEN COMPLIED WITH. GEAR HANDLE DOES HAVE A DETENT AND EVERYTHING WAS NORMAL WHEN THE GEAR WAS FIRST PUT IN THE DOWN POSITION. COMPANY WAS AWARE IF THE SVC BULLETIN WAS NOT COMPLIED WITH, THE GEAR COULD RETRACT AT ANY TIME. IS NOT SURE IF THIS BULLETIN CAME FROM THE FAA OR MFG. NO INJURIES ON EVAC.

Data retrieved from NASA's ASRS site as of August 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.